How to Rid Cannas of Japanese Beetles

The Japanese beetle is actually attractive, for a bug. It has a shiny green body with brown wings. Unfortunately, what it has in looks, it lacks in decorum. Japanese beetles are attracted to the scent of the canna's flowers, then they munch on the leaves. First, however, they release a pheromone, inviting other Japanese beetles to the feast. Sometimes there are so many beetles clustered on the canna's foliage, the entire leaf is covered. Take action in the spring to get rid of the larvae and then deal with the adults in July.

Things You'll Need

• Insecticide soil drench
• Bucket, 4 qt.
• Dishwashing soap
• Insecticide

Instructions

1. Use an insecticide soil drench, listed for use on Japanese beetles, in the spring. Use it not only on the soil around the canna, but any adjacent lawn area as well. This will kill the larvae.

2. Fill the bucket with warm water and add 2 tbsp. dish detergent.

3. Take the bucket to the garden in the early morning and remove the adult Japanese beetles from the canna by hand. Drop them into the soap mixture in the bucket. This not only kills the beetle but stops the pheromones from attracting additional beetles into the garden.

4. Battle larger Japanese beetle infestations of your canna with insecticide spray. Call your country cooperative extension office to find out which insecticides are registered for use against the Japanese beetle in your area. Follow the directions on the label of any product that you purchase and reapply if needed.

References

• Penn State: Japanese Beetle on Ornamental Plants
• University of Illinois Extension: Japanese Beetles
• State of Connecticut: Canna