Description of the Pest
Flea beetles are minor pests of potatoes in California, except in the Klamath Basin production area where they are becoming a substantial pest. The adults are small, 0.06 to 0.1 inch (1.5 to 2.5 mm) in length, metallic greenish brown to black in color, and tend to jump like fleas when disturbed. The larvae live in the soil, are slender, whitish, and about 0.25 inch (6 mm) long when mature.
Adult flea beetles overwinter in weeds or debris outside the field. In spring they feed on weeds until potato plants emerge, then fly into potato fields and feed on foliage.
Damage
The beetles feed on leaves and stems resulting in many small holes in the leaves. This damage is seldom extensive enough to be of concern but may indicate future damage to the tubers. Watch for foliage damage when monitoring fields for this and other foliage-feeding pests, and keep records of your results (example form. Most damage is caused by the larvae, which hatch from eggs scattered by adult females in the soil around potato plants. The larvae feed on roots, underground stems, and tubers. Larval feeding on tubers gives them a pimpled surface with small brown tunnels extending 0.06 to 0.25 inch (1.5 to 6 mm) into the tuber. When damage is extensive, the potatoes are unsuitable for processing.
Management
Systemic insecticides and foliar sprays applied for green peach aphid usually keep flea beetles below economically damaging levels. Even in areas where these treatments are not used, flea beetle infestations are sporadic and special controls are rarely necessary. Flea beetle damage often is not noticed until harvest, when it is too late for control measures.
| 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. | DINOTEFURAN | |||
| (Venom, soil application) | 6.5–7.5 oz | 12 | 0 | |
| (Venom, foliar application) | 1–1.5 oz | 12 | 7 | |
| MODE OF ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Do not apply more than 0.754 lb/acre per season. If an application of imidacloprid (Admire Pro) was made at planting, choose another treatment material with a different mode of action Group number to help prevent the development of neonicotinoid resistance. | ||||
| B. | IMIDACLOPRID | |||
| (Admire Pro) | 5.7–8.7 fl oz | 12 | 0 | |
| MODE OF ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Apply to soil following label directions. Do not exceed 8.7 fl oz/acre per crop. Do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| C. | LAMBDA-CYHALOTHRIN | |||
| (Warrior II with Zeon) | 1.28–1.92 fl oz | 24 | 7 | |
| MODE OF ACTION GROUP NUMBER1: 3A | ||||
| D. | CARBARYL* | |||
| (Sevin 4F) | 0.5–1.0 qt | 12 | 7 | |
| MODE OF ACTION GROUP NUMBER1: 1A | ||||
| COMMENTS: Not recommended in fields where potato psyllids are present because it promotes increases in their numbers. | ||||
| ** | 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 to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| 1 | Rotate insecticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B. Mode-of-action group numbers for insecticides and miticides (un=unknown or uncertain mode of action) are assigned by IRAC (Insecticide Resistance Action Committee). |