Flea beetle is a generic name given to several species of jumping beetle which attack plants. Their name refers to the capacity of the adult beetles to jump by using their powerful, modified hindlegs and, as you unfortunately know all too well, they can have a devastating effect on the home vegetable garden. Flea beetles are often brightly colored or metallic in appearance and are often only around 5 mm in size. In Pennsylvania, the most common of these flea beetles is the corn flea beetle, Chaetocnema pulicaria, which, as the name suggests, are commonly found in cornfields. They will also feed on a variety of other hosts, including those in the nightshade family (e.g. tomato and eggplant), and those in the cabbage family (cauliflower, broccoli etc). These beetles produce very characteristic damage to their host plants by chewing holes in the leaves. This is commonly referred to as shotholing as it resembles buckshot damage. Severe infestations can render plant leaves little more than a skeleton.

Flea beetles overwinter in the soil as adults and emerge in early spring to to feed on plants and lay eggs. Females lay their eggs in the soil at the base of plants and the larvae emerge to feed on the leaves. The larvae then return to the soil to pupate and re-emerge as adult beetles to cause more damage and repeat the cycle.

The method used to control these beetles will very much depend on the type of vegetable garden you are producing. If you are growing your vegetables organically then control may be more difficult than the other option of spraying with an insecticide, especially if you have a heavy infestation. Nonetheless, there are a few things you can try in the organic garden:

1. Delay planting of young plants in the garden until the overwintering adults have emerged to reduce the damage and give the plants a better chance of surviving any later damage.

2. Plant 'trap plants'. These plants will vary depending on the beetle species but intercropping with the beetles preferred food choice may help lure them away from your vegetables. These plants can then be sprayed with an insecticide to prevent them migrating to your vegetables, or removed entirely and disposed of after soaking in a bucket of soapy water and sealing in a plastic bag.

3. Use row covers to protect your plants. Floating row covers (those that do not need a supporting frame) can be very effective at preventing the beetles reaching the plant. These are used to best effect after planting with a non susceptible crop plant, otherwise beetles which may already be present in the soil will still emerge under the cover.

4. Use a thick covering of mulch. This will not completely eradicate the problem, but may prevent at least some adults emerging from the soil.

5. Physically remove the beetles from the foliage. This can be done with a small, handheld vacuum but will have to be repeated frequently.

If the infestation reaches very high levels and the above methods are not working then the use of a chemical insecticide is probably the best option. Opt for one containing carbaryl, spinosad, bifenthrin or permethrin. Spraying should control the insect for approximately a week before a reapplication is required.

Hope this helps! Good Luck!!