If you grow cucumbers, squash or melons at your Hillsborough home, you may have watched healthy-looking vines collapse in the middle of summer. Small yellow beetles with black stripes or spots are often behind it. These are cucumber beetles, and they're a gardening pest more than a household one. They won't come inside or hurt your family, but they can wipe out a vegetable patch. Below, we'll explain what they are, why your plants wilt and what actually works. Most of the fix happens in the garden itself. For insects that move from the yard toward your house, our outdoor pest control service can help.
What Cucumber Beetles Are
Two kinds show up in New Jersey gardens. Both are small, about a quarter inch long, and both target the same family of plants: cucumbers, squash, zucchini, pumpkins, melons and gourds.
| Striped Cucumber Beetle | Spotted Cucumber Beetle | |
|---|---|---|
| Look | Yellow with three black stripes down the back | Yellow-green with black spots |
| Diet | Mainly cucumbers, squash and melons | Feeds on cucurbits and many other plants |
| Larvae | Feed on the roots of cucurbit plants | Feed on roots of other crops and plants |
The adults spend the winter sheltered in leaf litter, weeds and plant debris near gardens and field edges. When the weather warms up in spring, they fly in looking for young plants, and they can find a new garden bed quickly.
Why They Show Up In Your Garden
Cucumber beetles find gardens by the plants themselves. Cucurbits give off scents that draw the beetles in, and young seedlings are their favorite target. A few things make a garden more appealing to them:
- Planting the same crop in the same spot every year. Beetles and larvae from last season are already close by.
- Leftover plant debris. Old vines, weeds and leaf piles give adults a place to spend the winter.
- Small, tender transplants. Seedlings with only a few leaves can't afford to lose much tissue.
The Damage They Cause
Cucumber beetles hurt plants in three ways.
- Chewed seedlings. Adults feed on young leaves and stems. Heavy feeding can kill seedlings outright.
- Scarred fruit and flowers. Later in the season they chew blossoms and scar the skin of developing fruit.
- Bacterial wilt. This is the serious one. The beetles carry a bacterium that enters the plant through their feeding wounds. It blocks the plant's water-carrying tissue, so leaves droop and then whole vines wilt and die, even when the soil is moist. Cucumbers and melons are hit especially hard.
A quick check for bacterial wilt: cut a wilted stem, touch the cut ends together and slowly pull them apart. If thin, sticky strands stretch between them, wilt is the likely cause. There's no cure once a plant is infected, so pull it and throw it away rather than composting it.
Are Cucumber Beetles Harmful To People Or Your Home?
No. They don't bite or sting, they don't carry diseases that affect people and they have no interest in the inside of your house. They're a threat to certain garden plants, not to your family, pets or the structure of your home. That's why most of the solution is about how you garden.
How To Protect Your Plants
No single step solves cucumber beetles. A few cultural habits, used together, make the biggest difference.
- Cover young plants. Lightweight floating row covers keep beetles off seedlings during their most vulnerable weeks. Seal the edges with soil. Take the covers off once plants begin to flower so bees can pollinate them.
- Rotate where you plant. Move cucurbits to a different bed each year when you can.
- Plant sturdier transplants. Bigger, healthier transplants handle some feeding better than tiny seedlings.
- Check plants often. Look under leaves and inside flowers in the morning. Knock beetles into a bucket of soapy water.
- Clean up in fall. Remove spent vines, weeds and debris so fewer adults have shelter for the winter.
- Choose varieties carefully. Some cucumber and squash varieties are less attractive to the beetles or tolerate wilt better. Seed catalogs and Rutgers Cooperative Extension are good places to check.
If you're unsure what's chewing your vines, our guide to leaf-footed bugs vs. squash bugs covers two other insects that target the same plants.
When To Call A Professional
Cucumber beetles are mainly a garden problem, and most homeowners handle them with the steps above. Garden-specific advice on crop treatments is best found through your local extension office or a garden center. Where EcoFusion can help is the bigger picture outside your home. If beetles, ants, stink bugs or other insects are building up around your foundation, patio or entry points, our technicians can inspect the property and set up an Integrated Pest Management plan using EPA-registered eco-safe products.
Cucumber beetles can't hurt your family, but they can cost you a summer's worth of cucumbers and squash. Cover seedlings, rotate beds, check plants early and clean up in fall, and your Hillsborough garden will have a much better season next year. For pests that won't stay in the garden, EcoFusion Pest Control offers a free inspection.