Phoenix Tropicals Gardening

[ajbcirc]

I recently bought a Nam Doc Mai mango from Top Tropicals in Florida about two months ago. The plant looked fairly healthy on arrival, with the exception of a handful of leaves that appeared to have some tip burn or necrosis along the leaf margins. I transplanted it into a 15 gal container that has a mixture of regular potting soil and palm/cactus mix and have been watering it every 3 to 4 days with drip irrigation (roughly three to four gallons for an hour). It gets sun for the morning and shade in the afternoon.

I fertilized it once, a month ago, with some fish emulsion and seaweed. Haven't sprayed it with insecticide or fungicide and I'm not misting the plant.

The plant just started to put out new growth last week. However, the leaves that are appearing are spotted along the leaf margins. The spots aren't raised and appear to be scattered across the leaf. There are a few dark areas on the branches as well, which I'm not certain where there or not earlier.

Does this appear to be anthracnose? Given the way TopTropicals irrigates their plants (overhead), I'm strongly leaning this way vs some sort of nutrient deficiency.

[mullenium]

Could be insect or fungus, try a copper foliar spray, cut off the drip irritation to them and water by hose manually when the pots start to lighten and the top starts to dry out.

No more ferts either.

Then just wait it out and cross your fingers, I wouldn't worry just yet

[ajbcirc]

Thanks for the reply. I'm assuming that this is fungal and will empirically treat this with myclobutanil (immunox) first since it's a systemic fungicide and then, in a week, alternate with a copper agent to knock out topically whatever spores are still around and to treat any possible bacterial cause.

I have two other mangos (Manila/Ataulfo) from Laverne next to it and two Timotayos on the other side of the property that have been treated similarly (same watering and fertilizer regiment, location) -- all four look happy as clams with good growth and a flush of unaffected leaves. I doubt the Manilas will be affected given the heat and lack of humidity, even if they're colonized with spores, but they'll get treated as well due to their proximity to the sick plant.

This sucks. The 7 gal Nam Doc Mai was on sale at Top Tropicals -- I have a feeling now why that was the case...

[ajbcirc]

Looks like it's anthracnose.

Just got an e-mail from someone who pointed out this link:

http://www.ctahr.hawaii.edu/nelsons/mango/

Here's a shot of young mango leaves with anthracnose:



So much for Nam Doc Mai being anthracnose resistant!

[phoenixtropicals]

As far as I know AZ is way to dry for it to be any kind of fungal problem. It could just be some leaf hopper damage. Your plant looks healthy overall to me. My mangoes always have some battle scars but do fine anyways. The most likely way to kill a plant is to overreact and dump a whole bunch of something on it. It looks like your plant is growing like crazy so I would stick with your current plan with some minor adjustments.

I agree with Mullenium that its possible you could be fertilizing it too much, especially if its in a pot. Plants can handle more fertilizer in the ground because they are surrounded by 1000's of pounds of earth that dilutes things more. I haven't tried seaweed on mangoes, but I did find that green sand burned them. I think you are better just sticking with the fish, and being conservative with it.

[mullenium]

what did you pay for the 7gal shipped?

did you use their 10% off coupons?

[ajbcirc]

I think it was $105.

Got confirmation that it's anthracnose from the University of Florida's expert on mango cultivation. Top Tropicals overhead watering practices is probably the cause. Anthracnose, unfortunately, is incurable without essentially destroying the plant with certain phytotoxic fungicides.

Even though we don't have any humidity, I guess all it takes is a ton of spores colonized over something slightly moist (bud point, healthy branch, et al), add heat and you get disease.

[mullenium]

Call top, see if they can do something for ya..don't email they never reply

Who knows, maybe with the dryness here it will go away? Or maybe u can flush the soil with diluted neem oil?

[ajbcirc]

Talked to Mike. The best he would offer was another 10% off coupon. Essentially, the gist of the conversation was that he wasn't responsible for anything that happens to the plant after a week after it arrives.

In hindsight, I should have hit the plant hard with daconil after it arrived, as a few had suggested on a few other blogs/forums that I frequent due to the prevalence of anthracnose in Florida.

After heavy fungicide spraying, it doesn't look like the fungus hasn't spread any further. Unfortunately, once a mango has it, it has it forever -- I doubt I'll see any further outbreaks this summer given our weather here (and my spraying).

I'm seeing new growth buds starting up and away from the diseased ones, as the older ones continue to shrivel up. That's a good sign.