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Northwest Indiana

Can anyone tell me what is wrong with these leaves almost all of them have these spots on them.
Picture: http://imgur.com/EufwFrc

7/15/2014 12:22:28 PM

Germany

Downy Mildew! (It´s surprisingly early as far as my experience with this stuff goes. As far as I know, exhausted plants are more likely to have a DM infection.)

7/15/2014 2:32:52 PM

Northwest Indiana

Almost all of my leaves have spots on them. Is there a chance the plant will recover if I treat them now, or is it to late.

7/15/2014 2:51:47 PM

Farming- a bunch of catastrophies that result in a lifestyle

That is the beginning stages of downy mildew. I've had enough of it over the years here to say:
Once you have it you can only control it's spread. Chlorothalonil has worked for me, at high rate. COAT both sides of leaves. REMOVE all infected leaves that are showing spores. All your leaves have it, but you can try and leave them for as long as possible. Burn the pile you make so you kill the spores. NASTY fungus. Nothing will stop it as far as I know, but you can control it. If you have more than one plant and they aren't all infected- get the uninfected sprayed, and yank the infected one. Sorry for the bad news, we deal with it here in the south every year, it's why we do systemic AND spray programs at the same time.

7/15/2014 2:59:19 PM

Farming- a bunch of catastrophies that result in a lifestyle

PS- best to do any removal in the mornings or during periods of rain. The spores travel when they are dry, working with them when they are wet helps combat the spore spread somewhat.

7/15/2014 3:00:32 PM

Northwest Indiana

Is there any chance that it could have been caused by letting liquid fertilizer get on the leaves, or is it for sure downy Mildew.

7/15/2014 3:11:26 PM

Germany

It´s DM for sure (in my opinion), because the yellow mosaic pattern with clear borders (which are the veins of the leaf) result from infection of the small leaf area in between the veins whereas infection of the adjacent mosaic pieces might take a few days longer (depends on where the spore entered the leaf). With liquid fertilizer you usually cover the whole leaf (bottom side) and there´s no good reason for such a mosaic pattern to form. If fertilizer is too stron, it is most likely too strong for all parts of the leaf.

7/15/2014 4:07:57 PM

Bethlehem CT

Bp I am not sure where you are located, I don't usually see downy mildew on my cucurbits until late in the season.
In my opinion I do think it could be from spray or fertilizer damage. If so those spots will brown and desicate out and then the whole leaf will brown and shrivel up. Your new growth and places that you haven't sprayed will still be healthy. Don't give up.

7/15/2014 4:30:34 PM

Farming- a bunch of catastrophies that result in a lifestyle

Well, I've been looking at DM in my cucurbits for....how long have I lived here....14 years.
Fertilizer burn, spray burn, is very specific looking. it doesn't resemble downey mildew in that the spots fall directly between the leaf veins without crossing them. Spray burn, and fertilizer burn happen over the entire leaf surface, veins included. If you turn the leaf up to the light and look at it from the back side you will see what I mean. The affected areas will be very light in color and will begin to form 'square' areas. These squares are actually affected leaf material between the veins. Right now it looks like 'speckles', very shortly you will see the 'square' patterns come out.
I'm not saying kill everything you have, you can control it, but so far as I know there is absolutely no CURE. You can prevent DM, you can control DM once you have it, you can't cure DM to my knowledge. Last year I had a plant in an entirely separate area all by it's lonesome- it got DM, I hadn't kept up with it as much as I did the regular patch- I was able to control it enough to get my pumpkin to seed stage...about 2 months of 'control'. It takes a lot of work, removing leaves that are actively 'fuzzy' (lack of better term) with spores. They will be brown, limp, and appear shredded after each watering. I got rid of them prior to that stage in order to help the spray control the spread.

7/15/2014 6:24:47 PM

Williamsburg,KY

You can always contact your Cooperative Extension Agent for your County and ask their advise. Its awful early for downy mildew. Just my 2 cents.

7/15/2014 6:52:10 PM

Colorado

Angular leaf spot-anthanose ?

7/17/2014 1:03:24 PM