Ponderosa Pine fungus?

Sandi

Hi Doc,

I have a Ponderosa pine that I got from Elandan gardens nursery. It is supposed to be l50-200 yrs old and was collected in the mountains. Sooo, I'm very worried about it. About 3 yrs ago when it was a warm wet winter, my tree got covered with a black sooty mold. I immediately sprayed it with a fungacide and it killed the mold but left a gray chalky look to the bark and now anytime it gets too damp it flares back up again and I have to spray again. It hasn't flared up in about a year cuz I've been real careful not to let it get damp. How do I get rid of the gray chalky stuff on the bark without damaging the bark or killing the tree? I've considered a light solution of lime sulfur and a soft toothbrush but am too afraid to do it without someone elses opinion that has more knowledge than me. I'll attatch a photo but you can't really see the chalky look in the photo.

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TreeBay

Nice Tree!

Marty Mann's seasonal suggestions for March/April suggests:

"Use Benomyl(r), Bravo(r), or Daconil(r) to kill mildew or other signs of fungus on the foliage and the tree bark."

I would protect the soil surface, because there are microflora elements in the soil that can be damaged.

I would be very hesitant to take a toothbrush to a pine!

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bnsaijim

I disagree that you can do much damage with a toothbrush. I use them all time, brass and steel also, depending on the task.

To rid yourself of the problem you need either sufficient contact time with the agent or mechanical removal of the spores. Since neither option is the best solution, what you've been given, a combined approach, is probably the best route.

While I can not offer an alternative agent, recognize that the lime sulfur will have a bleaching effect on the bark, just as it would a jin. Most effective treatemnts would have a similar result. Rinsing after treatment would minimize this but you would, of course, lose the residual benefits of the treatment.

Use a "soft" bristled brush. Don't be heavy handed and take particular care where the bark is loosely adhered or flaky. Holding bark platelets with a free finger while you gently scrub the nooks may make for stinky fingers but it will prevent you from popping off platelets that take years to develop. Wash your hands well afterward...

Take particular care in the future with your watering habits- water the soil only and provide the pine with good ventilation. Hopefully this will prevent a recurrence.

J. Stone
TX

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Jim Stone
Seki Bonsai Studio
sekibonsai.com
Santa Fe, TX

TreeBay

Jim,

Just to clarify - you use nylon and brass brushes on pines with bark like this?

My oldest pines are 50-60 years old. With a couple of these trees I sometimes apply a very light wrap of the finest wire to hold the bark plates in place and flat so they aren't shed by curling during winter wet & dry cycles.

I honestly can't imagine using a brush on these as I know what it does to juniper, where the effect is intended!

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Moni

Heh, heh. At the risk of really throwing a nail into the works here, might I suggest the pine bark adelgid? That would also explain the black sooty stuff that was observed at the beginning of this poor pine's problems. An adelgid is of the aphid family.They can be much smaller but they exude honeydew just like normal aphids. The honeydew gets moldy and looks like black sooty stuff which can be washed off. They are a problem on pines out here in the great northwest. Don't know if they are a problem there. You may need a 10x lens to spot them.
If it is a fungal root problem, Subdue is the way to go. But I would look at the roots first. In root rot it is the nice feeder roots that are the first to disappear. Not a good thing for us.
Moni

Moni

On second thought, forget the adelgid. They look like white fuzzy things and you would have been able to see that. What was I thinking? Sorry about that. I've been home sick all week and spacing out on the computer.

I still say, though, that it could be an insect problem. That would explain the black sooty stuff that you saw initially. Check for regular aphids, scale, anything that exudes sticky stuff. That is usually what encourages black mold.

Also, have you thought about using Neem Oil? That works on both insects and diseases. Fairly harmless otherwise. Read the label.
Moni