I really hope someone will be able to help.

My Kent (probably) mango tree is mature, if small, and for years has yielded delicious fruit. For the last 3 years, we see an increasing occurrence of what what I assume to be mango internal decomposition - AKA jelly seed (note that this is a bit of a misnomer, as the damage is to the pulp around the seed, not the seed itself). The fruit pulp in the center develop a jelly like texture, but even worse, a sour, fermented flavor. The fruit outermost side is tasty as always. This seems to develop before picking the fruit, and the sourness increases with time if is is left after harvest. The more colorful side of the fruits (they are mostly green when ripe) tends to be in a worse state.

As said, this has started about 3 years ago in a few fruits, and now I rarely find un infected fruits. We have a very warm mediterranean climate, with this summer being quite harsh. There was also an incredible amount of fruit flies this year, but we sprayed the fruits and had none infected with maggots.

The tree suffers a little from leaf rust, I will spray it with copper based antifungal soon after harvest.

Can it be the effect of extreme heat, or perhaps the fruit is infected with fungi? Can fruit fly "stinging" (I know that's laying and not stinging) transfer pathogens?

Any suggestion will be greatly appreciated. Shai

EDIT: Made it more clear that the damage is to the pulp, not the seed.

  • Whoa, gotta have pictures on this mango with a jelly center. Mangos have a heavy duty elliptical heavy seed. Sure you don't have papaya? Grins. Your fruit flies might just be part of the problem.plantvillage.org/en/topics/mango
    – stormy
    Commented Sep 19, 2016 at 20:01
  • "Jelly seed" is a bit of a misnomer, it's not the seed that turns to jell, it's the pulp around it.
    – Shain
    Commented Sep 19, 2016 at 20:06
  • That sour smell is caused by the fruit fly larvae just under the skin by this article and they kinda 'jellify the meat of the fruit' couldn't find anything about the seed. How old are your trees? Fascinating.
    – stormy
    Commented Sep 19, 2016 at 20:08
  • We are at the same point...funny. The article I sent talks about the 'jellification' of the pulp by the fruit fly larvae. Let us know what you think after reading that article. Sounds like you've been reading similar articles.
    – stormy
    Commented Sep 19, 2016 at 20:10
  • I see. The outer area is mostly intact. Considering the fact that internal decomposition is mostly considered to be a texture issue, and not a flavor one, perhaps it's a combination of both - the inner flesh is damaged, and the fermentation can therefore penetrate dipper into the fruit. Thank you for trying to help!
    – Shain
    Commented Sep 19, 2016 at 20:12

1 Answer 1


where are you located? Depending on where you are located, you might need to seek specifically available advice.

Internal Decomposition can be quite tough in terms of root cause determination. It is likely that the problem is fungal or bacterial in origin, and the fact that it has been ongoing for 3 years means the problem is deep.

Heat should affect the skin and the fleshy parts first, before affecting the seed. I am not sure maggots can damage the seed the way you describe either.

As to fruit flies spreading infection, do you have any neighbors, or other trees yourself (mangoes or otherwise) that are infected similarly? If not, then the fruit flies themselves may not be to blame.

The leaf rust seems to point to a fungal infection perhaps.

In any case, what might be the best thing to do is to contact a local agricultural college or a professional farm services firm and discuss either having them come out to look at your tree and/or sending samples of the fruit in for analysis. This would be the absolute best way of figuring out how to treat the mango tree.

In the absolute worst case, you have to be prepared to forego eating the fruits or having the tree come down, if it represents a risk to other trees.

  • 1
    Found that the mango has a disease problem that LOOKS like rust but is actually ALGAE. A first for me, but I don't live in the tropics anymore. Also mangos seemed short lived?
    – stormy
    Commented Sep 19, 2016 at 20:05
  • 1
    After looking up some more pictures, It seems like powdery mildew. It looks judt like this , only much less severe.
    – Shain
    Commented Sep 19, 2016 at 20:18
  • Then try the copper spray. That should help. It may take until next season to be sure. Commented Sep 19, 2016 at 23:16

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