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jswartsel

Mango leaves have slight yellowing, grey necrotic spots..

jswartsel
12 years ago

Hey Everyone,

I have two young (under 2 years) Mangos: a Haden and a Lancetilla. Both are exhibiting some yellowing and this nasty grey spot. It isn't happening on all of the leaves and the trees overall seem to be very healthy. I have not been watering them much lately.

I haven't been able to figure out if this is a fungus or deficiency or what. Can anyone shed some light?


Shot at 2011-12-31

Thanks,

Justin

Comments (11)

  • phucvu
    12 years ago

    i don't know why all the mango experts are silent on this one.

  • hmhausman
    12 years ago

    Sorry, Justin, I missed your post.....with all the holiday activities. What's going on on the underside of these leaves with this necrosis. Any creatures lurking and feasting?

    Harry

  • mango-maniatico
    12 years ago

    That's call Alga Spot (Cephaleuros sp).Use a copper fungicide and you will be fine.

  • hmhausman
    12 years ago

    The use of copper for this would be no problem, but I am not convinced that this is alga spot. IFAS shows alga spot to look like this:

    Hmmm...can't get the link to post the picture with in the post....the link is below.

    Here is a link that might be useful: Mango diseases

  • jeffhagen
    12 years ago
  • hmhausman
    12 years ago

    Thanks, Jeff. I am no expert on spots, alga or othrwise. The picture of what IFAS says is alga spot appears to be something entirely different. Jeff.....any comment?

    Harry

  • jeffhagen
    12 years ago

    I think it's anthracnose. A picture of the underside would help. If it's anthracnose the underside will likely have dark brown / black spots. Anthracnose on older leaves will develop necrosis like that.

    A shot of the entire tree would help in determining the overall health of the tree. The leaves in the close-up appear to be deficient.

    I'd probably start hitting it with a good chelated micronutrient foliar spray 3 times a year and see if that ameliorates the problem for next year. A healthy tree can better fend off fungal infection.

    Jeff

  • mango-maniatico
    12 years ago

    My bad.I have the same problem before and i fixed with copper.I just forget the name but i find it.Gray leaf spot (fungus, Pestalotiopsis mangiferae = Pestalotia mangiferae)

  • jeffhagen
    12 years ago

    Depends on what the underside looks like. If the underside is dark brown/black then it's more likely anthracnose.

    If you can ameliorate the problem by increasing the health of the tree (eg, with foliar micronutrient spray), then that would be a better approach. Spraying copper isn't necessarily a good thing to do unless you really need to.

    Dr Campbell mentioned that the reason why he can't grow lychees at fairchild farm is because of the amount of copper built up in the soil from spraying copper for many years on what was once an avocado orchard. He now uses a copper free fungicide. I pretty rarely use fungicide myself.

    Jeff

  • jswartsel
    Original Author
    12 years ago

    Thank you so much for the replies, everyone!

    After doing more research the grey areas do seem to resemble Grey Leaf spot. But i've attached two more pictures (underside, overside, respectively) for your consideration. I just recently sprayed a nutritional spray and plan to do so again in the spring. So unless you all feel like I should correct this quickly I'm thinking about waiting until feb/march.

    Underside:

    Overside:

  • jeffhagen
    12 years ago

    OK. That's anthracnose. See figure 2 on this pdf document for comparison.

    Since it's the older leaves getting the anthracnose infection, micronutrient application should help in the long term. A healthy tree should be able to fight that off on older leaves. Younger leaves are a different story: even a healthy tree can't fight off antracnose infection on younger/emerging leaves.

    You're doing the right thing. You don't need to immediately address.

    Jeff

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