Thursday, November 26, 2009

Increase of Squash Vine Borers

Squash vine borers are the most common and most damaging pests of squash. The larvae are borers so they will cause damage as they tunnel into the stems. They usually feed on squash and related wild plants but also can feed on melons and cucumbers.
The adult moths resemble a wasp, with a red abdomen surrounded with black bands at each segment; their front wings are covered with metallic brown scales and their back wings are clear with a brown band. Adult females lay eggs on the leaves and stems of primarily squash. The larvae hatch and begin burrowing into host plant stems. The larva is white in color with a brown head and grows to be an inch in length. The larvae will produce sawdust like frass near the base of the plant which may cause the stems to wilt and die. The larvae then climb from the stems to pupate in the soil.

Some Control Suggestions:

Some Non-Chemical Controls:
Keep natural enemies in the garden such as parasitic wasps that will attack squash vine borer eggs and larvae. Also adult ground beetles (Family Carabidae) will attack squash vine borer larvae. Split vines should be covered with soil immediately after the larvae have been removed. Also remove vines soon after harvest to destroy any larvae still inside stems.

Some Chemical Controls:

Some chemical suggestions include such active ingredients as pyrethrins, permethrin, or carbaryl. Apply the chemicals to the base of the plant, underneath the foliage and underneath the stems of the plant.

Southwestern squash vine borer, Melittia calabaza (Lepidoptera: Sessidae), adult. Photo by G. McIlveen, Jr, http://insects.tamu.edu/images/insects/common/images/cd-43-c-txt/cimg251.html.

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