Cucumber Beetle Information

Cucumber Beetle Information

By Kat Yares, Garden Guides Contributor
cucumber beetle

About Cucumber Beetles

The cucumber beetle is just one of several varieties of leaf eaters of the insect genus Diabrotica. Most common are the spotted and striped beetles, identified by the yellow stripes and black spots on the beetle bodies. The spotted cucumber beetle resembles in shape the ladybug but, unlike the ladybug, is not beneficial to the garden.

The larvae are laid in eggs on the underside of the leaves of the affected plants. After hatching, they bore underground and attack the roots of the plant.

Prevention and Control

Pyrethrum containing insecticides are the most used way of controlling the cucumber insect beetles. To prevent future re-infestations, the plants and debris should be removed from the area. The ground around remaining plants should be free of litter and cultivated regularly to remove hiding places for the beetle and the larvae.

Affected Plants

Cucumbers, squashes, pumpkins and melons.


Adult cucumber beetles attack the leaves and stems of young plants and later attack the buds and fruits of the mature plants. As larvae, the cucumber beetles attack the roots and stems beneath the soil causing the plant to die. Cucumber beetle larvae are often called corn rootworms and can decimate a young corn crop.

Predator Insects

Soldier beetles, parasitic nematodes, Braconid wasps and Tachnid flies will prey on the adult cucumber beetle. The eggs fall prey to lacewings and ladybugs.

Natural Insecticides

A mix of 1 cup wood ash, 1 cup hydrated lime and 2 gallons of water can be used as a spray for the cucumber beetle. Spray both sides of the plant leaves thoroughly.

Other Methods of Control

* Mulch heavily around plants that cucumber beetles favor. Adult beetles have difficulty moving from one plant to another over mulch.
* Plant radishes, nasturtiums and odiferous marigolds as a border around cucumber beds or circling squash, melon and pumpkin hills.
* Planting castor beans among the plants also appears to repel the cucumber beetle.
* Well-placed bat houses can help in the eradication of many unwanted insect pests.

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