TWO-SPOTTED SPIDER MITE EUROPEAN RED MITE

A, Peach twig showing typical "russeting" of foliage by" mites. B, Life stages of two-spotted spider mite: a, egg; b, young (note 6-legged at this stage); c, half grown; d, adult male; e,adult female; and f, overwintering female. C, "Russeting" of apple foliage. D, Stages of European red mite: g, egg; h and i, nymphs; and k, adult female. (B and D, very greatly magnified.)

ORCHARD MITES

Tiny, eight-legged sucking pests, closely related to insects, known as mites and often called spider mites because of their resemblance and relationship to spiders, cause major damage to orchard trees throughout the United States. Many kinds of mites suck the sap from the leaves of deciduous fruit trees (apples, pears, peaches, plums, and cherries), causing them to become bronzed or brown and dry. When injury is extensive, many of the leaves drop off and the fruit is small and poorly colored.

The habits and life history of most such mites are much the same. The most important differences are that some spin webs on the leaves and about the twigs and some do not. Some (like the clover mite, which attacks many kinds of plants as well as fruit trees) and the European red mite overwinter in the egg stage on the trees. Others (like the two-spotted spider mite and the Pacific mite) overwinter as adult females in protected places, mostly on the ground. Mites may develop from egg to adult in a week or 10 days. There are several generations a year. Hot, dry weather speeds up development and favors a rapid increase to outbreak numbers. Mites are usually most numerous in July and August.

Control: Application of a 3 percent lubricating oil emulsion late in the dormant season will destroy the overwintering eggs of the European red mite and of the clover mite. Mites may be controlled during the summer with the following insecticides (per 100 gallons of spray): 1 pound of 15 percent parathion wettable powder; 1/2 pint of 40 percent tetraethyl pyrophosphate (TEPP) liquid; 1 1/2 to 2 pounds of 15 percent 2-(p-tert-butylphenoxy)-1-methylethyI 2-chloroethyl sulfite (Aramite) wettable powder; 1/2 pound of 27 percent O-ethyl 0-p-nitrophenyl benzene-thiophosphonate (EPN) wettable powder; or 1 pint of 25 percent 1, 1 -his (p-chlorophenyl) ethanol (DMC) liquid. The summer mite-control program may be preventive (if you include a recommended material in two or three early-season sprays applied for other pests) or it may be corrective if you delay until mites begin to increase noticeably, usually the last of June or later but before injury reaches the bronzing stage. In a corrective program at least two applications, 7 to 10 days apart, are usually necessary. Occasionally, if infestation persists, a third application may be needed. The spraying must be thorough.

Parathion and TEPP are especially dangerous to handle; the safety precautions on the package must be followed. EPN is also dangerous to handle. Be careful with it. Do not spray fruits later than 3 weeks before picking. Scrub or peel sprayed or dusted fruits or vegetables before eating them.