Elytroderma needle cast in pines

[Don McQuilliams]

I have a client that has 10-12 various species of pine trees within the Seattle area that are showing signs of needle cast. These trees are all in a row next to each other and are about 80-100 feet tall. I have done some research and believe it is Elytroderma Needle Cast casued by the fungus, Elytroderma deformans. (see picture)

I was planning on having the infected areas pruned out as well as conducting some vertical mulching of the trees. I am a little hesitant to do vertical mulching as I may cause additional damage by trenching around the root systems. I could prescribe the use of a air spade but I doubt the client would pay for that.

In addition, I was planning on removing the turf for about 12 feet around each tree and adding about 2 inches of black compost to boost the nutrient levels in the ground.

I am wondering about some ideas for conducting the vertical mulching as well as the use of the compost. Should I do this, or just recommend the pruning with follow up pruning next year? Any input would be appreciated. -Thanks

 

[John Paul Sanborn]

Usualy fungal infestations are due to environmental problems; drainag, pH...

If you are fgoing to remove turf and mulch, then use of an air tool for radial trenching would be the best option. I've heard of good responce to Cytospora in srpuce with soil injection of seaweed fertilizer.

You might talk to Scott Baker, I've found him to be very aproachable. He has an air tool in his bag of tricks.

 

[Don McQuilliams]

Thanks John, I know Scott, I'll give him a call.

In an effort to pin this down, I have some pines by my office that are experiencing similar conditions. I was curious about the presence of spider mites so I went and shook the tree with paper underneath and sure enough, there's a bunch of the little critters on it. I looked up a good picture of the spider mite and they look similar. Do you think spider mites cause a similar set of problems? I know they can usually be found in most trees out here but I would imagine they would have to have pretty substantial numbers before any really noticable damage was done.

 

[Stumper]

Don, Re: Spider mites. Yes they can cause things similar in appearance to you photo. There is some threshold level beyond which their numbers explode and ssevere damage occurs very rapidly to the host plant. If you are getting several per shake on a piece of typing paper then I would recommend treatment to zap the mites (insecticidal soap works well but beware of using it on spruce). We had a large number of Junipers killed locally by spider mites this year.

 

[geofore]

mites

Be sure to do the spidermite spray at the right time of the year and do a second dose if the rains come and wash the spray off before it has a few days to work. You want to get the mites at the right time to interupt their breeding cycle.