powder mildew? help from smart growers?

[SoCoMMJ]

Also consider a product called Oxidate for PM during flower or simply use water adjusted to a pH of 10 using common pH UP and spray daily until it's gone.


it works.

Or if you wanted to use a commercial product that raises the PH and includes a nice sticker spreader...
GreenCure

Potassium Bicarbonate. I used it at 1/2 strength and it works fine.
hit everything in the room.

There is a PM thread somewhere on here that talks about it

[organicmedicine]

thanks guys this has been helpful - I'll try those options. someone told me that I might have tobacco mosaic virus or spider mites so looks like I'll have to learn more about all three afflictions!

[SpaceNeedle]

All the advice given has been very good. Nobody has however mentioned what the cause is, and I feel everyone should know, that generally it is caused by too high a relative humidity. No matter what you end up using to get rid of the powdery mildew, keep as low a humidity as you can, because the stuff thrives in 60% and high humidity.

for what its worth,

sn

[khyberkitsune]

All the advice given has been very good. Nobody has however mentioned what the cause is, and I feel everyone should know, that generally it is caused by too high a relative humidity. No matter what you end up using to get rid of the powdery mildew, keep as low a humidity as you can, because the stuff thrives in 60% and high humidity.

for what its worth,

sn

I don't have any problems getting PM in 10% RH in SoCal. Mildew thrives in low-light conditions more than high-humidity.

[Weezard]

I don't have any problems getting PM in 10% RH in SoCal. Mildew thrives in low-light conditions more than high-humidity.

I don't know that to be a fact, sir.

Got a strain here that gets PM when da buds swell up.
More correctly, they get PM whenever, and it "blooms" when they swell.
Got more light and ventilation than you can shake a stick at here, (Kona Coast).
Night time temps are high 60s, but the humidity can be fierce at times.
Got another strain, growing in the same cage that never shows PM.

Jus' a few more facts to mull.
Draw your own conclusions.

Aloha,
Weezard

[copobo]

ideal growing conditions for pm are temps below 70 and rh above 60. Big temp drops from day to night will cause dew and promote PM growth.

BUT, once you have it, those thresholds are out the window. Taking RH down to <40 and having temps >80F help allot. You'll want to be pushing some CO2 if you are going up to that level with the temps (tops at 85F w/1500ppm)

Weezard - is it a strain (different seeds, distinctly different grows), or cuts from the same plant? If cuts off the same plant, you may be spreading a latent infection from the mother plant - use some eagle 20 and break the chain if you need to save genetics. Certain strains are more prone to PM than others - strains with tons of foliage like blueberry are more susceptible. If this is the case, and you are having big temp drops or nighttime temps of below 70, it's important that you prune a bunch and/or shake the plants daily to release water trapped between leaves.

Try it. Go out and grab your tree by the stalk and shake. Does water fall when the plant otherwise appears dry? If so, you need to prune.

PM is a mutha.

[Weezard]

ideal growing conditions for pm are temps below 70 and rh above 60. Big temp drops from day to night will cause dew and promote PM growth.

BUT, once you have it, those thresholds are out the window. Taking RH down to <40 and having temps >80F help allot. You'll want to be pushing some CO2 if you are going up to that level with the temps (tops at 85F w/1500ppm)

Weezard - is it a strain (different seeds, distinctly different grows),

Different strains..

or cuts from the same plant? If cuts off the same plant, you may be spreading a latent infection from the mother plant - use some eagle 20 and break the chain if you need to save genetics. Certain strains are more prone to PM than others - strains with tons of foliage like blueberry are more susceptible.

Oddly enough the G13-Blueberry has no PM problems.
The lemon-skunks were ravaged, and I only managed to save some tops from HI Homie-III by harvesting early.

If this is the case, and you are having big temp drops or nighttime temps of below 70, it's important that you prune a bunch and/or shake the plants daily to release water trapped between leaves.

Runs between 82F. by day and 68F. by night this time of year and we seldom hit our dew point.
And they really are not that dense. Fairly open, and I have them roofed so the don't even see rain.

Try it. Go out and grab your tree by the stalk and shake. Does water fall when the plant otherwise appears dry? If so, you need to prune.

Nope, but it does annoy the whitefly.
It's their "nectar" that supplies a landing spot for drifting spores.


PM is a mutha.

Indeed! It's rampant on da islands.
I've read reams from all sources and they all agree that once infected, the outlook is grim.
('druther risk smokin' some PM than some of the stuff used to kill it.)
It looks like my only option is to breed my own PM resistant strain here.
I've got ahold of some Gainsville Green seeds that survived in Florida and want to cross them with the blueberry that grows so well here.
Any suggestions on breeding stock?

Aloha, and Mahalo
Weezard

[copobo]

if you are gonna smoke it, you can certainly wash it before drying/curing. PM does wash off.

it is a mutha!

I would go with what works for you in your area. the sativas seems to be more resistant to me. if the bb-g13's hold up. do more of that and drop out the ones prone to mold.

[khyberkitsune]

I don't know that to be a fact, sir.

Got a strain here that gets PM when da buds swell up.
More correctly, they get PM whenever, and it "blooms" when they swell.
Got more light and ventilation than you can shake a stick at here, (Kona Coast).
Night time temps are high 60s, but the humidity can be fierce at times.
Got another strain, growing in the same cage that never shows PM.

Jus' a few more facts to mull.
Draw your own conclusions.

Aloha,
Weezard

Noted. I've personally seen PM attack many of my landscaping clients out here in the high desert, even at sub-20 RH.

[khyberkitsune]

if you are gonna smoke it, you can certainly wash it before drying/curing. PM does wash off.

it is a mutha!

I would go with what works for you in your area. the sativas seems to be more resistant to me. if the bb-g13's hold up. do more of that and drop out the ones prone to mold.

PM permeates the entire plant, from leaf to stem, at least in the decorative flowering plants I planted last year over in southern Los Angeles for a hair salon.

Took about a week and PM all over the place.