Plant Pest Profile: Cucumber Beetles

We have heard reports of cucumber beetles attacking squash, cucumber, and melon seedlings in our community gardens.  Here are some quick tips for preventing and responding to cucumber beetles:


  • There are two types of cucumber beetles, both are ¼ of an inch long (.5 cm).  
  • Striped cucumber beetles are yellowish green with three black stripes down the back.
  • Spotted cucumber beetles are yellowish or orangish green with 12 black spots on the back.

Crops Affected

  • Cucumber beetles will eat the leaves, flowers, and fruits of the following crops:
  • Beans
  • Cucumber, 
  • Melon
  • Asparagus
  • Corn
  • Eggplant
  • Squash plants and 
  • Cucumber beetle larvae (babies) will also chew on the roots of these plants. 


Cucumber beetles are vectors (carriers) of cucumber bacterial wilt and cucumber mosaic virus, which 

affects squash, melons, and cucumbers. Once a plant is infected with either bacterial wilt or cucumber mosaic, it cannot be cured and will either die or become unproductive after they are infected. 

Preventing Cucumber Beetles

Row covers: Cucumber beetles will emerge in mid spring, so row covers should be in place as soon as the plants are put in the ground to protect them from the cucumber beetles. Don’t forget to remove them when the plants bloom!    You want pollinators to be able to access  the flowers

Combatting Cucumber Beetle- the organic way

Physical Removal: Come in the early morning or evening and remove the cucumber beetles by hand.  You can simply crush them between your fingers or throw in a bucket of soapy water.

Attracting Predators: Many beneficial insects eat the cucumber beetle, including Soldier beetles, Tachinid flies,  Ground beetles, and Braconid wasps.  Welcome them to your garden by doing the following:

  • Mulch around your crops with leaves or straw- ground beetles and soldier beetles like to live in this kind of material and will hunt your cucumber beetles!
  • Plant cilantro, dill, and coriander around your garden.  These attract tachinid flies and Brachonid wasps, which eat cucumber beetles.

Organic Treatments: 

  • Neem oil- As a last resort, you can spray twice a week with an organic pesticide such as neem oil.  Just make sure to spray the undersides of the leaves, not just the top!  Spray either in the early morning or evening so it doesn’t burn your plants.
  • Kaolin clay- Spray the leaves with Kaolin clay, which the beetles do not like to eat through.  Reapply after every time it rains.
  • Diatomaceous Earth- Sprinkle around the base of the plant.  The texture will cut through the exoskeleton of the beetles/larvae and will cause them to dessicate.