How to Manage Pests
UC Pest Management Guidelines
Tomato Russet Mite
Scientific name: Aculops lycopersici
(Reviewed 12/13, updated 12/13)
In this Guideline:
Description of the Pest
Russet mites are so small that a 14X hand lens is needed to see them. Because of their size, these mites are rarely noticed until plants are damaged. By this time, there may be hundreds of yellowish, conical-shaped mites on the green leaves immediately above the damaged bronzed leaves.
Russet mites remove cell contents from leaves, stems, and fruit cells. Usually starting near the ground, infestations of this mite progress up the plant and lower leaves dry out, giving the plant an unhealthy appearance. The color of the stems and leaves frequently becomes greasy bronze or russet colored. If not controlled, this pest can kill plants.
Monitor and treat for these mites if damage is observed. If infestations occur in the same field in successive years, be sure to remove alternate hosts such as nightshades and morningglory.
Organically Acceptable Methods
Mined sulfur dust or sprays are acceptable on organically certified produce.
Monitoring and Treatment Decisions
Look for bronzing on lower leaves and stems, then check damaged leaves and the green leaves immediately above them for mites. Damage is typically first observed when green fruit reaches 1 inch (5 cm); rarely is it first observed after more than 25% of the fruit are ripe. Determine the extent of each infested area in the field by examining leaves and stems for bronzing, and mark the boundaries of the infested areas. Check these areas again in 2 or 3 days to see if they are increasing in size. Immediate treatment is necessary when damage symptoms begin to spread.
UC IPM Pest Management Guidelines: Tomato
Insects and Mites
E. T. Natwick, UC Cooperative Extension, Imperial County