Oh dear GOD. I am in zone 7A outside NYC, NY. OK I will start looking on Houzz. It does feel like I cannot defeat them.

The folks at Cornell University can probable give the best information for your area. Here they are prevalent from late June through September. I usually get all the summer squash I want by planting in April. Would not work for you. I helps to remove all plant debris over the year and till the soil so the pupa are exposed during the winter. That way you can reduce the numbers to the migratory ones. Contact insecticides applied when the moths are present will destroy the eggs. Once the larva hatch out, Bt injected into the stem or surgical removal of the larva from the stem Is often used but not overly efficient. As Dan said, Row covers and hand pollination are very effective against the migratory moths. Does not protect if pupa have over wintered in the soil.

"Oh dear GOD" is exactly what EVERYONE says about SVBs, and it does really feel like they cannot be defeated. In my opinion, SVBs are by far the worst garden pest. That being said, they don't live in the western U.S. So summer squash there is pretty much just a matter of dropping seeds in the ground and standing back. Been there, done that. Those were the days. Sigh ...

For pupae that have over-wintered in the soil, it is said that upward-facing cone cups around the stems shield them from the emerging moths. Of course, if you have row covers over your plants, you've then just locked them in. It's hard to win.

I've been fighting the SVB for years, and have learned to live with them, because they are well established. I'm still able to grow many pumpkins and squashes, but it take a little extra work,

In the Spring your best bet is to start them real early indoors, and bring them out in mild days or use some grow lights. Until the danger of a hard freeze is mostly passed, then I put them in the ground and have a tarp or other cover handy in case of a light freeze or frost. Usually I am able to get a good head start and by the time the SVB start doing damage, my plants are huge, have already started producing, and can survive the onslaught much better.

I dont bother planting for summer cause its too hot here and the SVB are too bad.

For fall, I will start the seeds directly in the ground late summer, but put up some row covers. I use a large sheet of tulle netting. Its cheap and comes in 108in wide rolls. I keep the plants under cover as long as I can, and when I remove the cover, the plants are large and well established, and the SVB populations are going down by then,

I've tried everthing else in the past and none of it really works, Injecting with BT works somewhat but its very tedious. The other thing that does REALLY help, but with vining plants such as pumpkins, is to bury the vines as much as possible as they grow out. Its tedious but it really helps the plants survive the SVB attacks much better.

I might add that to the extent the SVBs aren't quite endemic for you, in that you successfully avoided them for many years, you might be able to get back there by NOT PLANTING SQUASH for a few years. Every year you plant squash that is killed by SVBs, new larvae are deposited in the soil that will come back to bite you next year. If you skip a year or two, you might be able to press reset on them.

If you pay the shipping costs, I can send you many many many squash! Anywhere from 6" to 3'!

I'm thinking just go to the farmers market.

Hi @nancyjane_gardener! Thank you... I really like to grow the summer squashes for the flowers and the tender leaves for making a kind of spicy asian style pesto/pate. I like the squashes too but even good, tender squash are not too hard to find.

I ask you all: I now see several YT videos, some with big following, where the gardener injects the bacteria Bacillus Thuringiensis var. Kurstaki in the stem every few days. Sometimes at very high concentrations, sometimes diluted. These people claim this method of control totally works for them. Not one person said any plant died or got sickly. Have any of you tried this??? I certainly will try it next year.

And: @daninthedirt (USDA 9a, HZ9, CentTX, Sunset z30, Cfa) about the reset: If you meticulously follow what is going on with your squash and at the first sign of infestation you cut open the stem and kill the larva(e) and or completely destroy the plant aren't you getting rid of this insect from your soil/garden? Those larvae in the stem will not pupate and reach adulthood. So no (or much less) adult SVB parents next season. Right?

Attacking with bacteria should work but it sounds too easy.

Thank you everyone!

If you're sure that you've killed every single SVB, I guess you can consider your garden free of them. If you closely inspect your plants and destroy any infestations religiously, you might have done that. That, and repeated injections of Bt might do the trick as well. Bt sprays certainly don't help. All this is a lot of work, and if you're up for a lot of work you might just use row covers, making all the work somewhat simpler, if not easier. Of course, row covers can prevent SVB infestation for a whole season, so would be just as effective against them as not planting any squash. That being said, SVBs deposited in the soil the previous year will just be trapped under those row covers. So some care is in order.

Unfortunately, up north you don't have the option of just waiting them out. That works wonderfully down here. My growing season is 300 days, so if I throw away 60 of those, who cares?