Understanding the lifecycle of a garden pest is the first line of defence. Knowing how to spot lily beetle eggs, recognizing their rather disgusting looking larvae and having a simple method for eliminating the adults can go along way to having better looking lilies in your garden this summer! In her second post, Jean Godawa tackles the subject of lily beetles.
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| Lilioceris lilii |
Like street lights, stop signs or fire trucks, the bright red colour of lily leaf beetles (Lilioceris lilii) certainly attracts our attention. The beauty of this insect, especially against a leafy green backdrop, becomes irrelevant however, as you see the damage it causes to your lilies.
Lily Beetle Eggs
After spending the winter protected from the elements, adult lily leaf beetles emerge in the spring, coinciding with the emergence of lily plants. They mate then lay orangey-brown lines of eggs on the underside of lily foliage. These pests can lay over 400 eggs in a season.
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| Lilioceris lilii larva |
When the eggs hatch, the orange larvae feed under dark shields of their own excrement. Well protected from predators, the immature insects grow and continue to damage the plant.
Healthy Lilies
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| Defoliated lily with buds intact |
Several adults and larvae together can completely defoliate the lilies in your garden.
After a few weeks, the larvae drop to the soil where they pupate for a few more weeks then become adults. In the fall, this new generation will seek out shelter or burrow into the soil to overwinter. The cycle begins again in spring.
The best defence against these red nuisances is to destroy them before they have a chance to lay eggs. If you’ve been plagued by lily leaf beetles in the past, keep watch for the emerging adults as soon as your garden starts to wake up in spring.
Hand-pick the beetles off your plants and squish them between your thumb and forefinger. Don’t worry, they won’t bite, but you have to be quick. When disturbed or threatened, the beetles drop to the ground on their backs. The underside of these bright red creatures is black and blends in well with the soil.
If the thought of squishing bugs is too unpleasant, you can drop them into a bucket of soapy water to destroy them. Where space permits, shake the plant gently over the bucket to get rid of any beetles you can’t see.
If you missed the opportunity to find the adults and there are already gooey black larvae munching away on the plants, you can hand remove those as well. Where several larvae or eggs are infesting a leaf, or if you just can’t bring yourself to squish poop-covered creatures, it might be more effective to just cut the leaf off, if the plant is otherwise healthy and robust.
Lily beetles are not originally from North America so there are no natural predators here to keep the population in check. A tiny parasitic wasp from Europe is being studied as a potential control agent for this introduced species.
We’ve been conditioned to recognize red as a warning colour. Whether by natural design or coincidence, bright red lily leaf beetles warn gardeners that their lilies are in danger.
About Jean Godawa: Jean is a science teacher and writer. She has been writing science-related articles for print and online publications for more than ten years. Jean holds a degree in biology and environmental science with a focus on entomology from the University of Toronto. She had conducted field research in the tropical rainforests of Asia and South America.
About Jean Godawa: Jean is a science teacher and writer. She has been writing science-related articles for print and online publications for more than ten years. Jean holds a degree in biology and environmental science with a focus on entomology from the University of Toronto. She had conducted field research in the tropical rainforests of Asia and South America.
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