Certain types of beetles have appetites for particular plants; the potato flea beetle has a penchant for the tomato plant. Identify the physical characteristics of the beetle, other types of plants that act as hosts and the symptoms and damage caused by the pests. Determine the best control methods. Catching insect pests early ensures a greater likelihood you can grow healthy tomatoes.
Potato flea beetles (Epitrix cucumeris, E. subcrinita, E. parvula) attack tomato plants and display yellow and black striped bodies measuring 1/2 inch long and 3/8 inch wide. The beetles are ovular and have arched backs. Eggs of the potato flea beetle have a vivid yellow hue, and the larvae that hatch are a rust color with black dots. Flea beetles jump when disturbed.
Adult potato flea beetles overwinter as deep as 12 inches into the soil near host plants. During the spring, the adults walk or fly, searching for food. They will continue until they find a host plant. Adults feed on tomato plants, usually seedlings, for up to a month, according to the Colorado State University Extension. After laying eggs near the soil line of tomato plants, the larvae hatch and feed on the lower regions of the plant, including the roots, though larval feeding is not as destructive as that of adult beetles.
Symptoms and Damage
The flea beetle's method of feeding is referred to as "shotholing" because they chew holes into the leaves, and leaves appear to have been shot with a bullet. Since potato flea beetles primarily feed on the seedlings of tomato plants instead of established plants, damage may be severe, including stunted growth or plant death.
Other Host Plants
The beetles feed on more than just tomato plants. Other preferences include nightshade plants such as eggplants and potatoes. Since these different plants attract the potato flea beetle, the University of Massachusetts Extension suggests rotating all of these crops to a field at a minimum of 200 yards from the land used for the previous year's plantings to reduce infestations.
Both natural and chemical control methods are appropriate for potato flea beetle management. Consider creating trenches up to 2 feet deep into which beetles will fall with no way out. The addition of a layer of straw around the tomato plants reduces the incidence of beetles as well, according to the UMass Extension. For chemical control, apply insecticides with the main ingredient carbaryl or permethrin, according to the Colorado State University Extension. A natural repellent approach is the use of diatomaceous earth as a powder applied directly to plants. Since these beetles reinfest areas rapidly, realize it will take considerable maintenance to manage this pest problem.