The squash vine borer is a diurnal species of sesiid moth. The moth is often mistaken for a bee or wasp because of its movements, and the bright orange hind leg scales. The females typically lay their eggs at the base of leaf stalks, and the caterpillars develop and feed inside the stalk, eventually killing the leaf. They soon migrate to the main stem, and with enough feeding damage to the stem, the entire plant may die. For this reason, it is considered a pest that attacks cultivated varieties of squash, zucchini, pumpkin, and acorn squash.
The squash vine borer is native to North America, with some reports as far south as Brazil and Argentina. It lives in most temperate North American states, except the Pacific coast. Southern states have two broods a year.
Squash vine borer
Often, frass on the stem of a squash plant is the first symptom of infestation. The second symptom follows soon - the death of the plant.
Zucchini squash plant stem cut open to show borers
Life cycle
The Sesiidae or clearwing moths are a diurnal moth family in the order Lepidoptera known for their Batesian mimicry in both appearance and behaviour of various Hymenoptera.
Sesiidae
Synanthedon tipuliformis, larva
Melittia cucurbitae hovering for nectar
Synanthedon sp.