Japanese beetles are devastating my veggies. Not surprising, really, since I did have a severe outbreak of grubs—from which Japanese beetles develop—in my vegetable garden’s soil over the last two months. The grubs (the larval form of the beetle) have now grown up, emerged from the ground and become the devastating chewers that they are. First they destroy roots underground as larvae, then they finish off what they started by eating leaves.

Signs of Japanese Beetle Damage

Japanese beetles feed on the tissues on plant leaves that are located between veins. What they leave behind is something that looks “skeletonized,” with just the veins remaining on the leaf. The plant may be able to recover if new leaf shoots emerge along the stem at the leaf/stem junction (known as an axillary bud). The beetles eventually do leave, so those axillary buds may be your chance to resurrect your plants.

Controlling Japanese Beetles

Control damage from Japanese beetles in several ways. From short- to longer-term control, those strategies are:

Hand removal. Japanese beetles are slow and easily caught. Pluck them off the plants and pop them in a bucket of soapy water.

Insect barrier. Place screening, insect barrier netting or a floating row cover over your plants. Secure the netting/screening against the soil so the beetles cannot crawl under.

Beneficial nematodes and milky spores. These are longer-term control measures I mentioned nematodes in a previous post. Treating your soil with beneficial nematodes and milky spores will control the grubs in the soil from which beetles develop.

I have heard mixed reviews about beetle traps that use pheromones as the beetle attractant. Some say the traps attract more beetles to the area than one would have had without the trap. For my purposes, I’m going to concentrate on the first three control methods and leave the traps for folks who find them useful.