We are growing raspberries in our suburban Toronto backyard. Many leaves of our plant are slowly acquiring small holes, then start to turn pale grey-brown and shrivel up. Please see the attached picture. We suspect that the beetle in the inset of the picture might be responsible for this. Could you please give us some advice concerning how to tackle this problem? Many thanks!!
Thank you for your inquiry. From your photo it appears that your raspberries are being attacked by japanese beetles. Japanese beetles are approximately 13mm long, and are metallic blue-green with coppery wing covers. Like the grubs of other scarab beetles such as June beetle and European chafer, the Japanese beetle grubs are milky white, “C”-shaped grubs about 2 cm in length. The larvae of scarab beetles feed on turf roots. Please refer to the following Ask a Master Gardener post onjapanese beetlesfor a detailed plan on how to control both the larvae and the adult beetles.