Russet mites on leaf tissue.

Last week a tomato sample was diagnosed with tomato russet mites (Aculops lycopersici). These conical-shaped insects, usually translucent and yellowish, cannot be seen without the aid of a 14X hand lens.

Russet mites cause damage by feeding on leaves and stems, giving them a greasy or bronze appearance. Infestation normally begins at the base of the plant and progresses upwards as lower leaves dry out. Left alone, these mites can kill plants.

Russet mite damage on tomato in greenhouse.

Fortunately, they can be controlled with miticides or sulfur. Hosts include tomato, potato, eggplant, petunia, tomatillo, and other solenaceous plant species.