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Tasmania Australia

Hi, Just a question regarding the older leaves on a plant.
The older leaves on my plant are brown around the edges, sort of like a rust around the edges.
Is this a sign of Calcium deficiency or too much Calcium, or something else?
New leaves look fine, nice and green.
Any ideas would be greatly appreciated.
Cheers.
Peter

2/2/2017 12:44:10 AM

Central Illinois

can you post photo

2/2/2017 10:19:31 AM

Tasmania Australia

Sorry, yes forgot that again.
Here is the leaves that i was mentioning.
http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=269188
This is what the newer leaves are looking like.
They have a slight yellowing on the extreme outside edge.
http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=269189

Any help and information would be greatly appreciated.
Cheers.
Peter.

2/2/2017 9:44:07 PM

Bavaria, Eurafrasia

Alternaria associated with the lack of potassium. Spray foliar potassium early in the season, but not short before flowering. After fruit set apply potassium foliar again and every three weeks then. I use forceps-nozzles to spray on and under the leaves at once.

2/3/2017 3:02:57 AM

Central Illinois

look here
http://www.bigpumpkins.com/Attachments/Leaf_Problems_Summer_2011.pdf

2/3/2017 10:05:07 AM

BC, Canada

The leaves look a bit beaten, Have you had much wind on the plant? Physical damage can then lead to opportunistic diseases taking hold in necrotic tissue or leaf parts that are no longer receiving nutrients.
Good call on the potassium. Also, I have become a real zealot for cal/mag spray. I add a little bit of nitrogen to this, Photosynthesis needs n and mg. Remember that it takes very small amounts of nutrients in a foliar spray. Most people put in way too much. If I have learned anything here at BP it is that we are trying to maintain "perfect" conditions from day one until season end. So you protect your plant and care for it everyday. A non-stop job.
I also now use neem on a regular basis to try and preempt some diseases.

2/3/2017 11:11:11 AM

Anamosa, IA BPIowegian@aol.com

It might have been some sunburn. Was it very hot and sunny when the leaves were young?

2/3/2017 1:19:54 PM

Bavaria, Eurafrasia

Dear Iowegian, Alternaria fungi always look like sunburn.

2/3/2017 1:52:59 PM

Tasmania Australia

Thanks for the replies, appreciated.
Yes it has been very windy season here, so much so the main stem broke early on in the season before fruit set, been windy ever since and plant has been knocked around.
It has also been a very hot month last month here as well.

I am guessing it is too late to do anything with those leaves, but a potassium spray might help with the rest of the leaves?
I will have to look up what to use for Alternaria, thanks for that link, very helpful and lots of information.

2/3/2017 3:58:04 PM

Little-TON - Colorado

Do your leaves flag under the hot sun? Misting will help with this. This is the same damage I see when the leaves get a bit too flagged....and damage occurs.

2/3/2017 4:04:33 PM

Oak Grove, Mn

that does not look like Alternaria to me. I think it looks like a classic case of sunburn. Grow it big..I think you can relax.

2/3/2017 4:50:01 PM

Western PA

I agree with the above posts, nothing to worry about.

I must say, your watermelon plants look great ! good luck with them.

2/3/2017 4:59:49 PM

Utah

I would agree with sunburn. if they are not to old and in direct sun more than other leaves.
if they are the oldest leaves in the plant- more in center near the stump. then I'd lean more toward disease. spider mites and/or gummy stem blight and/or soil diseases - in conjunction with hot dry air.

Watermelon does look great !

2/3/2017 7:02:52 PM

Utah

sunburned leaves

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=38596

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=51604

2/3/2017 7:10:10 PM

Torrance, Ca.

I'm with Gordon on this one. Learn what diseases are in your patch through testing the soil and tissue. This way you now what your up against. Then you can be prepared for the following year to stay ahead of what ever it is. I started doing these tests a couple years back and was ahead of disease this past 2 grow seasons. I don't see this on my leaves until mid to late September now.

Theres a chance sunburn is the issue but this looks a lot like my plants a couple years back.

And yes, the watermelon plant looks wonderful!

2/3/2017 7:18:28 PM

Tasmania Australia

Thanks for the replies, very much appreciated.
Here is what the entire plant looks like, new leaves seam to be looking ok.
http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=269201

Had a look at the two diary posts above, my young leaves not seam to look like that with the purple ish spots and the light green spots in the middle of the leaves, but hoping it is sunburn.
Yes, it appears to be more the older leaves from the stump and moving out.
Here is a photo of around the stump area, sorry i couldn't get a better one,
http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=269202
Thanks for the words on the watermelon, hopefully it gets to a good size.

2/3/2017 10:01:10 PM

Tasmania Australia

Forgot to ask, how many leaves do you normally send in for a tissue test and also which ones?
The youngest ones at the growing tips or a few leaves back from the growing tips?
Cheers again.

2/4/2017 12:22:50 AM

Tasmania, Australia

Hey bluesilver, I would also guess wind damage. How the fruit going on the plant?

2/4/2017 1:07:33 AM

Tasmania Australia

Hey ACpumpkin, current OTT measurements are 193, so not huge but getting there slowly this year.

2/4/2017 2:46:17 AM

BC, Canada

Looked at the photo of the whole patch. I noticed the water sprinkler set up. Probably no need to say it but, if you are overhead watering in the sun or heat that can lead to leaf damage, and water on the leaves also encourages fungal diseases. Just a thought.
After looking at how the sunflower leaves are flagging I am guessing you are having some hot days and a lot of sun. That could be the main source of the leaf damage along with the wind. You may need to make sure the moisture in the soil is sufficient and deep enough as the plant grows and has greater moisture demands for the fruit (don't over do it). This off season you can concentrate on cover crops for the patch to get the organic and humus content up so the water holding capacity is greater. (if that is what it needs)
Lovely pic. You raise cattle? About the favorite trip I ever took was a week in Tassy. Great place, similar climate to where I live. One of the best meals I ever had was at a little restaurant in Strahan.
Best of luck mate.

2/5/2017 12:00:56 PM

watering in the sun can never burn leaf UNLESS its from a hot hose laying in sun .theres a big myth water when sun out burns. we would all starve if rain in iowa burnt down the corn when sun is out

2/5/2017 1:10:12 PM

Tasmania Australia

Cheers, Appreciate the inputs.
I only water in the early morning, just as the sun is coming up.
Yes have had some real hot days here, have to say haven't really been looking after the sunflower too much, just a self sown seeds from last year.
Yes, raise cattle, keeps me busy.
Cheers again, appreciate the inputs.

2/5/2017 4:06:17 PM