Description of the Pest
Flea beetle adults are small (about 0.12 inch long), shiny beetles with enlarged hind legs that allow them to jump like fleas. The palestriped flea beetle has a broad white stripe down each brown wing.
Damage
Adult flea beetles do most of the damage by feeding on the undersides of leaves, leaving small pits or irregularly shaped holes on the leaves. Large populations can kill or stunt seedlings. Older plants rarely suffer economic damage although their older leaves may be damaged. In the Imperial Valley, larvae feeding on roots has caused serious damage on occasion. This damage is easily confused with cavity spot symptoms.
Management
Manage palestriped flea beetles by removing weeds along field margins and deeply discing plant residue in infested fields after harvest. Do not direct seed or transplant artichoke crops near alfalfa fields.
Check newly emerged seedlings twice weekly for flea beetle damage until plants are well established. Relatively low populations can cause economic damage when plants are in the cotyledon or first true leaf stages. Treat if you find several damaged plants in multiple rows; spot treatment of outside rows or borders may be sufficient. Baits are not effective.
No economic thresholds are available, but treatments, especially on young plants, should be considered if damage reaches a moderate level. Insecticide treatment should rarely be required, but if it is, one application should suffice. Once plants have several true leaves, they can tolerate several beetles per plant without damage. Older plants are even more tolerant. Chemical treatment may disrupt biological control of aphids and whiteflies.
| 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. | IMIDACLOPRID | |||
| (Admire Pro) | Foliar: 1.4–3.5 fl oz
Soil: 7–14 fl oz |
12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Highly toxic to bees. Do not apply more than 14 fl oz Admire Pro (0.5 lb a.i.)/acre per crop season. | ||||
| B. | BIFENTHRIN | |||
| (Brigade WSB) | 16 oz | 12 | 5 | |
| (Brigade 2 EC) | 6.4 fl oz | 12 | 5 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Do not exceed 16 oz/acre between bud formation and harvest. Do not exceed 80 oz/acre per season. | ||||
| C. | ESFENVALERATE | |||
| (Asana XL) | 5.8–9.6 fl oz | 12 | 1 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Apply no more than 0.15 lb a.i./acre between bud formation and harvest. Highly effective against adults and larvae. | ||||
| D. | PERMETHRIN | |||
| (Perm-Up 25DF) | 6.4–19.2 oz | 12 | 0 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Limited to 1.5 lb a.i./acre per season. | ||||
| ** | 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. |
| 1 | Rotate insecticides with a different mode-of-action group number, and do not use the 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 are assigned by IRAC (Insecticide Resistance Action Committee). |