Hemlock scale

Jed1124 · Sep 4, 2014

I am seeing a lot of hemlock scale in the hems I treat for adelgid. We use safari on the larger hems but spray oil on just about anything we can reach. I was talking to someone the other day that said he uses insecticide in his second adelgid app with a lot of success at controlling scale as well. The owner of the co I work for said he has he has never seen any folier spray ap working for hemlock scale. Any suggestions?

Raintree · Sep 5, 2014

Using Safari for elongated hemlock scale will also give you off label control of the woolies.
Insecticide apps during the scale crawler stage can be used. However mite outbreaks are a concern, soaps would be a good choice.
For heavily scale infested trees a single app of Dinotefuran then maintenance oil sprays should suffice.

Jed1124 · Sep 5, 2014

I was leery of imidicloprid because of the mites. Would the dinotefuran be effective outside of crawler stage for the scale. I have to check my book but I believe crawler faze is in October for the scale anyway. Maybe a low dose in with the oil during the fall. Stuff is so expensive. I have all my hems pretty much wooly free, just hate to see the yellowing from the scale.

Jed1124 · Sep 5, 2014

Thanks again rain. Always helpful!

Ed Roland · Sep 5, 2014

"woolies" are off the Safari label? Listed alphabetically as the #1 pest here http://www.valent.com/Data/Labels/2011-SAF-0012, R1 XCANY Safari 20 SG Forestry.pdf

Raintree · Sep 6, 2014

You are correct Ed, must have been recently added. Thanks for the heads up.

Jed, Safari is labeled for armored scale, I apply a trunk app in the spring only on problem trees with heavy scale. The control is very good, with inspection you should find one app will suffice. The issue with imidicloprid is over use on Hemlock. Studies have found 3-4 years of control from a single app.
So bottom line for my customers, I only pull out the heavy hitting insecticides for the big difficult to control infestations. One time app on the stressed trees, annual inspections and oil maintenance sprays as needed. My goal is not to completely eradicate all pests, only to reduce populations down to levels not harmful to the tree.