Row covers at the beginning of the season until they stop laying, but sometimes they don't. I just pulled up 4 plants, two healthy ones by accident, with vine borers in it, one plant with 3 in just one vine. It just goes to show you they don't stop laying so always be prepared and prevent them.

You can inject bt, but it didn't work for me. I rubbed them down in vics vaporub, the rub killed my yellow squash seedlings and didn't prevent anything. You can use paper mulch so they can't build nests under the squash to live in before boring a hole.

I companion planted nasturtiums with the squash plants and it did nothing as did the marigold. The marigold might have worked, but the ones I planted had apparently been bred for no odor, it's the odor that chases them away. You need mexican or french marigolds or you will not have a true feeling of its capabilities. I can't say it doesn't work, but next year I might because I'm only planting Mexican and French marigolds. Be aware that the marigolds don't bloom until June, so by then the bug will have already infected your vines unless you trick them into blooming sooner. You do this by putting them under lights. They bloom when they reach a certain amount of daylight hours. Stay away from nursery marigolds because they might be bred for low odor. Ask to make sure you are getting the right kind.

My family uses chemicals in their garden, seven dust, and none of them have had any problems with squash bugs and vine borers. I've heard some say even with it, they lost their plants. I haven't used it yet, don't want to.

If you really want to get scientific, I just posted a topic on this in the organic forum, The push-pull technology. It's a companion planting done with cowpeas and Napier grass that pushes the borer bugs away from the cowpeas, the napier grass planted on the outside of the garden pulls it in with a sappy molasses like excretion that kills them, and the ones that live are just stuck there until the parasitic wasps get them.

Parasitic wasps are natural predators. Hover flies are similar to those and are natural predators. Lizards and birds eat them, so do ground beetles.

My game plan is to plant goldenrod, cilantro, and several other plants to attract ground beetles for next year. Let some lizards go.

I read on another forum a guy used a bug zapper about 5 feet above the ground. It would attract them and/or frogs who would eat the bugs that fell out of the bug zapper.

Pick your poison, good luck.

scarletdaisies gave some great advice. The only thing I can add is rotation. I know that can be hard in a home garden, but sometimes it is the only way. Also, I read on another post that they take a shop vac and suck up the bugs which I thought was pretty smart.

I have the same problem so I feel for you.

Here is a link that might be useful: My blog post

I use silver plastic mulch on my squash rows, and that really seems to help, as does interplanting with nasturtiums and radishes. Neem oil is fairly effective for squash bugs; I'm not sure whether it does as much for borers. Rotation isn't enough to make a dent in the problem on its own because the insect responsible for the borer larvae flies. I always rotate and I still have problems, but the silver mulch and the interplanting seem to allow me to get some zucchini, at least. Last year I had a good harvest until mid-August, which was phenomenal for me. This year the squash bugs were a serious problem until I sprayed with neem, but it looks as though my tatume squash still succumbed to borers, although others are doing well.

Last year someone told me to use Vapo-rub on the stems and to wrap them in aluminum foil. It was too late to help last summer but this year I started using the rub on the stems as soon as they got any thickness to them and then wrapped them all in tinfoil.

I usually lose most or all of my squash plants to borer but this year I only lost 2 (out of about 20) and those two plants the foil had come off and I hadn't replaced it nor put the rub on recently. By the time they died they had also already produced quite a bit so I didn't mind as much.

I suppose the Vapo-rub (I use walmart brand) is not technically organic although it doesn't bother me since it is non-toxic enough to rub on our skin and so little of it would ever come into direct contact with the fruit anyway.
Certainly the foil is low impact--I even recycled used foil from the kitchen.

They took out both of my squash plants so I planted a few more and they got those too. I hate them.

I also read of one post saying he had none near where he planted bread poppies, but who knows. Poppies do have an opium type chemical that might scare away bugs, not sure why only the bread poppies worked, but it could be it was the only poppy he planted.

Pyrethrum daisies, shasta daisies, and painted daisies are professionally grown to for the pyrethin oil sold as an insecticide, so the pyrrethrum daisy is an early bloomer and the shasta nd painted are later bloomers, alternating the two around your plants might be an option. That's an experimental thing, but you just buy the pyrethrum oil or insecticide on the internet or at a local nursery.

The vics vaporub didn't work for me, but I also used too much, don't glob it on in spots. I thought I smeared it, but found a glob rotting the plants. I still have the newly planted acorn squash, it might be squash vine borer resistant.

If flowers do nothing else other than attract beneficial insects, go that route. They tested several different fields of squash, one letting parasitic wasps handle the bugs, one the damacius earth, and one with nothing. The wasps did better than the two, with the other two fields getting nothing out of them. The damacius earth got 30 percent of it's yield if I'm not mistaken, but the plants died.

That's why even a flower that doesn't repel bugs will help just by attracting the right predators.

I hate them too; I've dug 3 borers out of my one remaining zucchini plant with a paring knife. I covered the part of the vine I operated on with potting soil and vine has not died but I think it is only a matter of time. I'm going to go to the Indian store today and get some neem oil and try that next year.

I haven't seen bore holes yet but I've seen moths twice. Tried to whack the bastards with a trowel but missed.

I had success injecting BT at the first sign of stem damage last year. My squash all produced to the end of the season, though one had a heavily damaged stem-->

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Believe it or not that squash was still producing.

This year I'm also spraying weekly with neem. Supposedly it does give some systemic effect, though I doubt it's enough to kill borers once they're in the stem.

For vining squash, melons and cukes (which are, it is true, more SVB resistant than vertical squash) I been trying BURYING the main vines in mulch. That has the beneficial effect of holding in water, and also seems to prevent SVB infestation. That is, if the SVBs can't get to the vine, they can't do bad stuff to it. Just throw a load of mulch over the plants, and brush it off of the leaves.