What are Cucumber Beetles?Cucumber beetles don’t make it easy for you to identify them. There are two species that go by the name Cucumber Beetle: the Striped Cucumber Beetle, and the Spotted Cucumber Beetle. The spotted cucumber beetle also feeds on beans, corn, potatoes and peanuts.
Damage Caused by Cucumber BeetlesCucumber beetles eat roots, leaves, flowers and transmit bacterial wilt disease along the way. The Eggs are laid just below the soil surface and the larva hatch and start feeding. They start by munching on tender seedlings and tunneling through roots.
They begin turning into adults in early Summer and start feeding on the flowers and leaves. The damage usually isn’t enough to kill the plants, but the loss of flowers means a loss of fruits.
Worse than the feeding damage is the spread of bacterial wilt, which can be deadly and quick. It starts with one leaf wilting and spreads. A telltale sign of bacterial wilt is the sticky, white sap-like substance that oozes from snapped stems. Bacterial wilt is a serious disease of cucumbers and muskmelons. It affects squash too, but to a much lesser extent.
Controlling the Cucumber BeetleControlling the damage done by cucumber beetles is a multi-step approach.
- Resistance: Choose wilt-resistant varieties.
- Trellis: Keeping plants off the ground lessens the early damage done by the larva.
- Sanitation: Make sure you remove all plant debris from the garden at the end of the season, so that adults can't hide out.
- Exclusion: Start the season by covering young plants with row covers. Leave the covers on until you start to see flowers.
- Cultural: You could also try some cultural practices like planting a trap crop of common marigolds, to divert the beetles away from your cucumber plants,and companion planting with plants that repel cucumber beetles.
Repellent plants include: broccoli, radish, pot marigold, catnip, nasturtium and tansy.
Beneficial insects, like lady beetles, green lacewings and soldier beetles, will feed on the cucumber beetle eggs and should be encouraged in the garden.
- Pesticide: If necessary, use a pesticide like Rotenone or Pyrethrum on your plants. Cucumber plants are sensitive to many chemicals, so use caution when spraying anything, follow the label’s instructions carefully and use them as a last resort.