When I do my daily rounds collecting Japanese beetles and other unwanted insects in the garden, I catch them using a bag with an opening diameter of about 6 inches (15 cm) and at least 1 foot (30 cm) long, like a bread bag.
By folding the edge of the bag over my fingers, I can turn it into a funnel and control the opening. The insects fall to the bottom and can’t get out.
When I’ve finished my harvest, I just seal the bag and put it in the freezer. The insect pests quickly fall into an eternal sleep.
The next day, I empty the bag in the garden, on the lawn or in the compost where they can decompose and enrich the soil, thus turning an enemy into something useful.
It’s less cruel and more ecological than most other insect control methods.