The squash-vine borers have been destroying my zuc and pumpkin vines. Any ideas how to avoid these pests without using chemicals ?

NON CHEMICAL TREATMENT

NON CHEMICAL TREATMENT

The above two websites give information on how to combat Squash Vine Borers without the use of chemicals.

I really hope it helps but I must say that I am not the worlds best gardenner.

This is a "chemical" of some sorts - but it is a natural option. It is also allowed in organic gardening, so may be a good option for your "non chemical" intent.

The product is by a company called Safer and the product is BioNeem. Here is a URL that gives some info. I've used it on a couple of bugs that the garden center told me are relatively new here and are immune to alot of other things. It works by numbing the mouth and they cannot eat and they die and will also keep eggs from hatching.

http://homeharvest.org/BioNEEMInstructions.htm
http://homeharvest.org/insectsprays.htm
http://www.colostate.edu/Depts/CoopExt/4DMG/VegFruit/organic.htm