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Help identify this mite?

Help identify this mite?


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I saw a decimal-sized dot walking on my hand. I wanted to know what this is, so I got it onto some paper and sandwiched below a piece of clear tape so I could keep it in place and photograph it. However it's so small that even with my camera lens almost touching the specimen, I can't get a great photo. It's small, about 0.8mm long, beige or gray or brown with a pattern on the back. It's a little smooshed from the tape so it's hard to tell if it has 6 or 8 legs and is an insect or an arachnid. But hopefully based on the shape, size, and pattern it can be identified.

Location is southern California.

Update: I now believe this to be a rat mite or bird mite. I'll include some additional photos that were better quality (photos were taken with a close-focus camera, mites were on printer paper underneath Scotch tape, back-lit by an LED light):


This appears to be a bird mite (or possibly rat mite) in the genus Ornithonyssus of the parasitic family Macronyssidae.

Credit: user Aewills on bugguide.com

Distinguishing between species is difficult.

In fact, according to idtools.org, identification of Mesostigmata to family or lower can usually only be accomplished only if the specimen is an adult female.

Blaine Mathison mentions the following features useful for identifying these mites to lower taxonomic levels under magnification [source: bugguide.com]:

  • chelicerae shape
  • dorsal plate breadth and degree of dorsal coverage
  • spiracle present between legs
  • genitoventral plate width
  • sternal plate shape and presence of setae

You can find existing answers to posts about bird mites on Bio.Stackexchange below:


It could be a tick nymph. Difficult to tell as you can't see the beak and the front legs very well. Check out this tick identification site:

http://www.tickencounter.org/tick_identification/tick_species

Looks most like the dog tick maybe?


Ministry of Agriculture, Food and Rural Affairs


Agdex#: 290/621
Publication Date: May 2014
Order#: 14-013
Last Reviewed:
History:
Written by: Graeme Murphy - Greenhouse Floriculture IPM Specialist/OMAFRA Gillian Ferguson - Greenhouse Vegetable IPM Specialist/OMAFRA Les Shipp - Research Scientist/Agriculture and Agri-Food Canada

Table of Contents

Introduction

Mites are more closely related to spiders than they are to insects. They are small (usually less than 1 mm in length), eight-legged organisms, with a wide host range, capable of causing extensive damage to a range of greenhouse crops. There are several species of concern. The most important is the twospotted spider mite (Tetranychus urticae) however, other species that can also cause significant damage include two other spider mites, the Lewis mite (Eotetranychus lewisi) and the carmine spider mite (Tetranychus cinnabarinus), as well as the broad mite (Polyphagotarsonemus latus), the cyclamen mite (Tarsonemus pallidus), the tomato russet mite (Aculops lycopersici) and the bulb mite (Rhizoglyphus spp).

Description and Life History

Mites pass through a few stages from egg to adult. The eggs of the above-mentioned pests are laid singly on foliage or in the growing points of plants (or in the case of the bulb mite, in the soil).

Newly hatched mites pass through a six-legged larval stage and two eight-legged nymphal stages known respectively as the protonymph and deutonymph. The last of these is an immobile resting stage from which the adult emerges.

The twospotted spider mite (TSSM) (Figure 1) has a host range of hundreds of plant species, including all major vegetable crops and many ornamental crops. The eight-legged female adult is approximately 0.5 mm long, with a rounded abdomen. The male is distinguished from the female by its smaller, narrower body and pointed abdomen. Adults range from pale yellow to orange to brown or black. Day-lengths of 12 hr and less, decreasing temperatures and a deteriorating food source will induce diapause (an overwintering stage similar to hibernation).

Figure 1. Twospotted spider mite adult.

The diapausing stage is reddish-orange in colour (Figure 2) and can tolerate very low temperatures. A short spell of heating is not sufficient to break diapause.

Figure 2. Overwintering twospotted spider mite.

Close examination of leaf undersurfaces will show the mites to be miniscule moving dots. There are usually two dark spots on the body of TSSM, although this can be somewhat variable. After mating, each female mite lays approximately six pearly white eggs (Figure 3) a day. Over an average lifetime, a female lays 100 or more eggs on the undersurface of foliage. The life cycle from egg to adult ranges from 23 days at 15°C to just 4 days at 32°C. Development is fastest under hot, dry conditions.

Figure 3. Adult twospotted spider mite with eggs.

The carmine spider mite and Lewis mite are closely related to TSSM. The carmine spider mite has not been positively identified in Ontario, but it is present in greenhouses in other countries. It is difficult to distinguish from TSSM in its immature stages, but the adult stage is bright red in colour and more commonly found on vegetable crops than in ornamentals. The Lewis mite is most often found on poinsettias and, in many ways, appears similar to TSSM, although it is often found with a few small spots on its back rather than the two distinctive spots of TSSM.

Broad mite (Figure 4) and cyclamen mite are microscopic in size (0.1-0.3 mm) and can be difficult to see even with a hand lens. For this reason, growers usually only know when they are present by the damage that they cause (see Damage). The life cycle (egg-to-adult) of these mites varies from less than a week under summer conditions to 10-18 days during winter, with the broad mite developing more quickly than the cyclamen mite.

Figure 4. Broad mite adult.

These two mites can be difficult to distinguish from each other in the mobile stages. The most reliable method of identification is in the egg stage. Eggs are laid on the surface of young leaves (often along the mid-vein) or in developing flower buds or new growth. The broad mite egg has a very distinctive appearance, with small bumps covering the surface (Figure 5), compared with the cyclamen mite egg, which has a smooth surface (Figure 6).

Figure 6. Cyclamen mite egg.

Tomato russet mite belongs to a different family of mites known as gall mites and is even smaller than the broad mite and cyclamen mite. It is an elongated mite approximately 0.2 mm long and 0.05 mm wide (Figure 7). It differs from other mites in having only two pairs of legs in all stages. Because of its size, it often develops large populations before being noticed. It is primarily a pest of tomato but can also occasionally be found on other members of the tomato family.

Figure 7. Tomato russet mite.

Bulb mite (Figure 8), as the name suggests, can be a pest of crops such as lilies, tulips, gladiolus, daffodils and amaryllis. Slow moving, bulb mite has a white body, 0.5-1.0 mm in length, and short reddish-brown legs.

Damage

Mites feed by piercing the epidermis of the plant with sucking mouthparts and removing the cell contents. The various mite pests attack different crops and can be found on different parts of the plant.

Twospotted spider mite, Lewis mite and carmine spider mite are found primarily on the underside of leaves. The feeding injury caused by TSSM and Lewis mite is very similar and starts as a yellow "stippling" where the cell contents of the leaf have been removed (Figures 9 and 10). As mite numbers increase, the entire leaf appears stippled or light-coloured on the upper surface and develops a bronzed appearance under heavy mite populations. Very heavily infested leaves become yellow and brittle, and in some cases (e.g., hibiscus), plants can exhibit a toxic response to feeding, with leaves yellowing and dropping from the plant even at quite low mite population densities.

Figure 9. Twospotted spider mite damage on rose leaves.

Figure 10. Lewis mite damage on poinsettia.

If infestations proceed without control measures, plants may be killed. These mites produce webbing that is used by the mites to disperse with the aid of air currents. Large mite populations can produce large quantities of webbing (Figures 11 and 12, which can be unsightly (especially in ornamental crops). The mites also use the webbing as protection, increasing the difficulty of control with predators and with pesticides.

Figure 11. Twospotted spider mite webbing on rose.

Figure 12. Twospotted spider mite webbing on cucumber.

Carmine spider mite feeding can result in feeding damage that includes widespread leaf yellowing and leaf drop (Figure 13).

Figure 13. Carmine mite feeding on tomato.

Broad mite and cyclamen mite each feed on a wide variety of crops and exhibit similar damage symptoms. They feed in the tight, newly emerging foliage and flower buds, with the damage becoming obvious as the plant tissue develops and enlarges. Toxins injected by the mites result in distorted, thickened and twisted growth at the top of the plant and in the flowers (Figure 14). The occurrence of these symptoms is usually the first indication that growers have a problem. These mites can be distributed throughout the greenhouse as hitchhikers on workers, equipment and even on insects such as whitefly (Figure 15).

Figure 14. Left, broad mite damage on peppers. Right, broad mite damage on cyclamen.

Figure 15. Broad mites hitchhiking on Bemisia whitefly (Source: D.E. Walter).

Although there are subtle differences in the biology and damage symptoms between these two mites, they are often treated in the same way in terms of recognizing the problem and management strategies.

Tomato russet mite is another mite where the symptoms of damage are the first sign of the presence of the pest. They are found on the leaves, stem and fruit of tomatoes and, in large numbers, result in the plant tissue taking on a bronzed appearance (Figure 16). Damage symptoms include yellowing, curling and wilting of leaves, flower abortion and bronzed, cracked fruit. If uncontrolled, they will eventually kill the plant.

Figure 16. Bronzed and cracked tomato fruit infested by russet mites .

Bulb mites live and feed on plant parts below the soil surface. Feeding scars on the bulbs can turn brown and necrotic, and the wounds can create entry points for plant pathogens. The mites are attracted to and use damaged and diseased tissue to enter the bulb and feed. Often bulb mites and disease are found coexisting. Infested bulbs can show above-ground symptoms in the form of yellowing and stunting.

Management Stategies

Spider mites

Good monitoring is critical to the early detection and management of spider mites. Pay close attention to new plant material entering the greenhouse and to susceptible crops and varieties. Monitor closely in areas of the greenhouse that are warmer and drier, e.g., around heating pipes, south-facing walls and open vents/doorways. In ornamental crops, make regular crop inspections to detect early infestations before mite populations build up. In crops such as rose, inspect both upper and lower canopies. In poinsettias, Lewis mite may be introduced on cuttings. Inspect them carefully and monitor closely throughout the crop, paying attention to all varieties.

