While the berry season is over in Wisconsin, growers should be thinking about how they’re going to
protect their crop from pests next year, while also promoting pollinators. This is according to Christelle Guédot, an associate professor in entomology at UW-Madison. She’s also an Extension fruit crop entomologist.
She says a pest that can be a huge issue for berry growers are thrips. This year, thrips were a huge problem for strawberry growers, Guédot says. Thrips are tiny insects — about a millimeter long.
“They’re not very conspicuous, so you really have to pay attention to them,” she says.
Thrips do not overwinter in Wisconsin. In the early spring, they fly in with strong storms coming from the south. When they arrive as adults, they reproduce here, and can cause tremendous damage to berries. To diagnose thrip populations, growers tap flowers onto a white sheet. The threshold for if there’s a problem is two to 10 thrips per flower that you see (not all thrips will fall onto the sheet). It’s up to the growers to decide when to take action — two or 10? Guédot says have a plan for next year on how you will mitigate thrip damage.
For the most part, the tool to combat thrips is insecticides.
Guédot’s specialty happens to be integrated pest and pollinator management — managing pests while boosting pollinators. She says berry growers can manage thrips with insecticide while promoting their vital pollinators — wild or domestic.
Attracting native pollinators, such as bees, and promoting those already around the farm can be done by planting flowers. This is the same for managed pollinators, such as honeybees.
“If you plant flowers, bees will come, there’s no question about it,” Guédot says. She adds to plant close to your crop but on the side so there’s no competition within the cropping system.
Other IPPM strategies include biological control agents, such as insects that feed on pests; reducing pesticides in your planting at time of bloom; reducing or changing the time of spray, such as not during bloom or in the evening when bees are not active; and choosing pesticides that are less toxic to bees.
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