This year, we’ve begun a project to determine the frequency and significance of strawberry clipper damage in annual plasticulture strawberries growing in the southeast. Female strawberry clipper weevils injure developing buds by laying their eggs in them and partially chewing through the peduncle (or stem supporting the flower). These injured buds will not develop into flowers or fruit, and growers are often concerned about the potential for this injury to result in yield loss. However, previous research in matted row strawberry prodution and observations from annual plasticulture fields in NC heavily injured by clippers in 2013 suggest that plants may compensate for bud loss. The goal of our project is to determine if clippers are actually causing damage and, if so, how widespread this damage is.
As part of this project, graduate student Doug McPhie is monitoring clipper populations and damage at 10 strawberry farms in North Carolina, and we are collaboring with colleagues in Virginia to monitor another field there. Doug is testing whether yellow sticky traps placed in fields can detect adult weevils before clipped buds occur, as well as tracking injury on plants to determine if yield is affected.
Last week, we started catching beetles in traps and also observing them active on plastic at three monitoring sites, and we started to observe clipped buds at one site.
This means that strawberry clippers are now active in central North Carolina, but we are still somewhat cautious about recommending any action against them. After the first year of this project, we will have a much better sense of if treatment is necessary for clippers, and if the traps we are testing can be used to time treatments. We what do know is that materials currently recommended to treat clippers come with some real risks. They are broad spectrum, which means they may be risky for pollinators, and some materials may flare twospotted spider mites, one of our major strawberry pests. We will post updates as clipper observations continue.