It started at the root or base of the trees and has been traveling up the tree onto the branches. It is a slow process but somehow this does not seem to be a healthy appearance to me - it looks like black soot although i have not touched it with my hands. I have asked several people about this and they say the trees are getting old - but i have only had them for about six years and they are maybe 9 or 10 feet, small trees. Can you tell me what to do about this?
A. I have not yet seen any disease or insect problems on
chaste tree here in our climate and a quick look on the internet I have not
seen any reports from reliable sources. This observation is a new one for me.
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| Vitex winter form. |
Aphids have been reported to be a problem on chaste trees
in other places. If aphids are present you would see them in the spring and
fall. Leaves might be cup-shaped due to their feeding.
Excretions
from aphids are full of sugar and will cause a blackening of limbs and leaves
due to a black mold that grows on the sugar. Even though extracts from seeds of
related trees have been reported to kill aphids.
I will
take a closer look at some here in town and see if I see anything but so far I
would have to agree with others. This is a good small tree for the desert with
few pest problems except when people water it too often.
If there
are no signs of the tree being sick other than this black soot on the trunk, I
would guess it is natural aging of the trunk. We do see this type of thing
happening on other trees as well.
Diseases
like sooty canker you would see a decline in the tree, bark splitting or
cracking and the “soot” (under cracked bark) would rub off on your fingers
exactly like heavy soot from an active chimney.
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| Sooty canker disease has black spores just under the bark that rub off on your finger like chimney soot. |
I also have a Chaste tree with blacken main stem and some branches. Tree seems fine. I realize this is in comment to a 2014 question. Any updates?
ReplyDeleteNothing new to report. Sometimes we have to compare what we are seeing on our tree with other trees that we know are healthy. For many trees they have a natural "color" to the bark that other trees do not. Some are grey, some brown and others are "patchy". They are all "normal". The bark of older wood is nonliving. Microorganisms that affect it would be considered "saprophytes" and seldom crossover and infect living tissue. If the tree is otherwise healthy I would guess the blackness is "normal".
DeleteI have this issue, as well. How to treat?
ReplyDeleteI have nothing new to report. if the tree looks healhty inspect it for aphids on the leaves and this can cause sooty mold from the aphid sugary excrement. If this is the case and the tree otherwise looks healthy then ingore it for this year and next Decmeber and January spray the tree with a dormant oil application. This should reduce the aphid problems in that year. Also this year and next year watch for ants climbing in the tree and kill off their nest if that is the case. You can use Amdro ant bait and follow the label.
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