September/October 2020 - 22

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Join the phosphite club
Potato growers could find themselves getting
used to a new weapon in their fight against
late blight, as OMEX®
Agrifluids agronomist
Dean Konieczka explains.
Is there a potato grower anywhere in the world who
doesn't worry about the devastating effects that late
blight might wreak in his or her crops? Regular and
frequent applications of fungicides, close monitoring
of weather and humidity, and a level of attention
bordering on obsessive are the only ways to be sure
of producing a quality crop, or indeed in some years
any crop at all.
While crop protection manufacturers continue to
develop new molecules and different modes of
action to keep ahead of new variants and resistant
strains, the increasing regulation surrounding
pesticides has - often for good reason - suppressed
the frequency at which novel products reach the
market. When they arrive the sheer cost of bringing
modern products to market often means they're
more expensive than the products they supersede,
while their specificity can result in a very short 'field
life' before resistance starts to affect their efficacy
and viability.
The worry is that as the pipeline of new products
starts to dry up, growers will be left with fewer
and fewer options to control late blight, while the
spiraling cost of extended fungicide programs
could persuade more and more growers that the
economic returns are not worth the hassle and
headache.
But it's not all doom and gloom. An increasing
body of research is indicating that phosphite - as
against the more widely known phosphate - could
turn out to play a vital role in the struggle to stay
ahead of plant pathogens. Several recent papers,
the results of studies from teams around the world,
have indicated that phosphites can bring all sorts of
benefits to a wide range of crops, including wheat,
canola, turf and, of course, potatoes - where results
show it not only induces defense responses against
Phytophthora but also displays a toxic effect against
the pathogen.
So what is phosphite? Chemically similar to
phosphate, in chemical terms it's a 'reduced form'
of phosphate (PO4
), meaning that it has one less
oxygen atom. But despite phosphorus being
one of the major nutrients required for healthy
plant development, plants can access it only as
phosphate; phosphite doesn't provide crops with
any P nutrition. In fact, if applied directly to crops it
would burn the plant tissue.
Instead, it's applied as a salt, as in OMEX® Agrifluids'
Cell Power® Phorcephite®. In field trials spanning
four years, researchers from the Swedish University
of Agricultural Sciences found that potassium
phosphite, in combination with reduced doses of
fungicide, provided potatoes with the same degree
of protection against blight as treatments with the
recommended full dose of fungicide.
Integrated Crop Management (ICM) doesn't get
much better than this: programs that can truly
reduce growers' reliance on chemical controls.
This is the future of crop production - doing more
with less. Through increasing our adoption of ICM,
we can please consumers, spend less on inputs,
minimize the risk of fungicide-resistant populations
developing, keep regulators and legislators happy
and reduce the crop's overall environmental impact.
September/October 2020

Table of Contents for the Digital Edition of September/October 2020
