It very well could be some type of borer, but I haven't seen borer damage that looked like this before. Would some type of borer hollow out a large single area like this? The layer below the sawdust is completely smooth with no signs of tunneling. I could have missed it, but I also didn't see any signs of entry. The sawdust part definitely seemed like borer damage to me, but everything else just didn't match up with what I think of when I think of borer damage. I just googled apple tree borer damage and didn't see anything that looked similar to my tree. Is there something else that this could be or does it still sound like borer damage? I would post a picture, but I haven't had a camera with me when I go out to the farm.

I would stick to information tailored to your region. It is very difficult to evaluate the basis of their guidelines and whether they are concerned only with replant issues. There is already ample P in many soils and you should prepare your soil based on info taking into account your particular soil

Katrina: The fact that you are seeing some infection in this old pruning cut is not a good thing. Also, what you are seeing I would guess is a fungal fruiting body, and it is my understanding that these do not develop unless the fungus is well established. BUT, BUT, BUT, there are many kinds of fungus that can infect pruning cuts, and some of these grow smaller than others and put out fruiting bodies very quickly. So, this infection may not be deep. Also, fungal infections sometimes develop in old pruning cuts and do not progress into the wood of the trunk of the tree--after the callus closes the wound they die or do not progress any further. O'Hara briefly notes some research findings in his article about this. I can report one experience I had with a very large and tall tuliptree that was in my yard where I used to live. This was a tree well over 100 feet tall and about 2 1/2 feet in diameter. I noticed a place about 25 feet up where a large old branch had broken off many years before and it had an incomplete covering with callus. Because I was in a neighborhood with houses close together, I was afraid and the risk of huge damage if this tree was blown over or broken with the wind, I did not really trust any arborists opinion--what if he was wrong? People could be killed, a house destroyed. So I had the tree taken down. As it turned out, the tree was still surprisingly sound and did not at that time have a great risk of breaking at that point. That does not say that some problem could have progressed in the future, but the tree was, after all, basically OK. My recommendation. If you can get up on a ladder and do a close inspection of this yourself (assuming you can do this securely, poke into the area and see what kind of softening of the wood has occurred. If there is a fungal fruiting body that you can collect and put in a jar, do that--it can be identified. And it may not be too late to treat the area with copper fungicide as I have been recommending. If the wood still seems fairly sound--not turned to some kind of soft mass, I would say it may not be too late. And for a first treatment on an area like this I would paint it twice so you get a good "soak in." If the callus later closes the wound the copper fungicide that will at that point be under the callus may have some effect on stopping or reducing the infection. If you want to hire an arborist that may be a good idea. But I am not sure how much training they have in identifying specific species of fungal rot pathogens, and I am not sure that methods they have to determine the exact extent of a fungal infection. Maybe some arborist can give me some information here in this forum about this. In any case, I would examine the area carefully yourself so you will know exactly what the arborist is talking about and you can decide if it makes sense based on your own observations. And you will know what kinds of questions you can ask. Anyway, to sum up, I think there is a good chance your tree will be OK. --Spruce

Hi! There are a couple of things it could be like gummosis etc. This is a like to texas A&M citrus division. The section on Diseases. I know it will help you. Here is a link that might be useful: Texas A & M citrus horticulture