Striped cucumber beetles, about 1/5 of an inch long, are serious pests of cucumbers east of the Rockies. - Whitney Cranshaw, Colorado State University, www.insectimages.org

The lime-green, twelve-spotted cucumber beetle is most common in the South. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

Despite its name, the banded cucumber beetle is more likely to feed on beans than cucumbers. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

Cucumber beetles feed on the leaves and roots of cucumbers, squash, melons, and pumpkins. Adult beetles lay eggs at the base of plants in the spring and the skinny, white larvae burrow into the roots; a serious attack can destroy the entire root system. The spotted cucumber beetle is also called the corn rootworm because its larvae burrow into corn roots. There are several species of beetles that live in the West, South, and Midwest, but all are recognizable by their size, shape, and patterns of either spots or stripes similar to the ones pictured here. The adults may also chew on beans, corn, peas, and the flowers of many garden plants.

Cucumber beetles can transfer diseases such as bacterial wilt that are often more damaging to plants than the beetles alone. When beetles feed on cucumber vines, they transmit the bacteria to healthy plants. The bacteria multiplies and travels quickly throughout the vine. Symptoms of the disease are wilting leaves following by vine collapse, often within 24-48 hours. Infection typically occurs when the first cucumbers are half-grown. Infected vines don’t recover—destroy them completely (do not compost).

To help avoid problems, you can use row covers to help deter infestations in early spring until the plants start blooming. To control beetles already present, spray with insecticidal soap or a product that contains neem or pyrethrin, but read the warning label because these are also toxic to bees which pollinate cucumber, squash, and other crops.

To help prevent infestations, clean up the garden at the end of the season.