Q. Last year my squash plants wilted and died in mid-summer. I think cucumber beetles were involved. Did they cause the problem and how can I control them?
A. The plants probably died from a bacterial wilt disease that is very common on plants in the cucurbit family. Cucumber beetles spread it.
While eating the leaves of plants, the beetles deposit droppings (defecate) on the leaves. It is a bacterium in the droppings that kills the plants. The bacteria enter the plant through the wounds created by the feeding beetles. Once they are within the plant they multiply rapidly and clog up the plant veins (vascular tissue). Because the clogged veins are unable to move water from the roots to the top of the plant, the stems and leaves wilt and die.
It is not possible to control the disease, so you must control the cucumber beetle. There are two choices. First, you can cover your plant, and try to keep the beetles off your plants. Second, you can spray the plants with an insecticide and try to kill the beetles. Please call the Home and Garden Information Center at the number listed below for more information.
1. In our haste to make plants grow quickly, we often overwater them and cause other problems. Water plants only when necessary.
2. Keep damaged hoses repaired. Hose leaks can cause large amounts of water loss.
3. Aphids rarely cause extensive damage. Many can be kept in check by spraying them with a sharp stream of water.
Dennis Bishop is an urban horticulture educator for the Baltimore office of the Maryland Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site, www.hgic.umd.edu.