Mountain Ash

[Steve Rosa]

I live in upstate New York and am experiencing a problem with some type of small caterpillar type worm eating the tree leaves from the bottom to the top. They crawl up the trunk and completely eat the leaves from each branch and then continue to the top. They have appeared within the past week.

I would appreciate it if you could tell me how to control these insects and how to prevent them from getting into the trees. Thank you.

Steve

 

[John Paul Sanborn]

It is a sawfly larve, any contact pesticide will take care of them. (Bt is neithe contact or effective on them since tjhey are a fly not lepidotarea)

I think Orthene is counterindicated due to phytotoxicity. (ie the leaves curl)

Read the label, for it is the law.

 

[Treeman14]

If you prefer an environmentally friendly alternative, use insecticidal soap. Best control is achieved early in the season while sawflies are young. When they reach about one inch in length, they stop feeding and start building cocoons.