This is my first post ever, and it looks like the text didn’t post. More details: They get 12 hours of grow lights a day, about 8-14″ away. I’ve had them for 15+ years and have never seen anything like this. I can’t wipe off the white with my nail or finger. ChatGPT says it’s some kind of calcification but this doesn’t make sense to me. Maybe a fungus?? I’m bereft because it seems to be spreading crazily to a bunch of them (though not always to plants next to each other). Please please help!
GoatLegRedux
I’d try treating it with fungicide.
Is that a Dioscorea seedling in the truncata pot?
Bucephala-albeola
Definitely looks fungal – reminds me of a similar fungus on an opuntia cactus that I helped my in-laws treat. I would just go with a general purpose fungicide from a garden center.
For any leaves that are very shriveled at the base, I would remove them to reduce the total amount of fungus on the plant – I would also repot (use new pots or sanitize those).
Also, I am assuming this is an indoor setup? You likely need more airflow and/or less humidity.
Final_Ad3219
Looks like damage I found on one of my plants that turned out to be due to thrips…
If that white damage doesn’t wipe off even with alcohol then I’d recommend searching for small black insects on and around the plants, as well as small round droppings on the leaves. The bugs are abt 1-2mm and the droppings are really tiny, under 1mm. If you don’t find any then definitely treat with an antifungal. If you’ve got thrips then pyrethrin or a systemic like abamectin tends to work pretty well.
xj305ah
Looks like powdery mildew. Copper or sulfur fungicide should work. There’s also oil-based treatments that work.
Pale-Fee-2679
If it’s thrips, a fungicide won’t work. I seldom saw adults, but found lots of the white larvae. If the white dots in the first two pictures can be smushed between your fingers or are inside the leaf, it could be thrips. If so, check out what is legal to use in your country/state.
I hope it’s fungus.
tripletexciton
In your last photo, the black shiny dots on the leaves could be thrips droppings. Thrips adults can fly to other plants to lay eggs, and part of their lifecycle takes place in the soil. In addition to other options mentioned, spinosad is supposed to be pretty effective against thrips.
ContributionGold2441
The white stuff doesn’t rub off. And yes, there are some little black flecks. I really don’t know which it is, thrips or fungus, so I’m going to treat half as one and half as the other, then see what does better. Thank you all *so* much. Additional thoughts more than welcome. It is VERY humid now where I live, so I can’t have them recover outside, which is a bummer.
8 Comments
This is my first post ever, and it looks like the text didn’t post. More details: They get 12 hours of grow lights a day, about 8-14″ away. I’ve had them for 15+ years and have never seen anything like this. I can’t wipe off the white with my nail or finger. ChatGPT says it’s some kind of calcification but this doesn’t make sense to me. Maybe a fungus?? I’m bereft because it seems to be spreading crazily to a bunch of them (though not always to plants next to each other). Please please help!
I’d try treating it with fungicide.
Is that a Dioscorea seedling in the truncata pot?
Definitely looks fungal – reminds me of a similar fungus on an opuntia cactus that I helped my in-laws treat. I would just go with a general purpose fungicide from a garden center.
For any leaves that are very shriveled at the base, I would remove them to reduce the total amount of fungus on the plant – I would also repot (use new pots or sanitize those).
Also, I am assuming this is an indoor setup? You likely need more airflow and/or less humidity.
Looks like damage I found on one of my plants that turned out to be due to thrips…
If that white damage doesn’t wipe off even with alcohol then I’d recommend searching for small black insects on and around the plants, as well as small round droppings on the leaves. The bugs are abt 1-2mm and the droppings are really tiny, under 1mm. If you don’t find any then definitely treat with an antifungal. If you’ve got thrips then pyrethrin or a systemic like abamectin tends to work pretty well.
Looks like powdery mildew. Copper or sulfur fungicide should work. There’s also oil-based treatments that work.
If it’s thrips, a fungicide won’t work. I seldom saw adults, but found lots of the white larvae. If the white dots in the first two pictures can be smushed between your fingers or are inside the leaf, it could be thrips. If so, check out what is legal to use in your country/state.
I hope it’s fungus.
In your last photo, the black shiny dots on the leaves could be thrips droppings. Thrips adults can fly to other plants to lay eggs, and part of their lifecycle takes place in the soil. In addition to other options mentioned, spinosad is supposed to be pretty effective against thrips.
The white stuff doesn’t rub off. And yes, there are some little black flecks. I really don’t know which it is, thrips or fungus, so I’m going to treat half as one and half as the other, then see what does better. Thank you all *so* much. Additional thoughts more than welcome. It is VERY humid now where I live, so I can’t have them recover outside, which is a bummer.