USDA grants fund fruit research in North Central region

By Laurie Vial

University of Wisconsin assistant professor and extension specialist in entomology Christelle Guédot has an ambitious summer research agenda while looking ahead to future projects she’d like to tackle.

Located in the heart of the North Central fruit belt it’s not surprising that one of the main targets of Guédot’s  research centers on spotted wing drosophila (SWD), an insect pest that economically affects berries. Guédot’s team plans to test whether or not there are spatial or temporal factors affecting infestations on ripening raspberries.

Guédot plans to set traps at various heights on raspberry plants (the spatial factor) and check the traps every three hours, when temperature and humidity fluctuates throughout the day. An outcome of the project may be data that underscores the need to spray the SWD at a height and/or time of day that optimize control of SWD while protecting pollinators.

Guédot is also part of a research group who received an Organic Research and Extension Initiative (OREI) grant through the United States Department of Agriculture (USDA). It is part of the multi-state project plan to examine feeding attractant baits and lures to optimize SWD trapping. They plan to test liquid baits and commercial lure attractants and combinations of those in different crops, different states, and at different times of the season.

Attractants may differ in their effectiveness depending on whether flies are most interested in seeking food or are looking for or an optimal place to lay eggs, especially during the first part of the season. And therefore the attractants in the traps may need to change to meet those desires.

A USDA Wisconsin Department of Agriculture grant is allowing Guédot and other researchers to scrutinize honeybees pollinating one of Wisconsin’s leading fruit crops – cranberries. Specifically, the team will determine impact of fungicide and fertilizers on visitation to cranberry. The group also wants to determine if cranberry blossoms offer limited nectar, forcing the bees to look elsewhere for food. One theory to be explored is whether supplemental sugar feeding of the bees would keep them foraging on the cranberries. And the team has also conducted research on the impact of hive placement on the marsh on cranberry pollination.

Guédot has also conducted research on social wasps in grapes, identifying the main species and assessing how each  species responds to different lures.  In the future they will look at refining attractants and repellents for social wasps that could be used to manage wasps with a push-pull strategy. The wasps would be pushed away with repellents and pulled to noncrop areas with attractants. Guédot would also like to determine if social wasps are a direct pest which pierces the grape skin, or a secondary pest that seeks previously damaged fruit.


Pic June93: Students installing pollen traps on honeybee hives at a cranberry marsh in Central Wisconsin. Photo by Lorry Erickson.

Wasps: Yellow jacket wasps feeding on grapes at a southern Wisconsin commercial vineyard. Photo by K. Hietala-Henschell

Emma’s SWD trap: Deli cup containing a yeast and sugar mixture used to trap spotted wing drosophila in commercial raspberry in southern Wisconsin. Photo by E. Pelton