What’s Bugging You? Red Lily Beetle

The Red Lily Beetle loves to feed on lilies and fritillaria. They will not attack daylilies.

If you grow lilies in your garden take a good look at the insect in the above picture.  Many of you may have already encountered this voracious lily eater on your property and the destruction it can leave behind.  It is called the Red Lily Beetle and be on the watch for it in egg, larval and adult form beginning in April right through to late September.

The Red Lily Beetle loves to feed on lilies and fritillaria. They will not attack daylilies. It was introduced into Canada from Asia in the early 1940’s and has been progressing westward ever since.  It has been in Saskatchewan for a few years but it’s worthwhile to remind new gardeners of its presence and how to identify it. 

Red Lily Beetles (Lilloceris lilii) will feed on any part of a lily above ground.  The adult is 8-10 mm long and can fly great distances to wherever there are growing host plants. 

 Photo Courtesy of Dr. Ken Fry; Entomologist – Olds College, Olds Alberta – Red Lily Beetle Eggs

Eggs

Cold weather in the latter part of September-October will signal the adult to burrow into the soil for a long winter nap.  They will emerge from the ground in late April to early May, fly for one to two weeks and settle down to feed and find a mate.  The females will lay red-orange eggs (1-2mm long) in batches of 12 on the underside of the lily leaves.  The eggs are usually laid in a crooked line.  Females can lay between 400 and 500 eggs over a three to four week period.   The eggs will hatch in 8-10 days.

 Photo Courtesy of Dr. Ken Fry; Entomologist – Olds College, Olds, Alberta – Red Lily Beetle Larvae

Larvae

Larva are white-yellow with a black head.  As a protective measure against predators and the hot sun they will disguise their bodies with their own feces.  They will first feed on the underside of the leaf and as they mature will move on to the rest of the plant.  This feeding frenzy will last for 20-25 days.  The larval stage is the most destructive stage of the red lily beetle life cycle.

 Photo Courtesy of Dr. Ken Fry; Entomologist-Olds College, Olds,  Alberta – Red Lily Beetle Larvae Covered in Feces

Pupae

When ready to pupate, the larva will burrow into the soil and its body will become orange in color.  It then will create a cocoon around its body and wait to become an adult.  This stage takes 21 days.  The adults will leave the soil and feed on the host plants until the fall. 

Photo: Pixabay

So what does one do about the Red Lily Beetle? 

Avoid chemicals if possible as they will also kill beneficial insects. 

Begin to look for the adults as soon as your lilies emerge in spring.  I would also spread diatomaceous earth on the soil around your lilies as they begin to grow.  If you have pets buy the food grade diatomaceous earth. 

Check the underside of leaves for the adults, eggs and larvae.  Pick them off and drop them into a bucket of soapy water.  Adults are especially talented at quickly dropping to the ground, black belly side up to hide or will just simply fly away.  They may also make a squeaking sound when distressed or feel threatened. 

Wash your packaged bare-root lily bulbs.  You can also soak them in a 10% regular bleach – 90% water solution for a few minutes.  

If you purchase potted lilies, unpot them over light- colored paper and check the soil for eggs, larvae and adults. 

A parasitic wasp lily beetle predator called Tetrastichus sefifer has been released in Ottawa and Southern Alberta in recent years.  This wasp is native to Asia and establishes quite well in areas where the beetle population is heavy.  It can tolerate our winters and have been successful in knocking the beetle populations back.

If the wasp is released in your area, do not use chemical controls.  This will kill the wasp as well.

Please report any beetle sightings to the Sask. Conservation Data Centre at

www.biodiversity.sk.ca/invasives.htm