Management of cucumber powdery mildew by new formulations of Reynoutria sachalinensis (F. Schmidt) Nakai extract / Management von Echtem Gurkenmehltau mit neuen Formulierungen von Reynoutria sachalinensis (F. Schmidt) Nakai-Extrakt

• Published in: Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz (1970) 2002-09, Vol.109 (5), p.478-490
• Main Authors: Petsikos-Panayotarou, Niki, Schmitt, Annegret, Markellou, Emilia, Kalamarakis, Anna E., Tzempelikou, Kalliopi, Siranidou, Eleni, Konstantinidou-Doltsinis, Stavroula
• Format: Article
• Language: English
• Subjects: Crop harvesting; Cucumbers; Disease susceptibility; Epidemiology; Experimentation; Fungicides; Leaves; Mildews; Plant diseases; Plants
• ISSN: 0340-8159; 2364-9968

Two new liquid formulations of the resistance-inducing Reynoutria sachalinensis extract, namely, Milsana® VP 1999 and Milsana® VP 2000, VP 2001 (one formulation, but lots from two different harvesting years) were studied in Greece and Germany for their impact on infection of cucumber with powdery mildew (Sphaerotheca fuliginea) and on yield. In four small-scale trials, it was shown that Milsana® effectively controlled powdery mildew when applied in 7-day intervals, and both highly and less susceptible cultivars could be effectively protected. Depending on the formulation and/or lot, different concentrations (0.5-1.5 %, v/v) were needed in order to achieve sufficient control of the disease. In three large-scale greenhouse trials, it was shown that Milsana® VP 1999, at the concentration of 0.5 % and Milsana® VP 2000 at 1.5 % when applied weekly and prophylactically, resulted in significant disease reduction. In a Greek trial, Milsana® VP 2001 at the concentration of 1 % (v/v) achieved only an insufficient efficacy level and this point is further discussed. A statistically significant increase in yield was observed in cucumbers treated with Milsana® formulations, which was at least as high as that obtained by fungicide applications. From the present study, it can be concluded that Milsana® reduces powdery mildew severity even in highly susceptible cucumber cultivars and results indicate that susceptibility to a pathogen is not the only parameter influencing the level of resistance induction on plants. Thus, Milsana® can substantially contribute to the management of cucumber powdery mildew in organic or integrated farming systems. In Griechenland und Deutschland wurde der Einfluss von zwei neuen Flüssig-Formulierungen des Resistenz induzierenden Reynoutria sachalinensis Extraktes, nämlich Milsana® VP 1999 und Milsana® VP 2000, VP 2001 (Chargen einer Formulierung von zwei verschiedenen Erntejahren) auf die Infektion von Gurkenpflanzen mit Echtem Mehltau (Sphaerotheca fiiliginea) und den Ertrag untersucht. In vier small-scale Versuchen wurde gezeigt, dass Milsana® bei 7-tägiger Applikationshäufigkeit den Befall mit Echtem Mehltau wirksam eindämmte. Sowohl stark als auch weniger anfällige Sorten konnten wirksam geschützt werden. Abhängig von der Formulierung und/oder der Partie, waren verschiedene Konzentrationen (0,5-1,5 %, v/v) nötig, um eine ausreichende Kontrolle der Krankheit zu erreichen. In drei kommerziellen Gewächshausversuchen wurde gezeigt, dass Milsan