pest management


Cranberry fruitwormis a recent arrival, and curtailing its spread will require grower vigilance. By Tamara Leigh


T


he cranberry fruitworm is a common pest of blueberries and cranberries in the United States


and Eastern Canada, but it has not historically been a concern for growers in British Columbia. During the past year, the B.C. Ministry of Agriculture and ES Crop Consult have been working to gather information that will help growers make better management decisions to control the new pest. “We first identified cranberry fruitworm in B.C. in 2011,” says Tracy Hueppelsheuser, entomologist with the ministry and project lead. “Our project is now in its second year, and we are trying to understand the lifecycle of the pest in our growing region.” The cranberry fruitworm


moth is a medium-sized (15 mm wingspan), grey-brown moth with white triangles on its wings. The hind triangles each have two dots. The eggs are very small (1 mm), and are laid singly or a few overlapping on the calyx of green fruit. Larvae are green and grow up to 1cm in length. “Because insects are cold-blooded,


they are completely influenced by temperature. Temperature differences in our growing region compared to other regions mean that we can’t use information from Michigan or Oregon. Each region has different temperatures and a different lifecycle,” she explains. Hueppelsheuser and the team at ES


Crop Consult used pheromone traps for weekly monitoring of adult moths from the end of May to late August in 34 cranberry farms and 27 fields throughout the Fraser Valley. Once adult moths were found in a field, the team collected fruit to look for eggs,


12 British Columbia Berry Grower • Spring 2014


larvae or fruit damage like bore holes or frass.


“Between the two years, peak moth


flight was three weeks earlier in 2013 than 2012, just because of


Monitoring critical


Damaged and undamaged fruit (top) and insect frass (left) resulting from cranberry fruitworm infestation.


temperature differences in spring and summer,” says Hueppelsheuser. “We’ve learned that the flight can be quite different from year to year, demonstrating the importance of monitoring for growers.” To date in B.C., the cranberry fruitworm is staying true to its name and has not affected blueberry crops in the region. Very few moths have been caught in blueberry fields, except for the odd occasion when the


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