Mountain ash problem.

Asked July 3, 2018, 5:29 PM EDT

I have a mountain ash tree where the leaves are all eaten off in a very orderly fashion and the veins are left intact. I suspect from my research this is a sawfly problem. If so what is there to do about it or is it too late. About 1/3 to 1/2 of the tree is eaten and we really didn’t notice it until just recently so I’m not sure if it is an active problem or done. Do you have any recommendations for a tree service of note In the Bemidji area

Beltrami County Minnesota mountain ash horticulture

2 Responses

If you are not seeing the sawfly now, then it is too late to treat this year. Your tree should put out new leaves, but defoliation weakens it, so be vigilant next year. There are various insecticides that can be used on sawflies. Read here:
https://extension.umn.edu/yard-and-garden-insects/sawflies

Also note that sawflies are not the only skeletonizers of mountain ash trees, so try to find what has done the damage.

Thx for the great input