Flea beetles are the smallest of the beetle family ranging in size from 1/16 to 1/5 inch long. Identifying characteristics include an oval shape body varying in color from blue-green to metallic black. They are also unique in that they have the ability to jump when disturbed, can walk, and are
Longevity 2-3 months
Photo © Jo Ann Po-McGavin
With the arrival of spring and warmer weather, vegetable gardeners are eager to get out in the vegetable garden and prepare the soil ready for planting, but they are not alone. When temperatures reach 50F - 10C; adult flea beetles emerge from cracks in the soil where they over-winter looking for food. When a food source is found, the female beetles will begin to lay their eggs in the soil at the base of your vegetable plants, and 10 to 12 days later a new generation of beetles are born.
Of all the vegetable garden pests, flea beetles can be more of a nuisance than a threat to your vegetable crops. That is, if you think ahead and learn from past experience. For the beginner gardener the following advice will be of great help to ensure the survival of your crops.
Adults feed on the leaves of a variety of vegetables such as turnip, cucumber, kale, rutabaga, melon, tomato, cabbage, spinach, eggplant, broccoli, radish, and cauliflower.
However, there are some species that are general feeders, meaning any vegetable plant leaf is fair game for a good dinner.
Photo courtesy Whitney Cranshaw, Colorado State University, Bugwood.org
Should you decide to grow any of the above vegetables, purchase established plants rather than young seedlings from your local nursery. They can be found as a single plant growing in a 3 or 5 inch pot and are
usually called transplants.
Because these transplants are well established before you plant them beetle injury is usually insignificant. Ten to twenty percent or more of the leaf must be destroyed before there is any affect on yield.
On the other hand young seedlings rarely survive a flea beetle attack. Put plain and simple, there are not enough developed leaves on seedlings to ensure their survival.
Adults chew small holes in vegetable leaves giving the appearance as if they have been damaged by fine buckshot.
As I mentioned above, well established or mature crops can withstand a beetle attack. But there are other preventative methods you can also take that will increase your chances of a good crop.
Photo courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org
Some gardeners have reported good success with trap cropping to help get their vegetables over the hump and past the point where this garden pest can seriously affect their crops.
Planting of radish plants is a good example of a trap crop popular with many gardeners to divert beetles away from their vegetable plants. Radish plants are fast growing and vigorous enough to tolerate flea beetle feeding. They can be harvested or destroyed after young vegetable plants have matured sufficiently to outgrow beetle injury.
Another method of control is the use of sticky traps placed near your vegetables and positioned about every five or ten feet apart. Two manufactured brands popular with gardeners is ARBICO and Golden Harvest Organics.
Because these beetles are migratory and new beetles are continuously visiting your garden, the use of any insecticide often produce disappointing results. But if you must use an insecticide, Sevin may help provide control but will only last for a few days.
I would suggest you first try the preventative methods mentioned above before using an insecticide. Remember, part of growing your own vegetables is to produce a crop free of chemical pesticides.
For more information on this beetle, you may want to read this article from Colorado State University.
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