# leaf curling



## gordonm (Aug 18, 2015)

I have St. Pipen and Lacrosse grapes. I've noticed that the young shoots will have leaves that like to curl and sometimes turn brown on the edges. I haven't seen any evidence of fungi. I've only used mancozeb and spectracide multipurpose. Looking at my pictures, can anyone tell me what might be going on here. These are second year plants and I noticed the same condition on them last year, mostly on the Lacrosse. thanks, Gordon


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## GreginND (Aug 18, 2015)

Looks like possibly damage from glyphosate. Has anyone around you been spraying roundup?

More info on herbicide damage: http://extension.oregonstate.edu/yamhill/sites/default/files/spray_drift/documents/3-preventing_herbicide_drift_to_grapes_osu_8660.pdf


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## gordonm (Aug 18, 2015)

yes, I did and there was no wind at the time and I thought I was far enough away. I guess not far enough. Making a note to be extra careful. Thanks for your fast reply. Gordon


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## grapeman (Aug 18, 2015)

Also check the underside of the leaf for mites or aphids. Their feeding can cause the leaves to curl downward.


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## gordonm (Aug 18, 2015)

yes, I did that, didn't see any aphids or mites but have seen ladybugs around, guess I'll double check. thanks, Gordon


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## gordonm (Aug 18, 2015)

read your Oregon extension and was wondering if Round-up sprayed early in the season to kill weeds round the plant might have entered the plant system even thought it mentioned that the herbicide becomes rapidly inactive once it contacts the ground. The leaf curling persists though-out the growing season WITHOUT heavy damage. ok, my plan is to kill the weeds by hand and not use herbicides and see what happens next year.


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## GreginND (Aug 19, 2015)

Glyphosate is a systemic herbicide and travels throughout the plant. There are some safer ones to use.

Glufosinate does a good job, even with roundup resistant weeds. It only affects the leaves it lands on and is not translocated throughout the plant. So if it did hit some grape leaves near the ground, it would only affect those leaves not the entire plant.

Two commercial products that I know of are Rely and Cheetah herbicides. You may need to contact your local agriculture chemical supplier for them as they aren't in the stores.


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## havlikn (Aug 19, 2015)

I have used glyphosate products for my one and two year vines and a major vineyard in Wisconsin recommends the same. The key is to be careful around the plants and not rush it. I have went through the added step of adding grow tubes but feel if you are careful, it isn't a problem. I have mistakenly sprayed some of the leaves that have escaped the grow tube. I pull the leaf off immediately and it hasn't appeared to have an adverse effect on the plant.


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## gordonm (Aug 21, 2015)

The only suggestion that has been given for the possible damage to the young leaves is by use of a glyphosate herbicide. That is a very good suggestion because I did spray around the plants early with Round-up to help keep the weeds away. I must add that I was very careful, no wind, used a barrier, etc. Could some of the herbicide gotten into the ground and traveled throughout the plant?? It seemed that only the new leafs were affected and this curling last through out the season. Well, no more herbicides for me this year and will not use any next year to see if that will make the difference. I still wonder, in the back of my mind, if there might be another possible cause. thanks everyone for your help, gordon


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## grapeman (Aug 21, 2015)

There is no possible way for the glyphosate to travel throuigh the soil and into the plant to cause the damage so don't worry about that. This could have another cause other than spray as you will see things you can't easily explain sometimes. Just be careful spraying and it should not be a problem especially as the vines get older. When young, even the bark of the shoots can absorb roundup type sprays, but as they become barkier later in life, that is minimal.


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## garymc (Aug 21, 2015)

If it's herbicide damage, I'm guessing from the curling of the leaf that it's a growth regulator type like 2, 4, d.


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## GreginND (Aug 22, 2015)

I suspected glyphosate vs 2,4-D as most of the examples of 2,4-D I have seen cause a fan shaped leaf. Not so much the curling. But it could be either. I suspect glyphosate if they have sprayed it. But 2,4-D could travel for a mile or more and you wouldn't know where it came from. Are there farms nearby that might spray 2,4-D?


