I had noticed that my summer squash plant was a little wilted. I erroneously believed it to be from lack of water.
Nope. It was because of these little creatures.
Here is another picture of one inside the stem of the plant.
In theory it is possible to save the plant by slitting the stem and removing the borer. The stem is then buried and should produce more roots in the damaged area and go on to produce more squash.
However by the time I had dug out NINE! of the little beasties I decided to pull the plant and try again next year. My fish thought the borers were a tasty treat!
I was unfamilier with what the adult form of the squash vine borer looks like but after I looked it up I realized that I had seen an adult hanging about.
This site has info. on the borer.
Here is a picture of the adult.
Row covers, foil or duct tape around the stem, and extra vigilance in noticing the entrance holes and signs of wilting are the current environmentally friendly methods for combating the beasties. I can see trying the foil or duct tape but I think the plants get too big for row covers.
On the plus side I planted the barely sprouted pole beans in the garden. I have four more that have not sprouted yet so will wait on those. I found some bits of root where the first ones never came up. Maybe a bird got in and ate them before I even knew they sprouted.