Why is my mango tree rotting and lots of dead branches
I've recently bought an old Queenslander with a large Mango tree in the backyard (approximately 6-8 metres tall). I've noticed the base of the trunk has what looks like some kind of fungal infection that is rotting the trunk. It also appear to have killed some of the branches growing from that part of the trunk, which are dry and leaf-less and will sometimes fall off in wind. The tree is generally fruiting quite well at the moment (hopefully not a sign of stress). I'd love to prolong the life of this tree but aren't sure what to do. I've cleared the mulch to keep it dry. I've included a photo of the trunk.
This could well be collar rot that has infected your mango tree. The disease is caused by a soil-inhabiting fungus and the first symptom is usually seen near ground level where some gum may ooze out from the bark. Later the bark may appear water soaked and when it dries out will become brittle and split. This fungus grows well in damp conditions and is often seen where mulch has been placed too close to the trunk of the tree. You have taken the correct action by removing the existing mulch. Anti Rot fungicide is a systemic product that can be applied to the foliage of the tree to control this disease. It acts as a preventative as well as a curative treatment. When your tree shows signs of recovery, you can then apply a fertiliser such as Thrive Citrus and Fruit Natural Plant Food which will encourage the tree to put on new growth while supplying all the necessary nutrients the tree needs to stay healthy. I am sure with all the attention your tree is going to receive, it will soon recover.
Answered: 14 Jan, 2014