Tomato Russet Mite (Aculops lycopersici)
Order Acari: Family Eriophyidae
Adult: Bodies are cigar-shaped, yellowish-tan or pink, microscopic, and 0.01 inch (0.3 mm) long (Fig. 9.18).
Figure 9.18 - Tomato russett mites are abundant during hot, dry weather.
Egg: Colorless to white, roughly hemispherical and extremely small. Requires a 100-power or greater magnification to be seen
Nymph: Resemble adults but are smaller.
Tomato russet mites are most abundant during hot, dry weather in the mid- and late summer. They attack a variety of vegetables including tomato, eggplant, pepper, potato, and other solanaceous plants. The russet mite has a high reproductive potential (up to 53 eggs per female) and can complete a life cycle (egg to adult) in a week at warm temperatures. Females live for about 22 days laying eggs on the undersides of leaves, leaf petioles, and stems. Young nymphs tend to feed close to where they hatch. Mite feeding is usually concentrated on the lower part of the plant, but when infestations are severe and plants become heavily damaged, mites will disperse to upper leaves. Tomato russet mites can crawl between closely spaced plants that are touching, and can be carried by the wind.
The presence of tomato russet mites often goes unnoticed due to their microscopic size until feeding injury is evident. Adults and nymphs insert their piercing-sucking mouthparts into plant tissue to imbibe plant juices. Injury from mite feeding can cause bronzing or “russeting” of the surface of stems, leaves, and fruits (Fig. 9.19). Damaged leaves may turn yellow, curl, wither, and fall from plants (Fig. 9.19). Mite feeding on fruits can cause longitudinal cracks and bronze coloration.
- Use clean transplants. Inspect transplants carefully to be sure they are free of russet mites.
- Avoid planting during hot dry periods. Stressed seedlings are more vulnerable to attack by the mites.
- Avoid transplanting seedlings near infested crops or weeds.
- Promptly remove or destroy infested plant debris.
- Sanitize equipment. Make sure any tools or equipment used on infested plants are properly cleaned before being used on healthy plants.
Once russet mites are present on plants, insecticide treatment is the primary control option. Apply the insecticide to the undersides of leaves where most mites are located.
There are several predatory mites that feed on tomato russet mites; however, there is often a lag time between increase in populations of tomato russet and predatory mites.
Figure 9.19 - Injury from mite feeding can cause “russeting” on plants, and leaves that curl, whither, and fall.