Antimicrobial activity of phosphites against different potato pathogens / Antimikrobielle Aktivität von Phosphiten gegenüber verschiedenen Kartoffelpathogenen

Phosphites have low-toxicity on the environment and show high efficacy in controlling oomycete diseases in plants, both by a direct and an indirect mechanism. We have shown that they are also effective in reducing disease symptoms produced by Phytophthora infestons, Fusarium solarii and Rhizoctonia...

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Bibliographic Details
Published in:Journal of plant diseases and protection (2006) 2010-06, Vol.117 (3), p.102-109
Main Authors: Lobato, M.C., Olivieri, F.P., Daleo, G.R., Andreu, A.B.
Format: Article
Language:English
Subjects:
Antimicrobials
Fusarium
Oomycetes
Pathogens
Phosphites
Plants
Potassium
Rhizoctonia
Scabies
Streptomyces
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Summary:Phosphites have low-toxicity on the environment and show high efficacy in controlling oomycete diseases in plants, both by a direct and an indirect mechanism. We have shown that they are also effective in reducing disease symptoms produced by Phytophthora infestons, Fusarium solarii and Rhizoctonia solarii when applied to potato seed tubers. To gain better insight into the direct mode of action of phosphites on different potato pathogens, and to ascertain chemical determinants in their direct antimicrobial activity, four potato pathogens were assayed with respect to sensitivity toward calcium, potassium and copper phosphites (CaPhi, KPhi and CuPhi, respectively). The influence of acidification and ionic strength changes after Phi addition on the antimicrobial activity, and the fungicidal or fungistatic activity, were evaluated. Results showed that phosphites were able to inhibit growth of all pathogens. Phytophthora infestons was the most inhibited pathogen by phosphites, followed by Streptomyces scabies, while Rhizocto nia solani and Fusañum solani were less inhibited. CuPhi had the highest antimicrobial activity against the four pathogens analysed, and CaPhi and KPhi showed similar antimicrobial activities. Inhibitions by CuPhi and CaPhi could be partially explained by acidification of the media. However, results obtained with KPhi demonstrated that the phosphite anion has antimicrobial activity itself. The increase in ionic strength after Phi addition was not important in the antimicrobial activity of Phi. The activity of phosphites on germination of F. solani spores showed to be fungistatic rather than fungicidal. Phosphite besitzen eine geringe Umwelttoxizität sowie eine gute direkte und indirekte Wirkung gegenüber Oomyceten-Pathogenen von Pflanzen. Wir zeigen hier, dass sie ebenfalls die durch Phytophthora infestons, Fusarium solani and Rhizoc tonia solani verursachten Symptome an Kartoffeln nach einer Knollenbehandlung vermindern. Vier Kartoffelpathogene wurden mit dem Ziel untersucht, die direkte Wirkungsweise von Calcium-, Kalium-und Kupfer-Phosphiten (CaPhi, KPhi und CuPhi) auf die Erreger sowie die chemischen Determinanten ihrer direkten antimikrobiellen Aktivität zu ermitteln. Weiterhin wurde die Wirkung von Azidifizierung und Ionenstärke nach Zugabe von Phosphiten auf antimikrobielle, fungizide und fungistatische Aktivität untersucht. Die Phosphite beeinträchtigten das Wachstum aller untersuchten Erreger. Phytophthora infestons wurde durch all
ISSN:1861-3829
1861-3837
DOI:10.1007/BF03356343