AusBonsai

I think I posted this concern once before but can't find the thread anywhere.... last time I was told not to be concerned, that it was just some form of harmless lichen. Well I have to report that it isn't harmless and is killing off branches which is concerning me bigtime. It is only on one of my Tridents, but it happens to be one of my best and oldest trees. I need to get rid of it, so can I please get some suggestions on what I can use to kill "it".... but not my tree. It's those little black dots which are slightly raised, which I think could be the problem.

Maybe paint on a weak dilute mix of lime sulfhur .
Shouldn't harm anything if you keep it away from the roots and leaves.

Vinegar?

Paulneill wrote:Maybe paint on a weak dilute mix of lime sulfhur .
Shouldn't harm anything if you keep it away from the roots and leaves.

Paul, I've delved a bit more, and it seems that I can spray the entire tree with the correct dilution of Lime SUlphur.....leave on for 15 mins, then wash off thoroughly with the hose an fresh water. Rose growers do it regularly to control fungus problems and the like.

I really don't think its the lichen causing your problems. I have trees here where the trunks and branches are completely white with this lichen and are flourishing. This lichen only grows where the air is clean, all my trees in the garden also have a lot of it growing on them. I would be very reluctant to spray any tree unless I had a very clear idea of exactly what I am trying to kill.
Craigw

craigw60 wrote:I really don't think its the lichen causing your problems. I have trees here where the trunks and branches are completely white with this lichen and are flourishing. This lichen only grows where the air is clean, all my trees in the garden also have a lot of it growing on them. I would be very reluctant to spray any tree unless I had a very clear idea of exactly what I am trying to kill.
Craigw

I agree that finding out what is causing the problem is very important, though may prove difficult - I've done some searching for the black spots on the bark & found absolutely nothing. Maybe you will have more luck.

Treating with lime sulpher may work & with a lack of any other information could be worth a try, but without knowing what you're fighting it could also be a waste of time.

Cheers

Hi Shane,

It looks like that tree is effected by some form of leaf curl. The growth certainly doesn't look like the strong healthy growth one would expect this time of year.
I would say the tree is weak and weak trees tend to drop branches.
Like Craig mentioned I have also seen trees totally covered in that silver lichen and growing happily.

That said if you are set on spraying, I have sprayed lime sulphur onto tridents in leaf with no ill effects. Recommended dilutions of course.

Joe.

Hi

Have been watching this thread with interest and have started doing some of my own Internet searching.

I have this on some of my plants, black pine, bottle brush, crepe myrtle, swamp Cyprus and azalea.

As I haven't noticed any detriment to the health of my trees I haven't treated them any different. I didn't realize that these black spots and silver blotches were a type of lichen.


Fiona

fae wrote:Hi

Have been watching this thread with interest and have started doing some of my own Internet searching.

I have this on some of my plants, black pine, bottle brush, crepe myrtle, swamp Cyprus and azalea.

As I haven't noticed any detriment to the health of my trees I haven't treated them any different. I didn't realize that these black spots and silver blotches were a type of lichen.


Fiona

Fiona,
On reflection, I don't think its the silver blotchey stuff thats the problem.... it's the little black raised dots that I think are the problem....almost like a miniature scale.... and pretty well lodged on the bark too.
I'm going to look beneath the soil today and inspect the root system just to make sure I don't have other issues....

Looks like Coral Spot. Or something similar. And has nothing to do with the lichen growing on the bark, other then the bark of the tree has been kept wet for a long time.

You have a fungus under the bark. The black dots are fruiting bodies.

Paul

Found this which seems to fit with your pictures...

Branch cankers Botryosphaeria sp. (and other fungi)

• Dead branches and twigs, often first observed in early spring
  Sunken, discolored canker on branches, oval shaped to completely encircling the branch
  Dark stained sapwood visible if bark is cut off of the discolored area of the branch
  Leaves on affected branches may wilt and die
  Small raised black pimple like bumps along edge of the discolored area
  Common on trees stressed by drought, recent transplant or other factors

Coral spot canker Nectria cinnabarina

• Dead branches and twigs, often first observed in early spring
  Sunken dark brown area on branch that is often cracked or has a ridge at the edge
  Raised cushion like bumps on affected branches, may be cream to orange or red, turn back with age
  Common on trees stressed by drought, recent transplant or other factors

Thanks Jason

This will give me more avenues to investigate.

The silvery lichen and black spots appear together on my trees so I make be mistaken thinking they are the one ailment.
Have just taken a toothbrush and scrubbed with a weak solution of lime sulphur to try and dislodge some of the spots. It seemed to work.

I am planning on attending the Merrylands show on the weekend so may take one of the affected plants for a diagnosise.

Fiona

fae wrote:I am planning on attending the Merrylands show on the weekend so may take one of the affected plants for a diagnosise.

If I make it remind me to keep my plants clear...

Lichen naturally have spots too.these images were sourced from Australian Government Department of Environment website . There are lots more other examples there too.

the Japanese Bonsai growers carefully cover the soil then spray everything during winter with diluted lime sulphur when the trees are dormant. They even spray the benches. It wouldn't hurt to use lime sulphur as long as it doesn't get into the soil.