It’s so sad isn’t it?! One day your squash plant is thriving and then the next it’s shriveled in a heap of wilt. Upon further inspection you may notice that the stem has disintegrated near the soil line. If you look close enough, well – it’s icky, don’t bother. Just gather it up and toss it in the compost heap because there’s no bouncing back from what ails it. But – WHY? It’s likely due to the dreaded squash vine borer, a nasty little moth who lives to disappoint gardeners. I don’t believe that there are any natural predators for this moth, other than gardeners.
They show up every year around the end of May and lay eggs on the underside of squash leaves. If you find a cluster of small orange/brown eggs on the bottom side of your squash eggs, squash them immediately! Just use your thumb, they won’t bite. Those eggs hatch little catterpillars who burrow their way into the stem of squash plants, which kills the plant. There are heroic measures such as surgically opening the stem, removing the worm, and burying the wound. However, I have never tried that because the thought turns my stomach. I have attempted to fill the stem with Thuricide BT, an organic catterpillar killer, with use of a syringe. I’ve heard of some people who also use the syringe to stab at the stem. That could kill the worm too! I may have done that.
Some people, in other parts of the country, seem to have success with wrapping the stems of their plants in foil. I’ve never tried it because I heard that it’s not effective here in Central Texas. Apparently, we have terminator moths.
The best success I’ve had in my attempts to outsmart the squash vine borer has been to control what I plant and when. This year, I started zucchini and yellow crookneck squash indoors. The plants I put out in the garden were more mature than store bought starts. I had a head start on the season and the borer! I got them in the ground mid-March and they did really well. Sadly (for summer squash harvesting), we happened to have a chilly spring which stiffed female bloom development.
Yes, it sounds like the dreaded squash vine borer strikes again. Here in Central Texas, this little guy is relentless.
The first year I grew squash they were big, beautiful and thriving. And the next day they were shriveling up and wasting away. I researched and researched and realized I had been infiltrated by the nasty squash vine borer. So I was like, okay great what can I do to get rid of it? Other pests I had were easily taken out with a splash of this or a sprinkling of that. But I quickly learned that this borer was different.
If you see holes with some stuff that looks like sawdust on the stems of your squash plants, that’s a tell tale sign the squash vine borer has arrived. You can try the syringe approach like Jenni mentioned above or try a little squash vine surgery. Find the “sawdust” entrance and head up a few inches, then carefully cut a lengthwise slit in the stem until you find that grubby borer. Kill it. The tricky part is that you are basically cutting the rest of the plant off from it’s roots so you will then have to try and bury the cut stem with some soil and water so it can heal itself and possibly produce new roots.
I’ve tried this method multiple times, and sadly I have not had much long-term success. Eventually I just have to pull the whole withered plant out of my garden and move on.
After that first year of dealing with the squash vine borer, I started researching how to avoid them in your garden. One recommendation was to plant squash varieties that were more resistant to this pest. Butternut, tatume, and crookneck yellow squash are the varieties I discovered. So the past few years I just stick to these and have had a little more success and a lot less heartache out in the garden.
I have also heard of people covering their plants with some netting so the squash vine borer wasp can’t reach your plants and lay eggs. While I haven’t tried this, it could be a good option for you next year if you want to give that summer squash another go.
Sadly, the squash vine borer is inevitable here in Central Texas so plant early, plant smartly with more tolerant varieties, and be (emotionally) prepared that this guy is going to show up.
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