sgp_info_2017_2

Poster 15
Natural Products to control black dot and silver scurf in
Potatoes
Josep Massana Codina 1,2 , Sylvain Schnee 1 , Brice Dupuis 1 , Stéphanie Schürch 1 , Jean-
Luc Wolfender 2 and Katia Gindro 1
1 Agroscope, Nyon,
2 Université de Genève, Genève, josep.massana@unige.ch
Black dot and silver scurf are two blemish diseases of Solanum tuberosum L. These two diseases
affect the quality of the tubers and are caused by two phytopathogenic fungi: Colletotrichum
coccodes and Helminthosporium solani, respectively. Chemical fungicides are commonly used to
control fungal pathogens, but this is not an option in consumption potatoes because of the residues
remaining on tubers.
Natural Products (NPs) are chemical compounds or substances that are produced by a living
organism: this definition encompasses both complex extracts, but also the isolated compounds of
these extracts, and they can be produced by marine organisms, bacteria, fungi or plants.
The use of Natural Products (NPs) as source of antifungal compounds has been largely used in the
past years. This strategy offers several advantages in comparison to the traditional chemical
control. First of all, few active ingredients are available in the chemical control fungicides, increasing
the risk of resistance development; second, residues of these compounds can be found on the
surface of the food products, with a potential effect on public health; and finally, the use of
synthetically produced antifungal compounds for the treatment of food products induces concern
in consumers.
The aim of this project is to use NPs for post-harvest treatments of potato tubers in order to control
the blemish diseases black dot and silver scurf. To this end, (1) plant species from different families
showing diverse secondary metabolite production were selected; (2) different extracts from these
plants were produced; (3) their biological activity was evaluated through a newly developed in vitro
biotest; (4) the activity of some of these extracts is currently tested in vivo; and (5) the active
compound will be isolated and characterized.
In total, more than 50 extracts from 21 plant species were screened for a biological activity against
Colletotrichum coccodes and Helminthosporium solani. Some of these extracts showed antifungal
activity to one of the fungal pathogens, but only three of them showed antifungal activity against
both. These three plant extracts were selected for further experiments, including the isolation of
the active compound and the treatment of infected tubers. Preliminary data show interesting results
that need to be confirmed. The use of efficient NPs to treat potato tubers against C. coccodes and
H. solani, appears then as a promising alternative.
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