You know you might have a cucumber beetle problem if your plant leaves are yellowing, wilting, or have holes appearing on them, or if your seedling stems are being chomped on.
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The beetles swarm on seedlings, feeding on leaves and young shoots, often killing plants; they also attack stems and flowers of older plants and eat holes in fruit. Their feeding can transmit wilt and mosaic viruses to your plants. The beetles can be found across North America, mostly in the West.
There are two types of pesky cucumber beetles: striped and spotted. Striped cucumber beetles mostly feed on circubit vegetables vegetables like cucumbers, squash, pumpkins, and beans, and rarely on other plants, while the similar spotted cucumber beetles feed on over 200 different crop and non-crop plants. They are both yellow, and and you can differentiate them by the shape of the black marks on their wing covers. Striped cucumber beetle adults are yellow, elongate, 1/4-inch beetles with black heads and three wide black stripes on wing covers (as opposed to the spots on the spotted beetle’s wing covers). Striped cucumber beetles lay eggs at the base of cucurbit plants and their larvae then feed on the roots of these plants. The adults feed on squash family plants, beans, corn, peas, and blossoms of many garden plants. Larvae feed on roots of squash family plants only, killing or stunting plants.
Read more: https://www.goodhousekeeping.com/home/gardening/a20705713/control-cucumber-beetles/