Potatoes… - Bayer CropScience

New combination of active
substances against potato blight
The new Infinito ® has already established itself in the
market as a highly-effective potato fungicide – within
only a few years of its introduction. The first registrations
were obtained in 2006; in the meantime, Infinito can be
used to control potato late blight (Phytophthora infestans)
in nearly twenty countries. The latest registration was
granted in Japan at the beginning of 2008. The product
will be marketed there under the trade name Reliable ® .
Bad news for potato blight, but good news for Infinito:
in the last few years, the product has been able to demonstrate
its strength in controlling the disease on aboveground
parts and tubers, thereby protecting the entire potato
plant. To achieve this, it draws on the combination of
two highly effective active substances: propamocarb-HCl
und fluopicolide.
Fluopicolide is a new active substance from Bayer
CropScience’s Research Unit. It has a unique mode of action
that leads to a rapid destabilisation of fungal cells.
Products based on this innovative active substance stand
out by virtue of the long-term, consistently high level of
protection they provide to crops, as well as through their
favourable environmental profile.
Fluopicolide’s new mode of action
Fluopicolide acts by disrupting the pathogen’s cell structure.
It inhibits the formation of spectrin-like proteins that
are assumed to play an important role in the stabilisation
of the pathogen’s cells. This unique mode of action is
effective against all of the most critical stages of the
pathogen’s life-cycle. However, fluopicolide’s main target
is the zoospore stage: the spores stop moving within seconds
of coming into contact with the active substance;
then they swell-up, and, eventually, burst. Fluopicolide
also reduces sporulation and suppresses the growth of
fungal mycelia within plant tissues. Moreover, it inhibits
both direct and indirect sporangial germination.
Fluopicolide’s partner in Infinito is the time-tested
active substance propamocarb-HCl, which has been on
the market for 30 years now. Propamocarb-HCl influences
fatty acid synthesis, so it has a completely different mode
of action from fluopicolide. The two active substances
complement each other very well to provide the effective,
long-term protection that Infinito affords. Both possess
systemic and trans-laminar distribution properties. Active
substance taken up by the stem is thus transported to other
parts of the plant, which means that newly-grown plant
tissues can also be protected from infection. ■
Late blight: the thread-like mycelium of the pathogen
Phytophthora infestans has formed a network within
the tissues of the potato plant. The Bayer active substance
fluopicolide is particularly active against the zoospores
(contained in the capsules at the ends of the mycelial threads)
that help the late blight pathogen to spread.
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