Is there a recommended deterent or insecticide for Japanese Beetles
Kalamazoo County Michigan
In a home garden, hand-picking beetles and dropping them into a bucket of soapy water is the best solution. Pheromone traps will attract lots of beetles and are not effective at eradication.
Pyrethrins and neem oil can be sprayed on leaves but must make contact with the beetles to kill them. Both of these products have less negative effects on beneficial species. Broad-spectrum insecticide options such as pyrethroids or carbaryl will provide longer protection against japanese beetle but are highly toxic to bees.
Since the larval life stage of Japanese beetles feeds in turfgrass as grubs, you may have greater success at treating your lawn with a curative insecticide in September to prevent newly hatched grubs from becoming adults in the following season. The bottom of this page provides more resources about Japanese beetle eradication in turfgrass: https://extension.umn.edu/yard-and-garden-insects/japanese-beetles#when-to-treat-1592860