yellowing leaves and black leaf parts on alocasia

Question

info

• alocasia plant
• bought from a nursery
• placed in a well-lit corner of the room, without direct sunlight
• plant is not over-watered, only watered when soil dries
• got it for about 3 weeks now

issues - day 21

1. some of the plant leaves are getting yellow: big ones and small, old ones and new.
2. some leaved suffer from a black spot / spec (similar to this). it's not over-watered, so i suspect a bacteria of some sort, but the black part is at the edge of the lead and doesn't look like bacterial spots (for example). i had another leaf that got lower for some reason, touched the floor, and had the same black symptom (and later was cut off).

issues - day 22

1. overnight the disease / virus infected the leaf. now it looks like a fungus / virus. my guess is black spot disease (also seen here), a severe case of Rust Fungus (as seen here) or Early Blight (also seen here, section 11).
2. this only infects some leaves - note that all others look healthy.
3. though stated before (because it's the first thing that comes to mind), i find it hard to believe that it was over-watered. i still consider the possibility - but the plant was only watered once (when put into current pot), and sprayed with water (just plain water) once.
4. i did notice in the first two weeks the plant was "sweating", meaning it was soaking water from the ground and expressing it out of his leaves. it always looked like there was rain just now.

any idea on what can be the issue?

Answer 1

your plant is perfectly fine, that's the way it goes with alocasia, oldest leaves of each stem are yellowing and dying but your plant producing healthy growth at the same time. Purple/brownish leaves underside is just a variety you have, mine is alocasia wentii and has very same, cheers

Answer 2

There are mixed signals here about fertilizer. Is this the original pot and soil that came with this plant? The plant is healthy so far, but these leaves are not at all a common sight.

First, I see chemical deficit (magnesium?) in the upper leaf (possibly) with either sunburn from a window pane or nursery injury.

Second, I see almost too green of leaves in your second picture meaning too much fertilizer. The older leaves are yellowing which means this is not nitrogen deficiency.

Third, I think the bottom picture showing the newest leaves a bit purple? is a sign of Phosphorus deficiency.

Is this pot and soil original from the nursery? The store? Was this plant inside or was it out of doors or was it in a green house? The yellow leaves look like they show major iron deficiency side by side with overly fertilized leaves?

I would start looking for a bit bigger pot; if this is 10" go to 12 to 14" in diameter. Clay is best, least expensive make sure there is a drain hole at the bottom. Get a saucer to match and find pieces of 1/4 broken tile to raise the bottom of the pot off the saucer or whatever surface the pot will sit upon...increases drainage.

Use plain old potting soil and make sure that that soil has no water holding gimmicks (sponges or gels) and absolutely no fertilizer added. Bacteria and fungi ADDED to the soil after sterilization is fine. Something is very wrong with your problem, grins. Send more information! Please. Do not add anything until we figure this out. Interesting!

Answer 3

To me, it looks as though the plant doesn't have enough humidity. These plants thrive in a high humidity (think jungle) environment. Without enough humidity, leaf tips begin to brown and whole leaves yellow and die, similar to what you are seeing in your plant. (Learned this from experience.)

Ensure your plant is not near any heating or cooling vents. These tend to blow dry air over the leaves, making matters worse. Then, try to increase the humidity around the plant and see if the new growth stays healthy to maturity.