White Powder Mildew Southern Ontario durning hot humid summer

[AllNewToThis]

Hi everyone, I live in southern Ontario Canada where during mid to late summer the weather is really hot and humid. I am wondering what people do to prevent white power mildew(WPS) during this time. 2 years ago it was really bad and last year, I followed people’s suggestions but still got some. Even the local hydroponics store says everyone gets in during the summer. Does anyone know of preventative sprays I can use that I can get in Canada and that don’t cost an arm and leg??? I have used Safer’s fungicide spray and it works great but it comes in such small bottle and I have 16 plants that it takes almost 2 bottles a plant every time and come middle of summer you can’t find it anywhere. I do have a sprayer if I can find something that concentrate and mix and spray that way. Any suggestions would be great. I want to try really hard this year to prevent it even if I have to spray every 7-10 days with something. Thank you for any advice.

 

[ComfortablyNumb]

Is this an outdoor grow?
If inside, what is your humidity level amd temp?

 

[mysticepipedon]

Spraying periodically with Green Cure might help. It's quite safe (potassium bicarbonate). The only issue with it is that when in flower, it will not only desiccate fungus spores and hyphae, it will turn white pistils red and dry, giving the appearance that the plant is nearly done.

I have never used it in late flower, and generally don't like to spray anything on a bud, no matter how safe. But it is very effective against fungus.

It will wash off in rain, so reapply after a rain.

 

[AllNewToThis]

Is this an outdoor grow?
If inside, what is your humidity level amd temp?

Outdoor grow

 

[AllNewToThis]

Spraying periodically with Green Cure might help. It's quite safe (potassium bicarbonate). The only issue with it is that when in flower, it will not only desiccate fungus spores and hyphae, it will turn white pistils red and dry, giving the appearance that the plant is nearly done.

I have never used it in late flower, and generally don't like to spray anything on a bud, no matter how safe. But it is very effective against fungus.

It will wash off in rain, so reapply after a rain.

Thanks, I will see if I can find it. Can I use in early flower?

 

[Farmer88]

Hi everyone, I live in southern Ontario Canada where during mid to late summer the weather is really hot and humid. I am wondering what people do to prevent white power mildew(WPS) during this time. 2 years ago it was really bad and last year, I followed people’s suggestions but still got some. Even the local hydroponics store says everyone gets in during the summer. Does anyone know of preventative sprays I can use that I can get in Canada and that don’t cost an arm and leg??? I have used Safer’s fungicide spray and it works great but it comes in such small bottle and I have 16 plants that it takes almost 2 bottles a plant every time and come middle of summer you can’t find it anywhere. I do have a sprayer if I can find something that concentrate and mix and spray that way. Any suggestions would be great. I want to try really hard this year to prevent it even if I have to spray every 7-10 days with something. Thank you for any advice.

If your plants have not presented any flower use a heavy metal fungicide like nucop wp or double nickel. Use a sticker spreader, I use NuFilm. You can also look into a very old pesticide treatment called Bordeaux mix. Spray when humidity starts to breach 65% and right after the rain, even if it finishes raining in the middle of the night, grab a green headlamp. Rotate products regularly between difderent metals and throw a biofungicide in the rotation to maintain active ingredient variety. You can, and it's a bit silly, run a low powered leaf blower into the plants to keep them dry if there is a lot of standing dew. We used to convert gas powered leaf blowers into blast sprayers which were great for tomato rows that didnt fit the tractor mounted blast sprayer. There are also actual backpack blast sprayers on the market.

Fungus spores work thier way up the plant and like to infect the underside of the leaves first so make sure you concentrate on your spray motion working bottom up. If you use a non agitated sprayer keep shaking it constantly to keep solutions suspended properly.

If fungus is a problem in your area prune very hard and keep the foliage far from the ground. This allows a very good air barrier. It won't stop the spores, but it centainly slams the brakes.

 

[mysticepipedon]

Thanks, I will see if I can find it. Can I use in early flower?

Yes. It's safe well into flower.

It doesn't have to be Green Cure. Google potassium bicarbonate for powdery mildew. You will likely be able to get a decent amount for about $25.

 

[Santa.ClausHOHOHO]

Hot,humid rainy conditions here in Michigan in August and September.
I used Lost Coast Plant Therapy last year for WPM and it worked great.
Just follow direction on the bottle. Any questions, call the number on the bottle, great customer service.

 

[oLd1]

I’m hoping this works. I misted mine with 50/50 mix of Apple Cider Vinegar and Water.

oLd1