My roses and vines were decimated by Japanese Beetles for the 3rd summer. I've avoided the pheromone bags, but is there anything that we can do to diminish the attack? I saw a flyer about Milky Spore on your lawn to destroy the grubs. Any truth to this for CO? Thanks
Arapahoe County Colorado
Milky spore, a bacterial disease of white grubs (larvae of Japanese and related beetles) has not been well established in Colorado. So it might be worthwhile to use - but it will only kill maybe 10% of the grubs - if there are any in your lawn/yard.
Since adult Japanese beetles can fly a couple miles to food sources, it is a sure bet that the ones you had this year were not "born and raised" from grubs in your lawn/yard.
Here's some Japanese beetle info from CSU Extension: http://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601/