For vegetable crops, conduct a proper clean-up at the end of the crop to reduce initial infestations in the crop that follows. It would be better to reduce, if not eliminate, populations just before the overwintering or diapausing phase of the spider mites, since the diapausing mites hibernate in the ground, hollow stems, pipe fittings, cracks and crevices during the fall and winter. The mites become active again during late winter and early spring, and infestations in the new spring crop are often found where "hot spots" occurred during the previous fall. To detect infestations early, scouts should ideally check every row weekly. The red mite stages are generally pesticide resistant and are not as readily fed upon by predators. When the red diapausing mites are detected, use soap sprays on lightly infested leaves, and remove and destroy more heavily infested leaves.

Biological Control

Spider mites can be controlled biologically using the predatory mite, Phytoseiulus persimilis. Other predatory mites used against this pest include some strains that are tolerant to high temperatures or pesticides. For example, the predatory mite Amblyseius californicus is reported to better tolerate dry conditions, while Amblyseius fallacis is resistant to some pesticides. Amblyseius andersoni is another predatory mite that has a wide range of temperature tolerances. Many Ontario growers have had good success with these predators.

Phytoseiulus persimilis - Phytoseiulus persimilis is about the same size as TSSM but is pear-shaped and pale salmon to bright orange (Figure 17). It also differs from TSSM in that it does not have two spots and moves more rapidly on long legs. It feeds on spider mites and does not diapause. Without spider mites, the predators die. This means new spider mite infestations require new introductions of the predator. Adult predators feed on about seven adults or 15-20 eggs per day. At 20°C, P. persimilis reproduces at almost twice the rate of TSSM. Control with P. persimilis is best between 20°C and 26°C. At temperatures above 30°C and humidity under 60%, the predators do not thrive and seek cooler, more protected areas lower in the crop canopy. In contrast, TSSM thrive under these conditions. The predators are available commercially either mixed with vermiculite, sawdust/wood chips or on bean leaves. With either carrier, treat infested plants at the first sign of damage. Try to place a few predators onto every infested leaf. Such placement is particularly important in crops (e.g., tomato) with sticky hairs that interfere with the mobility of the predator between leaves. Before releasing the predators, ensure that they are alive and active.

Figure 17. Phytoseiulus persimilis.

Amblyseius californicus - Amblyseius californicus is a tan-coloured predatory mite similar in size to TSSM and P. persimilis. While it feeds primarily on spider mites, it can survive for longer in their absence than P. persimilis, feeding on other insects such as thrips, other mites and pollen. Its advantage over P. persimilis is that it develops more quickly at higher temperatures, remains active and effective at temperatures above 30°C and is less affected by low humidities. Amblyseius californicus can be used simultaneously with the more specialized P. persimilis, but this latter predator is best used by itself under low population conditions or in "hot spots," because A. californicus will also feed on P. persimilis.

Amblyseius fallacis - Similar in appearance to A. californicus, A. fallacis is a naturally occurring predatory mite in North American orchards. Likewise, it can survive in the absence of spider mites by feeding on other small insects and pollen. It has the benefit of remaining active and reproducing at lower temperatures than either P. persimilis or A. californicus. They can be used with other mite predators such as P. persimilis, Feltiella and Stethorus.

Feltiella acarisuga - Feltiella is a gall midge, a small predatory fly that lays its eggs on leaves infested by spider mites. When the larva (Figure 18) emerges from the eggs, it feeds on all stages of mites. The adult midge is not predatory. Feltiella enters diapause under short day conditions and as such is only suitable for use from March to September.

Figure 18. Feltiella larva.

Stethorus punctillum - Stethorus is a small black ladybeetle (approx. 1.5 mm) (Figures 19 and 20) that feeds primarily on spider mites. Both adults and larvae are predatory. The adult is a good flier, locating spider mite infestations in the crops and laying eggs within the colony. This predator may not thrive on some host plants that have sticky hairs (e.g., tomato).

Figure 19. Stethorus adult.

Figure 20. Stethorus larva.

Cultural Control

Misting plants and raising the humidity will help suppress spider mite populations. For example, at 20°C and 36% relative humidity, a female TSSM will lay about seven eggs per day, while at 95% humidity, approximately 30% fewer eggs are laid.

Chemical Control

Because of their great reproductive potential, TSSM can quickly develop pesticide resistance. To effectively manage this pest using pesticides, observe these guidelines:

  • Direct sprays to the underside of leaves where spider mites usually congregate.
  • Be sure to achieve good coverage, particularly when using contact miticides such as Dyno-Mite, Floramite and Shuttle.
  • Use higher spray pressures to penetrate the web in areas of high mite density to reach the mites and the eggs within and beneath the web.
  • Use non-chemical control options as much as possible to minimize the development of pesticide resistance.

Broad mite/cyclamen mite

Observation of damage is usually the first indication of the presence of these mites. Know what the damage looks like and which crops are most susceptible to damage. Educate greenhouse workers so that any suspect plants are quickly brought to the attention of the grower or IPM manager. Early removal of infested plants or plant parts and good weed control inside and outside the greenhouse can slow the establishment and spread of these mites.

Various predatory mites are reported to feed on these mites, including Neoseiulus cucumeris, Amblyseius swirskii, A. californicus and A. andersoni. Neoseiulus cucumeris, A. californicus and A. swirskii have demonstrated effective suppression of broad mites on crops such as peppers and begonia in greenhouse studies. As with many pests, however, it is likely to be much more effective when the predatory mites are already in the crop prior to any infestation developing. If using biocontrol, apply higher numbers of predators in areas where damage is observed.

Pesticides can control broad mites and cyclamen mites, but not many pesticides are registered for their control in Canada and there is the potential for compromising biocontrol of other pests. Use pesticides with caution and check with the side-effects lists at sites such as Kopert and Biobest.

Tomato russet mite

As with broad mite and cyclamen mite, the first indication that growers usually have of their presence is when damage is observed. The mites disperse though the greenhouse on the hands, clothing and equipment of workers. When detected, take appropriate measures that could include removing plants or affected plant parts.

Predatory mites such as A. fallacis and A. swirskii may have some potential for managing tomato russet mite. One Ontario study indicated that several releases of high populations of A. swirskii on tomato plants, particularly at the "leading edge" of tomato russet mite infestations, can suppress spread of this mite on individual plants. However, it may be best to adopt an integrated approach that includes monitoring, registered biocompatible pesticides and releases of predatory mites on plants showing symptoms.

Ensure that there are no potential host plants in the greenhouse between crops. A thorough clean-up inside and outside the greenhouse will help reduce incidence and spread.


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By Andrew R. Moldenke, Oregon State University

THE LIVING SOIL: ARTHROPODS

Many bugs, known as arthropods, make their home in the soil. They get their name from their jointed (arthros) legs (podos). Arthropods are invertebrates, that is, they have no backbone, and rely instead on an external covering called an exoskeleton.

The 200 species of mites in this microscope view were extracted from one square foot of the top two inches of forest litter and soil. Mites are poorly studied, but enormously significant for nutrient release in the soil.

Credit: Val Behan-Pelletier, Agriculture and Agri-Food Canada. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Arthropods range in size from microscopic to several inches in length. They include insects, such as springtails, beetles, and ants crustaceans such as sowbugs arachnids such as spiders and mites myriapods, such as centipedes and millipedes and scorpions.

Nearly every soil is home to many different arthropod species. Certain row-crop soils contain several dozen species of arthropods in a square mile. Several thousand different species may live in a square mile of forest soil.

Arthropods can be grouped as shredders, predators, herbivores, and fungal-feeders, based on their functions in soil. Most soil-dwelling arthropods eat fungi, worms, or other arthropods. Root-feeders and dead-plant shredders are less abundant. As they feed, arthropods aerate and mix the soil, regulate the population size of other soil organisms, and shred organic material.

Shredders

Many large arthropods frequently seen on the soil surface are shredders. Shredders chew up dead plant matter as they eat bacteria and fungi on the surface of the plant matter. The most abundant shredders are millipedes and sowbugs, as well as termites, certain mites, and roaches. In agricultural soils, shredders can become pests by feeding on live roots if sufficient dead plant material is not present.

Millipedes are also called Diplopods because they possess two pairs of legs on each body segment. They are generally harmless to people, but most millipedes protect themselves from predators by spraying an offensive odor from their skunk glands. This desert-dwelling giant millipede is about 8 inches long.
Orthoporus ornatus.

Credit: David B. Richman, New Mexico State University, Las Cruces. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Sowbugs are relatives of crabs and lobsters. Their powerful mouth-parts are used to fragment plant residue and leaf litter.

Credit: Gerhard Eisenbeis and Wilfried Wichard. 1987. Atlas on the Biology of Soil Arthropods. Springer-Verlag, New York. P. 111. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Predators

Predators and micropredators can be either generalists, feeding on many different prey types, or specialists, hunting only a single prey type. Predators include centipedes, spiders, ground-beetles, scorpions, skunk-spiders, pseudoscorpions, ants, and some mites. Many predators eat crop pests, and some, such as beetles and parasitic wasps, have been developed for use as commercial biocontrols.

This 1/8 of an inch long spider lives near the soil surface where it attacks other soil arthropods. The spider's eyes are on the tip of the projection above its head.
Walckenaera acuminata.

Credit: Gerhard Eisenbeis and Wilfried Wichard. 1987. Atlas on the Biology of Soil Arthropods. Springer-Verlag, New York. P. 23. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

The wolf-spider wanders around as a solitary hunter. The mother wolf-spider carries her young to water and feeds them by regurgitation until they are ready to hunt on their own.

Credit: Trygve Steen, Portland State University, Portland, Oregon. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

The pseudoscorpion looks like a baby scorpion, except it has no tail. It produces venom from glandsin its claws and silk from its mouth parts. It lives in the soil and leaf litter of grasslands, forests, deserts and croplands. Some hitchhike under the wings of beetles.

Credit: David B. Richman, New Mexico State University, Las Cruces. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Long, slim centipedes crawl through spaces in the soil preying on earthworms and other soft-skinned animals. Centipede species with longer legs are familiar around homes and in leaf litter.

Credit: No. 40 from Soil Microbiology and Biochemistry Slide Set. 1976. J.P. Martin, et al., eds. SSSA, Madison, WI. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Predatory mites prey on nematodes, springtails, other mites, and the larvae of insects. This mite is 1/25 of an inch (1mm) long. Pergamasus sp.

