I am not a violent person, but I am seeing red. Invasive, non-native red lily beetles are eating my Asiatic, trumpet, Oriental, and tiger lilies. I have been at war with them since they entered my gardens. I have become an expert at catching the crafty little buggers, and crunching them in half between my thumbnail and index finger has become disturbingly satisfying.
Liliocerus lilli, AKA scarlet lily beetles, red lily beetles, or lily leaf beetles, are native to Europe and Asia where a natural wasp enemy keeps them in check. Those wasps don’t exist in North America. The beetles first appeared in Canada in 1945, and then in the U.S. in Massachusetts in 1992. I suspect they entered my gardens around 2017 when I noticed my trumpet lilies were missing leaves and not thriving like they had in past years. Those tall lilies were in the back of the garden behind other plants, so it was a while before I discovered tiny red beetles. I have been battling them ever since. The adults, and especially the larvae, devour lily leaves and buds, leaving nothing but a bare stem. Without leaves to send stored energy to the bulb, the plants get weaker and weaker until they eventually cease coming up in the spring.
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Red Lily Beetle Life Cycle:
Eggs: These are teeny, tiny orange or brownish ovals. The adult beetles overwinter in the soil and emerge in early spring as the lilies begin to sprout up. They start munching, mating, and laying eggs. The eggs are always located on the underside of the leaves, so the only way to see them is to tip the leaf over.
Warning: If you are easily grossed out, you may not want to read any further!
Larvae: This is the thoroughly repugnant stage. As if slug-like larvae aren’t revolting enough, these ingenious little vermin cover themselves in feces. And since the larvae voraciously eat for about 3 weeks, they produce a lot of poop. It seems their main defense mechanism is to be so disgusting that nothing wants to touch them.
Adults: The larvae burrow into the ground to pupate. About 3 weeks later they emerge as adults, and continue to eat.
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When I first began researching lily beetles, I rolled my eyes upon reading the best defense is to not plant lilies. That was not an option for me. Some of the first plants I planted around our new house way back in 1994 were Asiatic lilies. I have added many more varieties in many different flowerbeds over the years. I simply love lilies. The only variety of lily that seems to be immune to this beetle are daylilies.
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Control: I keep fighting the battles (who knows if I’ll win the war)
As a general rule I don’t use insecticides in my gardens because I don't want to risk harm to bees and butterflies. If you want to control lily beetles that way, you’ll have to do your own research. My method is crushing the eggs, larvae, and adults.
Adults: When I first began the fight, I would crush the adults between two rocks if I caught one of the crafty little buggers. The adults’ main method of defense is evasion. They often hide in the unfurling leaves at the tip of the lily. If they are munching on lower leaves and sense movement, they immediately drop from their perch, and get lost in foliage, or camouflaged on the ground lying on their backs with their black bellies up, or crawl into the dirt. I’ve learned to go at them from above with one hand, while cupping the other below them and they fall right into my cupped hand. Occasionally they’ll fly away, but that’s rare. Their shells are very tough, and although at first I was squeamish about crushing them with my fingernails, now I find it the fastest and most effective way do deal with them. I’ve read you can also drop them in soapy water like Japanese beetles, but even though I despise them, a quick death seems more merciful than a slow, torturous death.
Eggs: Running a finger over the eggs easily squashes them. The hard part is locating them, and it’s a time consuming process because you have to look under each leaf.
Larvae: Originally I couldn't bring myself to touch the feces covered grubs. I would scrape them off the leaves with a twig, then squash them between two rocks. This took time, and time is a premium commodity with so many gardens calling me. I have discovered that with a simple pair of close-fitting nitrile-covered gardening gloves, I can slide the brown, squishy mound off the leaf and crush it with my fingers. It’s slippery and might slide around a little, but when I feel them pop I know it's one less beetle I’ll have to contend with.
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I don’t always win the battles. An Asiatic lily sprouted up surrounded by a large lupine plant in the spring. By the time I discovered it when I was cutting down the lupine seedpod spikes, all the foliage had been stripped from the stem, but there were no signs of larvae. I know they are pupating underground as I write this. I’ll be waiting for them to emerge from the soil with my thumb nail and index finger locked and loaded.