How to Manage Pests
UC Pest Management Guidelines
Scientific Names: Epitrix fuscula, E. hirtipennis, Systena blanda
(Reviewed 4/10, updated 4/10, pesticides updated 5/16)
In this Guideline:
DESCRIPTION OF THE PESTS
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.
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.
The key to preventing flea beetle damage is early detection.
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.
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.
UC IPM Pest Management Guidelines:
Insects and Mites
J. L. Aguiar, UC Cooperative Extension, Riverside County
Acknowledgments for contributions to Insects and Mites:R. H. Molinar, UC Cooperative Extension, Fresno County