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market-farming - Re: [Market-farming] New Tomato blight

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  • From: "Bill Shoemaker" <wshoemak AT inil.com>
  • To: "Market Farming" <market-farming AT lists.ibiblio.org>
  • Subject: Re: [Market-farming] New Tomato blight
  • Date: Mon, 29 Aug 2005 08:26:48 -0500

I would have to see it to be sure but it sounds like it could be one of the bacterial blights, perhaps bacterial spot. I would defintiely contact someone in Virginia Extension to get a positive ID on the disease. If it's bacterial, you have a challenge on your hands. Not that it can't be brought under control, but bacterial pathogens are very persistant.
 
Bill Shoemaker, Sr Research Specialist - Food Crops
University of Illinois - St Charles Horticulture Research Center
www.nres.uiuc.edu/faculty/directory/shoemaker_wh.html
We are seeing a tomato blight this year I have never seen before. It appears as yellow spots on the upper surfaces of leaves and are about 3-5 mm in diameter. The same spot presents on the back side of the leaf as a brown spot with a yellow halo. We are also seeing white and yellow blotching on the skins of the fruits which are probably manifestations of the blight. It is definitely not early blight or septoria leaf spot, both of which I am familiar.  I don’t think it is characteristic of late blight either.

 

This blight appeared first in my hoop houses where I had mulched with double layers of plastic, black on the bottom and red on top with drip irrigation.  One consultant told me that this was being caused by the unusually hot and humid weather we were experiencing in late July and early August here in Virginia. We are definitely not getting soil splash or leaf wetting from rain or overhead irrigation but we do have a lot of sweating inside the hoop houses with condensation forming on the underside of the plastic covering and dripping down onto the plants.  When I realized I was in trouble I did a foliar application of Oxidate, a hydrogen dioxide based product which is supposed to work in a similar fashion to that of hydrogen peroxide but it didn’t help much.

 

Marlin Burkholder

Virginia zone 6



  • Re: [Market-farming] New Tomato blight, Bill Shoemaker, 08/29/2005

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