Hardy Orange tree - branches dying - Ask Extension
Hello, My hardy orange tree has branches that turn gray and die. I pruned the dead branches, but the issue is continuing. The bark appears to separate...
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Hardy Orange tree - branches dying #826962
Asked April 24, 2023, 2:08 PM EDT
Hello,
My hardy orange tree has branches that turn gray and die. I pruned the dead branches, but the issue is continuing. The bark appears to separate in places. I applied root grow on an ongoing basis last year to help, I'm not sure it worked. The tree produced fruit over the past year. I'm trying to figure out what is wrong with the tree and how I can help it. Photos attached, I have more if you need them.
Thank you.
Arapahoe County Colorado
Expert Response
Thank you for using Ask Extension and for sending photos of your tree.
It is more difficult to diagnose trees in the winter as there are no leaves which can help us to get a better picture of the tree and how it is growing.
I have observed several factors from the photos you have sent:
1. In photo #1: in the upper right, the branch that has two pruning cuts, the bark appears to be very dark in color and this could possibly be sooty mold which is caused by a fungus. This may have been evident on the leaves last season. Sooty mold is the result of aphid or other insect feeding on the leaves and/or other parts of the tree. It will be a sticky, sweet residue that may attract other insects.
Also there is an area of discoloration and loss of bark on this same branch. I cannot tell for sure from the photo if this area could possibly be a canker. The branch running parallel also looks like the bark could be sloughing off. These are symptoms of a stressed tree and/or a unhealthy tree. Here is a website with citrus tree diseases and disorders, pay close attention to the section titled "Bark Oozing, Cracking, Peeling or Distorted Growth":
https://ipm.ucanr.edu/PMG/C107/m107bptrunkrootdis.html
2. In photo #2: The base of the tree has several splits and areas that does not appear to have healthy bark. This could be a symptom of a root issue. It is possible that you may have seen some "gummy" areas last season around these splits. There are a number of plant disease that will cause this. It looks like there is a sucker that is coming up and this would be from the root stock below the graft. Sometimes trees will send up suckers as a result of disease or other stress.
3. In photo #3: In the upper right section where there is a joint with 2 limbs, the joint is dark in color and has what looks like a canker or streak of black coming down the main branch. Slightly to the left on a branch that is green there are two dark areas that could be cankers or sooty mold. It is hard to tell from the photos.
It is possible that this tree is in slow decline and the issues that I have observed are the result of decline, disease and/or insect activity. The use of a root growth hormone may add more stress to the tree. You can watch this tree closely this growing season and see if the same problems occur. If all the issues continue it may be time to make a decision about removing this tree.
It is more difficult to diagnose trees in the winter as there are no leaves which can help us to get a better picture of the tree and how it is growing.
I have observed several factors from the photos you have sent:
1. In photo #1: in the upper right, the branch that has two pruning cuts, the bark appears to be very dark in color and this could possibly be sooty mold which is caused by a fungus. This may have been evident on the leaves last season. Sooty mold is the result of aphid or other insect feeding on the leaves and/or other parts of the tree. It will be a sticky, sweet residue that may attract other insects.
Also there is an area of discoloration and loss of bark on this same branch. I cannot tell for sure from the photo if this area could possibly be a canker. The branch running parallel also looks like the bark could be sloughing off. These are symptoms of a stressed tree and/or a unhealthy tree. Here is a website with citrus tree diseases and disorders, pay close attention to the section titled "Bark Oozing, Cracking, Peeling or Distorted Growth":
https://ipm.ucanr.edu/PMG/C107/m107bptrunkrootdis.html
2. In photo #2: The base of the tree has several splits and areas that does not appear to have healthy bark. This could be a symptom of a root issue. It is possible that you may have seen some "gummy" areas last season around these splits. There are a number of plant disease that will cause this. It looks like there is a sucker that is coming up and this would be from the root stock below the graft. Sometimes trees will send up suckers as a result of disease or other stress.
3. In photo #3: In the upper right section where there is a joint with 2 limbs, the joint is dark in color and has what looks like a canker or streak of black coming down the main branch. Slightly to the left on a branch that is green there are two dark areas that could be cankers or sooty mold. It is hard to tell from the photos.
It is possible that this tree is in slow decline and the issues that I have observed are the result of decline, disease and/or insect activity. The use of a root growth hormone may add more stress to the tree. You can watch this tree closely this growing season and see if the same problems occur. If all the issues continue it may be time to make a decision about removing this tree.
