Asked July 25, 2019, 5:30 PM EDT
Arapahoe County Colorado
The fight against Japanese beetles is fought on two fronts: the larvae found in irrigated lawns and the damaging adults that feed on over 300 species of plants.
CSU has provided a great Fact Sheet on Japanese beetles. Pay special attention to Table 2, as this explains the different insecticides which vary considerably in features such as how long they can persist and control beetles, what plants they can be used on, whether they move systemically in the plant, and their hazard to desirable insects, notably pollinators.