Credit: Gerhard Eisenbeis and Wilfried Wichard. 1987. Atlas on the Biology of Soil Arthropods. Springer-Verlag, New York. P. 83. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

The powerful mouthparts on the tiger beetle (a carabid beetle) make it a swift and deadly ground-surface predator. Many species of carabid beetles are common in cropland.

Credit: Cicindela campestris. D.I. McEwan/Aguila Wildlife Images. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Rugose harvester ants are scavengers rather than predators. They eat dead insects and gather seeds in grasslands and deserts where they burrow 10 feet into the ground. Their sting is 100 times more powerful than a fire ant sting. Pogonomyrmex rugosus.

Credit: David B. Richman, New Mexico State University, Las Cruces. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Herbivores

Numerous root-feeding insects, such as cicadas, mole-crickets, and anthomyiid flies (root-maggots), live part of all of their life in the soil. Some herbivores, including rootworms and symphylans, can be crop pests where they occur in large numbers, feeding on roots or other plant parts.

The symphylan, a relative of the centipede, feeds on plant roots and can become a major crop pest if its population is not controlled by other organisms.

Credit: Ken Gray Collection, Department of Entomology, Oregon State University, Corvallis. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Fungal Feeders

Arthropods that graze on fungi (and to some extent bacteria) include most springtails, some mites, and silverfish. They scrape and consume bacteria and fungi off root surfaces. A large fraction of the nutrients available to plants is a result of microbial-grazing and nutrient release by fauna.

This pale-colored and blind springtail is typical of fungal-feeding springtails that live deep in the surface layer of natural and agricultural soils throughout the world.

Credit: Andrew R. Moldenke, Oregon State University, Corvallis. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

Oribatid turtle-mites are among the most numerous of the micro-arthropods. This millimeter-long species feeds on fungi. Euzetes globulus.

Credit: Gerhard Eisenbeis and Wilfried Wichard. 1987. Atlas on the Biology of Soil Arthropods. Springer-Verlag, New York. P. 103. Please contact the Soil and Water Conservation Society at [email protected] for assistance with copyrighted (credited) images.

What Is In Your Soil?

If you would like to see what kind of organisms are in your soil, you can easily make a pitfall trap to catch large arthropods, and a Burlese funnel to catch small arthropods.

Make a pitfall trap by sinking a pint- or quart-sized container (such as a yogurt cup) into the ground so the rim is level with the soil surface. If desired, fashion a roof over the cup to keep the rain out, and add 1/2 of an inch of non-hazardous antifreeze to the cup to preserve the creatures and prevent them from eating one another. Leave in place for a week and wait for soil organisms to fall into the trap.

To make a Burlese funnel, set a piece of 1/4 inch rigid wire screen in the bottom of a funnel to support the soil. (A funnel can be made by cutting the bottom off a plastic soda bottle.) Half fill the funnel with soil, and suspend it over a cup with a bit of anti-freeze or ethyl alcohol in the bottom as a preservative.

Suspend a light bulb about 4 inches over the soil to drive the organisms out of the soil and into the cup. Leave the light bulb on for about 3 days to dry out the soil. Then pour the alcohol into a shallow dish and use a magnifying glass to examine the organisms.

What Do Arthropods Do?

Although the plant feeders can become pests, most arthropods perform beneficial functions in the soil-plant system.

Shred organic material. Arthropods increase the surface area accessible to microbial attack by shredding dead plant residue and burrowing into coarse woody debris. Without shredders, a bacterium in leaf litter would be like a person in a pantry without a can-opener &ndash eating would be a very slow process. The shredders act like can-openers and greatly increase the rate of decomposition. Arthropods ingest decaying plant material to eat the bacteria and fungi on the surface of the organic material.

Stimulate microbial activity. As arthropods graze on bacteria and fungi, they stimulate the growth of mycorrhizae and other fungi, and the decomposition of organic matter. If grazer populations get too dense the opposite effect can occur &ndash populations of bacteria and fungi will decline. Predatory arthropods are important to keep grazer populations under control and to prevent them from over-grazing microbes.

Mix microbes with their food. From a bacterium&rsquos point-of-view, just a fraction of a millimeter is infinitely far away. Bacteria have limited mobility in soil and a competitor is likely to be closer to a nutrient treasure. Arthropods help out by distributing nutrients through the soil, and by carrying bacteria on their exoskeleton and through their digestive system. By more thoroughly mixing microbes with their food, arthropods enhance organic matter decomposition.

Mineralize plant nutrients. As they graze, arthropods mineralize some of the nutrients in bacteria and fungi, and excrete nutrients in plant-available forms.

Enhance soil aggregation. In most forested and grassland soils, every particle in the upper several inches of soil has been through the gut of numerous soil fauna. Each time soil passes through another arthropod or earthworm, it is thoroughly mixed with organic matter and mucus and deposited as fecal pellets. Fecal pellets are a highly concentrated nutrient resource, and are a mixture of the organic and inorganic substances required for growth of bacteria and fungi. In many soils, aggregates between 1/10,000 and 1/10 of an inch (0.0025mm and 2.5mm) are actually fecal pellets.

Burrow. Relatively few arthropod species burrow through the soil. Yet, within any soil community, burrowing arthropods and earthworms exert an enormous influence on the composition of the total fauna by shaping habitat. Burrowing changes the physical properties of soil, including porosity, water-infiltration rate, and bulk density.

Stimulate the succession of species. A dizzying array of natural bio-organic chemicals permeates the soil. Complete digestion of these chemicals requires a series of many types of bacteria, fungi, and other organisms with different enzymes. At any time, only a small subset of species is metabolically active &ndash only those capable of using the resources currently available. Soil arthropods consume the dominant organisms and permit other species to move in and take their place, thus facilitating the progressive breakdown of soil organic matter.

Control pests. Some arthropods can be damaging to crop yields, but many others that are present in all soils eat or compete with various root- and foliage-feeders. Some (the specialists) feed on only a single type of prey species. Other arthropods (the generalists), such as many species of centipedes, spiders, ground-beetles, rove-beetles, and gamasid mites, feed on a broad range of prey. Where a healthy population of generalist predators is present, they will be available to deal with a variety of pest outbreaks. A population of predators can only be maintained between pest outbreaks if there is a constant source of non-pest prey to eat. That is, there must be a healthy and diverse food web.

A fundamental dilemma in pest control is that tillage and insecticide application have enormous effects on non- target species in the food web. Intense land use (especially monoculture, tillage, and pesticides) depletes soil diversity. As total soil diversity declines, predator populations drop sharply and the possibility for subsequent pest outbreaks increases.

Where Do Arthropods Live?

The abundance and diversity of soil fauna diminishes significantly with soil depth. The great majority of all soil species are confined to the top three inches. Most of these creatures have limited mobility, and are probably capable of &ldquocryptobiosis,&rdquo a state of &ldquosuspended animation&rdquo that helps them survive extremes of temperature, wetness, or dryness that would otherwise be lethal.

As a general rule, larger species are active on the soil surface, seeking temporary refuge under vegetation, plant residue, wood, or rocks. Many of these arthropods commute daily to forage within herbaceous vegetation above, or even high in the canopy of trees. (For instance, one of these tree-climbers is the caterpillar-searcher used by foresters to control gypsy moth). Some large species capable of true burrowing live within the deeper layers of the soil.

Below about two inches in the soil, fauna are generally small &ndash 1/250 to 1/10 of an inch. (Twenty-five of the smallest of these would fit in a period on this page.) These species are usually blind and lack prominent coloration. They are capable of squeezing through minute pore spaces and along root channels. Sub-surface soil dwellers are associated primarily with the rhizosphere (the soil volume immediately adjacent to roots).

Abundance of Arthropods

A single square yard of soil will contain 500 to 200,000 individual arthropods, depending upon the soil type, plant community, and management system. Despite these large numbers, the biomass of arthropods in soil is far less than that of protozoa and nematodes.

In most environments, the most abundant soil dwellers are springtails and mites, though ants and termites predominate in certain situations, especially in desert and tropical soils. The largest number of arthropods are in natural plant communities with few earthworms (such as conifer forests). Natural communities with numerous earthworms (such as grassland soils) have the fewest arthropods. Apparently, earthworms out-compete arthropods, perhaps by excessively reworking their habitat or eating them incidentally. However, within pastures and farm lands arthropod numbers and diversity are generally thought to increase as earthworm populations rise. Burrowing earthworms probably create habitat space for arthropods in agricultural soils.

Bug Biography: Springtails

Springtails are the most abundant arthropods in many agricultural and rangeland soils. populations of tens of thousands per square yard are frequent. When foraging, springtails walk with 3 pairs of legs like most insects, and hold their tail tightly tucked under the belly. If attacked by a predator, body fluid rushes into the tail base, forcing the tail to slam down and catapult the springtail as much as a yard away. Springtails have been shown to be beneficial to crop plants by releasing nutrients and by feeding upon diseases caused by fungi.


What do mite bites look like?

The term “mites” refers to microscopic arthropods that feed on plants, insects, animals, and even humans. People may not realize they have come in contact with mites until they develop itchy, red bumps that resemble bites.

Mites range from 0.5–2.0 millimeters (mm) in length, making them virtually invisible to the naked eye.

Continue reading to learn how to identify and treat mite bites. We also discuss possible alternative bites.

Some mites do bite animals and humans. Examples of mites that bite humans include:

Chiggers

Chiggers are the larva of the Trombiculid mite family .

While adult chiggers feed on decaying material in soil, their larvae feed on the skin cells of living hosts. When a chigger attaches to a person’s skin, it secretes digestive enzymes that soften the epidermis, causing skin rashes.

Symptoms

Chigger bites create clusters of small red bumps on the skin accompanied by intense itching that can last for several days to 2 weeks .

Treatment

A person can treat chigger bites using:

Demodex mites

Demodex mites feed on dead skin cells and oil inside hair follicles. There are two demodex mites : Demodex folliculorum and Demodex brevis.

