The borers just hit my Zucs/summer squash so I thought I'd do a thread on how I deal with them.
The adult moth lays eggs at the base of the stem. When the larva hatch they turn into worms/caterpillars and bore into the stem, then work their way up the vine eating as they go killing the plant. The hole they enter may get quite big. They enter just where the vine starts to get hollow as the base is pretty solid on most squash. Hard stemmed squash like butternut are somewhat resistant. They seem to really like Zucs that have soft hollow stems.
Borer damage to Zucchini stem (today)
There is suggested ways to deal with them (see below, damm site won't let me attach the PDF "too big", hope you can read it). Slit the stalk and kill the worms or pull up and bury the infested plant. They "say" you can't deal with the worms with pesticides once inside the vine.........well you can.
I've found a way which seems to work and may also be a "vaccine"; it works better than the Pfizer or Moderna ones...........
I always have a concentrate of BT to deal with caterpillar pests. I make up ~ pint solution and get a 3- or 5-mL syringe from the drug store.
For infected vines I inject 3-mL of solution every ~ 3-4" above the borer holes for 1-2 feet. Above the holes the vine will be hollow and you may see the solution run out the borer hole.
I just did this to my infected Zucs. I only found one infected summer squash so far, and they had not got to my winter squash or pumpkins.....yet.
To the remaining squash I inject as close to the solid bottom part of the stem that will take liquid, then again ~ 3-4" above that. This seems to protect the squash if if a borer tunnels in. I'm still not sure how long the protection lasts, and the squash need a "booster". I inoculated all the remaining squash this morning.
I hope this helps anybody with borer problems. If you try my method, post here and let me know how it works for you?