Description: Cucumber beetles can either be striped or spotted. Striped cucumber beetles are more common with ¼-inch long bodies, black head and antennae, straw-yellow thorax and yellowish wing covers. There are three parallel longitudinal black stripes down the body. Spotted cucumber beetles have 12 black spots on the wing covers with yellow on the underside of the abdomen.
Life Cycle: There are two generations of cucumber beetles each year. They overwinter as adults. After mating the females lay eggs in the soil at the base of cucurbit plants making it easy for larvae to feed on roots when they emerge. Two to three weeks later the larvae pupate in the soil giving rise to the second generation later in the growing season. It takes about four to six weeks for a single generation to go from egg to adult.
Damage: Cucurbit plants are targeted by cucumber beetles whose feeding reduces growth and can cause plant death. Young pumpkin and squash plants are common targets. Holes in leaves, stems, flower and fruits caused by feeding can affect yield. Cucumber beetles also transmit the disease, bacterial wilt, which causes sudden browning and death of cucumbers and muskmelons. Once infected the plant cannot be cured making prevention key.
Control: Protect young plants now by using row covers, cones or another physical barrier. Seal the edges of the barrier to prevent beetles from entering. Use transplants which can stand up to bacterial wilt better than seedlings. Mulch with straw around plants to create a habitat for predators such as wolf spiders. Remove crop debris after each growing season and manage weeds. Monitor plants regularly and manually remove cucumber beetles. Sticky cards can be used to help monitor for pests present in the garden.
Insecticides with permethrin (Bonide Eight Vegetable, Fruit & Flower Concentrate and Hi Yield Garden and Farm Insect Control) can be used when pollinators are not present. Always follow all label instructions and only use insecticides in combination with proper cultural controls.
