The flea beetle (family Chrysomelidae) is a pesky visitor to most gardens. The beetle targets tasty plants in the families Solanaceae (potatoes, tomatoes, eggplant, peppers) and Brassicaceae ( including cole crops: broccoli, kale, cabbage, collards). Its capacity to overwinter in soil and plant debris makes it challenging to manage, and very sneaky. The flea beetle inflicts both above and below-ground injuries to its target.
Adults are small (1/10 inch long), shiny, dark brown or black beetles with large hind legs that allow them to jump when disturbed. Some species may have white or yellow stripes on their wing cases. Larvae are small, cream-colored worms (1/8 – 1/3 inch long). They live underground and feed on the roots and tubers of young plants as well as on germinating seeds.
Note: Flea beetles transmit viral and bacterial diseases.
Adults overwinter in the soil or garden debris and become active in the spring, feeding on host plants as new growth appears. Tiny white eggs are laid on or in soil cracks around the base of plants. These hatch in about one week, and the slender white larvae feed on plant roots for approximately 2-3 weeks. Pupae usually remain in the soil for 7-9 days until adults emerge and the cycle is completed. There are one to four generations per year, depending on species and climate.
How to Control
- Remove garden trash and plow or rototill under weeds to reduce overwintering sites.
- Floating row covers are extremely effective when placed on seedlings and left in place until plants are old enough to tolerate beetle damage.
- Place yellow sticky traps throughout garden rows every 15 to 30 feet to capture adults.
- Beneficial nematodes applied to the soil will destroy the larval stage, reducing root feeding and helping to prevent the next generation of adults from emerging.
- Apply organic Diatomaceous Earth for long-lasting protection. Made up of tiny fossilized aquatic organisms, that look like broken glass under the microscope, DE kills by scoring an insect’s outer layer as it crawls over the fine powder. Contains NO toxic poisons!
- Surround WP (kaolin clay) forms a protective barrier film, which acts as a broad spectrum crop protectant for preventing damage from insect pests.
- BotaniGard ES is a highly effective biological insecticide containing Beauveria bassiana, an entomopathogenic fungus that attacks a long-list of troublesome crop pests – even resistant strains! Weekly applications can prevent insect population explosions and provide protection equal to or better than conventional chemical pesticides.
- 70% Neem Oil is approved for organic use and can be sprayed on vegetables, fruit trees and flowers to kill eggs, larvae and adult insects. Mix 1 oz/ gallon of water and spray all leaf surfaces (including the undersides of leaves) until completely wet.
- Least-toxic botanical insecticides should be used as a last resort. Derived from plants which have insecticidal properties, these natural pesticides have fewer harmful side effects than synthetic chemicals and break down more quickly in the environment.