Usually if you see one - you spray all... the spores are already in the air

Preventive - if you have this problem year after year - like every fall and spring - you can use some mild preventive - Neem oil, Physan - to stop it from coming. Never had any success with Lysol. Running a fan is good,

I have both Neem and Physan on hand now. I've been using the Neem for pm and Physan in the reservoir for green algae. But I meant to ask, how do you use Physan for pm? Is it sprayed on?

Spray. You can google the dosage - but probably a tablespoon per gallon is OK,

PM at my house is really strange at times. I have fans running on my plants all the time. I periodically move plants from one shelf to the other if they start showing signs of too much or not enough light. No matter where I put them or how close to the fans they are, my mini's will periodically get it. None of the standards, just mini's.

In the wintertime, I step up the amount of humidity amongst the plant shelves by adding water more often to the river rocks in the trays. Sort of makes up for running the heat in the house. When I do this, the PM is sure to show up on the mini's.

No big deal, one or two will get it every month or so. I do the Ron Popeal method. I spray em and forget em.

I was thinking of spraying all my plants with neem for preventive measures too. Especially since I have brought different plants into the house. After much reading, I can see my zealous efforts to grab up the sickly plant on sale at Lowe’s,etc and nourish it back to health was a dangerous game. I am still tempted to rescue but now I am isolating and removing blooms n soil then sticking it in a baggy. There are reasons the plant was sickly and I thought it was from neglect not from some contagion or vector!! So much to absorb.

should I preventatively stay too?

If you are noticing widespread powdery mildew amongst your AV's, then yes, a preventative spray would probably be helpful. What really needs to be done though is to determine what is causing the environment that enables the PM.

If you are complaining primarily about one or two plants, especially if they happen to be mini's, I would treat the ones with the disease, leave the others alone. (Powdery Mildew is a nuisance but not immediately deadly. It normally does not warrant preventive treatment of the entire herd when one or two show up with it.)

Widespread and chronic powdery mildew is a problem that is fairly easily diagnosed and the prevention methods are well documented. If it persists, I would have to say that you will have to take steps to increase the ventilation amongst your plants.

PS

I am sure that you are well versed in this but as an aside note, I would mention that the sprayed plants should not be placed back under lights or in sunlight until the leaves are dry again.

Jeff - you cannot imagine how devastating PM can be in full blast, It kills. I lost some gessies because of it. It is way beyond nuisance. If you already have it showing - it is not a prevention - it is a beginning of a plague you need to stop. Prevention - is a good air movement, temperature control etc. Neem oil and Physan is prevention. The idea is - you got a plant - or several infected - you need to nail it until before all of them are and you are thinking - industrial grade fungicide - or just lets burn the house.

Oh my! I certainly did not mean to suggest that a large, grey, furry, cloud of powdery mildew spores that permeates your entire house is not dangerous. Call ghost busters!

I get that stuff all the time. Timely intervention is normally all that is needed. If left untreated for weeks at a time, yep, probably no good.

for me - it is twice a year. if I have a house fan running - i may be avoid it. There are PM magnets - like a canary bird for miners - croaked ahead of them in a presence of methane gas- if the conditions are PM conducive - SInningia conspicua will catch it first.

I don't currently have any sinningia conspicua. (conspicua=conspicuous?) My mini's are the only guys that ever get it. I have rack fans blowing right on them and they still get it once or twice a year. I never fail to treat it when it shows up and even if I don't notice it for a couple of days, I never even lose a leaf.

Left untreated, TLC will kill a plant much quicker than PM!

OH YEAH! That is so true.

There are AV PM magnets- the current one for me is Psychedelic Snow. Smithianthas catch PM easily too.

I.

Does anyone know whether you need to wear gloves and mask when spraying products like Physan 20 and Neem? For anyone who does wear a mask, what kind do you use?

This may be overkill but I was looking at purchasing this...

https://www.amazon.com/3M-8577CA1-C-PS-Chemical-Valved-Respirator/dp/B0052EA7NY/ref=sr_1_3?ie=UTF8&qid=1516282671&sr=8-3&keywords=chemical+face+mask

Get a good canister mask. I don't use it when I spray Neem, Ortho or Physan 20 but then again I try to do that in an open air environment, spraying downwind and then I wash my hands good when I am done.

I do use my canister mask when spraying "poison". (Avid, etc.) Even a very small amount of that stuff can do real bad things to you. Long sleeve shirt, rubber gloves, mask, safety glasses, etc.

As long as you have it, I would use it anytime I thought there was a chance I might breath in compromised air.

(Keep in mind, all canister masks are not the same and the el-cheapos often don't come with canisters capable of stopping all sizes of particles.) Get a half decent one that comes with canisters that actually stop smaller, dangerous particles and not just half your air supply.)

Anything is better than nothing. Physan and Neem oil are not dangerous to people in concentration we use - we do not drink them out of the bottle. We do not do a lot of stupid things - the table salt will kill you if you consume half cup of it.

The pesticides and herbicides sold for the lay people are usually very mildly toxic in concentration we use - there is a parameter LD50 - that measures how much mg per 1 kg of body weight the warm blooded organism needs to absorb - to have 50% mortality - usually they test it on rats. So Avid /imidacloprid - 330mg/kg -400 mg/kg - so basically you need to eat half of a container of 0.5 % Marathon to do yourself in.

Still even very small doses are not vitamins - so we need to minimize the exposure.

