black mold spots on my backs of my phal leaves

[Lynnzerr]

Greetings! I'm new to the board and a 'sort of' orchid newbie. I started growing a few years back, was doing pretty well with it, then fell ill and all my plant babies were lost. I'm starting again and trying to refresh my knowledge. I'm in Central Florida, in an apartment so I grow inside for now. I've recently purchased several healthy gorgeous phals from a local grower who sells at farmers markets. They all have beautiful root systems and huge blooms. These are the first plants I've ever brought home where the buds on the stalk are continuing to open.

Two days ago when I was wiping down the leaves on all my phals, I noticed that there were small spots of what looks like black mold spores on the backs of several of the leaves on my biggest one, which is 6 individual phals in a huge pot. I just brought it home over the weekend and hadn't even watered it yet. I was wiping them down with filtered garlic infused water, which the plants all respond to really well. As soon as I realized these leaves had spores, I switched out to a new cloth on every leaf I could see spores on. I checked all my other plants and saw no signs of spores anywhere else. The big one has been kept separate from all the others.

Tonight, I see spores on the leaves of all my plants Sigh.

I just checked the bacterial and fungal diseases link at the top of this forum. I didn't see anything that resembles what I've got. These look like spores that start on food left too long in the fridge, and they wipe right off.

Any advice would be really helpful!

[tmoney]

howdy, and welcome to the ob!

im sure more experience folks will chime in as well, but that doesn't look to be anything too serious. we get that occasionally on some of our phals. some wipe away, some seem to be permanent. either way, it doesn't seem to be a big deal for the plants.

we gently wash all our leaves thru the year with dilute soap and water. if you spray liberally and gently wipe the leaves top and bottom then it should be fine.

best of luck with the new plants and your growing orchids collection!

[estación seca]

Welcome to the Orchid Board!

What are your temperatures and relative humidity? Mold might grow on a carbon source spread on the leaves. I suggest you not use garlic infused water on them.

[Lynnzerr]

Yes I was thinking that might be part of my issue. The Temps in the unit range between 75 and 77 degrees Fahrenheit. There's decent air circulation.

The spots first appeared on my larger plant, whi h I hadn't used anything on or watered when I brought it home 2 days earlier. So I'm certain the garlic water isn't the source for the spots on that one.

[zzgirl7588]

Idk about your spots - but Im interested in any advantages of using garlic water. Is this to just wipe leaves or to actually water the plants with? I've never heard of that before....

[MateoinLosAngeles]

A few things:

1) Never share a cloth between plants, if the new plant arrived with a disease it will be carried through either the wipe or the water. If you're going to wipe leaves, use different cloths or disposable paper towels, and do not dunk the cloth in the solution after it touches the plant as many pathogens can live and reproduce in water.

2) The garlic thing is a traditional DIY solution that has been trending and pushed on social media. The claim is the allicin present in garlic has fungicidal and pest-repellent properties and the garlic additionally offers some nutritional value. This has also been popularized due to research to find affordable solutions against the huge problem of antibiotic-resistent bacteria, mostly for the developing world. So, yes, Garlic has potential but we don't know for what yet and, ironically, it has only shown antifungal properties on funghi that doesn't infect plants Lol.

3) I agree with estación that the organic film leftover by the garlic mix on the plant leaves could've contributed to the harboring of whatever you're dealing with.

4) Fungal spotting is usually due to leaves staying too wet, for too long, under too hot conditions, and with inadequate air movement. So even if you spread it from one plant, your conditions were appropriate for the disease to progress. Phalaenopsis do need warmth, and thrive in humidity, so do funghi, so leaving the leaves wet in a stuffy humid environment is not a great idea. I grow my orchids on shelves and I make sure to run the fans directly on them after I water them.

