There are a number of powdery mildew resistant summer squash (C. Pepo) these will be newer hybrid cultivars. Only the C. moschata (butternut groups) and to a lesser extent C. mixta ( Cushaw group) are resistant to SVB. Mostly these are considered winter squash. Trobocino is often grown as a summer squash.

edster,

After battling SVB last year, I shifted all squash this year to moschata varities and have had no problems. My neighbor lost all his zuccinis to borers. Also, I have had no powdery mildew problems (yet), but it has been an unusually dry summer, which perhaps explains this.

I grew the Tromboncino (also known as Rampicante) mentioned by farmerdilla. Everyone agreed it tasted very good, and it is amazingly productive. It is best grown on a large trellis, if you want straight squash. You can pick them young (say, under 12") or let them get big -- and they will get really big! I have decided to make this my standard summer squash from now on.

I also grew a small Japanese pumpkin, Futsu, (again a moschata variety) and again have had no borer or mildew problems, though this pumpkin wilted a lot in the heat and probably would have done better in a spot shaded from the afternoon sun.

I believe there are two reasons why moschata varieties are resistant to borers: (1) the stems get very hard making it hard for the borers to get in; (2) the plants root at nodes on the stems where they touch the ground, thus providing additional sources of nutrition to the growing squash, in the event that you do get borers.

You might also consider the "Costata Romanesco" zucchini. It's a sprawling plant that runs along the ground. I gave up growing other squash because of the SVB but they don't bother Romanesco. I've never had a problem with mildew either but I don't think it's resistant. Just be sure to give it plenty of room.

Here is a link that might be useful: Costata Romanesco Zucchini

Thanks to all for the feedback. I have heard Tromboncino mentioned a few places. Is it also resistant to powedery mildew?

No, but powdery mildew is easier to control than SVB. Powdery mildew needs humid weather to do its thing so some years it will be bad and some years never make an appearance. Many fungicides will stop it including baking soda.

All 6 of my Costata Romanesco were totally destroyed by SVB. full of them. I did get a few nice squash and they cook up real nice. But CR is a c pepo and the SVB attacks.

You can take care of powderly mildew with Serenade. I hear one aspirin per gallon water sprayed will also work. Hydrogen Peroxide will kill the spores. PM must be fought as a preventive. nothing will get rid of it once it gets deeply established into the leaves. butternut seems more resistant than pumpkins for example.

By the time I see PM the season is pretty much over and I never bother with it. it might look terrible but it seems to NOT hurt the squash. about the time it overwhelms the vine the season is over. it usually hits the pumpkins more than anything else.

Powdery mildew is rampant in my spaghetti and buttercup squashes right now. I'm close enough to the coast that the fog comes in at night and creates perfect conditions, no matter how warm and dry the afternoons. I'm going to have to forego some of the heirloom varieties and go for butternut and resistant varieties only.

SVB like my "Costata Romanesco" zucchini.

Interesting about the SVB liking Romanesco zukes. This is only my 2nd yr growing them but a friend near by has grown them for several yrs w/o a problem. Any other squash I've grown has been decimated by the SVB before I ever get a squash from them.

My Romanesco zukes were destroyed by SVB last year. This year I planted ordinary zuchini and covered it with Remay until July 5th. No problem with borers - only problem is keeping up with picking!

The SVB even invaded my butternut this year, and they aren't supposed to do that! Just got a real grouchy bunch of SVB this summer in North Carolina.

The SVB like my Romanesco too. I probably got more borers in that plant than in my regular zucchini! I have to say it was probably the tastiest summer squash I've had so far -- I hope I get a few more before it kicks the bucket :(.

You can look for eggs every day, but it seems you can't find them all.

I found several borers in my Rampicante (dug them out of course), but comparatively not many; for the most part it's pretty unscathed. I also picked off a lot of eggs, but not nearly as many as on some of my other squashes.

Even picked a few eggs off watermelon. The SVB are very bad here this year!

Mel

I ordered my Tromboncino seeds this weekend. I am looking forward to a squash that will not succumb to the dreaded SVB. I also ordered some Black Futsu... not sure that I have the space for that one. Also, what is the best treatment for powdery mildew, as I usually have a problem with that.

Thanks to all for their feedback.