Description of the Pest
Flea beetles are present throughout the growing season but are primarily a concern in the month following transplanting.
The adult Epitrix fuscula flea beetle is a small (2 mm), black beetle, whereas E. hirtipennis is brown. Like all flea beetle adults, their hind legs are thickened, allowing them to jump rapidly. Eggs are laid in the soil near the bases of plants. They hatch in about one week and larvae remain in the soil and feed on roots for 2 to 3 weeks. They pupate in the soil and after 7 to 10 days, adults emerge and move to the plant where they feed on leaves for 2 months or more.
The adult palestriped flea beetle, Systena blanda, is about 0.12 inch (3 mm) long and has a shiny brown body with a broad white stripe down each wing.
Most flea beetles overwinter in the adult stage in plant debris in the field, on field margins, and in adjacent areas. Adults emerge in spring to feed and lay eggs.
Damage
Flea beetle adults can be very destructive to young plants, often defoliating and killing them. They cause the greatest damage by feeding on cotyledons, stems, and foliage. Older leaves and plants are usually more tolerant of their feeding.
Management
The key to preventing flea beetle damage is early detection.
Cultural Control
Methods that may provide partial control of these beetles, which can be especially important in organically certified crops, include the use of trap crops such as Chinese Southern Giant Mustard (Brassica juncea var. crispifolia), interplanting with radishes ('Chinese Daikon' or 'Snow Belle'), the use of row covers, white or yellow stick traps, and good field sanitation. For more information on cultural control options, see Flea Beetle: Organic Control Options. (PDF)
Organically Acceptable Methods
Cultural controls and sprays of PyGanic or the Entrust formulation of spinosad are acceptable for use on an organically certified crop.
Monitoring and Treatment Decisions
Monitor young transplants every few days the first month after planting for damage because flea beetles can move quickly into a field. If damage is detected, consider a treatment to prevent loss of plants.
| 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. | SPINOSAD | |||
| (Entrust)# | 1.25–2.5 oz | 4 | 1 | |
| (Success) | 4–8 oz | 4 | 1 | |
| MODE-OF-ACTION GROUP NUMBER1: 5 | ||||
| COMMENTS: Early treatment provides only about 50% suppression of flea beetles, but the Entrust formulation is an organically acceptable alternative. Do not exceed 29 fl oz of Success or 9 oz of Entrust/acre per crop. Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| B. | CLOTHIANIDIN | |||
| (Belay) | 3–4 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. Review and follow the California neonicotinoid regulations effective January 1, 2024. Permissible application rates of this insecticide may be lower than label rates if applying more than one neonicotinoid active ingredient or using more than one application method in the same season. |
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| C. | THIAMETHOXAM | |||
| (Actara) | 2–3 oz | 12 | 0 | |
| (Platinum) | 5–11 fl oz | 12 | 30 | |
| MODE-OF-ACTION GROUP NUMBER1: 4A | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. Review and follow the California neonicotinoid regulations effective January 1, 2024. Permissible application rates of this insecticide may be lower than label rates if applying more than one neonicotinoid active ingredient or using more than one application method in the same season. |
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| D. | PERMETHRIN | |||
| (Pounce 25WP)* | 6.4–9.6 oz | 12 | 3 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| E. | ESFENVALERATE | |||
| (Asana XL)* | 5.8–9.6 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| F. | PYRETHRIN# | |||
| (PyGanic 1.4EC) | Label rates | 12 | 0 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Short residual material; always buffer pyrethrin to pH 5.5 or lower. | ||||
| ** | 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. |
| # | Acceptable for use on organically grown produce. |
| 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). |