SWD and Aronia: Conflicting Information

10/28/2013

A small-scale, late-summer trial that investigated the potential for spotted wing drosophila to infest aronia berries and blueberries was conducted by Rufus Isaacs at Michigan State University's Berry Crops Entomology Lab in East Lansing, Mich. Isaacs, MSU professor and extension specialist in the department of entomology, used 10 containers, five each of ripe aronia and ripe blueberries, and added five male and five female SWD to each container. After a sufficient amount of time to allow egg laying and development, he found that the aronia berries were free of infestation, compared with damage in approximately 25 percent of blueberries. At the time, an Illinois aronia grower observed SWD bypassing aronia when in the presence of raspberries.
 
While aronia growers might have been elated over this news, University of Wisconsin-Madison entomology graduate student Emma Pelton, conducting research under Christelle Guedot, a department of entomology assistant professor and extension specialist, became aware of aronia infestation in southern Wisconsin during the mechanical picking of ripe berries. "The grower and I both observed larvae on the packing line," Pelton reports, "which he estimated at 20 percent. A random sample also showed reared adults." This field was isolated from other fruits.
 
"I'd trapped SWD on two other farms with large fields of aronia and infested raspberries," Pelton continues. "One might have had raspberries as a trap crop."
 
Aronia growers may want to protect their fields with Entrust SC, which is on the OMRI list, but pest resistance may increase over time, according to John Pilcher, president of Coldbrook Farm, Inc., Crete, Ill. (www.ColdbrookFarm.net). For more information, email him at aronia.us@att.net or call 708-227-2807.