Russ, I am currently dealing with trying to preserve the largest healthy Madrona (Arbutus menziesii) in WA state. We have major problems in the area with both "Nattrassia" and "Botryosphaeria/ Fusicoccum". It is necessary to prune some small lower branches from the tree and I am concerned that, irrespective of how well the pruning cuts are made, we will be creating wounds attractive to the above pathogens.Do you think orange shellac would be of any use in this situation? Is there anything which might reduce the likelihood of wound infection? Is "Borax" phytotoxic? if it can be used to stop invasion of "Annossus" on cut hemlock stumps might it work here?. Sure would appreciate any and all feedback,
James Causton.

Reply to post by James Causton, on May 22, 2000 at 19:54:14:

Jim, I'm not sure you will gain much with the shellac. I'm not familiar with Nattrassia, but I know Botryosphaeria can infect easily through lenticels and other minute wounds, not just pruning cuts. It can infect throughout most of the year, too. Minimizing stress and relying more on the natural immune response seems to work best.

I've heard of the borax treatment, but don't have any literature to support. Boron is toxic to plant material when applied to soil in large amounts, but I don't know if that applies to pruning wounds. There may be some marginal necrosis around the wound. I also don't know exactly what the mechanism is at work, if does prevent infection.

To summarize, without more information, I'm not too sure the treatments would be of much help. The shellac won't hurt, but may not be much of a barrier to Botryosphaeria.