Subject: Re: [SANET-MG] soybean rust a new dread

From: Steve Diver <[email-masked]>
Date: Sat, 4 Dec 2004 09:43:00 -0600

The organic soybean network addressing soybean rust is
familiar with the fungicidal efficacy trails in South Africa
and South America.

The proposed next step is screening of organically
approved disease controls, in South African field trials.

Keep in mind that spraying fungicides on soybeans has
not been a common practice in conventional or organic
production, but soybean rust will change that.

In some years soybean rust might effect 10-30% of the
crop, in other years it can effect 90+% of the crop.  Disease
outbreaks are connected to a set of "conditions" like weather,
presence of pathogen, susceptible host, etc.

Rust is one of those diseases that descend in clouds
of spores across the whole countryside.

I'm hopeful that new generation organic farming practices
like compost teas, foliar fertilization, foliar biostimulants --
practices that bioaugment phyllosphere microbial communities,
boost crop health, or alter the ability of phylloplane-landing
pathogens to gain a foothold -- will be effective, but nobody
knows yet.

Steve Diver

jcummins wrote:

> Interestingly USDA has undertaken screening of chemical fungicides to
> treat the soy rust in Africa and South America since about 2002 in South
> America and Africa. However, they focused on high priced chemical
> fungicides and did not test the fungicides used for certified organic
> production. They also seem to ignore the need to screen soy for rust
> resistance. This may be a cultural thing, the main commercial soy in US
> is reported to include only a few genetically uniform strains so that
> screening those lines may not be fruitful.

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---

From: Steve Diver <[email-masked]>
Date: Fri, 3 Dec 2004 19:49:42 -0600

The eventual arrive of soybean rust has been tracked
for several years.

The organic soybean industry has likewise been following
soybean rust, and USDA has facilitated networking to
see what strategies should be explored.

Fungicides are the primary control in conventional soybean
production.

Organically approved fungicides -- such as those on the
OMRI List -- will likewise be the main approach taken
in organic production.

Germplasm resistance is not too great.

Cultural practices don't amount to much, either.

Steve Diver

James Kotcon wrote:

>
>         The more important issues is how should soybean rust be managed,
> now that it is here.  This will prove especially critical for organic
> growers who cannot rely on synthetic fungicides, even if they were a good
> idea.  Does anyone have suggestions for organically approved remedies
> that
> organic soybean growers might use?  Or that researchers should be
> evaluating?
>
> JBK