research update


Raspberry crown borer’s larva stage is not usually visible because it overwinters inside the hollow cane near the root.


Psst...Wanna help beat the borer?


Grower participation can useful in development of a pheromone-baited trap to control populations of raspberry crown borer.


By Judie Steeves A


researcher working on non-chemical controls for the raspberry crown borer is willing to make pheromone-baited traps available for growers interested in trying them for monitoring or in volunteering their field for her research.


Carolyn Teasdale, of E.S. Cropconsult, says she is now going into the third year of her research into controlling the borer, Pennisetia marginata, funded by the Raspberry Industry Development Council and the Lower Mainland Horticulture Improvement Association. Although the pheromone is not yet commercially available, it has proven effective at luring adult moths for monitoring populations of the borer.


Since the adults are difficult to identify in raspberry fields because they look very similar to wasps, often growers have no idea when the borer is there. The larva stage is also not usually visible because it overwinters inside the hollow cane near the root. Raspberry crown borer has a two-year life cycle in B.C. fields and the adults fly for about six weeks in the summer.


That is when trapping with a pheromone bait can indicate their presence in the field so growers know when to spray, once their presence has been detected. Part of Teasdale’s work has been in evaluating the type


Female raspberry crown borer looks much like a wasp, as does the male.


of trap that is most useful, and she has found the triangular or delta trap or the wing trap work best. Populations build slowly, she notes, so “There’s a possibility that mass trapping to suck in enough adult moths could be quite effective.”


Both monitoring and mass trapping could significantly reduce the number of sprays growers use. Currently sprays are applied as a preventive, without knowing if the borer is even present, she noted.


In field work Teasdale did this past summer in the British Columbia Berry Grower • Winter 2010-11 13


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