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.
Damage
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.
Management
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 morning glory.
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.
| Common name | Amount per acre** | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used. | ||||
| A. | SULFUR DUST# | |||
| Label rates | 24 | 0 | ||
| . . . OR . . . | ||||
| WETTABLE SULFUR# | Label rates | 24 | 0 | |
| MODE OF ACTION: An inorganic insecticide. | ||||
| COMMENTS: Check with your certifier regarding the suitability of the specific product for use on organically certified crops. Thorough coverage is required; ground application is preferred. Sulfur dust has better coverage. Do not apply when temperatures are in excess of 90°F or during a heavy dew or fog. Do not use if an oil was applied recently or will be in the near future. Avoid drift. Also suppresses powdery mildew. | ||||
| B. | ABAMECTIN* | |||
| (Agri-Mek SC) | 1.75–3.5 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 6 | ||||
| COMMENTS: Also effective against leafminers, psyllids, and tomato pinworm; does not harm natural enemies. | ||||
| ** | See label for dilution rates. |
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment until harvest can take place. In some cases the REI exceeds the PHI. The longer of these two intervals is the minimum time that must elapse before harvest may take place. |
| # | Acceptable for use on organically grown produce. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| 1 | Rotate chemicals with a different mode-of-action group number, and do not use products with the same mode-of-action group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a group number of 1B; chemicals with a 1B group number should be alternated with chemicals that have a group number other than 1B. Mode-of-action group numbers are assigned by IRAC (Insecticide Resistance Action Committee). |