Let's Talk Squash Vine Borer and BT

[Setec Astronomy]

Yes, the borers got both of my Delicata last year.

[Setec Astronomy]

Last year I saw a moth, then put out my Trece trap...this year I can't find where I put the lure, so I haven't put the trap out

Well, now that it's too late in the season, I found my SVB lure--IN THE TRAP. I apparently wrapped it all up very nicely in a ziploc bag including the receipt from where I bought it, and put it in the trap so it wouldn't get lost during the winter, except I guess I forgot I did that.

Not the first time I've outsmarted myself.

[Setec Astronomy]

So, this morning I confirmed that I have SVB in my Delicata, and while pruning them I saw some frass on one of the squash, so assuming it fell from a vine above, I wiped it off. What I found underneath was a hole:

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I decided this needed more investigation:

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I kept going:

PXL_20230909_132924396.jpg

Yup, a worm:

PXL_20230909_133121198.jpg

So the question is, is this a lost SVB? Or something else?

PXL_20230909_133156265.jpg

[JRinPA]

SVB or corn ear worm? I've never taken super close pics of either. To me they are just white worms that must die.
I'll have to check mine, I do lose some of those Delicata each year.

[Setec Astronomy]

Well, according to the Rutgers SVB page they will go into the squash, they even have a picture of a pumpkin with a hole in the side. I checked my other Delicata fruit, and found another one with a hole, probably the nicest one I have, I cut it off and put it in the refrigerator. I cooked the one from this morning, it was ok, not really ripe.

As others have mentioned, and what they said at the Rutgers page, which was also I think exactly the same as a UMinn page, is to plant a second summer squah crop after July 1 since they infer the ovipositioning window as three weeks from late June to mid-July. Not sure how that helps for winter squash...unless I grow big Delicata seedlings inside and plant out July 15.

I think next year I'll also put out the pheomone trap, maybe more than just the one I have now. The Rutgers page says usually one "crop" of borers per season, but sometimes two depending on the weather. Last year I'm pretty sure I had 2 rounds, this year it seemed to be only one.

[pepperhead212]

Many years ago, while I was still trying to figure out how to deal with the SVB, I planted some summer squash in mid September, after reading that they would no longer be present well before that. Even that didn't work! They still turned up in the plants, well before flowers. That was around the time I gave up on anything prone to them. Yet, a friend, about 2 miles away, never had a problem with these, or pepper maggots. I have never read anything referring to it, but I have a feeling that, like the pepper maggot flies, there must be a native host plant, which is why they are always in my area, even after I stopped growing squash for 10 years, and the SVB was there as fast as ever, when I resumed.

[Setec Astronomy]

Pepperhead, this is another one I have mentioned before, when I started growing vegetables, how did I get these plant-specific pests when I'm not aware that are other gardeners nearby? It's got to be one of 3 reasons--there ARE people growing vegetables nearby, or these pests come from far away, or as you say, there are some non-garden plants that are hosting them.

The other one that has surprised me is the fruit flies, which seem ever-present outside once you get some split tomatoes. I always considered them to be an "inside" pest brought home from the supermarket, but once I started growing tomatoes, they seemed to be an "outside" pest that I brought inside with me.

Circling back to SVB, I have only been growing squash for...this might be the 4th year I am growing, I know I tried some in 2020, but I think I may have skipped 2021, but last year was the first time I realized I had SVB. To your point about them being active in September, and as I mentioned earlier, last year somewhere along the way, I saw empty pupal shells on the surface of the soil (I have these in pots on my deck) and realized that the larvae had already hatched instead of waiting for next year. As I paraphrased from some of the ag extensions, you can have 2 generations per year "if the weather conditions are favorable", so it seems completely possible that you could have moths around in mid-Sept., depending.

[pepperhead212]

The problem I have with the pepper maggots is that native host plant - horse nettle - that is a weed growing around wetlands, and there is a creek less than 100 yards away from my house! Fortunately, those are gone around August 1st every year, or a little earlier, so I can uncover the plants, but nothing was that easy with SVBs! And I think that there has to be something else out there that the SVBs are living in, to show up in such huge numbers immediately after not growing for years.