Description: The clearwing moth is the adult of the squash vine borer and is about ½-inch long with metallic-green front wings and clear back wings. The abdomen is orange with black spots. Eggs are flat, brown and very small. Larvae resemble maggots with a whitish-cream colored body about one-inch long with a brown head.
Life Cycle: From late June through early July adult moths emerge from the ground to lay eggs. Eggs hatch in about one week and begin feeding within the stems of squash plants. In four to six weeks the larvae pupate in the soil until the following summer. There is one generation of squash vine borer each year.
Damage: Squash vine borers feed on summer and winter squash as well as pumpkins causing yellowing leaves and wilting. Holes in the stems near the base of the plant along with the appearance of a sawdust-type material that is moist and green/orange colored are symptoms of squash-vine borer. One of the first indicators of a problem is when squash plants are wilted even during cool parts of the day.
Control: Treating plants that have active larvae is difficult. It is best to monitor plants for the adult moth and treat before the larvae can infest plants. Planting a successive crop of summer squash in early July is another control method. This allows the crop to mature when the borers are pupating rather than when they are most active. Crop rotation is another important control measure. Borers can be manually removed by slicing open the stem if you know the pest is present. Insecticide applications need to begin when the squash vines start to spread. Applications should be repeated every seven to ten days through the end of June. If using an insecticide, spray the crown and the base of the runners.
Some chemicals that may be used for borers are permethrin (Eight Vegetable, Fruit & Flower Concentrate; Garden and Farm Insect Control; Lawn & Garden Insect Killer) or bifenthrin (Hi-Yield Bug Blaster II, Bug-B-Gon Insect Killer or Lawn and Garden) applied as a spray or dust.
