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How to identify it
- The mites are very small and light colored. Young stages are paler, and the mites are pale to bright green for most of the season; UC IPM describes them as yellow to cream. They sometimes turn bright red when food is scarce.[1][3][4]
- The mites that overwinter are bright orange adults, found in the crowns of wheat plants or in soil, dead leaves and weeds.[2][3][1]
- Unlike some spider mites, it does not have long front legs. Adults have pigmentation along both sides and the rear of the body.[1][2]
- Colonies live on the undersides of leaves and spin silk webbing that protects the eggs, young and adults. Look for webbing and for tiny moving dots, or shake the grass over a sheet of white paper.[2][1]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| Brown wheat mite | Brown wheat mites are metallic brown to black with pale yellow legs, the front pair distinctly longer than the rest, and they spin no webbing. The Banks grass mite is the only prominent wheat mite that webs the leaves.[5][4] |
| Winter grain mite | The winter grain mite is dark bluish black with red-orange legs and a reddish patch on its back, and it does not web the leaves.[4] |
Where it lives
Colorado State calls it common in Colorado, where it occurs throughout the grain-producing areas and in turf. Kansas State describes it as historically a serious pest of corn and sorghum that moves into fall-sown wheat. UC IPM lists it among the mites of small grains in California.[1][2][3][4]
Biology and life cycle
It is a grass-feeding specialist. Corn is its main summer host on farms, along with sorghum and many grasses, and as these mature and dry down the mites move to newly planted winter wheat.[2][3]
Adults overwinter and feed until spring, when they lay small, pearly white eggs. Colorado State's turf page describes the eggs as cream-colored and laid in clusters on stems and leaves.[3][2][1]
A generation can be completed in 10 to 20 days, and several overlapping generations develop from late spring through summer. The webbing also helps the mites disperse to new plants.[2][1][3]
Hot, dry weather favors the mites and also makes plants more susceptible to their feeding.[3][2]
Damage and signs
- In turf, early injury shows as fine stippling, sometimes with slight purpling of the grass blade, and chlorotic spots that can spread until the whole leaf dies back. Severe injury can progress quickly and is almost always tied to drought stress. Dead grass is stiff and brown to yellow.[1]
- In corn, yellow spotting and a silvery look on the lower leaves are signs of mite activity. Leaves then yellow, brown and die back. Heavy infestations can kill small corn plants and reduce kernel size on larger ones.[2]
- In wheat, damage can show in fall or spring as yellowing, browning leaves covered with webbing. UC IPM describes leaves turning silvery, then browning at the tips and margins.[3][4]
Health risk
These sources describe it only as a pest of turf and grass crops and mention no risk to people or pets.[1][2][3][4]
Control
Prevention
Water. Banks grass mite problems are often avoided when grass is adequately watered, and Colorado State recommends keeping turf adequately watered year-round, because control often fails on drought-stressed grass. In grain crops, a timely irrigation usually relieves the problem.[1][4]
For farms, drought-resistant corn hybrids may reduce outbreaks during drought, but Colorado State suggests them only for drought-prone areas. Winter wheat is more likely to be infested in the fall when it is near maturing corn.[2]
Biological control
Predatory mites, thrips and pirate bugs feed on Banks grass mites. Avoid broad-spectrum pesticides that kill them: insecticide sprays can trigger spider mite outbreaks, especially during drought.[1][2]
Pesticides
Chemical control is often unnecessary in healthy turf. When symptoms appear in crops, check the undersides of leaves near the base of the plant weekly or more often, especially in warm, dry weather. To protect wheat, treating the margins of fields that border corn or other drying summer hosts in the fall is often enough. Products differ in how well they work on different mites, so confirm the species first; miticides also work less well on drought-stressed plants.[1][2][3]
Common questions
- Could mites be why my lawn is turning straw-colored in a drought?
- Yes, Banks grass mite is one possibility. Look near the base of the grass, on the undersides of the blades, for fine webbing and tiny moving dots, or shake some grass over white paper. Injury starts as stippling and chlorotic spots. Severe injury, almost always in drought-stressed grass, can progress quickly, and dead grass turns stiff and brown to yellow.[1]
- Do I need to spray my lawn for Banks grass mites?
- Usually not. Chemical control is often unnecessary in healthy turf, and problems are often avoided by watering adequately. Spraying broad-spectrum products can kill the predatory mites, thrips and pirate bugs that feed on the mites.[1]
- Where do the mites in my wheat come from?
- From corn, sorghum and grasses that are drying down at the end of summer. The mites move to newly sown wheat, so fields next to maturing corn are more at risk, and treating just the field margins in the fall is often enough.[3][2]
Sources
- Colorado State University Agricultural Biology, “Banks grass mite.” agsci.colostate.edu/agbio/ipm-pests/banks-grass-mite-2/ (accessed 2026-11-08)
- Colorado State University Agricultural Biology, “Spider mites in wheat and corn.” agsci.colostate.edu/agbio/ipm-pests/spider-mites-in-wheat-and-corn/ (accessed 2026-11-08)
- Kansas State University Department of Entomology, “Banks Grass Mite (Wheat Pests).” entomology.k-state.edu/extension/crop-protection/wheat/banks.html (accessed 2026-11-08)
- University of California Statewide IPM Program, “Mites (Pest Management Guidelines: Small Grains).” ipm.ucanr.edu/agriculture/small-grains/mites (accessed 2026-11-08)
- Kansas State University Department of Entomology, “Brown Wheat Mite (Wheat Pests).” entomology.k-state.edu/extension/crop-protection/wheat/brown-wheat-mite.html (accessed 2026-11-08)
- iNaturalist, “Oligonychus pratensis taxon page (order and family).” www.inaturalist.org/taxa/297586 (accessed 2026-11-08)