I've been organic for 15 years now- never had an insect problem go so out of control as the squash bugs this year- they are EVERYWHERE! they've killed all the squash and zucchini...now they have moved on to the melons...nothing has deterred them- any suggestions?!?!?!
I have been going nuts with them this summer too. I started by picking the adults off by hand and scraping the eggs off the leaves with my fingernail, and then dropping the critters into a jar of water with a little soap in it to break the surface tension so they'd drown more quickly. But the leaves got too big and numerous. So I got some 100% neem oil spray and applied it to as thoroughly as I could to the tops and undersides of the plants, and also to the base. According to someone who was quoting from an article, it's an anti-feedant, oviposition deterrent, a growth inhibitor and a mating disrupter.
Here's the recipe for spray that "Tapla" on DG uses. You can see that you need very little of the oil:
Neem Oil Spray
Here is what 'tapla' uses for spray, would be safe for food related plants.
1 pint rubbing alcohol
1 pint very hot water
1 tsp pure, cold-pressed neem oil
3-4 drops Murphy's oil soap
Add neem & soap to hot water & shake well. Add alcohol. Spritz plants thoroughly, covering all surfaces - especially underside of leaves & leaf axils. Be sure to shake vigorously as you use the spritzer to keep the neem mixed with the solution. Works great - the neem oil renders all the insects it contacts unable to complete metamorphosis or reproduce, while the alcohol provides reasonable knock-down for current generations.
Previously I sprayed the plants/leaves with Neem oil and it kept them back. I did it twice early in the season and didn't have problems late in the season, so I didn't need to re-apply after that. I also squished eggs on occasion.
Anyway, it's probably too late for you this year, unless you can replant, but if you use the neem oil it should supposedly keep the population in check for next time.