Where Squash Bugs are known to be problems the best defense is to cover the plants with Floating Row Covers to keep them away. Poisons, such as Carbryl (Sevin), tht are very broad spectrum will kill off any predators of these wee buggers and probably not do much harm to the target insect.
Other means of control can be spraying the plants with a kaolin clay mixture, apparently changes the appearance of the plants so the squash bugs do not recognize them and intercropping so the squash bugs are confused by the many different plants and do not know which ones to go after.
Perhaps the link attached will be of some help.

Here is a link that might be useful: Squash bug control