Michigan Fruit Growers on High Alert for Spotted Wing Drosophila

Posted by Christina Herrick|July 17, 2018

In a recent bulletin, the research team at the Northwest Michigan Horticultural Research Center (NWMHRC) detailed spotted wing drosophila (SWD) catches, saying SWD numbers are six times higher this year than in past years during this part of the season.

“Although trap numbers are down this week, be cautious with management decisions as rain, humidity, and wet weather will likely stimulate SWD activity,” Nikki Rothwell, Michigan State University (MSU) Station Coordinator and District IPM Educator; Emily Pochubay, MSU IPM Extension Educator; and Karen Powers, MSU Extension research technician, write.

Rothwell, Pochubay, and Powers report previous data indicates dry and hot weather is less conducive to SWD activity, noting temperatures above 86°F seems to slow down the flies’ activity, and temperatures above 91°F inhibit egg-laying.

However, they caution “growers should not become complacent with management programs as this wet weather will likely increase SWD activity, and spray intervals should not be stretched.”

For spray recommendations and further trap catch data, read their full report.