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Subject:  Is this powdery mildew?

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Date Posted


Boston, MA

Noticed some white spots on my leaves, about a week after planting outdoors. One leaf is extra bad. Ran to the store for fungicide and could only find Bonide sulfer-based spray. Nervous to lose my plants so early.


5/17/2021 8:26:45 PM


Did you spray anything recently?

5/17/2021 8:33:22 PM


Or splash them when watering with ferts?

5/17/2021 8:35:41 PM


Boston, MA

When I snapped the photo it was about 30min after I applied the sulfur spray, if you look close you might see some dried hazy white spots on the leaves from the spray itself. I hadn't fertilized the patch since transplanting, just whatever was in the topsoil, compost, and manure. It's definitely possible they got splashed, the first night they were outside they were accidentally rained on...

5/17/2021 8:41:21 PM

The Gridiot

10,000 BC Younger Dryas 2

My guess is some kinda splash and high humidity/ moisture. Summer weather :(dry & sunny) should change things around. I've got some bad looking leaves like that too but it doesnt mean my season is over. It doesnt look like PM but you could cut just the rotted part off. Ive done this & sometimes that has helped I think.

5/17/2021 10:47:11 PM

McMillin Giants

Salem Ohio

That bright white looks more like sunburn to me.

5/17/2021 11:05:06 PM


Syracuse, NY

Easy, now - it is NOT powdery mildew (PM) and you sprayed for it. Whatever it is determined to be, don't rush into anything or you'll create more problems. It COULD be, but I'm not saying that it IS, aphids; Please read what others have said about it and go to that link on that page to see an extreme example of aphid damage.

I think what happens is something is dragging a leaf or two 'down' to begin with and the insects see that as an opportunity to feed on those leaves that are more susceptible to them ('Kick 'em when they're down?');


If not aphids, where I would literally lay on my side with a spotlight to see if i could see any or evidence of them under the leaves (I've never knowingly had them), I'd be equally as worried about the yellow seed leaves.

Do not worry or rush into, lol;

IIIIIIIIIIIIIIIIIIIIIII would water my plants with only 1 Tbsp./gallon H2O Miracle-Gro 24-8-16, 1, maybe 2 times a week, @ one gallon - the formulation on the shelf for a couple of years now.
It is odd that the one thing that everyone in the world uses on plants is rarely spoken of here. Go figure. It's all I use until male flowers appear. Easy for me to say ALL of this - i have about 23+ plants in my basement and only 15 will get planted, so, Sir Plus is in the House! Best of luck and keep us posted---eg

5/18/2021 1:51:00 AM


Syracuse, NY

For much NICER people giving you similar advice with the same end result, minus aphids consideration, lol:


DO check that it is aphids, or even cucumber beetles, though(!)---eg

5/18/2021 9:03:28 AM


Boston, MA

Thanks everyone for taking a moment to calm my nerves! I am glad to hear this doesn't look like powdery mildew. I will keep an eye on splashing/sunburn/fertilizer and hopefully get these vines looking sharp again soon!

5/18/2021 8:16:16 PM

big moon

Bethlehem CT

Good call on the seed leaf color, that is why I recommended some Nitrogen.

5/19/2021 7:47:00 AM

Total Posts: 10 Current Server Time: 5/16/2022 6:14:12 PM
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