5) Treatment: I have never had an issue with spotting spreading. It's not like erwinia or black rot, those are terrible. The spots usually stay localized but they can spread quickly so there are different things people do: spray hydrogen peroxide or Physan on the leaves to kill the spores, any big lesions you can cover with nail polish or glue (I use a home-made poultice mixing glue with cinnamon), try not to be shaking the plants or moving them around while treating and have the windows open or an air purifier running, if they remain wet after treating them, in your conditions I would pat them dry after 30 mins to an hour, or at this point it should be safe to run a fan assuming you killed most spores. If you see the infection spreading you might need something systemic, Copper Fungicide has somewhat systemic properties (I use it) but can only be used on succulent-like leaves such as Phalaenopsis and not on thin-leaved plants like Dendrobiums. Other options are Daconil (kills on contact) and Cleary's 3336 (systemic), neither of these two are labeled for home residential use and therefore I don't use them, they also pose environmental concerns. If I have a plant that might exhibit a few black dots, I will use hydrogen peroxide every time. If I see something that is serious I have tried a DIY solution of cinnamon and alcohol in addition to the poultice, which has worked for me but leaves a dusty film on the leaves for what seems like forever and damages their shine. I have also treated infected wounds with Chlorhexidine, which is sold as prescription antiseptic mouthwash to treat gingivitis, it worked great at the human solution on pseudobulb wounds but I could not find any studies on additional effects on plants. I experimented with it because it's potentially less toxic to humans than other disinfectants.

[Lynnzerr]

Hello and thank you for your lengthy response

I know my wiping cloths aren't carrying bacteria or spores. I do stick to changing cloths while wiping down leaves and always use a sprayer to moisten the cloths as well. When I'm done, they go in the rag bin to run through the laundry. I'm highly sensitive to chemicals so my laundry gets a final rinse with vinegar to remove all residues and tannins and in place of fabric softener.

I actually saw the grower on Friday, and it turns out what I had was mildew from not enough air circulation, which doesn't damage the plants when controlled. I've added small fans to all the areas where my plants are now. and so far so good!

I'm actually using the garlic for the natural auxins which have been shown to promote cellular division to promote blooms and root growth. I've found that my plants really perk up after they've been fed with a tonic of garlic and distilled water. Not that they were drooping before, they just look super perky for a day or two afterwards.

[estación seca]

Fungal and bacterial infections are very uncommon inside homes because the humidity is rarely high enough. Even in my sunroom, with relative humidity often 60% or higher, I have never had any fungal issues. I have never used any fungicides, nor cinnamon. I had Erwinia once on Phals. when I had to close it tightly for two weeks during the hottest part of the year when I had surgery and couldn't care for my plants. The relative humidity was probably above 90% with temperatures always above 85 F / 30C.

You likely have fungus growing on something smeared on the leaves, not on the plant itself. This kind of fungus is rarely invasive. Spots on leaves in homes or lower humidity outside areas are almost always problems with culture rather than infections.

[Lynnzerr]

Originally Posted by zzgirl7588

Idk about your spots - but Im interested in any advantages of using garlic water. Is this to just wipe leaves or to actually water the plants with? I've never heard of that before....

I do both but only once a month. I'm using it mostly for the auxins present in garlic, to support blooming and root growth.

[MateoinLosAngeles]

Originally Posted by estación seca

Spots on leaves in homes or lower humidity outside areas are almost always problems with culture rather than infections.

Agreed, thus why my suggestions were about improving culture.[COLOR="Silver"]

---------- Post added at 05:43 PM ---------- Previous post was at 05:30 PM ----------

Originally Posted by Lynnzerr

I actually saw the grower on Friday, and it turns out what I had was mildew from not enough air circulation, which doesn't damage the plants when controlled. I've added small fans to all the areas where my plants are now. and so far so good!

I've never seen or heard of mildew growing as black spotting on plants, but okay. Some people use it as a very generic term to refer to a moldy growth.

The reason for treatment is mostly to reduce the concentration so you minimize the amount of plants that get spotting for aesthetic reasons. Another reason is that without testing you don't really know what it is, so some people might prefer to take preventative measures. If I get something spreading through my plants, I will address the different possible issues and remedy them.

This decision, of course, varies depending on the plant. I wouldn't treat Oncidiums or Zygos, they always get spotting. For a Phalaenopsis, they have such resilient, succulent leaves that seeing that would worry me. I recently had a Phal grow a little black lesion and I washed it with hydrogen peroxide and then simply waited and observed, didn't cut the leaf or anything. If I saw it spreading to other plants I would've probably taken a more aggressive approach. Usually, if I have plants showing signs of stress for no apparent reason, I move them away from the crowd to avoid possible disease transmission.

Originally Posted by Lynnzerr

I'm actually using the garlic for the natural auxins which have been shown to promote cellular division to promote blooms and root growth. I've found that my plants really perk up after they've been fed with a tonic of garlic and distilled water. Not that they were drooping before, they just look super perky for a day or two afterwards.

Ah, I see. Some people use coconut water for that. Why not drench the pot instead of going through the hassle of wiping the leaves?