JBs and the Winsome Fly? - Ask Extension
I just saw a Facebook post by the Lyndale Park Gardens about Japanese Beetles and the Winsome Fly (Istocheta aldrichi). Inspecting my own resident JBs...
Knowledgebase
JBs and the Winsome Fly? #701602
Asked July 16, 2020, 2:52 PM EDT
I just saw a Facebook post by the Lyndale Park Gardens about Japanese Beetles and the Winsome Fly (Istocheta aldrichi). Inspecting my own resident JBs, I have found some, but not all, that appear to have these white dots on their backs which might be the eggs of the Winsome Fly. If this information about the Winsome Fly being a JB predator is for real, this could be big news! I am attaching a picture of a JB who was alive, but not very active, and had at least 5 of these spots on his back. I would love to start sharing the word, but looking for confirmation.
Here's a link to the Lyndale Park Gardens facebook post: https://www.facebook.com/<personal data hidden>4/posts/<personal data hidden>192135/?d=n
Here's a link to the Lyndale Park Gardens facebook post: https://www.facebook.com/<personal data hidden>4/posts/<personal data hidden>192135/?d=n
County Minnesota
Expert Response
Let me do some checking! I'll get back to you ....
I got in touch with our Extension entomologist and here is what he had to say:
I too have gotten reports of parasitized JB. This is the second year in a row that they have been noticeable. However, this is not the first they have been in the state. Both Istocheta aldrichi and Tiphia vernalis (a grub parasitoid) were released in 2004 by the USDA. There was evidence that they successfully overwintered. However, their numbers have always been small (until last year). I can not remember ever seeing a parasitized JB during that time.
I too have gotten reports of parasitized JB. This is the second year in a row that they have been noticeable. However, this is not the first they have been in the state. Both Istocheta aldrichi and Tiphia vernalis (a grub parasitoid) were released in 2004 by the USDA. There was evidence that they successfully overwintered. However, their numbers have always been small (until last year). I can not remember ever seeing a parasitized JB during that time.
So for now, I am noting when people see them but I am going to wait to see what happens. It is unclear how effective they have been. I am also hearing reports of large numbers too. That would be great if they could moderate JB populations. Time will tell.
So it is a "wait-and-see" situation!
So it is a "wait-and-see" situation!
