Controlling Zucchini Insects: Learn About Zucchini Pests

Insects On Zucchini Plant Leaves
zucchini pests
(Image credit: phollapatv)

The amazing bounty of zucchini is undoubtedly one of the season’s greatest pleasures. These squash are one of the most prolific producers and zucchini growing problems are rare. They are, however, prey to numerous insect pests whose feeding activity can seriously damage the crop. Zucchini pests range from the tiny aphid to the ½ inch (1 cm.) squash bug, but the damage to the plants can often result in death. Early detection to find zucchini bugs on plants is crucial, as some of these pests can kill the vines in just a few days.

Zucchini Growing Problems

Most gardeners have a good laugh at the size some of their zucchini fruit attain. It stops being so funny when the fruit is taking over your garden and you can’t seem to give the stuff away quick enough. That type of exuberant growth should be celebrated and lauded, and it would be sad if anything happened to stop the consistent march of produce. Unfortunately, some insects do plague the plant and jeopardize the harvest. Identification is important as each pest has a different treatment. For instance, you can’t just say the plant has zucchini worms when it is more likely some species of larva or caterpillar. Here are just a few of the most common zucchini bugs on plants.

Vine borers and worm-like zucchini pests

Zucchini plants that look limp are often falling victim to any number of fungal diseases. They can also be experiencing the bite of the squash borer. Squash borers are hard to see because the hatched caterpillar crawls inside the zucchini stem. These hidden zucchini worms feed on the stem for up to six weeks before pupating and finally becoming adults. Adults are a type of moth but more closely resemble a wasp. In addition to wilting plants, look for tiny holes in the stems and sticky black excrement. Early treatment as adults are laying eggs is the best way to control borers. Use neem oil every three to five days at the base of the plant from May through June. Other worm-like pests of zucchini include:

Other Zucchini Insects

  • Aphids are one of the most common of the pests that affect zucchini plants. They are small, winged insects that tend to mass together and leave sticky honeydew on leaves. Often ants are seen in tandem with aphids because ants feed on the honeydew. Zucchini aphids aren’t the only pest in town though.
  • Thrips are another miniscule insect that you might need a magnifying lens to view. Thrip damage occurs from adult and nymph stages and their feeding can transmit tomato spot virus.
  • Flea beetles are tiny dark brown insects which jump when disturbed. In large infestations, the leaves will have shot holes through out. Heavy populations of flea beetles can diminish plant health or kill it.
  • Cucumber beetles are actually quite pretty but their damage can be serious. These insects are ¼ to ½ inch (6 mm. to 1 cm.) long, bright yellow with black spots. Leaves, stems, and fruit will become scarred and damaged from cucumber beetle's feeding.
  • Squash bugs are another common pest of zucchini. Nymphs are greenish gray and adults are brownish gray. Female squash bugs lay copious quantities of bronze-colored eggs on the underside of leaves. Feeding causes speckled yellowish brown leaves, wilting, stunted runners, distorted or dead fruit.
  • Stink bugs are similar in form but smaller and cause pinpricks on fruit with yellow halos. These areas of damage caused by stink bugs become necrotic and mushy.

Most of these insects can be controlled by using row covers, practicing good weed management, and using appropriate insecticides or horticultural oils and soaps for chemical free controls.

Bonnie L. Grant

Bonnie Grant is a professional landscaper with a Certification in Urban Gardening. She has been gardening and writing for 15 years. A former professional chef, she has a passion for edible landscaping.