Pest

Cucumber beetles

Yellow beetles with black stripes or spots that chew cucumbers and melons and spread bacterial wilt.

What you'll see

• Shiny yellow or yellow-green beetles about 1/4 inch (6 mm) long, with three black stripes or twelve black spots.
• Holes in leaves and flowers, scarred stems and rinds, and seedlings eaten or killed.
• Vines that suddenly wilt, a sign of the bacterial wilt the beetles carry.

Why it happens

Adults spend the winter in weeds and garden debris and move onto young cucumbers, squash and melons as they come up. Their larvae feed on roots, and the beetles spread bacterial wilt and some viruses.

How to fix it

1. Cover seedlings and transplants with floating row cover, sealed at the edges, until the plants flower.
2. Remove the cover once flowers open so bees can pollinate.
3. Knock beetles into a jar of soapy water held under the leaves, since they drop when disturbed.
4. If beetles swarm young plants, use a spray labeled for cucumber beetles in the evening, away from open flowers, and keep kids and pets away.

Keep it from coming back

• Clear garden debris and weeds in autumn, where the beetles spend the winter.
• Grow cucumber varieties that resist bacterial wilt or are less attractive to the beetles.
• Protect plants most while they are young; older plants tolerate the beetles much better.

Sources

• UC IPM: Cucumber beetles
• University of Maryland Extension: Cucumber beetles: spotted or striped on vegetables
• Clemson HGIC: Cucumber, squash, melon and other cucurbit insect pests

General guidance, not a diagnosis. For valuable, edible or outdoor crops, check with a local extension service or plant expert. Use any product exactly as its label says, and keep children and pets away while it dries.