Description of the Pest
The potato leafhopper is a potential pest of citrus in some areas, especially in groves near tomato fields, cotton fields, or pastures in the San Joaquin Valley. It is a green, slender insect with bristlelike antennae and rows of spines along its hind legs. It breeds in large numbers on wild plants and field crops. During late summer and fall, the leafhoppers may migrate to citrus groves to spend the winter in the shelter of the trees.
Damage
The potato leafhopper feeds on fruit by puncturing rind cells in and around vascular tissue, causing yellowish to light brown, roundish scars on fruit. The scars are particularly apparent on green fruit and resemble thrips oviposition (egg laying) scars except they are more clustered and do not have darkened centers.
Management
Leafhoppers are not a problem every year. In addition, they do not remain in the orchard long. Usually by the time they are detected, the leafhoppers are already gone; a preventive spray is best if there is a history of problems with this pest. A yellow, sticky card, such as the one used for the California red scale, or traps can be used to help determine if leafhoppers are present.
If you apply a Bordeaux spray in fall against brown rot and Septoria, you may want to add some additional hydrated lime to repel leafhoppers. Because this is a preventive spray, it must be made before migration into the grove occurs.
| Common name | Amount to use | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (type of coverage)** | (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. | HYDRATED LIME# | |||
| 15–30 lb/100 gal (OC) | 0 | 0 | ||
| RANGE OF ACTIVITY: Pests: narrow (leafhoppers); Natural enemies: interferes with searching ability of many natural enemies | ||||
| PERSISTENCE: Pests: long; Natural enemies: long | ||||
| COMMENTS: For use on all varieties. | ||||
| ** | OC - Outside coverage uses 100 to 250 gal water/acre. |
| ‡ | 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 to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| # | Acceptable for use on organically grown produce. |