Flea Beetles on tomatoes
I found the following information from another master gardener that I would like to pass on to you:
Flea beetle adults are metallic greenish brown to black in color and from 0.06 to 0.12 inch long. Adults jump when disturbed. Larvae [youngsters] live in the soil, are slender, whitish, and about 0.25 inch long when mature. Adult beetles chew numerous small holes in leaves, giving them a sieve-like appearance. Larvae feed on underground parts of the plant. High populations of flea beetles on seedlings may destroy a number of plants whereas leaf damage to mature plants is not considered serious. If mature plants are heavily attacked, it’s likely they’re stressed for other reasons, among them water, fertilizer, and/or extreme temperatures. Treat when you see the very first small holes in the leaves. If your tomato plants are still productive, consider using a product with the active ingredient azadirachtin which is labeled for use against flea beetles. Apply according to label directions. If the tomato plants are failing, they’re likely past the point of no return; remove and discard them. Next season, plant your tomatoes in a different area previously unaffected by flea beetles. Set transplants into the garden when temperatures are consistently above 55 degrees, then immediately protect with row cover which will warm the plants somewhat and will be a barrier to the beetles. You can remove the row cover when the plants are ready to bloom. All season, ensure the plants receive adequate water and fertilizer so that the mature plants can withstand some damage.