Zucchini is a prolific summer squash, often rewarding gardeners with an abundant harvest. This rapid growth attracts a wide variety of creatures who view the foliage and developing fruit as a food source. Damage can range from minor cosmetic issues caused by small insects to the complete destruction of plants by larger wildlife. Identifying the specific culprit is the first step toward effective protection.
Pests That Target Zucchini Leaves and Stems
Small insect pests often target the vegetative parts of the zucchini plant. The squash bug (Anasa tristis) is a common threat, with both nymphs and adults sucking sap from the leaves and stems. This feeding causes yellow spots that turn brown, leading to wilting and the death of young plants. They are recognizable as flat, brownish-gray, shield-shaped insects that lay bronze-colored egg clusters on the undersides of leaves.
The cucumber beetle, which appears in both striped and spotted varieties, is another concern. These beetles chew ragged holes in the leaves and stems, but their greater threat is transmitting bacterial wilt disease. If a plant suddenly wilts and collapses, a squash vine borer (Melittia cucurbitae) may be the cause, as the larvae tunnel into the stem, blocking water and nutrient flow. Slugs and snails leave behind irregularly shaped holes in the leaves and telltale silvery trails indicating their movement.
Wildlife That Damages Zucchini Fruit and Entire Plants
Larger animals inflict extensive damage, often targeting the fruit or consuming entire plants. Deer, which lack upper incisors, typically leave behind foliage or stems with a torn, ragged appearance. Their feeding damage can occur high up on the plant, sometimes reaching six feet above the ground.
Rabbits and groundhogs feed closer to the ground, but their methods differ. Rabbits leave a clean, angled cut on stems and leaves due to their sharp incisor teeth, with damage usually under two feet high. Groundhogs, or woodchucks, are known for their appetite for entire young plants and for the large burrows they dig near the garden. Squirrels and raccoons are usually responsible for fruit damage, often leaving behind messy, partially eaten zucchini.
Targeted Methods for Deterrence and Protection
Protection strategies must be tailored to the specific pest. For small insect pests like cucumber beetles and squash bugs, floating row covers placed over young plants can physically block access during the early season. These covers must be removed once flowering begins to allow for pollination.
Applying insecticidal soap or neem oil directly to soft-bodied pests like aphids and young squash bugs is an effective contact method. For larger mammals, physical exclusion is the most reliable defense. A fence designed to deter deer must be at least eight to ten feet tall, as deer are capable jumpers.
To keep out rabbits and groundhogs, a shorter fence of two to three feet is usually sufficient, but it must be buried six to twelve inches deep and bent outward to prevent burrowing. Taste and scent repellents, often containing putrescent whole egg solids or hot pepper wax, can be applied to foliage to deter mammals. These repellents require frequent reapplication, especially after rain, and gardeners should rotate products to prevent animals from becoming accustomed to a single deterrent.