I will offer some general information that may or may not take care of this particular beetle. If you have been using chemicals then the soil isn't healthy and pests can have a population explosion because things are out of balance. There is a remedial prescription for "sick trees" that would work for your lawn - just don't do the tree part (unless you have sick trees in your yard!)
http://www.dirtdoctor.com/Sick-Tree-Treatment_vq4586.htm Steps three through five will help get your lawn into a healthier place. Once your soil is healthy you'll find you are less likely to have blooms in populations of pest insects because the natural predators are present. If you could only do one thing, then spread the dry molasses, but if you can do at least one application of the zeolite, greensand, lava sand, and cornmeal you'll give your turf a boost. The sick tree treatment is meant to be performed more intensively than you might want to do for just your lawn alone. If you spray monthly with the compost tea (there is a commercial version called Garrett Juice) your lawn will be more resistant to pests.
Here are some of the recipes for homemade organic products, including garlic pepper tea, compost tea, Garrett Juice, and the vinegar and orange oil herbicide that has become very popular.
Rather than focus on that one insect and look for a product to kill it, look at that insect as a harbinger of a problem in the lawn or garden that can be remedied with an overall organic treatment. With the rain you're having, you may at some point decide you want to spread an application of beneficial nematodes. Don't it in the sunshine or heat of the day, it needs morning or evening coolness and moisture so the nematodes can get into the soil. They'll eliminate the larval stages (in the soil) of a variety of garden pests including cutworms, fire ants, hornworms, various beetles, and more. See the package instructions for how to apply for various pests.