D. brevis mites tend to feed on gland cells in the hair follicles and tend to be in the chest and neck area.

D. folliculorum mites commonly inhabit the face, including:

  • the cheeks
  • the nose
  • the chin
  • the temples
  • the eyelashes
  • the eyebrows
  • the ears
  • the skin folds that extend from the nose to the corners of the mouth

Symptoms

While a few D. folliculorum mites can live on humans completely unnoticed, an infestation can lead to undesirable symptoms, including:

  • patches of red, inflamed, or dry skin on the face
  • inflamed, crusty, or watery eyelids
  • itchy skin
  • acne-like blemishes

Treatment

A person can use topical insecticides, such as crotamiton or permethrin cream to treat Demodex bites.

To prevent the bites from worsening, a person should:

Oak mites

Oak mites typically feed on midge fly larvae, but they can bite people if they remain on the skin.

The oak leaf gall mite has caused a series of human outbreaks in Missouri, Nebraska, and Texas over the years, and causes yearly outbreaks in Kansas.

Symptoms

Oak mite bites look similar to chigger bites.

People may develop itchy red welts on their face, neck, arms, or upper body.

Treatment

A person can treat oak mite bites by using:

  • calamine lotion
  • oral antihistamines
  • over-the-counter (OTC) hydrocortisone product

Scabies

Scabies is a skin condition caused by an infestation of Sarcoptes scabiei mites.

The S. scabiei mite burrows into the upper layer of the skin, where it reproduces and lays eggs.

Scabies is contagious. According to the Centers for Disease and Control (CDC) , S. scabiei mites typically pass between people through direct skin contact and, less commonly, through exposure to infested clothing or bedding.

Symptoms

A scabies infestation can lead to an itchy, red skin rash accompanied by intense itching. The rash may contain tiny bumps, hives, or welts under the skin.

Scratching the affected skin can lead to open sores and increase a person’s risk of infection.

Treatment

Doctors can treat scabies with oral medications and topical ointments that kill S. scabiei mites and their larvae.

Doctors may also prescribe antihistamines to reduce itching and antibiotics for infections.

Mites are so small that people are unable to see or feel the bites until after a mite has bitten them.

Unlike other insect bites or stings that form a single lump on the skin with a noticeable puncture site, mite bites induce skin rashes on the legs, arms, and trunk.

General signs to look for include:

  • small, hard bumps on the skin
  • red patches of skin
  • irritation, itching, or swelling near the bites

According to the Institute of Environmental Health Sciences, dust mites commonly inhabit house dust.

They feed on dead skin and dander that falls off of humans and pets. Dust mites live in house dust, mattresses, furniture, and carpets. These tiny creatures do not bite or live on humans.

Instead, proteins in the exoskeletons and feces of dust mites can induce allergic reactions in people.

Exposure to mites can lead to patches of small, red bumps on the skin accompanied by the following respiratory symptoms:

  • nasal congestion and sneezing
  • itchy, red, or watery eyes
  • itchy nose, mouth, or throat
  • a cough
  • chest tightness
  • difficulty breathing

The Asthma and Allergy Foundation of America (AAFA) warn that dust mites can worsen a person’s asthma.

Treatment

Treatment for dust mite allergies include:

  • over-the-counter (OTC) antihistamines
  • oral or liquid decongestants
  • nasal sprays containing corticosteroids or cromolyn sodium

Immunotherapy is an effective treatment for dust mite allergy, according to the AAFA. Immunotherapy involves exposing a person to progressively larger doses of an allergen.

People cannot eliminate dust mites from their homes entirely, but the following tips can help reduce the effects of dust mites:

  • frequently vacuuming, mopping, and dusting
  • washing sheets, pillowcases, clothing, and any other household fabrics in hot water (130-140°F)
  • wiping dust with a damp cloth
  • using a dehumidifier or air conditioner to reduce humidity levels in the house
  • removing carpets and curtains
  • covering mattress, pillows, and cushions with hypoallergenic or dust-proof covers

The following precautions can help prevent mite bites outdoors:

  • applying insect repellants, such as DEET or Picaridin
  • wearing long boots, long trousers, and long-sleeve shirts when walking through tall grass or dense vegetation
  • taking a hot shower or bath and washing clothes in hot water immediately after leaving an infested area

People should see a doctor if they believe they have scabies bites because S. scabiei mites can easily transfer from one person to another.

Bites from chiggers and oak mites rarely require medical attention. People can treat their symptoms with OTC antihistamines and decongestants.

Try not to scratch mite bites, as this can lead to an infection. Anti-itch cream and topical corticosteroids may help reduce itching and swelling.

People should contact a doctor if they experience signs of an infection, including:

  • a fever
  • the skin near the bite appears red, swollen, and warm
  • fluid or pus leaking from the bite

House or dust mites that live in dust do not bite, but they can induce allergic reactions.

Chiggers are mite larvae that feed on skin cells and leave clusters of small, red bites on the legs and feet.

Most mites do not bite humans, but they may bite if they remain on a person’s skin.

In general, mite bites cause mild skin irritation and itching and do not require medical attention. People can treat mite bites with OTC and prescription antihistamines, topical corticosteroids, and allergy injections.

People who believe they have scabies should seek immediate medical attention. The mites responsible for this skin condition can live under the skin for several months.

Scabies infestations are highly contagious, so people must seek treatment as soon as possible to prevent further transmission.


Persea Mite

Historical review. Persea mite (Fig. 1), Oligonychus perseae, was first described in 1975 from specimens collected from avocado foliage that were intercepted from Mexico at an El Paso, Texas quarantine facility. Persea mite is native to Mexico and damages avocados in arid regions, but it is not a major pest in the state of Michoacan where Hass avocado production is greatest. Persea mite has also been recorded from Costa Rica. Persea mite was first discovered attacking avocados in San Diego County in 1990, and was originally misidentified as Oligonychus peruvianus. By the summer of 1993, the pest had spread north to Ventura County. Santa Barbara had its first record in spring 1994, and in 1996 persea mite had established in San Luis Obispo County. There are no records of this pest in the San Joaquin Valley. Contaminated fruit bins, harvesting equipment, and clothing probably assisted in the dispersal of persea mite throughout California. High mite densities (>100-500 per leaf) and subsequent feeding can cause partial or total defoliation of trees. Mite-induced defoliation opens the tree canopy, increasing the risk of sunburn to young fruit and exposed tree trunks. Premature fruit drop can occur.

Pest identification. An important step in any pest management program is the accurate identification of the pest. This is particularly true for biological control because natural enemies are often specific to just one pest or group of pests (e.g., spider mites). Persea mites feed in colonies beneath protective webbing (i.e., nests) along midribs and veins on the undersides of leaves, and feeding damage produces characteristic circular necrotic spots. Avocado brown mite, Oligonychus punicae, feeds on upper leaf surfaces and, when populations are high, mites will feed on the undersides of leaves. Feeding damage by avocado brown mite results in bronzing of upper leaf surfaces. Six-spotted mite, Eotetranychus sexmaculatus, is very similar in appearance to persea mite and it also feeds on undersides of leaves. Six-spotted mites prefer to feed adjacent to the midrib and large lateral veins. Feeding damage is different from that caused by persea mite in that six-spotted mites do not produce circular feeding colonies covered with dense webbing and necrotic spotting is purplish and irregular in appearance. All three pest mites damage leaves by removing chlorophyll during feeding.

Biology of the persea mite. Persea mite has five developmental stages (egg, larva, protonymph, deutonymph, and adult). All lifestages are predominantly found in nests where feeding, mating, reproduction, and development occurs. Sex ratio is generally two females to one male. A generalized life cycle for persea mite is shown in Diagram A, and Table 1 summarizes important aspects of persea mite biology.

Monitoring persea mite populations. When deciding to initiate control measures (chemical or biological) against persea mite, it is important to have an estimate of the number of mites infesting leaves and the percentage of leaves infested on trees so treatments can be applied to maximize impact. The number of mites per leaf can be quickly estimated in the field by counting the number of mites on part of a picked leaf. To estimate persea mite numbers, move through a section of the orchard and pick 10 leaves of mixed age at random. Using a 10-14x hand lens count the number of motile mites that are within the viewing area of the lens along the upper side of the half second vein of each leaf. The half second vein is located on the left side of the upturned leaf and it is the second complete vein that extends from the midrib to the leaf margin (Diagram B). Tally the total number of persea mites on all 10 leaves, divide by 10 to get the average across all sampled leaves. Multiply the average by 12 (this is the correlation factor used to estimate the total number of persea mites per leaf) and the resulting number is an estimate of the number of mites per leaf (see Machlitt 1998 for more details on this technique). An example estimating the number of persea mites is given below:

Diagram B
Eliminating persea mite numbers

Predator mites feeding on persea mite inside nests can be estimated from half second vein counts in a similar fashion. The correlation factor for predators on randomly selected leaves is six.

Persea mite densities can also be estimated by visually assessing damage levels on infested leaves. The use of photographs with known levels of damage, mite densities responsible for observed levels of damage, and the number of necrotic spots resulting from mite feeding can be used in treatment decision-making. Colored photographs of avocado leaves showing 1%-50% feeding damage and the numbers of persea mites required to cause recorded amounts of damage are shown in Diagram C.

Pest control advisors can be hired or orchard workers can be trained to monitor numbers of persea mites and predators using this sampling method.

Impact to Cultivars

Photographs of avocado leaves damaged by persea mite feeding can be used to assist with decisions regarding control measures. Measurements of persea mite feeding damage to leaves that have fallen from avocado trees to the ground indicates that average feeding damage to the leaf surface of fallen leaves is 15-22%. However, 86-90% of fallen leaves have damage equal to or greater than 7.5-10%. From these data it appears that the probability of leaf drop increases greatly once 7.5-10% of the leaf surface is damaged by persea mite feeding and control measures may need to be implemented before this 7.5-10% level of damage is observed. There are no experimental data to verify the effectiveness of using these damage estimates as treatment thresholds.

