Wednesday, July 28, 2010

Late Blight Confirmed on Tomatoes In Henderson County

Late blight has been positively identified in Henderson County on tomatoes. With the afternoon showers and reports from other parts of the eastern U.S. it was only a matter of time.
Growers are encouraged to scout their fields and begin with control measures.

Sorry I don't have a lot of time to put details in this afternoon, but review my post from last year for some basic information.

Recommendations for conventional producers are chlorothalonil as a preventative if late blight is not found in your field or nearby. If late blight has been identified in your field applications of cyazofamid (Ranman at 2.1-2.75 fl oz/acre), fluopicolide (Presidio at 3-4 fl oz/acre) or mandipropamid + difenoconazole (Revus Top at 5.5-7 fl oz/acre) are recommended. Always read and follow the label when using pesticides! The label is the law.

For organic recommendations, see this article from Alex Stone on eXtension.

More to be reported later. Sorry again for the short note.

This just in from NCSU Plant Pathologist Dr. Kelly Ivors:

"Hey Everybody-
This morning we found and confirmed late blight (by microscopic examination) in one small shaded area of a conventional tomato field in Henderson County. We have not been able to confirm its presence anywhere else in the tomato production areas of NC this summer, so I believe this is the start of the tomato late blight epidemic in WNC. We've had some rains recently and I'm sure it's out there elsewhere now, or soon to arrive.
Fungicide recommendations for controlling late blight on fresh market tomatoes start at week 9 in the NC tomato foliar fungicide guide.
It can be found at this link.
In addition, there is information (fact sheet) on this disease in North Carolina, including pictures of the symptoms at this link.
Check out the different diseases and select the one under Tomato Late Blight.
Please make sure to get your preventative sprays on as soon as possible if you grow tomatoes in late blight prone areas. Chlorothalonil works well as a protectant if you do not yet have the pathogen in your field. If already established in your tomato field, it would be best to apply something more than a protectant like Presidio (+ chlorothalonil) or Ranman.
If you need a confirmation of late blight in your fields, please do not hesitate to call your agent or my lab to submit a sample.

No comments: