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Re: Late blight and soil



Here is the ATTRA publication on late blight in potatoes,
which provides some background ideas and resources:

Alternative Controls for Late Blight in Potatoes
http://www.attra.org/attra-pub/lateblight.html
http://www.attra.org/attra-pub/PDF/lateblight.pdf

Interestingly, compost teas were shown to be effective against
Phytopthora infestans in German research by Weltzein.

The relation between soils and diseases is complex.

A lot is known about soil-borne pathogens and suppressive
soils, organic amendments, soil microbiology, and biocontrol.

Yet, late blight is an above-ground pathogen affecting
foliage.  Now you are getting into a situation that is
akin to induced resistance or systemic aquired resistance.

Harry Hoitink's research group at Ohio State comes to mind.
They found that disease suppressive composts that come in
contact with just one segment of the root system can, in fact,
initiate a whole-plant systemic induced resistance to certain
pathogens; i.e., a signal was turned on by composts and
microbes interacting at the root interface, thus enabling
above-ground foliage to withstand infection from pathogens.

Another approach is to use commercial biocontrols,
typically functioning as microbial antagonists.

Here is the website providing a comprehensive summary
of commercial biocontrol products available for plant
pathogens.  It is located at OhioState University, compiled
in cooperation with USDA.

Commercial Biocontrol Products Available for Use Against
Plant Pathogens
http://www.oardc.ohio-state.edu/apsbcc/productlist.htm

Regards,
Steve Diver


"wdl@xminy.nl" wrote:

> Dear list,
>
> I have a question on late blight. In our experimental garden we had several plots of
> potatos this year. Besides the commercial farmer next to use also grew potatos.
> At the end of the growing stage (at 98 days) late blight did hit the garden. In my own plot
> all but 4 plants died, though the potatos were ok. So four plants survived! and  we saw
> in some plots there were more survivors. Other plots were totally destroyed and also
> some damage even occurred in the commercial field where the potato's were sprayed.
>
> In consultation with a scientist of the BD research centre I learned that in gardenplots it
> happens frequently that not all plants die in a late blight attack.  This was news to me.
> I now obviously wonder what is behind the survival of these potatoplants. Could there
> be a relationship with the condition of the soil and survival? I obviously am going to use
> the surviving plants potatos for planting next year but I would like to learn if anybody
> knows about research into the possible relationship between soilquality and late blight
> resistance.
>
> regards
> Wytze de Lange

.