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Tuesday, April 19, 2011

Strawberry clipper update

Last Wednesday, I visited Lee County to check on our strawberry clipper traps and take counts. We continued to see clipped buds (20 of 30 plants checked), but the damage appeared older and no adults were captured on the traps. It will be interesting to see if the damage continues this week. Clipper counts are also picking up at other locations in the Sandhills, I have now heard reports from 3 different locations where clipper has been observed.

Strawberry clipper weevil adults on wild blackberry buds. How many clippers can you find? There are 11 in this container. Photo: HJB

More exciting, however, was what I found this morning in my growth chamber. The clipper eggs that I collected 2 weeks ago have completed their larval stages and are now adults. This answers the first question I had in mind when I brought them back to the lab. At a constant temperature of 28C, the strawberry clippers took about 15 days to complete their larval stages. Now that I know I can successfully rear beetles from infested buds, my next goal is to collect enough adults to conduct a laboratory bioassay of registered and unregistered materials to control clipper weevil adults. This will go a long way to making more meaningful treatment recommendations, particularly for newer, reduced risk materials. However, we still need to understand the real impact of clipper damage in terms of yield for our production system before I am willing to advocate an aggressive pesticide program.

In the meantime, I will be keeping my adult beetles on flower buds, since they have been documented to feed on flowers and pollen. This appears to be correct, because the beetles went straight for the unopened blackberry buds I placed them on and started chewing away.

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