Asian Lily Beetle invades local gardens
A mainstay of local backyard perennial gardens is under attack by an increasing threat - the Asian Lily Beetle.
The nasty little red-backed beetle has been in the area for five years, said George Scott of Scott's Nursery Ltd. on Lincoln Road.
The adult beetles emerge in the spring and lay their eggs on the underside of Asiatic, Oriental and tiger lillies, lily of the valley and Solomon's seal.
The beetles cover their larvae in their own mud-like excrement, leaving black-looking patches over and under the surfaces of lily leaves.
They have no easily identifiable predators in North America, but in the United States, University of Rhode Island researchers are experimenting with the introduction of a couple of natural biological attackers, including European wasps.
Determined gardeners can pick the beetles off their plants by hand, squish them or drown them in detergent and water, or use chemical deterrents.
"It depends on how much a person really wants to use chemicals," Scott said. "Neem oil is a natural-occurring treatment that is used for insect and disease control, and in the right combination it can be quite effective.
"(The beetles will) totally defoliate a plant if you're not on top of it. It certainly is a challenge to eliminate the (beetles), especially if you're a person strictly opposed to using chemicals."
Pesticides such as Seven, pyrethrin and rotenone are other alternatives.
The tough part about controlling a beetle is that they'll spread their wings to find a feast and some types are known to migrate as much as 20 kilometres in a day, Scott said.
"Your problem with beetles is that they really are good flyers," Scott said.
Since the beetles will seek a cool spot on a hot summer day, some gardeners place a flat board nearby, gather up the beetles which collect on the cool underside, and then crush them as they collect on the board.
Beetles will winter in the soil and their entrance into Eastern Canada could be linked to warmer weather, Scott said.
"It seems to be a product of our global warming or milder winters," Scott said. "It just seems to be moving in as we get into milder or slightly milder winters."
Dr. John Sweeney, a research scientist with Natural Resources Canada at the Atlantic Forestry Centre, said the beetles have been found in climes as cold as Siberia, so even extreme chill might not kill them off as they over-winter in the soil.
Asian Lily Beetles were first discovered in Montreal in 1943.
"It only gets the true lilies," Sweeney said. "It doesn't attack the day lilies. It has actually been found on native Canadian lilies, which is a rare kind of endangered plant."
Sweeney, who spotted the beetles in his own garden this year, says a single lily stalk can have 200-400 eggs on it.
"Homeowners in Fredericton basically have to keep a look out for red eggs, ugly black-covered larvae," Sweeney said. "I managed to control them with hand-picking, but I really did have to be vigilant."
There's a whole series of home remedies that people have come up with, including rinsing off their bulbs in a mild solution of ammonia before planting them, or using rhubarb leaves to try to control them.
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