When you spray - you have 2 kinds of exposure - dermal and inhalation. Keeping yourself covered, wearing glasses and gloves pretty much takes care of it. Inhalation - we are dealing with minuscule drops of water with dissolved pesticide. Gas mask with canister probably totally eradicate these drops, My take is a cheap dust mask or a piece of cloth tied to cover a nose and a mouth - is SO much better than nothing - use whatever you have. Get everything ready and lined up, make your solution - spray everything in one go - take a shower and wash your clothes. Done.

So informative -- So appreciated -- So reassuring. Thank you.

I'm expecting my masks delivery today -- a couple of different kinds. The dust masks will keep from me breathing in the perlite dust clouds when I'm sifting it. That stuff just can't be good for you. The other disposables are for filtering aerosols. Who knows if they'll work but as you say, something is better than nothing.

And Jeff, I do have a good chemical canister mask I use occasionally. I use it for spraying Krylon fixative on my colored pencil paintings. Phew -- now I Know that stuff isn't good for you. Probably neither is my hair spray. :-(

A little bit of water in your Perlite bag - will help keep the dust down. And In knw people that just put a perlite on a big sieve - and hose it with a garden hose - n a garden naturally.

Water. Great idea! Can the bag be closed up and stored if the perlite is wet, or is this to use up during that day’s potting session?

And just to be clear, the garden hose will wash out that fine dust we don’t want in the mix, right?

Correct. The fine dust is probably just useless. We need good size chunks in our soil to delay the settling and to provide air pockets. LIke the best loam for the outside plants - it has clay, it has sand, it has humus, may be small stones and sticks...and a lot of life in it. Basically - different size particles. If it is mostly clay - the particles are too small - and they settle to a brick squeezing air out.

What I am thinking is the combination of water and light - can stimulate the green algae growth - as we were explained recently - it should be called cyanobacterium.

I am thinking that if you want to keep your perlite wet - after you done sieving and hosing - you can store it in a crate or a non-transparent box and open it as needed.

Very informative thread. Was wondering...can anyone speak as to the effect on the flowers/buds the mentioned treatments (Physan, Immunox, Ortho Rose Pride, etc.) will have?

PM is a big issue for me. I have improved the ventilation, but for months my violets' flowers and ONLY the flowers continue to be infected with the PM, and the only spray I've ever tried for PM (Phyton 27) does a number on the flowers and maturing buds, which kind of defeats the purpose. If I could find a spray that doesn't mar the blooms, I would be pretty thrilled.

Interesting side note (to me, anyway): it's the red blooms (terribly) and dark pink blooms (moderately) that get the mildew. Blue or blue-violet blooms are entirely unaffected in my growing area. And we're not talking a bit of PM that might show up on old or decaying blooms...I mean heavy PM that shortens flower life to a few days while all the leaves are clean! So frustrating.

Order Fungicide Topaz from eBay. It is a systemic, works for 6 months, doesn't mar the blossoms. Since I do not see the other side of the package - I cannot say the dilution rate - but should be 5ml per 10 liters. Leaves and blossoms that have already got PM damage - are not going to be magically cured - better remove them - they are the source of reinfection.

You probably have a significant difference between night and day temperature in your growing area. While I understand the desire to save money on heating and sleep in a cool room - it would be better if you manage to keep the temperature more even. That's why we have it mostly in a fall and spring - we turn the furnace off - but nights are chilly and the drop of temperature produces minuscules drops of moisture - dew - on the leaves - and PM spores need this moisture to sprout.

Thank you so much, Irina! That fungicide sounds perfect, and I will look for it. Even the possibility of success at suppressing this mildew issue makes me giddy with joy, haha.

You are spot on with your diagnosis of my growing conditions. In the future I would love to have a violet room with an individual thermostat for this very reason. Just trying to "make do" the best I can at the moment, and I probably get ahead of myself sometimes, hoping for "perfect" violets when my growing area (and level of skill) are far from that ideal! At least they generally grow and bloom well for me, finally, thanks in no small part to the advice I read from you and others on this forum! :-) Thanks again!

Welcome- it is not only your growing conditions. It is everybody's growing conditions.

I turn the fan on the thermostat from automatic to 'ON' in spring and fall. It helps.

Does spraying Physan 20 affect the blossoms or buds? I noticed Neem doesn't but I want to switch to Physan.

One more thing - Does anyone know whether Physan 20 would stain fabrics or affect wood or painted surfaces if sprayed indoors? (Of course playing it safest with mask , gloves, and no pets or human beings around while misting... :-) ) Bad idea?

Wow, I'd have to haul around a lot of plants and plantlets if I had to do it all outside in one day. I was hoping to apply a light misting for preventative treatment where the plants are sitting now, and only take the affected plants outdoors for a more thorough application.

I do not think you need to worry about Physan 20. The chemical there is similar to the one they use in swimming pools to prevent algae. It is not fish friendly - so if you have a fish tank there - cover it - otherwise it is not dangerous. You can spray your plants at home - and it shouldn't affect blossoms.

It will not damage your wood surfaces - but you better wipe them dry after the treatment - water will damage wood polish.

Speaking now from experience ------- as a preventative Physan 20 spray does affect the blossoms a little, although I may have sprayed a bit more than a mist. In any event, I really don't mind as long as it keeps the PM away.

I have not had much in the way of bloom damage as a result of physan spray. I switched to Ortho Rose PM spray a while back and it does no damage either.