Sweet Tart leaf damage

[Dbny5000]

We planted this Sweet Tart in August 2023, late in the season in the Orlando area. It spent the winter with worsening leaves and now they look like this. Besides looking like tiger dermis, what is it? Anthracnose? I didn't get to it with sulfur and copper until February when this condition was well established. Lots of new leaf growth lately; the tree seems determined to shed all of these old leaves. Any ideas on keeping this from happening again, whatever it is? On the oldest set of new leaves, there are some brown tips, so I'm already nervous. I think we got this tree from Everglades Farm because it was one of the few places that had Sweet Tarts in stock at the time. Wondered if there's any chance it's not on Turpentine rootstock and that might weaken it? We planted a Valencia Pride in April '23 and a NDM 4 in July '23 and they didn't turn out like this! The 15-gallon VP grew throughout '23 and now has eight or 10 emerging mangoes on it . . . Thanks for any thoughts!

[gozp]

Fertilozer burn. Trees looks good.

[roblack]

Mangoes grow roots first, when planted in ground. Can go many months, especially over winter, and not show any signs of growth above ground. Water when young, will also help wash out any excess fert.

[Dbny5000]

Yes indeed, roblack, we certainly saw no growth above ground after the cooler months started. Would be curious how much root growth happens during that time! But thank you and gozp for pointing out fertilizer burn. I have tried to fertilize conservatively but apparently not conservatively enough!

[Dbny5000]

Just an update on our issue of fertilizer burn. I skimmed off the top inch or two of soil from all of our mango trees because I think I threw down too much potassium. Then I watered excessively for 2 weeks. And now it's been two or three weeks and the new leaves no longer have any browning tips.


Feeling relieved!

[Dbny5000]

The relief did not last! The problem returned to all leaves:



Since it was initially thought that we'd overfertilized the tree (based on replies here), we backed off on fertilizing altogether. By the end of last year, the whole tree had become pale! I decided that it had nitrogen deficiency and began fertilizing more heavily. In 2 months it greened up, indicating I really hadn't overfertilized. But the strange edge striping returned. I had been judging it as a potassium deficiency, or lately a potassium-calcium imbalance -- I had not put down a bunch of gypsum in conjunction with the 8-10-10 fertilizer I now was using. But tonight I found a video on Truly Tropical's youtube that pointed me down the path of what this all may really have been: BORON DEFICIENCY.

https://www.youtube.com/watch?v=PW1qQxE00PE

So I'm answering my own question -- hopefully correctly -- and maybe it'll be of use to someone.

[fruitnut1944]

The video says boron toxicity. But he's not 100% sure. And they're symptoms look a lot worse than yours.

[Dbny5000]

I did expand the sources beyond the video and posted one example of them.

[JakeFruit]

Any weed & feed grass fertilizers being used near the tree? The weed-killing chemical can cause damage to mango leaves that looks similar