Patty O'Hearn Kickham: Attack of the Lily Leaf Beetle!

Two years ago I was distressed to find these brightly coloured insects chowing down on my Oriental and Asiatic lilies. To avoid using pesticides I removed the beetles and foolishly relocated the plants to another area in the garden. I thought I had gotten rid of the pests since my lilies seemed to recover in the new location. I had convinced myself that I had outsmarted the troublesome bugs. Problem solved, or so I thought.

Much to my dismay, the pests returned the following Spring in even greater numbers. My precious plants were covered by the hungry beasts. After a bit of research, I discovered that they were Lily Leaf Beetles (Coleoptera: Chrysomelidae). Even though they are considered a minor pest, they were certainly a major problem in my little corner of the universe!

Once again, I resisted

the urge to use a pesticide. I diligently followed the instructions on the University of Guelph’s site, squashed the insects and manually removed as many of their eggs as I could see. There wasn’t very much left of any of my lilies and most of my Stargazers, fragrant, Oriental and Asiatic lilies failed to produce any blooms. I left the plants in the ground and this time did not do any transplanting. I certainly did not want to move the beetles to a new home to start all over again!

Winter finally passed and with the arrival of warm weather, the lilies began to emerge from the ground. Shortly after the leaves appeared, the beetles returned, but in far fewer numbers than the previous year. I repeated the process of killing the beetles and washing any eggs from the undersides of the lily leaves. To date, there is no sign of further infestation or damage. I check the plants daily and carefully look for any new visitors. Healthy buds are on the plants and that leads me to look forward to those wonderful blooms! So far so good! Keep your fingers crossed for me. (All photos by Patty O'Hearn Kickham 2010)

For more information on the Lily Leaf Beetle, visit the University of Guelph’s Pest Diagnostic Clinic.