What is it?
Squash vine borers, or melittia curcurbitae are insect pestswhich can attack primarily the summer squash, winter squash and gourd varieties of the curcurbit family. Squash vine borers rarely attack or cause damage to the other members such as including cucumbers, muskmelons, pumpkins, and watermelon plants.
What does it look like?
Melittia curcurbitae is a borer that is very small and often you will only notice the damage to the curcurbit family plants, rather than see any actual sightings of the squash vine borer larvae or their adult moth form. However, the moths might be noticed occasionally because of a glare off of their metallic green bodies as they fly about plants. Damage from squash vine borers most likely will start with wilting vines.
Upon inspection you may then notice that there are holes in the stems which are filled with a material that looks like sawdust. To confirm squash vine borers, cut a stem off the plant and slice it lengthwise. Inside you will find white worms that vary in size up to about 1 inch long if you have squash vine borers.
How does it manifest?
Adult squash vine borers in the form of the metallic green moths, lay their eggs on the actual curcurbit vines. They typically lay eggs during April and May in the southern areas of the United States, while laying eggs in June and July in the northern regions of the United States.
The squash vine borer eggs hatch and become white larvae which feed on the stems for four or five weeks as they bore into them, leaving their sawdust-like trail. Squash vine borer larvae pupate within the soil around the stems they have fed from and will emerge as adult moths.
What can you do about it?
In order to be effective, insecticides must be applied prior to the squash vine borer entering the stem of the curcurbit family plant. It is best to dust plants during your regions egg laying period with methoxychlor containing insecticide. However, if these pests have already penetrated the vines, you can slit the infested stems open with a knife and kill the borers.
If the plant has not succumbed to death from borer damage you can then cover the damaged portion of the stem with soil and water frequently to encourage growth and new roots. However, the vine’s recovery is not guaranteed as often damage is too severe or the stem becomes reinfested with squash vine borers.