Adult -Rust mites are generally broader than other eriophyid gall mites and are more sclerotized. Microscopic examination is usually required to see these minute mites. Unlike other mites, eriophyid adults have only four legs in the adult stage. Adult privet rust mites are slightly curved, spindle shaped with numerous microtubercles encircling the body, brown, and slightly less than 0.2 mm long.
Egg -The egg has not been described.
Nymph -The nymphal stages look similar to the adult.
Host Plants -Since eriophyid mites are usually very host specific, the privet rust mite is probably-restricted to privet.
Damage -Infestations of the privet rust mite will cause the leaf surface to appear scratched, the leaves to turn brown, and the young leaves to curl.
Life History -Privet rust mites become active shortly after the leaves begin to develop in the spring. In the spring and early summer, the mites multiply rapidly on the leaves and green stems; but by the end of June, no living mites can be found on the leaves. Hot weather decreases the Mite population, and it is not until the cooler fall weather that the mites revive and begin to multiply vigorously again. During the warm summer period, the mites survive as aestivating females under old bud scales at the base of the current season's growth.
The typical life cycle of eriophyid mites includes an egg, two nymphal instars, and an adult stage. Mites can develop from eggs to adults in only 1 week under favorable conditions. The mites can be distributed to other plants by wind, insects, and birds.
For specific chemical controls, see the current state extension service recommendations.
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