Scotch Pine, Death!

[dhuffnmu]

In my area here in south east Michigan I got a call to a office complex that had several big mature Scotch Pines around. Two of the larger ones have just recently have had the needles turn all brown. He is concerned with it happening to all of the other pines on the property. Can someone give me a little more insight on a cause and what can be done to keep it from spreading to the other trees on the premesis.

Thanks for the help.

 

[JeffE]

Any number of things could be going on. One very common problem with Scots pine in the midwest is pine wilt nematode, which can cause sudden whole-tree wilt and death in apparently healthy trees. It's a native nematode spread by native beetles, and it's not a problem for our native pines, but Scots and Austrian pines are susceptible. Big problem in Europe, where the nematode is an exotic pest.

An extension office could do a diagnosis. If that's what's going on in that site, best to remove the trees and chip them (remove chips also) to reduce the likelihood of spread to other Scots pines in the area. Primary spread is in the spring, when the <i>Monochamus</i> sawyer beetle adults spread it through maturation feeding on the shoots.

 

[HELSEL]

In my area here in south east Michigan I got a call to a office complex that had several big mature Scotch Pines around. Two of the larger ones have just recently have had the needles turn all brown. He is concerned with it happening to all of the other pines on the property. Can someone give me a little more insight on a cause and what can be done to keep it from spreading to the other trees on the premesis.

Thanks for the help.

I live in northern Mich. We have been tree farmers for many years. I am also an arborist. The reason your scotch pine are turnig brown is because of a weavel.I do not know the correct name of it. We always called it Root collar weavel.If you dig down by the stump about 6 in you will see where the bark is white and the tree has been ate on all the way around.These weavels will lay 6 eggs and each one will move to another tree.The way to stop it is to spray all of the stumps. We use to spray lindane I dont know what they use today.Good luck


Rick Helsel

 

[dhuffnmu]

Thanks for the reply guys. I thought that's what it was. I am just courious of what to spray it with now.

 

[Husky288XP]

You don't want to spray Lindane, unless you want cancer in the next 30 years and bioaccumulation. Try Onyx, Bifenthrin, a pyrthroid thats safer on you and the environment.

 

[JeffE]

dhuffnmu, as you can see from the responses here and elsewhere, there are quite a number of possibilities, and you'll need to do some detective work before concluding what the cause is, so that you can have an effective treatment on the remaining trees.

As Helsel said, root collar weevil (<i>Hylobius radicis</i>) is another possibility. They frequently kill smaller Scots pines, but large, mature ones can be killed if repeatedly attacked, especially if the root collar is covered with mulch or shaded by low branches. Older, mature trees are especially susceptible to pine wilt nematode.