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## gordonm (Aug 25, 2015)

thanks guys, there is a farm right across the street and they have used chemicals to control weeds in the pass. Not sure now because the guy raises cattle and he's getting out of the business and retiring. I used Round-up early in the season to kill weeds around my plants. I was extra careful so was wondering if it might have entered through the ground and roots. I was told this was probably not the case. Anyway I will be avoiding herbicides and see what happens next year. My plants are doing good so this shouldn't be a problem. thanks again, gordon


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## mgmarty (Aug 25, 2015)

I really think you got hit by a cloud of 2-4-D I have not seen a problem with round up as long as I was careful. My neighbor, however, uses 2-4-d regular. I can show you pics of that damage, and it's a lot like yours.


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## GreginND (Aug 26, 2015)

Thanks for the input Marty.

Most pictures I have seen of 2,4-D damage look like this:







But curling of new leaves may happen as well.

Here's a picture of glyphosate damage:


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## mgmarty (Aug 26, 2015)

Now I'm confused. What do you think got these grapes?


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## GreginND (Aug 26, 2015)

Hard to say from the picture. Could be dicamba? Or 2,4-D or glyphosate. Definitely looks like herbicide.

Here are a couple more documents (PDF) that show pictures of various herbicide damage:

https://ag.tennessee.edu/herbicidestewardship/Documents/utextension_factsheet_W297-B.pdf

http://extension.oregonstate.edu/yamhill/sites/default/files/spray_drift/documents/3-preventing_herbicide_drift_to_grapes_osu_8660.pdf


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## barbiek (Aug 27, 2015)

mgmarty said:


> View attachment 24208
> 
> Now I'm confused. What do you think got these grapes?



Those are grapes? They don't even resemble a grape leaf!


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## mgmarty (Aug 27, 2015)

Those are great links. Now I think I got hit with some form of Dicamba. Thanks.


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## gordonm (Aug 27, 2015)

well, it can be difficult to tell what type of herbicide caused the problem and how it happened considering how far these chemicals can drift. Even though my leafs curled downward and not up, if you've seen my pictures, it was probably a herbicide that effected my plants. Another sign that it might have been a herbicide is the picture I posted here. It seems to be the older leafs that get this yellowing I would guess from the loss of chlorophyll. With all the help that I've gotten on this site, my goal of growing and bottling my own wine just might happen. thanks, gordon


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## GreginND (Aug 27, 2015)

The brown spotted leaf looks like black rot - a fungus. Are you employing a fungicide spray program?


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## garymc (Aug 27, 2015)

And the pale color in the space between the veins and darker green close to the veins looks like a nutrient deficiency to me.


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## GreginND (Aug 28, 2015)

Yes, I agree about the nutrient deficiency. 

What is your soil pH? Have you had a soil test to test for nutrients?
I would also recommend getting a petiole test to see what nutrients the plants are lacking. Best time to take petiole samples is right around bloom and at verasion. So maybe plan for that next year.


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## gordonm (Aug 29, 2015)

yes, I have been using a fungicide but over the last week after the rain its been just to windy to spray anything. The fungi haven't been a big problem, I only have fifty plants and everyday will walk down and cut off any leaves that show these signs. I may be able to spray in the next couple days but was wondering if it would do any good since whatever fungi have settled won't be effected by the spray now, would it?? My ph was good so I'll try the petiole test next year. I did use some merical-grow early on these two year plants, could that cause to much nutrients?


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## garymc (Aug 31, 2015)

Miracle Grow is formulated so you can pour it directly on the foliage for foliar feeding if you mix it according to directions, so it's not likely to burn anything. There's probably some micro nutrient missing, and I'm guessing it's not one of those in Miracle Grow. I have to give my muscadines magnesium sulfate because they require a lot of magnesium. I don't know if other grapes have that requirement, so somebody else will have to make a guess. I use a little Ironite on mine also, just to make sure there aren't any missing minerals.


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