Voracious invaders were hiding in plain sight in Pat Young’s backyard.
The Red Deer resident was hanging wash on her clothes line Monday morning when she noticed the lilies she’d transplanted decades ago from her parents’ garden were looking decidedly ratty.
She took a closer look and was startled to see an army of red beetles feasting on the leaves.
“My lilies were being decimated! … I picked off as many (bugs) as I could and I flushed them down the toilet,” said Young, who lives in West Park.
After some online investigating, she discovered these red lily beetles (also known as scarlet lily beetles or lilioceris lilii) are wreaking havoc on many gardens and green spaces in the province.
The flying bugs, originally from Europe and Asia, have been in Eastern Canada since 1943, but only reached Alberta a few years ago. They look like rectangular ladybugs without spots, with bright red bodies that narrow at the shoulder, and black heads, legs and undersides.
The beetles destroy native lilies, and Asian species, but don’t care for day lilies (which are actually not a true lily) or more resistant Oriental lilies, said Christine Cornelius a horticulturist for Parkland Garden Centre.
Cornelius has fielded a few calls about these beetles from Central Alberta gardeners over the past couple of years, but she believes populations have become more entrenched in this area, since many more calls have been coming in this summer.
There aren’t a lot of products that can combat the pests. Cornelius said gardeners can try Trounce, which gets rid of other beetles and insects organically. A City of Calgary website recommends sprinkling diatomaceous earth (an organic silica-based material) directly on the beetles. It will cause abrasions that will cause the bugs to dry out.
Cornelius believes it’s more effective to hand-pick the red beetles off lilies, and also removing the small black larvae and translucent eggs hidden on the underside of leaves. (The Calgary website recommends dropping them in a bowl of soapy water to prevent escape).
Since the bugs overwinter in the soil beneath the plants, Cornelius also recommended checking the soil around bulbs in the fall.
Once infested lily stalks are cut down, she asks gardeners not compost them, since this could spread the insects to other areas.
Young said she plans to burn the leaves and stalks in the hope next year’s lilies are beetle free.