If you have lilies in your garden, you should be on the lookout for the red lily beetle (Lilioceris lilii).
First discovered in Alberta about 10 years ago, this beautiful but destructive beetle can completely defoliate and potentially kill Asiatic, Oriental, martagon, tiger and Turk’s cap lilies. The beetle also feeds on Solomon’s seal, lily-of-the- valley and fritillaria, but only breeds on true lilies.
The adult red lily beetle is six to nine millimetres long with a bright red body and black head, antennae, legs and underbody. Adult beetles overwinter in the soil, mulch or under plant debris and emerge about mid-April. Females lay 200 to 400 yellow-orange eggs along the midrib on the underside of lily leaves. The eggs hatch in seven to 10 days and larvae feed voraciously on foliage. To discourage predators, larvae cover themselves with their own feces. After 16 to 24 days, larvae fall to the ground to pupate for about 10 days. The second generation of adults emerges mid-July to mid-August to feed on foliage before overwintering in the soil.
To control the spread of the lily beetle, handpick and crush adult beetles as soon as they appear on emerging lilies in the spring. Destroy any egg cases or larvae on the underside of lily leaves and remove and destroy mulch from around infected plants. Lilies should be checked frequently from spring through fall for eggs, larvae and adult beetles. Red lily beetles are strong flyers, so educate your neighbours about identification and control as well.
The Alberta Regional Lily Society and Dr. Ken Fry from Olds College are tracking the spread of the lily beetle in Alberta. Their data will be contributed to a national database in support of efforts to release a parasitoid wasp in western Canada. To report a sighting, contact Dr. Fry at firstname.lastname@example.org
Visit the Calgary Horticultural Society’s website at www.calhort.org