Hi, I live in Northglenn and found the Japanese Beetles yesterday July 31. While looking for more I found them on my grape vines. So far I'm pushing them off the leaves into a glass of rubbing alcohol. This is the first year I have seem them. Any advice? Thank you Diana Gamble
Since I sent this email I have also found them on my peach tree and am pushing them into the glass of rubbing alcohol. Are my grapes and peach tree doomed? I have my own little echo system in in my yard so I do my best not to use poisonous chemicals.
Adams County Colorado
I'm sorry for the slow response to this.
Japanese beetle is a growing problem in the north metro and there are no easy solutions. Handpicking like you are already doing can help, especially if you are on top of it early in the season. It won't totally eliminate feeding but can reduce it. You can use soapy water instead of the alcohol if you like.
Other options include, neem based products which will provide a couple of days of control (spray early in the morning or late in the evening when pollinators are not around), Kaolin clay based products which discourage feeding (uniform coverage is very important) and products containing Acelepryn which is a very low toxicity and narrow spectrum pesticide. We have a fact sheet that goes into more detail about the issue which can be found here: https://extension.colostate.edu/topic-areas/insects/japanese-beetle-5-601/
I hope this helps, please let me know if you have further questions.