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Old August 22, 2009   #16
carolyn137
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Join Date: Jan 2006
Location: Upstate NY, zone 4b/5a
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Responses for both Heather and Mark

Quote:
Originally Posted by hasshoes View Post
Cool info.

I'd really like to know what tests Serenade goes through to be able to list as "controls or suppresses" Late Blight.

I have an ongoing joke with a friend about this that I won't post here.
Heather, actual challenge experiments are done with a known number of spores to determine the efficacy of any such products. it isn't a matter of just noting what does and doesn't work in a field situation where there might be, could be, some LB spores around.

The same thing is true, that is, controlled challenge experiments, in order for a specific tomato variety to have any of the alphabetical notations after the variety name, such as VFNT in different combos, etc.

Mark, good information, but folks should realize that many of the products noted are not available to the home grower. Even Bravo, which is a higher concentration of chlorothalonil, is not available in most states without a pesticide license, which is true of almost all the other products mentioned.

We home growers have Chlorothalonil ( 29.6% in the concentrate), Mancozeb, in some states, but not all, and copper sprays.

I noted Tom Zitter's name there. I've talked to him several times in the past and he's a terrific tomato pathologist but our talks revolved around what I ended up calling the CRUD and he suggested at the time that it was an aberrant form of Early Blight ( A. solani), but I've heard nothing more about that and he said at the time that they couldn't prove it.
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