For healthy potatoes - Bayer CropScience

A further fitness-advantage of the
„new“ population is that it has a shorter
latent period, i.e. the interval between
infection and the appearance of symptoms
(see Fig. 1). Whereas the standard latent
period quoted for the pathogen Phytophthora
infestans used to be 5 to 7 days, isolates
collected from the field nowadays
show latent periods of less than 3 days.
The latent period is a vital indicator in
epidemiological terms. A shorter latent
period means that more generations can
occur within a year. The latent period also
has an important influence on the likelihood
of success of curative treatments to
control of the pathogen. These differences
in the properties of the „new“ population
indicate that the pathogen is „fitter“: in
other words, more aggressive. This
increased fitness of the “new” population
explains why it has been able to out-compete
the old population in most areas of
potato cultivation within only a few years.
Implications for
agricultural practice
The results of tests of the effectiveness of
curative treatments show that it is almost
impossible to prevent the outbreak of an
epidemic once infection has become successfully
established. Therefore, it is
important that the establishment of the
pathogen is avoided through preventative
measures. A pre-condition for this is the
correct timing of the start of the spraying
programme, before the first symptoms
appear. Computer-aided decision models
are an important tool in planning timely
fungicide applications. Modern communications
media provide the basis for the
rapid translation of decision into action.
The integration of the latest research
results coming from the areas of phytopathology,
plant breeding and crop protection
will provide the basis for the successful
control of the pathogen Phytophthora
infestans into the future. ■
New, ultimate protection of
potatoes
The increasing Phytophthora infection pressure has urged scientific research for
the search for new control technologies. With fluopicolide, Bayer CropScience has
developed a promising, new-generation active substance for the control of late
blight in potatoes. This modern product provides an innovative form of disease
control, with a long-lasting action.
Fluopicolide is the first active substance in the new class of acylpicolides. It has
a novel mode-of-action that allows it to provide effective and sustained control of
late blight, targeting all the important stages of the pathogen’s life-cycle. Both
direct and indirect germination of the spores and sporangia are inhibited, along
with the sexual reproduction of the pathogen.
Fluopicolide is an active substance with translaminar properties: following
application to the upper side of the leaf, the active substance penetrates the
leafsurface and moves into the leaf tissues, providing protection through to the
underside of the leaf. If applied to the leaf-base or the petiole, the active substance
is distributed towards the leaves: this property means that it is capable of
protecting the new growth that develops between successive spray applications.
In 2006, Bayer CropScience obtained the first registrations for fluopicolide, in the
UK and China. Further registrations are expected in coming years.
Fluopicolide is marketed for use in potatoes in a mixture with propamocarb,
under the trade name Infinito ® . The two active substances fluopicolide and
propamocarb complement each other perfectly: they offer the farmer an effective
tool for avoiding the development of resistance. Infinito can also be used against
strains of oomycete fungi that are resistant against standard fungicides.
Field trials in recent years have demonstrated Infinito’s robust and very high level
of action against Phytophthora infestans infections on leaves and stems and
tubers. Also the international field trials clearly demonstrated the reliable longlasting
protection it brings. Thanks to its very favourable environmental profile,
Infinito is suitable for use in integrated crop management programmes and a
product of choice for the partners in the food chain.
Bayer CropScience is currently testing this highly-active fungicide in trials around
the world, in order to develop it into a product for controlling downy mildew in
vegetables, ornamental plants and grapes. For example, fluopicolide will be made
available for use in grapes in a pre-mix, under the trade name Profiler ® .
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