Cultivar susceptibility. Avocado cultivars vary in their susceptibility to persea mite feeding damage. By calculating the average percentage of leaf area damaged by mite feeding, cultivars can be ranked from least susceptible to most susceptible. When cultivars are ordered in this manner the following ranking is attained: Fuerte (average leaf area damaged by feeding persea mites is 13.3%), Lamb Hass (16.9%) = Reed (16.9%) < Esther (29.7%) < Pinkerton (30.2%) < Gwen (37.4%) < Hass (38.4%). The mechanism by which Fuerte and Lamb Hass reduce feeding damage is unknown. Host plant resistance may be due to leaf chemistry which reduces mite survivorship or lowers reproduction rates, leaf hairs that favor natural enemy activity, or some form of repellancy that causes mites to abandon the tree to search for more suitable host plants. Increasing cultivar diversity in orchards should be considered as a strategy to reduce damage and associated yield reductions from persea mite.

Host plants. In addition to avocados, persea mite can develop on a wide range of fruit, ornamental, and weed plants. This pest has been recorded feeding on leaves of Thompson and Flame seedless grapes (Vitus spp.), apricots, peaches, plums and nectarines (all Prunus spp.), persimmons (Disopyrus spp.), milkweed (Asclepias fuscicularis), sow thistle (Sonchus sp.), lamb's quarters (Chenopodium album), sumac (Rhus sp.), carob (Ceratonia siliqua), camphor (Camphora officinalis), roses (Rosa spp.), acacia (Acacia spp.), annatto (Bixa orellana), willow (Salix spp.), and bamboo (Bambusa spp.). Good sanitation practices (i.e., elimination of favored weed species) and removal of alternate host plants (i.e., ornamental plants and non-commercial fruit trees in orchards) that act as persea mite reservoirs are useful cultural control practices that should be employed in a persea mite management program.

Biological Control of Persea Mite in California

There are several species of predators that occur naturally in California avocado orchards which have been observed to feed on persea mites. None of these natural enemies provide effective control of persea mite. However, their presence in orchards is desirable because generalist predators probably lessen the severity of persea mite infestations and will feed on other pest species.

Figure 3.
Euseius hibisci (Acari: Phytoseiidae)

Euseius hibisci (Acari: Phytoseiidae). (Fig. 3) This predatory mite is extremely common in avocado orchards and is considered an important generalist predator. Euseius hibisci can build to high densities in the absence of mite prey and can successfully survive and reproduce on a diet of pollen (this predator can reproduce on as little as 6.6 avocado pollen grains per square inch of leaf), aphid honeydew, mildew, lantania scale crawlers (Hemiberlesa lataniae), and leaf exudates. Euseius hibisci can become entangled in spider mite webbing and, in some instances, webbing may have a repellant effect. Euseius hibisci is too large to invade persea mite nests but will feed on mites wandering outside of nests. In the presence of pollen, consumption of spider mites by E. hibisci is reduced by 26%, but this reduction is offset by a 63% increase in reproduction when compared to a diet of mites alone. Aspects of E. hibisci's biology are summarized in Table 2.

Stethorus picipes (Coleoptera: Coccinellidae). This predator is very important in controlling outbreaks of avocado brown mite. Stethorus is able to suppress avocado brown mite outbreaks because adults quickly find brown mite populations, exhibit high prey preference for spider mites, and reproduce quickly on a diet of spider mites. Reproduction by Stethorus slows when day lengths are less than 10 hours, as this indicates the onset of winter. Releases of Stethorus into avocado orchards have been shown to control brown mite outbreaks, but this approach was economically unfeasible. This predator does not appear to provide suppression of persea mite outbreaks. Aspects of the biology of S. picipes are summarized in Table 2.

Figure 4. Scolothrips sexmaculatus (Thysanoptera: Thripidae)

Figure 5.
Galendromus helveolus (Acari: Phytoseiidae)

Scolothrips sexmaculatus (Thysanoptera: Thripidae). (Fig. 4) Six-spotted thrips, Scolothrips sexmaculatus, is a specialized predator of spider mites. In some instances, this predator has been responsible for causing substantial reduction of spider mite populations on peaches, cotton, strawberries, and rhubarb. This predator is commonly found feeding within persea mite nests in late summer and predation by six-spotted thrips may hasten the decline of persea mite populations. Aspects of six-spotted thrips biology are summarized in Table 2.

Commercially Available Natural Enemies

Several species of predacious mites are commercially available in California. Species that have been studied in field trials for persea mite are discussed below.

Galendromus helveolus (Acari: Phytoseiidae). (Fig. 5) This predator is a specialist spider mite predator that plays a significant role in mite suppression in subtropical fruit crops in Florida. Galendromus helveolus was introduced into California from Florida and is found throughout Texas, Mexico and Central America. The sex ratio of this species is strongly biased toward females. This predator will feed on all stages of spider mites but prefers eggs and protonymphs, and in the absence of food, females will feed on their own eggs. Galendromus helveolus has been released in California for control of avocado brown mite and six-spotted mite, and recovery attempts suggest that this predator does not persist naturally at high densities in avocado orchards. Releases of this natural enemy onto avocado trees indicate that it is an effective persea mite predator because it has the ability to enter nests to feed and reproduce. Aspects of the biology of G. helveolus are presented in Table 2.

Galendromus annectens (Acari: Phytoseiidae). (Fig. 6) This predator has a widespread distribution from North America through Latin America and into South America. This mite has been found in coastal California avocado orchards but is very rare. Galendromus annectens is among the smallest known phytoseiids and this probably allows it to reproduce on low quantities of food and hide in places inaccessible to larger predators. Studies indicate that this predator is not closely associated with dense web-producing spider mites that have clumped distributions, and it does not show a strong tendency to remain in spider mite nests. Field observations suggest G. annectens may be a predator of fungi-eating tarsonemid mites. Aspects of the biology of G. annectens are presented in Table 2.

Neoseiulus californicus (Acari: Phytoseiidae) (Fig. 7) This phytoseiid is found in arid and humid areas of semi-tropical and temperate South America, and arid areas of southern California and Europe. Neoseiulus californicus is a specialized spider mite predator that has been used to control spider mites on strawberries, corn, soybeans, apples, peaches, and ornamental plants. Neoseiulus californicus will feed on pollen and over winters in the adult stage. With the onset of warm temperatures this predator will move from ground cover into tree canopies in search of prey. Aspects of the biology of N. californicus are presented in Table 2.

Results of Trials with Predatory Mites to Control Persea Mite on Avocados

Based on the results of field trials, the commercially available phytoseiids with the most potential for controlling persea mite are G. helveolus and N. californicus. Work is currently in progress refining release rates and timings of these predators. More research is required before recommendations for use of these predators can be made. However, some practical guidelines for using phytoseiids in avocado orchards in southern California are:

  1. Monitoring persea mite populations. If predator mite releases are being considered, it is best to make releases based on the percentage of leaves infested with persea mite rather than the average number of mites per leaf. Consider the following example where 86 persea mites are counted on just one leaf in a 10 leaf sample thus the average number of mites per leaf is 8.6 however 90% of those leaves have no persea mites. If predators are released under these conditions, they will only find food on one leaf in every 10 searched. A better strategy is to release predators when 25 leaves out of 50 randomly inspected leaves has one or more persea mite (i.e., 50% of leaves are infested with low numbers of persea mites). Here, every second leaf predators search will have food, and this increases the likelihood of released predators establishing in the orchard and reproducing in response to increasing persea mite population growth. Our work has shown that at 25% leaf infestation, there are too few persea mites available for predators to establish. Predators will establish at the 50%, 75%, and 95% leaf infestation levels. However, at 75% and 95% leaf infestation, persea mite populations are too high for the predators to afford control.
  2. Assessing predator quality. Predatory mites are shipped in bottles of vermiculite or corn grits which should be packaged in styrofoam boxes with ice packs to reduce heat stress during transit. Before releases are made, a sub-sample of the shipment should be examined to ensure a good quality product has been received. To check quality, gently shake the bottle of grits to evenly distribute predators and pour some grits with predators into a small clear jar. If a lot of small, fast running mites are seen, you can assume the shipment has arrived in good condition. If few predators are seen, call the supplier and negotiate a deal for more predators or change the supplier.
  3. Release methodology. Even coverage of trees is very important when releasing phytoseiids and this can be very difficult to achieve. In field experiments, grits are poured into eight small paper cups which are evenly distributed around trees and attached to branches with binder clips. Predators disperse from cups onto foliage. Some PCAs use leaf blowers to spray phytoseiids onto trees that are damp with dew. The dew temporarily traps predators which, upon freeing themselves, begin searching for prey. The effectiveness of the leaf blower technique has not been determined experimentally. Mechanical distribution technology which sprays predatory mites into the canopy is currently being developed. This technique shows promise for use in avocado orchards. Releasing predators at a few release points (e.g., 1-3 trees are treated and dispersal by predators from these trees throughout the orchard is anticipated) is an ineffective approach to using these biological control agents.

Alternatives to Biological Control

In some instances persea mite infestations will be severe enough to warrant chemically-based control to reduce damage to leaves and the possibility of defoliation. Field trials evaluating the efficacy of miticides in Ventura County indicate that water, Agri-Mek (this miticide is not registered for use on avocados), and NR 435 oil were the most effective compounds tested for control of persea mite. These treatments reduced persea mite numbers by 75%. However, a corresponding decrease in natural enemy numbers may also be observed. Pesticide evaluation studies are continuing. Water applied to trees with a hand gun at 150-200 psi, physically disrupted persea mite nests and exposure because of nest damage may increase this pest's vulnerability to natural enemies or adverse environmental conditions (e.g., increased risk of desiccation).

To reduce the likelihood of resurgence (recovery of pest populations, sometimes to levels higher than before treatments began), and secondary pest outbreaks (release of non-pest insects from biological control due to natural enemy mortality from pesticides), it is necessary to use pesticides that have minimal impact on natural enemies and to provide refuges for biological control agents. Compatible pesticides have short residual activity or are non-toxic to natural enemies. Biological control agents can be protected in refuges. Untreated trees provide refuges for natural enemies, allowing them to re-colonize sprayed areas. Natural enemies can be purchased from insectaries to re-inoculate orchards after pesticide treatments have been made or to augment the orchard's indigenous natural enemy fauna (see Hunter 1997 for suppliers of beneficial insects).

