Return to the Growing Tomatoes Forum | Post a Follow-Up

what is this and how do I treat it?

Posted by matthew18 5 (My Page) on
Mon, Jun 18, 12 at 18:15


Follow-Up Postings:

RE: what is this and how do I treat it?

Looks like blight. Will start at the bottom and move up. From my experience if it doesn't start too early you can still get a harvest but since it kills off the leaves your tomatoes will be "sunburned." I have never successfully treated this. Has anyone else found something that works?

RE: what is this and how do I treat it?

The picture is rather blurry so I can't see the inner part of the spot, but if you see concentric rings, then it's Early Blight ( A. solani), and if you don't it's probably Septoria Leaf Spot.

Take of all affected leaves ASAP and dispose of them.

Since the two pathogens above are two of the most common fungal foliage pathogens what you need to do is to get on a regular spray schedule with a good anti-fungal and what I suggest is Daconil which works quite well.

What the molecules do is to attach to the specific sites on the upper leaf surface and prevent the spores of either of the above from attaching.

Two of the best Daconil preps are Ortho Garden Disease Control and Bonide and you MUST check the label to be sure that the active ingredient, chlorothalonil, is present at a concentration of 29.6% b'c there are products with different concentrations.

THe spores of both are spread by wind and embedded in rain drops. And you want to get rid of all the affected leaves b'c if you don't the spores will fall to the ground and then next year you can have what's called splashback infection which happens when rain or irrigation splashes those spores back onto the lower foliage and infection starts. Mulching can help prevent splashback infection.

So I assume from what you said that you've never seen this kind of infection before which means that your soil is not yet infested, if you will, with spores from last year.


RE: what is this and how do I treat it?

Bacterial leaf spot. You can control it. But not cure it.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Growing Tomatoes Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here