How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PESTS

Mites are tiny arthropods that feed on the sap of host plants. Because they are so small, use a hand lense to see them. They have 8 legs (6 in the first stage). The brown wheat mite is about 0.025 inch long (0.635 mm), oval shaped and dark red or brown in color. The winter grain mite is larger, 0.04 inch long (1 mm) and dark bluish black with red-orange legs and a reddish patch on the upper side. Banks grass mite is extremely small, 0.001 inch (0.025 mm), and yellow to cream colored. It is the only prominent wheat mite that webs the leaves.

DAMAGE

Leaves injured by brown wheat mite first appear silvery and later take on a scorched appearance. Injury caused by the winter grain mite results in yellowish leaves and stunted plants. The damage caused by this mite is similar to winter-kill. Banks grass mite turns leaves silvery and the tips and margins later turn brown. Webbing is an additional sign that injury is caused by the Banks grass mite. In California, mites seldom cause sufficient damage to be of concern.

MANAGEMENT

Cultural Control
Both brown wheat mite and Banks grass mite cause the greatest injury to water-stressed grain. A timely irrigation will usually alleviate the problem. Crop rotation is detrimental to the winter grain mite.

Management Decisions
Chemical controls are not generally recommended as cultural techniques generally suffice. Application of chemicals for aphid control may lead to a build-up of mites, however, leading to the occasional need for an acaricide.

PUBLICATION

UC IPM Pest Management Guidelines: Small Grains
UC ANR Publication 3466
Insects and Mites
C. G. Summers, Entomology, UC Davis/Kearney Agricultural Center, Parlier
L. D. Godfrey, Entomology, UC Davis
Acknowledgment for contributions to the insect and mite section:
D. Gonzalez, Entomology, UC Riverside

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