Gardens & Beetles: An Invasive Insect

Written by Master Gardener Volunteer: Amanda Koran

“The second bug is the red lily beetle. The red lily beetle is an invasive pest that was accidentally introduced to North America in the 1940s. It has been reported in the United States since 1992. There are no naturally occurring predators of the red lily beetle in the area. Adult beetles overwinter in the soil or leaf litter emerging in the spring to lay eggs. Eggs hatch after 1-2 weeks. Once hatched, the larvae feed for around 3 weeks before becoming adults.

Red lily beetle's foods of choice are Asiatic lilies oriental lilies, tiger lilies, Easter lilies and fritillaries. They also will feed on Solomon seal, Lilly of the Valley, hostas, hollyhocks and potatoes. They can cause extensive damage to the leaves, stems, buds and flowers of affected plants. They don't seem to bother day lilies.

Currently, in the garden, we are trying to keep our population under control by hand removing any red lily beetles that we see. When looking for pets, it's important to check under the leaves. Often you will find the pest or eggs attached to the underside of leaves.

Something to keep in mind when you encounter an insect that is causing you problems in the garden is that less than 1% of the insects we encounter are problematic. Often there is a beneficial bug that keeps the problem in check if we give it a chance to do it's job. If pesticides are used it is important to follow the directions on the label and to apply when it will have the least effect on our beneficial bugs. Unfortunately, the same chemical that gets rid of a problem bug can also take out a beneficial bug.”

We are lucky to have received some beautiful photos of her findings.

Reference sources: Attracting Beneficial Bugs to Your Garden: A Natural Approach to Pest Control by Jessica Walliser

https://www.canr.msu.edu/news/lily_leaf_beetle_watch_out_for_this_garden_pest