Ken Fry is well known in the world of bugs. He is head of Olds College’s Entomology department and curator of their extensive bug collection. He has also co-authored a book “Garden Bugs of Alberta” which should be on every gardener’s shelf
At present time, Ken and the college are involved in a study to control or eradicate the Lily Beetle in Alberta. This beetle was first discovered in Airdrie in 2004. In the past 14 years, it has spread north and south along the Queen II corridor. If left unchecked, it will continue to spread decimating the lily population.
The Lily Beetle has a bright red to scarlet back with a black head, legs and underside. They are narrow at the shoulders and range in size from 6- 8 mm long.
Adults overwinter in the soil emerging the last part of April to mid-May, at the same time as the lily emerges. The insects mate and lay a line of tiny reddish orange eggs on the underside of lily leaves.
In mid-June, the yellowish white larva with black eyes emerge from the eggs and start feeding on the underside of the leaves. As the larva grows so does its appetite. The Lily Beetle covers itself with its own feces as protection from predators. If left unchecked larva often consume the complete plant; leaves, buds and flowers. Without leaves the plant cannot replenish the bulb.
By mid-July the larva have burrowed into the soil as a pupa to emerge as an adult at the end of August to continue to feed on lilies. Mid-October they burrow back into the soil and repeat the cycle next year.
Small infestations can be hand-picked as adults, larva or eggs. Watch the lilies as they emerge for red insects that DO NOT have spots. Look at the undersides of leaves to remove eggs. During the summer months, check lilies regularly for damage and remove all larva. If larva isn’t found on the leaves, dig around the plant in the first ½ inch of soil looking for cocoons and larva. Unfortunately, not all lava pupate under the lily plants and can be further afield making them harder to find and destroy once they are in the ground.
If purchasing lilies from outside of Alberta, check soil for larva or adults. If in doubt, discard all soil into the garbage.
At present time Ken, and his team at Olds College are trialing the use of a parasitic wasp, Tetrastichus Setifer, in Alberta. The tiny wasp lays eggs in the larva which then feed on the larva, killing it. So far the wasp has been successful removing most of the beetles from the plots at the college and also been introduced at another site.
The parasitic wasp is native to Asia and has migrated into part of Europe keeping the lily beetle population to a minimum. As Tetrastichus Setifer, only targets the larva of the lady beetle and is tiny, it does not pose a problem to humans or other insects.
Dr. Fry is tracking Lily Beetle infestations across Alberta and needs the assistance of every gardener to report any Lily Beetle sightings to KFry@oldscollege.ca or lilybeetle@arls-lilies.org
Parasitic wasps are being raised at the college, but not in great enough numbers benefit all gardeners. For now, the best solution is to catch and destroy all insects, eggs and larva as they are detected. If there is a known beetle problem, in your garden or neighborhood, check and destroy daily.
Linda Tomlinson is a horticulturalist that lives near Rocky Mountain House. She can be reached at your_garden@hotmail.com