Beetle Attacks Hound's Tongue

LETHBRIDGE - Jul 31/01 - STAT -- A root-feeding weevil imported from Europe and released on research plots in British Columbia's East Kooteney Valley is successfully attacking the hound's-tongue weed.

The success this year is likely due to a combination of drought and the insects, says lead researcher Dr. Rose De Clerck-Floate of the Lethbridge Research Centre, but the control sites remain infested with hound's-tongue despite the drought, showing the beetles are having a significant effect on the weed.

"It's exciting, because the weevils not only ate up plants at the release point, but are also locating new hound's-tongue patches on their own."

Hound's-tongue is widespread throughout B.C.'s southern interior, and becoming a problem on rangeland in the Southern Alberta foothills. A colonizer of disturbed areas, hound's-tongue often infests forest sites cleared for cattle grazing, mining operations, road construction and abandoned cropland.

Hound's-tongue hinders forage establishment and its burrs irritate cattle and can reduce their market value. The weed is also toxic and can poison the animals. It is considered by B.C. cattlemen as second only to knapweed as a priority for control.

Biocontrol involves using living organisms as control agents against a target weed, disease, or insect pest. Classical weed biocontrol, a promising method for controlling hound's-tongue, involves establishing a few insects that are natural enemies of the weed at strategic sites until their numbers are self-sustaining. Once the insects are established, they should be able to move on their own and follow the weed, De Clerck-Floate says.

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