Pinewood nematode & Pinus strobus

[rfwoodvt]

Over the past few years I've been noticing a fair number of Pinus strobus that have basically "up and died" within a short period of time.

Most of the owners said the trees died within 6 months of looking sick. Some said they really hadn't noticed until it just turned brown and died.

All of them have kept thier needles after death.

I myself had one give up the ghost two years ago. I really didn't delve into why but this year I had a Pinus sylvestris pine do the same thing but that took less than 2 months to crap out.

Anyhow, the progression and symptoms are the same and the P. sylvestris looked like a classic pinewood nematode attack. So did my [p] P. strobus[/i]

Here is my quandry. From what I've been able to find P. strobus is resistant to the PWN, yet I am seeing what looks like PWN damage to PS quite frequently.

If a species is resistant, what is a reasonable frequency to see such damage?

If the tree shows classic signs of PWN but it is a "resistant" tree speicies, should I delve further?

Thots?

 

[BCMA]

Question- How are you identifying trees that died from pinewood nematode? What are the signs and symptoms?

There are two other areas that I would recommend that you familiarize yourself with- bark beetles and root diseases.

Bark beetles will cause a tree to turn brown fairly fast. You can ID them from pitch tubes, boring frass, small exit holes, or removing the bark and look for their galleries.

Root diseases are a little harder to get a handle on and will probably require some reading or instruction from an experienced person in the area. Try contacting a pathologist from the forest service or State DNR for some help. Your county extension may be of some help also.

 

[allmark]

I too have seen this over the last 15 years. It is in the adirondacks and my area. one tree will die and another 20' away is still alive. I havent seen beetles but borer damage is eveedent( secondary aftre stess)

 

[Sylvia]

We have been hearing more reports from homeowners in the east on various forums on white pine deaths. Some trees are showing signs and symptoms of beetle activity but some not. Just trees "suddenly dying". Nematodes are beginning to be suspected. Typically if the tree is infected by the Pine Wilt Nematode in the fall it will succumb the next spring. If it is infected in the spring, it will succumb that season.

One diagnostic test you can do yourself, is to soak a piece of wood taken from close to the trunk in water overnight (or at least for 1 hr). You should be able to see the nematodes with a 10 power scope or hand lense swimming in the water.

I hope someone performs this simple test to either rule out the nematode or confirm them as this is a scenario cropping up more and more. And this is a condition that warrants immediate removal (if between May 1 and October 1) of the tree with proper disposal of brush and wood to limit spread.

With infection by nematodes once symptoms appear the tree is dead, sap is no longer flowing ( the resin ducts have died prior to the visible symptoms). Therefore, if there is visible dieback AND the tree is still exuding sap, I would suspect some other causal agent such as beetles or a pitch canker, etc.

Sylvia

 

[allmark]

what would be proper disposal? will they spread through chipping...should it be burned?

 

[Sylvia]

The information I have on proper disposal is the typical "burn, bury or chip" and "do not keep for firewood".

This sounds like the typical beetle control. Longhorn beetles, such as Caroline and Southern Pine sawyer beetles are the vectors. They feed on healthy trees before moving to dead trees or logs to breed and lay eggs. They can carry the nematodes in their trachea, under wing covers and on their bodies. They are active from May 1 through October 1. (Evidently, on October 2 they are grounded by the Beetle Air Control.

)

However, an article from the USDS shows where pine nematodes have been found in untreated conifer chips so I would use caution where I disposed of these chips. So, personally, if pine wilt nematodes were identified I would probably opt to burn.

Sylvia