May 2, 2019

This paid piece is sponsored by Aspen Arboriculture Solutions.

By Sam Kezar, owner, Aspen Arboriculture Solutions

The phone rang one day with a man curious if I could help him with his pine trees. He had had a few other people look at them and was looking for a second opinion.

We walked into the backyard, and I thought I already knew what his questions were going to be based on what I saw.

He then asked me a completely different question that wasn’t related to what I had already thought was his concern.

He had a row of several scotch pine (Pinus sylvestris). One had already died, and the other was dying.

It was clear to me that the trees were being killed by the pine wilt nematode; the trees had pine wilt disease. But he wasn’t asking about that. Instead, he was asking about Zimmerman pine moth. He had been told that his trees had Zimmerman pine moth, or ZPM, and Diplodia tip blight and that he needed to have the trees sprayed to prevent and keep more trees from dying. He was asking me if that was the right course of action to save the trees and a worthwhile investment. That was an easy answer: No.

His scotch pine didn’t even have Diplodia tip blight or ZPM! The other bummer was he had already had the trees sprayed for ZPM in late July. The proper timing to spray for ZPM is either early spring in April or late summer/early fall in September. Even if the pines had ZPM, there wouldn’t have been any control because the spraying was done at the wrong time of year.

So how can you know if the issues you have are getting taken care of properly? There are a few key factors when it comes to plant diagnosis:

1. Plant identification
   To diagnose problems, the person must be able to know what kind of plant they are looking at. So many pest and disease issues are species specific. For example, emerald ash borer will attack and kill trees only in the ash (Fraxinus) genus. So it will not attack mountain ash (Sorbus aucuparia). If you or the person looking at your tree cannot identify the tree to its species, diagnosis will be very difficult.
2. Pest or disease life cycle
   Another important factor is being able to know how the pest or disease attacks or infects the tree. For example, you can find spruce spider mite damage year round, but the mites are actively feeding and active in the spruce trees only in the early spring or fall. You can find other mites in the summer, but those are not the ones doing the damage.
3. Timing
   This goes along with knowing the pest. In the spider mite example — like the ZPM example above —  if you spray in the summer, the treatment will be ineffective. So many tree health-related issues require specific timing for the application, or there will be inadequate or incomplete control of the issue. The best example is apple scab. If the spraying is even missed by a day or more, there will not be adequate control of the fungal infections!
4. Pest or disease identification
   This one is a bit obvious, but being able to properly identify the exact issue is very important. Some issues will be present but not causing the damage. Other issues look like one thing but actually can be something completely different.

“I don’t know.”

Being able to say when I don’t know what is going on is just as important as saying when I do know what the issue is. There are times when it isn’t clear what the problem is. If that is the case, I will gather as much information as I can and research the issue, consult with other professionals and find out what the issue is before recommending a treatment action.

Here is how we do that for you:

• Give us a call at 605-759-6020.
• Set up a consultation.
• We will provide a plan to help you make the best decision for you and your tree.