Need Help: Unidentified Mango Disease & Nothing is Working

12 years ago

I am having a problem resolving whatever is killing any new growth that emerges on my Valencia Pride seedling. I am going to post pics below in hopes that someone can tell me what is causing this. This seedling has tried to push new growth all summer and each time this black shiny coating creeps up the branch and up the vein of the leaf then spreads over the branch and kills it. It is not sooty, can't be wiped off and acts like a dried shellac like finish. As you can see in the pics it actually has cracks it it. I have shown branches to several nurserymen who sell mango trees and no one can tell me. PS This is the mango seedling I previously posted about -where the tap root was broken when I up-potted it. I have tried Bromide and copper to cure it. Nothing has worked so far.

Comments (5)

ohiojay
12 years ago
Dr. Crane has some great videos on mangos and some deal with disease. Might help.

http://trec.ifas.ufl.edu/fruitscapes/
gomango
12 years ago
Marinfla, it could be a bacterial infection. Possibly apical necrosis, caused by a bacteria pseudomonas syringae var. syringae. It typically starts as a small angular lesion on the leaf which spreads to the central vein and then to the growing tip. Fungicides will not kill it, but antibiotics such as streptomycin injection, if you have access to it may do it ( that is illegal in Australia, but I understand it is used in USA). It is generally spread on wind and rain and appears to becoming a worldwide problem in the cooler mango growing regions. It was first detected on mango in the 1990's in Spain, but now seems be in most temperate regions. The bacteria comes down with the rain and enters the plant through wounds in the stems or leaves. If there is a lot of minor damage to leaves caused by wind then it helps the bacteria get into the plant. Spraying with copper oxychloride regularly combined with a sticking agent will help stop infection. If you cut infected branches or leaves off I suggest sealing the wound with paint to prevent the wound being a source for new infection. It is also associated with frost injury as it uses the injury from frost as a point of entry.
Hopefully, it may be something else, as I do not see signs of the angular type of injuries on the leaves.
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marinfla
Original Author
12 years ago
This actually starts at the bottom of the new branch and climbs upward towards the leaves. Does anyone know of a place I can take a sample of the branch to get it checked?
hmhausman
12 years ago
I suppose the Ag. Extension Office in either Dade or Broward might be of help. I have no clue what your seedling has. I've thankfully never seen it before. If it were me, I'd dispose of the plant before it spreads to your other trees.

Harry
bsbullie
12 years ago
I agree with Harry. I understand it is a seedling you have grown and raised, but...a seedling VP is not worth the headache or risk especially when the expense to replace it with a grafted one is minimal compared to what you will "spend" in all aspects to nurse the seedling along.

Rob