Powdery mildew? Or hard water spots?

deltronZER0

Active member

• Aug 5, 2020

• #1

Hi all,

Feeling like I’m going crazy, so I wanted a sanity check. I’ve been dealing with some white spots on my plants. First instinct was that it is PM, but now I’m doubting it? I’ve been using doctor zymes eliminator as well as spot spraying H2O2. When I hit it with H2O2, it doesn’t seem to fizz like I’d expect it to, but it does seem to keep coming back. Plants are outside, I’m in the Bay Area, and while days have been a lil cloudy, I just can’t believe this would be a problem right now

Is this powdery mildew?

 

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Fixer

Active member

• Aug 5, 2020

• #2

It doesn't look like water spots to me perhaps the H2O2 is causing it. If you have an RO filter I'd try to see if you can rinse the spots off. Distilled water would work too.

 

Creeperpark

Well-known member

Mentor

Veteran

• Aug 5, 2020

• #3

Looks like spider mite damage, but I can't be sure. Take a magnifier and look closely and rule out bugs, just to be on the safe side. .

 

tobedetermined

Well-known member

Premium user

ICMag Donor

• Aug 5, 2020

• #4

Fixer said:

II'd try to see if you can rinse the spots off. Distilled water would work too.

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Try this. I did have a teeny bit of PM two weeks ago, which I attacked with water/detergent/baking soda mix. It solved the PM but a few days later I saw more - except it wasn't - it was only baking soda residue which did wash off.

 

Fixer

Active member

• Aug 7, 2020

• #5

Nice! Tragedy averted.

 

deltronZER0

Active member

• Aug 13, 2020

• #6

Hey all,

I thought I’d beat this, but still seeing some white spots that got me trippin. What do you guys think? Is this all PM?

 

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troutman

Seed Whore

• Aug 13, 2020

• #7

Hydrogen peroxide on leaves will burn them. Water the soil or grow medium and not the plants.

 

I

I wood

Well-known member

• Aug 13, 2020

• #8

troutman said:

Hydrogen peroxide on leaves will burn them. Water the soil or grow medium and not the plants.

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3% right out of bottle will shrivel pistils, yes, maybe even burn leaves.
A solution of up to 1 % will not have any adverse effects in my experience.
H2O2 is useful to buy a couple of days to find a better solution or spot treat in between other treatments. Also useful to get you through the last week of flowering.

 

deltronZER0

Active member

• Aug 13, 2020

• #9

I’ve been using super diluted H2O2, and haven’t seen too much burning on my leaves. Do the most recent pictures look like PM?

 

I

I wood

Well-known member

• Aug 13, 2020

• #10

yes

 

Tynehead Tom

Well-known member

• Aug 13, 2020

• #11

it depends...... are you spraying your plants often?
it could be residue left from evaporation of a foilar spray, concentrated at the lowest part of the leaf as that would be the last area to dry.
I get hard water , or mineral spots on the lower leaves of my plants and it does trip me out sometimes having me think I have PM starting.
In my experience, pm starts out as roundish blotches that visibly have a fuzzy and raised appearance.
That leaf tip photo , the first pic.... that looks like thrip damage to me but hard to say.

 

deltronZER0

Active member

• Aug 13, 2020

• #12

Here’s another picture of one not pictured in the 3 pix above. It doesn’t appear ‘fluffy’ or raised or anything. It does seem to be occurring a lot at the junction of leaves, which I’ve totally noticed holding onto water in a strange surface tension-y way. Does PM usually start where there is standing water? Or does it need air to actually get going?

 

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Tynehead Tom

Well-known member

• Aug 13, 2020

• #13

that looks like evaporation residue to me