In many gardens what was once a yellow zucchini might be dying right before your eyes. The big culprit is the squash vine borer. Squash vine borers will attack zucchini, summer squash, winter squash, a lot of those cucurbit family plants. What they do is lay their eggs at the base of the plant near the stem. When the egg hatches and turns into a little larvae or a little worm, it tunnels its way up through the stem!
In the process of tunneling, it allows diseases to get in which causes wilting of the stems. If it's really far gone, there's probably not a lot you can do. There are probably a lot of those worms in the stems at that point. But, if you catch it early on, and you have just a few larvae, you can go in and play surgeon. With a little knife, cut along the stem and remove that little larvae. It's a little cream-colored worm. You can do a lot of things with him, but want to get him out of the stem. Then bury the stem in soil. What happens is the stem will reroot itself. It will continue to grow and you can get a good production out of that plant.
Another way to prevent this whole problem is early in the season put some netting over your squash plants. What the netting does is prevent the adult flies from laying the egg in the first place. Once you start getting flowers forming you have to take the netting off so the bees can get in and cross pollinate the flowers. At that point, you have to start watching and see if there are any holes in the stem where the squash vine borer will start tunneling. Check it every few days or so, and once you see a hole, do your surgery and hopefully you'll help your plant survive.
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