Adult beetles migrate to wooded, bushy areas, crawling under bark and litter to overwinter. Removing leaf litter back to bare ground and cultivate soil if possible over winter to expose adult beetles. Unfortunately these beetles have a fairly decent range so may fly to your property from as much as a mile away. A period of several years not growing squash cucumber may reduce infestations to managable levels. Unfortunatly I believe these beetles also feed on beans peas as well.
Natural predators include soldier beetles, tachinid flies, braconid wasps and certain nematodes.