Frequent use of a limited number of pesticides with similar modes of action (e.g., nerve poisons) can result in the development of resistance. Pesticide resistance is the developed ability of a pest population to withstand pesticides that were formerly effective. The rate at which resistance develops in a population is related to the intensity of pesticide use. To prolong pesticide efficacy for persea mite, it is advisable to limit the frequency of applications by spraying only when necessary, to alternate between miticides with different modes of action, and to leave areas of the orchard untreated (this will conserve natural enemies and allow survival of susceptible persea mites that can breed with mites with resistance genes thereby reducing the rate at which resistance develops). Decisions to spray should be based on population monitoring results of both persea mites and natural enemies and consultation with a PCA may be warranted before applying pesticides for persea mite control.

Additional Information

For further information on biological control and research on persea mite contact:

  1. Ricky Lara, Dept. of Entomology, University of California, Riverside, CA 92521, phone: (951) 827-4360, [email protected]
  2. Mark Hoddle, Dept. of Entomology, University of California, Riverside, CA 92521, phone: (951) 827-4714, fax: (951) 827-3086, [email protected]
  3. Ben Faber, Cooperative Extension, Ventura County, 669 County Square Drive, Ste. 100, Ventura, CA 93001, phone: (805) 645-1462, fax: (805) 645-1474, [email protected]
  4. Gary Bender, UCCE Office, 5555 Overland Ave, Bldg 4, San Deigo, CA 92123, phone: (619) 694-2848, fax: (619) 694-2856, [email protected]
  5. Joseph Morse, Dept. of Entomology, University of California, Riverside, CA 92521, phone: (951) 827-5814, fax: (951) 827-3086, [email protected]

A free factsheet on the biology and managment of the persea mite is available from the California Avocado Commission by calling 949-341-1955 or by requesting it directly on their website.

Acknowledgments. Photographs used in this factsheet were taken by: Mr. Jack Kelly Clark (UC Photographer). Persea mite life cycle schematic and avocado leaf illustration were prepared by Dr. Vincent D'Amico III (Bean's Art Ink, CT). Preparation of this web page was supported in part by the California Avocado Commission.


Biology

Sarcoptes scabiei var. hominis, the human itch mite, is in the arthropod class Arachnida, subclass Acari, family Sarcoptidae. The mites burrow into the upper layer of the skin but never below the stratum corneum. The burrows appear as tiny raised serpentine lines that are grayish or skin-colored and can be a centimeter or more in length. Other races of scabies mites may cause infestations in other mammals, such as domestic cats, dogs, pigs, and horses. It should be noted that races of mites found on other animals may cause a self-limited infestation in humans with temporary itching due to dermatitis however they do not multiply on the human host.

Life Cycle:

Sarcoptes scabiei undergoes four stages in its life cycle: egg, larva, nymph and adult. Females deposit 2-3 eggs per day as they burrow under the skin . Eggs are oval and 0.10 to 0.15 mm in length and hatch in 3 to 4 days. After the eggs hatch, the larvae migrate to the skin surface and burrow into the intact stratum corneum to construct almost invisible, short burrows called molting pouches. The larval stage, which emerges from the eggs, has only 3 pairs of legs and lasts about 3 to 4 days. After the larvae molt, the resulting nymphs have 4 pairs of legs . This form molts into slightly larger nymphs before molting into adults. Larvae and nymphs may often be found in molting pouches or in hair follicles and look similar to adults, only smaller. Adults are round, sac-like eyeless mites. Females are 0.30 to 0.45 mm long and 0.25 to 0.35 mm wide, and males are slightly more than half that size. Mating occurs after the active male penetrates the molting pouch of the adult female . Mating takes place only once and leaves the female fertile for the rest of her life. Impregnated females leave their molting pouches and wander on the surface of the skin until they find a suitable site for a permanent burrow. While on the skin&rsquos surface, mites hold onto the skin using sucker-like pulvilli attached to the two most anterior pairs of legs. When the impregnated female mite finds a suitable location, it begins to make its characteristic serpentine burrow, laying eggs in the process. After the impregnated female burrows into the skin, she remains there and continues to lengthen her burrow and lay eggs for the rest of her life (1-2 months). Under the most favorable of conditions, about 10% of her eggs eventually give rise to adult mites. Males are rarely seen they make temporary shallow pits in the skin to feed until they locate a female&rsquos burrow and mate.


How to Tell if Your Bird Has Mites

This article was co-authored by Pippa Elliott, MRCVS. Dr. Elliott, BVMS, MRCVS is a veterinarian with over 30 years of experience in veterinary surgery and companion animal practice. She graduated from the University of Glasgow in 1987 with a degree in veterinary medicine and surgery. She has worked at the same animal clinic in her hometown for over 20 years.

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Birds are susceptible to external parasites like mites, and if a mite infestation is not treated, it can spread to human hosts and lead to serious illness or death for your bird. Certain bird species, like parakeets, parrots, and finches, are more likely to contract mites. [1] X Research source Bird mites feed on your bird’s blood, can live and thrive in your bird’s nest or cage, and can reproduce at a rapid rate. However, there are steps you can take to treat the infestation so it does not return.


Help identify this mite? - Biology

All products listed on this page were created and/or funded by ITP. Use the filters below to find the identification support you need. Please see the About ITP page for more information about these product types. If you have problems accessing any of the tool websites, mobile apps, or PDF screening aids listed here, please contact ITP.

If you don't find a product that includes the pest(s) you're looking for, try visiting Search IDaids to see if we've found a product that covers the pest(s).

North American Hornet Screening Tool

This website helps users to differentiate between invasive hornets, specifically Asian giant hornet, and other common non-targets, including bees and wasps. Included are fact sheets and a filterable image gallery that can be used as a rudimentary key.

Longicorn ID

Longicorn ID supports identification of all cerambycoid (or longhorn) beetles to the tribe level globally, and includes many photos of representative adult species. The tool also supports identification of longhorn larvae with species descriptions, photos, and a key to larval subfamilies.

TingID

TingID supports identification of lace bug (Tingidae) genera intercepted at U.S. ports of entry. The website includes fact sheets, a key, images, and interception and quarantine information for lace bug species.

Exotic Bee ID, Edition 2

Exotic Bee ID assists users in the screening and identification of bees that may have been introduced, or have the high potential to invade, the U.S. The website includes fact sheets, images, keys, specimen prep instructions, an illustrated glossary, and more.

Sawfly GenUS, Edition 1

The first edition of this tool includes keys, fact sheets, images, and other supporting information for sawfly families Xyelidae, Diprionidae, Cimbicidae, Pergidae, Argidae, Cephidae, Siricidae, Anaxyelidae, Xiphydriidae, and Orussidae. Fact sheets and keys for Tenthredinidae sawflies will be added in Edition 2.

Aquarium and Pond Plant ID

This Lucid Mobile app includes a key and fact sheets for identifying aquatic plants cultivated worldwide for the aquarium and pond plant industry.
Android (on Google Play)
iOS (on the App Store)

Southeast Asian Ambrosia Beetle ID

This tool offers identification support for all 34 genera and 316 species of xyleborines. Also included are fact sheets, a key, a filterable image gallery, an illustrated glossary, and additional background information and anatomical diagrams.

IDphy: identification of Phytophthora based on types

IDphy is ITP's first tool for identifying plant pathogens. This website includes both molecular and morphological resources for the identification of all 161 culturable species of Phytophthora described as of May 2018, with all data based on the types or other well-authenticated specimens.

Velvet Longhorn Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Trichoferus campestris adults collected from CAPS traps in the United States.

Pinecone and Bamboo Longhorn Beetles Screening Aid

This aid is designed to assist in the sorting and screening of two species of Chlorophorus adults that may be collected during CAPS visual surveys in United States.

Agrilus of Concern Screening Aid

This aid is designed to assist in the sorting and screening of Agrilus adults collected during CAPS surveys in the United States.

Tomato Fruit Borers Screening Aid

This aid is designed to assist in the sorting and screening of Neoleucinodes adults collected from CAPS pheromone traps in the continental United States.

Coconut Rhinoceros Beetles Screening Aid

This aid is designed to assist in the sorting and screening of Oryctes suspect adults found during visual inspection or collected from traps in the United States.

Spruce Longhorn Beetles Screening Aid

This aid is designed to assist in the sorting and screening of Tetropium adults collected during CAPS surveys in the United States.

City Longhorn Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Aeolesthes sarta adults found during CAPS visual inspections in the United States.

Aquarium and Pond Plants of the World, Edition 3

APPW Edition 3 offers identification support for all aquatic plants cultivated globally for the trade as of 2018, including 270 genera. Also included are fact sheets, a key, a filterable image gallery, an illustrated glossary, and additional background information.

Antkey Mobile

This Lucid Mobile app includes a key and fact sheets for identifying invasive, introduced, and commonly intercepted ants from across the globe.
Android (on Google Play)
iOS (on the App Store)

Avocado Seed Moth Screening Aid

This aid is designed to assist in the sorting and screening of Stenoma catenifer suspect adults collected from CAPS pheromone traps in the continental United States.

Black Maize Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Heteronychus arator suspect adults collected through visual surveys in the continental United States.

Cabbage Moth Screening Aid

This aid is designed to assist in the sorting and screening Mamestra brassicae suspect adults collected from CAPS bucket traps in the continental United States.

Cherry Bark Tortrix Screening Aid

This aid is designed to assist in the sorting and screening CBT suspect adults collected from CAPS pheromone traps in the continental United States.

Christmas Berry Webworm Screening Aid

This aid is designed to assist in the sorting and screening Cryptoblabes gnidiella suspect adults collected from CAPS pheromone traps in the continental United States.

Guatemalan Potato Moth Screening Aid

This aid is designed to assist in the sorting and screening Tecia solanivora suspect adults collected from CAPS pheromone (sticky) traps in the continental United States.

Large White Screening Aid

This aid is designed to assist in the sorting and screening of suspect Pieris brassicae adults collected during CAPS visual surveys in the continential United States.

Nettle Caterpillar Screening Aid

This aid is designed to assist in the sorting and screening Darna pallivitta suspect adults collected from CAPS pheromone traps in the continental United States.

