Garden Web has an ORGANIC section. You will get a better answer there.

Here is one recipe I found with the search:

Garlic & Pepper Spray

Protect your garden plants from cabbageworms, caterpillars, hornworms, aphids, flea beetles and other chewing/sucking insects by routinely using a natural spray that you can make at home. The spray must be applied regularly, especially after a rainfall.
6 cloves of garlic
1 Tbsp dried hot pepper
1 minced onion
tsp pure soap (not detergent)
1 gallon hot water

Blend & let sit for 1 - 2 days. Strain & use as spray. Ground cayenne or red hot pepper can also be sprinkled on the leaves of plants (apply when leaves are slightly damp) to repel chewing insects or added to the planting hole with bone meal or fertilizer to keep squirrels, chipmunks, dogs and other mammals away from your gardens. Be sure to reapply after rain.

Search GW using "garlic spray recipe" for others. For SVB, I'd go with BT. Good luck.

I found a recipe and just used it the other day so I cannot say if it effective or not, but I am using it to deter the darn squirrels from eating - um I mean picking them off and the just leaving them. the recipe is
2 crushed red chili peppers (the hotter the better)
1 head of garlic
1 quart of water
Blend, strain with a chesse cloth and then add to your sprayer of choice.

Here is a link that might be useful: My Organic Garden Blog

"In place of Sevin or other chemical insecticides, some organic growers will use Rotenone, diatomaceous earth and Bt. They are fairly effective in controlling the larvae stage, but do nothing in hindering the adult in her egg laying activities. Since she lays her eggs singly, the chances of finding all of these single egg locations are very slim. Once the larvae is inside the vine, only extraction can prevent it from totally killing that section of the vine. Extracting the borer can be as injurious to the plant as the borer itself, and much care must be taken to prevent the entrance of diseases into the plant's system after the extraction. It is better to prevent the borer from entering in the first place, and this can only be prevented by deterring the adult moths.

Other non-chemical procedures which will help in reducing borers are fairly simple practices. Since the pupae overwinter in the top 1-5" of soil, frequent cultivation before planting will reduce their numbers later. Begin this in the Fall, and continue right up until planting. Also, burning infected vines will kill any active borers that are contained in them. These practices should be followed by any grower, regardless of using chemical or organic insecticides."

Here is a link that might be useful: Squash Vine Borer Fact Sheet HYG-2153-92

I saw my first SVB moth yesterday. Almost managed to kill it, I caught it in a butterfly net (an invaluable garden tool), but it was too quick and zipped out just before I stomped on it. I saw where it laid an egg. Reddish-brown, slightly oval, and sort of flattish. I searched my three summer squash plants and found and destroyed 8 eggs. I didn't find any on my winter squashes (the 3 kabochas are pretty big, but the butternuts are still a little small-- they got a late start this year -- and SVBs are said not to like butternuts much).

I'll search them again for eggs in a couple days. I've never had SVB problems before and definitely don't want to start. I think I'll dust the vines with Rotenone as well.