I have been picking and drowning these monsters by the thousands for 3 years but they persist. Is there some type of trap that I can make? I have a large property so could attract them away from the the poor peonies, roses and lilies.
Thanks for your help.
Thank you for contacting Toronto Master Gardeners, some nurseries offer traps for rose chafer beetles and there are some companies selling organic based traps online. Some other strategies to control rose chafer beetles include:
Drenching the soil with a parasitic nematode to kill the larvae living in the soil;
Erecting a physical barrier, such as cheesecloth or floating row cover around them. The barriers should be placed when the rose chafers become active and then taken down after they are done feeding (after June); and,
Applying pyrethrin (an organic control) when there is a severe infestation.
For further information please refer to these links