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grey leaf spot

Posted by ashley9597 Orange County, CA (My Page) on
Sat, Apr 23, 11 at 14:07

I believe my tomato plants have grey leaf spot and I am not sure what to do. I am in Southern CA and I planted my tomato plants in the middle of March. About 10 days later we had rain for an extended period of time and shortly after the rain stopped I noticed the spots on the underside of my leaves. I thought it was due to the rain so I waited patiently to see if it would go away once things dried out. Well they haven't and it is spreading up the plants. From my research, it looks like grey leaf spot to me. My questions that I desperately need help with are:

1. Should I even bother with a fungicide that covers leaf spot or should I pull out my plants and start over?
2. If I should spray, what fungicide do you recommend?
3. If I spray with a fungicide now that the plants are infected, will it stop the spread? (some sites I read say no)
4. If I don't pull out the plants, will I have a good harvest still? (again, some sites say no)

This is only my second year growing tomatoes. I know some diseases you can live with and it won't affect the plants too much to interfere with fruit production. I am hoping someone has had first hand experience with this disease so you can give me your opinion on what you would do. Thanks so much.

Follow-Up Postings:

RE: grey leaf spot

any chance of pictures?

RE: grey leaf spot

I just cut off all the damaged leaves yesterday and didn't think to take a picture :( I am sure more will show up and I will take a picture then. Do you have suggestions on treatment?

RE: grey leaf spot

Please don't pass judgement...I am desperately trying to solve this problem and dug through my trash to find the diseased parts I cut off. Here is a link to some pictures. Please let me know if it does not work as this is my first time posting pictures. Thanks for your help.

Here is a link that might be useful: pictures of leaves

RE: grey leaf spot

Not a disease. Instead environmental stress. Likely ran short of water, or it was windy and the roots couldn't keep up with what the top needed.

RE: grey leaf spot

I really don't think it was due to a short of water. This all started from over a week straight of rain. Since the rain has stopped they are watered twice a week while the temps are cool and it is increased when the summer temps increase. I thank you for trying to help but I am really doubtful it is from a lack of water.

RE: grey leaf spot

Well, I'll still go with water stress. In water stress, the tissues farthest from the veins collapse & die. That's what your plant shows.

It goes like this:
- Overly wet roots are damaged by excess water.
- Once that happens, the roots can't keep up with the top's demands.
- Cells farthest from the veins collapse and die, creating the tan areas as shown on your leaves.

I didn't mention it before, but thanks for posting the images.

In any event, stick with an environmental cause because it's definitely not disease.

RE: grey leaf spot

Thanks Jean. I will try to be a little more patient and see if it stops as things dry out. I just don't want to go too far into the season and then wish I got rid of these plants while I had time. If it continues I will take pictures on the actual plant and repost. Go rained today. Not enough to actually help water anything, but enough to make foliage wet. Just lovely.

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