Everyone loves fresh cucumbers from the garden, but often getting them to grow can be a problem. The biggest threat to your cucumber crop is the cucumber beetle. These black and yellow, spotted or striped, small beetles are found in gardens around the country. They emerge as soon as your cucumbers start growing and can kill the tender seedlings with their feeding. Even once your plants are growing strong, not only can cucumber beetle feeding stunt the plants and reduce production, but the beetles can also spread a deadly bacterial wilt disease. It’s a double whammy!
Luckily, some strategies can prevent or control the damage. Try growing disease-resistant varieties, such as ‘Olympiad’, that will resist succumbing to the bacterial wilt. For small infestations, handpick and drop beetles into a pail of soapy water. To kill adult beetles, hang yellow sticky traps coated with tanglefoot (a vaseline-like substance) near the cucumber patch. The beetles are attracted to the color yellow, so they land on the traps and get stuck. You can also mulch the rows between cucumber plants heavily with hay or straw. This will help prevent beetles from finding your plants and spreading. Another method is to dust plants with kaolin clay or diatomaceous earth to create a dusty environment that beetles hate.
If your plants are already devastated from cucumber beetles, replant. In most areas a later planting will still mature before frost and the beetles will be less of a problem later in the year. Cover these later-planted cucumber seedlings with a floating row cover to protect them from the heat and to speed their growth. The row cover should also prevent adult beetles from finding the plants. However, it’s a good idea to check under the row cover periodically for any beetles that may have snuck in. Either remove row cover when plants are flowering to allow the bees to pollinate the flowers, or grow varieties such as ‘Little Leaf’ that don’t need pollination to form cucumbers. Also, try growing cucumbers in containers on a deck or patio, where the beetles are less likely to find them.