Palm Weevils Screening Aid

This aid is designed to assist in the sorting and screening of suspect Rhynchophorus adults found during CAPS visual surveys in the continential United States.

Stem Borers Screening Aid

This aid is designed to assist in the sorting and screening Chilo suspect adults collected from CAPS pheromone (sticky) traps in the continental United States.

Sugar Cane Weevil Screening Aid

This aid is designed to assist in the sorting and screening of suspect Rhabdoscelus obscurus adults found in CAPS pheromone traps in the continental United States.

Yellow Peach Moth Screening Aid

This aid is designed to assist in the sorting and screening Conogethes punctiferalis suspect adults collected from CAPS pheromone traps in the continental United States.

Hispine Pests of Palms

Part of the Palm Resource, this website includes fact sheets and images for the 23 palm pest genera of the Family Chrysomelidae, which all fall in the former subfamily Hispinae.

Bee Mite ID

Bee Mite ID enables users to identify mites that may be found on bees or in their nests and to distinguish harmful from non-harmful mites. Included are a key, fact sheets, quick-reference guides, morphology guides, a filterable image gallery, and a glossary.

Hawaiian Scarab ID Key

This Lucid Mobile app includes a key, fact sheets, and an anatomy guide for identifying adult scarab beetles that may occur in Hawaii, Guam, and other tropical Pacific islands.
Android (on Google Play)
iOS (on the App Store)

Hawaiian Scarab ID

Hawaiian Scarab ID includes over 70 native, established, and possibly invasive scarab species from the islands of the Pacific, particularly Hawaii and Guam. Included are a key, fact sheets, behavioral videos, an anatomy guide, a sortable image gallery, and a glossary, as well as DNA barcode data to help identify larvae.

Grasshoppers of the Western U.S. Key

This Lucid Mobile app includes keys and fact sheets for identifying adult and nymphal stages of commonly occurring grasshoppers from the western U.S.
Android (on Google Play)
iOS (on the App Store)

Citrus Pests Key

This Lucid Mobile app includes a key and fact sheets to assist in the screening of insect pests of citrus in the U.S.
Android (on Google Play)
iOS (on the App Store)

Citrus Diseases Key

This Lucid Mobile app includes a symptom-based key and fact sheets for diseases of citrus grown in the U.S.
Android (on Google Play)
iOS (on the App Store)

Dried Botanicals Key

This Lucid Mobile app includes an image-based key and fact sheets for dried botanical products.
Android (on Google Play)
iOS (on the App Store)

Palm ID Key

This Lucid Mobile app includes a key and fact sheets for identifying palms that are commonly cultivated in the U.S. and Caribbean.
Android (on Google Play)
iOS (on the App Store)

Citrus ID Key

This Lucid Mobile app includes a key and fact sheets for over 500 cultivars and relatives of citrus grown in the U.S.
Android (on Google Play)
iOS (on the App Store)

Federal Noxious Weeds Key

This Lucid Mobile app includes three keys for identifying disseminules of federal noxious weeds (FNW), as well as fact sheets for all FNW taxa.
Android (on Google Play)
iOS (on the App Store)

Screening Aid to Palm Pests Key

This Lucid Mobile app includes keys and fact sheets to assist the novice entomologist in identifying arthropod pests of palms grown in the U.S. and Caribbean.
Android (on Google Play)
iOS (on the App Store)

Palm Symptoms Key

This Lucid Mobile app includes a symptom-based key and fact sheets to assist identifying palm diseases and disorders.
Android (on Google Play)
iOS (on the App Store)

Terrestrial Mollusc Key

This Lucid Mobile app includes a key and fact sheets to assist in the identification of adult terrestrial slugs and snails of agricultural importance and quarantine significance.
Android (on Google Play)
iOS (on the App Store)

TortAI Key

This Lucid Mobile app includes keys and fact sheets to assist in the identification of tortricid adults and larvae of agricultural importance.
for Android (on Google Play)
for iOS (on the App Store)

Ambrosia Beetles Screening Aid

This aid is designed to assist in the sorting and screening of Platypus quercivorus and Megaplatypus mutatus suspect adults collected by Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

European Oak Bark Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Scolytus intricatus suspect adults collected through visual surveys in the continental U.S.
high-resolution PDF
low-resolution PDF

European Spruce Bark Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Ips typographus suspect adults collected in CAPS Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Great Spruce Bark Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Dendroctonus micans suspect adults collected through visual surveys in the continental U.S.
high-resolution PDF
low-resolution PDF

Mediterranean Pine Engraver Screening Aid

This aid is designed to assist in the sorting and screening of Orthotomicus erosus suspect adults collected in CAPS multi funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Mountain Oak Longhorned Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Massicus raddei suspect adults collected through visual surveys in the continental U.S.
high-resolution PDF
low-resolution PDF

Pine Sawyer Beetles Screening Aid

This aid is designed to assist in the sorting and screening of Monochamus alternatus and M. sutor suspect adults collected in Lindgren funnel traps and by visual surveys in the continental U.S.
high-resolution PDF
low-resolution PDF

Pine Shoot Beetles Screening Aid

This aid is designed to assist in the sorting and screening of Tomicus spp. suspect adults collected through visual survey and Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Redbay Ambrosia Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Xyleborus glabratus suspect adults collected in CAPS Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Six-toothed Bark Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Ips sexdentatus suspect adults collected in CAPS Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Six-toothed Spruce Bark Beetle Screening Aid

This aid is designed to assist in the sorting and screening of Pityogenes chalcographus suspect adults collected in CAPS Lindgren funnel traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Federal Noxious Weed Disseminules, Edition 2.2

This interactive tool provides images, text, and keys that aid in determining whether or not an unknown disseminule (e.g., seed, fruit) is a federal noxious weed (FNW) and is therefore actionable. The tool includes three keys, a key to keys, fact sheets, an image gallery, and an illustrated glossary.

Grasshoppers of the Western U.S., Edition 4

Grasshoppers of the Western U.S., Edition 4 offers keys to identify both adult and pre-adult stages of many of the most commonly encountered grasshoppers in the western U.S., as well as fact sheets, a sortable image gallery, and an illustrated glossary.

Asiatic Rice Borer Screening Aid

This aid is designed to assist in the sorting and screening of Chilo suppressalis suspect adults collected from CAPS pheromone (sticky) traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Castniid Palm Borer Screening Aid

This aid is designed to assist in the detection of Paysandisia archon suspect adults through visual surveys for adults and larval damage.
high-resolution PDF
low-resolution PDF

European Grape Berry Moth Screening Aid

This aid is designed to assist in the sorting and screening of Eupoecilia ambiguella suspect adults collected from CAPS sticky traps in the continental U.S.
high-resolution PDF
low-resolution PDF

European Grapevine Moth Screening Aid

This aid is designed to assist in the sorting and screening of Lobesia botrana suspect adults collected from CAPS sticky traps in the continental U.S.

False Codling Moth Screening Aid

This aid is designed to assist in the sorting and screening of Thaumatotibia leucotreta suspect adults collected from CAPS sticky traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Fruit Piercing Moth Screening Aid

This aid is designed to assist in the detection of Eudocima phalonia through visual surveys in orchards.
high-resolution PDF
low-resolution PDF

Horse Chestnut Leaf Miner Screening Aid

This aid is designed to assist in the detection of suspect Cameraria ohridella by visual observation of larval damage (leaf mines) on Aesculus or Acer.
high-resolution PDF
low-resolution PDF

Pear Leaf Blister Moth Screening Aid

This aid is designed to assist in the sorting and screening of Leucoptera malifoliella suspect adults collected from CAPS sticky traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Pine Beauty Screening Aid

This aid is designed to assist in the sorting and screening of Panolis flammea suspect adults collected from CAPS bucket traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Pine Lappets Screening Aid

This aid is designed to assist in the sorting and screening of pine lappet (Dendrolimus spp.) suspect adults collected from CAPS pheromone traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Processionary Moths Screening Aid

This aid is designed to assist in the sorting and screening of processionary moths (Thaumetopoea spp.) suspect adults collected from CAPS pheromone traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Summer Fruit Tortrix Screening Aid

This aid is designed to assist in the sorting and screening of Adoxophyes orana suspect adults collected from CAPS sticky traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Variegated Golden Tortrix Screening Aid

This aid is designed to assist in the sorting and screening of Archips xylosteana suspect adults collected from CAPS sticky traps in the continental U.S.
high-resolution PDF
low-resolution PDF

Light Brown Apple Moth Screening Aid

This aid is designed to assist in the sorting and screening of Epiphyas postvittana suspect adults collected from CAPS sticky traps in the continental United States.

Scale Insects, Edition 2

This tool is designed to help the user identify almost any scale insect to family, and in some cases to species, without the need for expertise in the group. The tool emphasizes scale taxa important to the U.S. ports of entry. It includes four interactive keys, fact sheets, a glossary, and a sortable image gallery.

Hispines of the World

This tool contains an interactive key, fact sheets, an image gallery, and an illustrated guide to hispine morphology. It includes 195 genera from the former subfamily Hispinae (family Chrysomelidae), now included within the subfamily Cassidinae.

LepIntercept

LepIntercept is a comprehensive resource for identifying intercepted Lepidoptera larvae and includes identification keys, detailed fact sheets, tutorials on larval morphology, information on studying Lepidoptera larvae, a full glossary, and a complete set of references.

Microlepidoptera on Solanaceae

This tool is designed to help identify larval and adult Microlepidoptera that feed on plants in the family Solanaceae, focusing on species from Florida and the Gulf Coast of the U.S. Included are a key, fact sheets, glossary, gallery, and a specimen preparation guide.

Flat Mites of the World, Edition 2

This tool is designed to help non-experts identify any flat mite to the taxonomic level of genus, and in some cases to species. The tool includes four keys, fact sheets, a glossary, an image gallery, and a wealth of background information about flat mites and microscopy.

Diabrotica ID

Diabrotica ID is designed to support non-experts in the identification of 112 Diabrotica species that originate from North and Central America. The tool includes a key, fact sheets, a sortable image gallery, and a glossary.

