Japanese beetle larvae are prone to desiccation (death by drying out). A big part of why they are so problematic is because we create an abundance of habitat for them with our expansive, over-irrigated lawns. Consider switching to a more drought tolerant turf species, like fescue or buffalograss. Most CO lawns consist of kentucky bluegrass, which is not that drought tolerant. Allowing the turf to dry out between waterings (and selecting a turf species that can withstand this drying out while still looking good) will cause the Japanese beetle larvae to desiccate and die. This fact sheet covers the pros and cons of various turf species.

https://extension.colostate.edu/resource/turfgrass-species-selection-guidelines/

This fact sheet covers other control measures for Japanese beetle. Consider biological controls such as nematodes or grubGONE! as alternatives to neonicotenoid insecticides (e.g. GrubEx)

https://extension.colostate.edu/resource/japanese-beetle/ 

This link shows lists of plants organized by how much Japanese beetle damage they experience. Use them to inform any non-turf plantings. 

https://douglas.extension.colostate.edu/horticulture/publications-2/