Antkey

Antkey is designed for non-specialists and includes over 115 ant species that are introduced, invasive, or commonly intercepted in the U.S. Features include an interactive key, fact sheets, a searchable media collection, video clips, a fully illustrated glossary, a searchable database of introduced ant literature, and more.

Anastrepha and Toxotrypana

This website attempts to bring together in a single package all of the relevant taxonomic information for these important genera of fruit flies. It provides a choice of two electronic keys (Intkey or Lucid), and detailed descriptions and images of each species are also included, as well as a morphological atlas.

Citrus Pests

Citrus Pests is aimed primarily at extension agents, inspectors, and other plant professionals with access to a light microscope and hand lens. It offers screening support for over 50 important insect pests of citrus in the U.S. A key, fact sheets, illustrated morphology guide, glossary, and sortable image gallery are included.

AphID

AphID includes a key to the 66 most polyphagous and cosmopolitan aphid species. AphID also offers users detailed descriptions of morphological features critical to identifying aphids along with annotated photographs to help illustrate each feature, as well as detailed fact sheets and a glossary of terms.

TortAI: Tortricids of Agricultural Importance

This tool includes resources for identifying adults and larvae of tortricids that threaten agriculture in the U.S. Features include detailed fact sheets, two interactive keys, dissection guides, a glossary, and an image gallery. A DNA barcode database allows confirmation of identifications.

Table Grape Weed Disseminule ID

This tool aids in the identification of weed disseminules that may occur in fresh table grape bunches grown in California's Central Valley. Features include two keys, fact sheets and comparison charts, a glossary, and guides to disseminule types.

Table Grape Spider ID

T his tool was created to support export of table grapes from California to Australia and New Zealand. Included are keys for identifying spiders and spider egg sacs that may be found in table grape bunches from the Central Valley, fact sheets, a DNA search page, a glossary, and an image gallery.

Ironclad ID

Ironclad ID is designed to aid in the identification of adult ironclad and cylindrical bark beetles in the family Zopheridae. Features include a key to genera and species, fact sheets, an image gallery, a morphological atlas, biology and taxonomy information, and a glossary.

Citrus Resource

Citrus Resource, a commodity-based identification resource, was created to provide growers, the industry, and those associated with citrus pest and disease detection an easily accessible portal for tools to assist with their identification needs. The site includes background info and links to all associated tools.

Citrus Diseases

Citrus Diseases provides support for symptom-based screening and identification of citrus diseases that were known in the United States as of 2011, as well as those of immediate concern. The tool includes a symptom-based key, fact sheets, a glossary, and a sortable image gallery.

Citrus ID, Edition 2

Citrus ID facilitates identification of over 500 citrus cultivars and relatives to at least the cultivar group level within citrus (e.g., sweet oranges, sour oranges, etc.), if not beyond for select cultivars. Included are a key, fact sheets, a sortable image gallery, and a glossary.

Terrestrial Mollusc Tool

Terrestrial Mollusc Tool was specifically designed to assist in the identification of adult terrestrial slugs and snails of agricultural importance and quarantine significance. It includes a key, fact sheets, biology and ecology info, a dissection guide, a glossary, and an image gallery.

Dried Botanical ID

This unique, image-based tool allows identification of a variety of dried botanicals, often used in potpourri, decorative plant arrangements, and handicrafts. In addition to the key and fact sheets, the tool includes an interactive image gallery that allows users to easily compare images and save them for later reference.

Pink Bollworm and its Look-alikes

This tool enables identification of adult moths found in pink bollworm pheromone traps, as well as larvae found inside cotton bolls. It includes two keys, fact sheets, an illustrated glossary, and the Pink Bollworm COI barcode sequence. Though pink bollworm has been eradicated, this tool is available for ongoing trapping and monitoring activities.

Oncid ID

Oncid ID is designed to aid in the identification of adult "twig girdlers," a large group of longhorned beetles in the tribe Onciderini which are widely distributed from the U.S. to Argentina. Features include a key, fact sheets, image gallery, biology and taxonomy info, a morphological atlas, a glossary, and an image gallery.

Wood Boring Beetle Resource

This site is a portal for identification and screening tools for wood boring beetles of the world. The site focuses on the nine families considered wood boring beetles: those taxa that bore into and develop within sound wood. You can search by family, geographic coverage, or release date.

Identifying Commonly Cultivated Palms

Part of the Palm Resource, Identifying Commonly Cultivated Palms supports users in differentiating among 82 palm species that are commonly cultivated in the U.S. Fact sheets for each species are included, as well as a key, glossary, illustrated morphology guide, and image gallery.

Bark Beetle Genera of the U.S.

This tool is designed to help identify bark beetles (Curculionidae: Scolytinae) to the taxonomic level of genus without the need for expertise in the group. It includes the genera that occur in the continental U.S. In addition to the key and fact sheets, this tool has an image gallery and a glossary.

Xyleborini Ambrosia Beetles

Xyleborini is the most important and species-rich tribe of ambrosia beetles. This tool provides identification support for all 36 Xyleborini genera from around the world. Features include a key, fact sheets, a morphological guide, and a glossary.

Palm Resource

The palm resource is a portal designed to support individuals involved with commodity-based palm surveys. The resource includes background info and links to tools for identifying palms grown in the U.S. and Caribbean and their pests, diseases, and disorders.

Symptoms of Palm Diseases and Disorders

This tool, part of the Palm Resource, uses visual symptoms to help preliminarily identify palm diseases and disorders that commonly occur in the U.S. and Caribbean. Features include a key, fact sheets, a glossary, and an image gallery.

Screening Aid to Palm Pests

Screening Aid to Pests (SAP), part of the commodity-based Palm Resource, is aimed primarily at the novice entomologist. It is designed to help users determine which type of arthropod palm pest they have found and features illustrated fact sheets as well as two interactive keys, a morphology guide, and an image gallery.

Bark Beetles of the Southeastern U.S.

This website features a key that allows the user to separate genera of Curculionidae bark beetle subfamily Scolytinae, of the southeastern United States, that are classified into the two tribes Hylesinini and Scolytini.

LBAM ID

This tool was retired on March 13, 2019, because a more recent and comprehensive resource for the family Tortricidae is available. TortAI includes all the taxa and content from LBAM ID and is a more complete source of information. Visit TortAI.

PIAkey - Invasive Ants of the Pacific Islands

PIAkey (Pacific Invasive Ant key) is an electronic guide designed to assist users to identify invasive ant species commonly encountered in the Pacific Island region. The guide covers four subfamilies, 20 genera and 44 species, and includes a key, fact sheets, videos, comparison charts, and a glossary.

Wood Boring Beetle Families

This tool allows users to differentiate among the nine families of beetles that are known to bore into and develop within sound wood. An identification key and fact sheets are provided, as well as a glossary, references, and background info.

Invasive Mites Identification Resource

This site includes nine keys designed to provide support for every level, from training in mite anatomy and identification to advanced taxonomic support. The tool also includes many detailed informational pages, fact sheets, and a glossary.

Cut Flower Exports of Africa

Cut Flower Exports of Africa is a tool to aid in the identification of genera of cut flowers produced in Africa and exported to major world markets. This tool includes an interactive identification key, flower images, and fact sheets. The interactive identification key runs as a Lucid3 Java applet.


Help identify this mite? - Biology

Neoseiulus (=Amblyseius) fallacis
(Acarina: Phytoseiidae)

This predaceous mite has a strong preference for pest mite species and will travel from tree to tree searching for them. It is found across the continental United States.

Adults are pear-shaped and slightly smaller than the European red mite adult. They are white until they feed when they take on the coloration of their prey (usually red or brown). The eggs are pear shaped, almost transparent, but slightly larger than the round European red mite eggs. The larvae are also transparent and difficult to see without a microscope.

Of the five N. fallacis life stages, only the larvae are six legged. All other post-egg stages have eight legs. In all stages, N. fallacis is indistinguishable from Galendromus pyri and G. occidentalis, other phytoseiid predatory mites, without a compound microscope.

Many this page deals only with fruit trees.

In North American orchards, Neoseiulus fallacis strongly prefers tetranychid mites--the European red mite and the two-spotted spider mite--and will actively seek these.

Mated adult females overwinter in crevices of the tree bark if prey are available in the fall. They emerge as early as bloom, but in reduced numbers due to heavy winter mortality. N. fallacis increases in number rapidly and adults become numerous by July or August. They live about 20 days and lay an average of 40-60 eggs. Eggs are laid along the ribs of the undersides of leaves. Four to six generations are completed in a season in New York state. N. fallacis moves vigorously over plant surfaces in search of prey.

Because N. fallacis is a voracious consumer of mites and because its population increases quickly in relation to its prey, it can overtake an expanding pest population. It develops into the adult stage in about one third the time required by G. pyri. However, when N. fallacis has reduced the prey population, it will leave the tree in search of more tetranychid mites whereas G. pyri thrives on alternate foods. Over the winter, N. fallacis has a higher mortality rate than G. pyri. Therefore, a mixed population of N. fallacis and G. pyri is desirable.

Predatory mites are susceptible to many of the chemicals used to combat herbaceous mite infestations. A single application of a chemical considered highly toxic to N. fallacis at any time during the season will have a large negative impact on its abundance.

The habit of N. fallacis to overwinter in crevices can be used to advantage in the early spring with a pre-bloom horticultural oil application. This greatly reduces the number of European red mite eggs while not affecting predatory mite populations.

Pest mite problems are most common where pesticides are heavily used because predatory mite populations are killed along with target species It may take up to three years to establish a population of predators high enough to control pest mites. Integrated pest management strategies, as outlined in the tutorial of this guide, can help establish colonies of predatory mites.

N. fallacis is readily available from commercial suppliers (see the off-site publication, Suppliers of Beneficial Organisms in North America, page of the California Department of Pesticide Regulation website).

Thanks to Jan Nyrop for reviewing an earlier version of this section.

Kain, D. and Nyrop, J. March 1995. Predatory Mites. Insect Identification Fact Sheet No. 23. Cooperative Extension, Cornell University, Ithaca, NY.