Search

Six field trials were conducted in Greece to study the efficacy of two formulations of Reynoutria sachalinensisextract (Milsana® Vp 1999 & 2001) and a formulation of Pseudozyma flocculosa(Sporodex® L) against powdery mildew (Uncinula necator) of grapes. In three trials where Milsana® was tested alone it was found that a) both formulations significantly reduced disease severity on berries, b) its efficacy was moderate to low but within the range of sulphur treatment alone and c) significant increase in yield was obtained in one out of two trials where yield was measured. In two field trials where Sporodex® L was tested it was found that a) it was effective on moderate to high disease pressure on bunches, but its efficacy declined when disease severity was extremely high and b) its efficacy was similar or inferior to that of sulphur alone. Alternated applications of Milsana® and Sporodex® L tested in one trial improved the efficacy of Milsana®, but not that of Sporodex® L. Alternation of Milsana® and Sporodex® L with sulphur did not result in significantly better efficacy than the stand alone applications of the control agents (one trial). The potential use of Milsana® or Sporodex® L in low input systems in grapes is discussed. Sechs Feldversuche wurden in Griechenland zur Untersuchung der Wirksamkeit zweier Formulierungen von Reynoutria sachalinensis-Extrakten (Milsana® VP 1999 & 2001) und einer Formulierung von Pseudozyma flocculosa(Sporodex® L) gegenüber dem Echten Mehltau der Rebe (Uncinula necator) durchgeführt. In drei Versuchen mit Milsana® als alleinigem Präparat wurde gefunden, dass a) beide Formulierungen die Befallsstärke des Mehltaus an den Trauben signifikant verminderten, b) die Wirksamkeit gering bis moderat, aber innerhalb des Bereichs von Schwefelbehandlungen war, und c) eine signifikante Ertragssteigerung in einem von zwei Versuchen mit Ertragsmessungen erzielt wurde. In zwei Versuchen mit Sporodex® L wurde festgestellt, dass das Präparat a) bei moderaten bis hohen Befallsstärken an Trauben wirkte, während die Wirksamkeit bei sehr hohen Befallsstärken abnahm, und b) seine Wirksamkeit mit der einer alleinigen Schwefelbehandlung vergleichbar oder geringer war. Abwechselnde Behandlungen mit Milsana® und Sporodex® L erhöhten die Wirksamkeit von Milsana®, nicht aber von Sporodex® L in einem Versuch. Abwechselnde Behandlungen mit Milsana®, Sporodex® L und Schwefel in einem weiteren Versuch erhöhten die Wirksamkeit der entsprechenden Einzelbehandlungen nicht signifikant. Das Potenzial von Milsana® und Sporodex® L im Weinbau mit geringer Bewirtschaftungsintensität wird diskutiert.

No cross-resistance was observed between pyrimethanil or cyprodinil and the fungicides benomyl, iprodione or carbendazim + diethofencarb. In vitro, both anilinopyrimidine fungicides were effective against strains of Botrytis cinerearesistant to benzimidazoles and/or dicarboximides and against a wild type strain insensitive to diethofencarb (EC50values ranged between 0.03–0.19 and 0.006–0.054 μg ml−1for pyrimethanil and cyprodinil, respectively). Preventive applications of anilinopyrimidines completely protected young cucumber plants and fruits that were inoculated with all strains of B. cinerea. The effectiveness of pyrimethanil against grey mould was studied in greenhouse grown tomatoes in relation to (a) the type of infection and the progress of the disease on different plant parts and (b) the response of the naturally occurring B. cinereapopulation to the selection pressure caused by eight successive applications of this fungicide. Pyrimethanil effectively controlled grey mould on leaves, fruits and stems but did not significantly reduce the number of dead plants and fruits with 'ghost spot' symptoms. The selection pressure caused by the consecutive applications of pyrimethanil resulted in reduction of its effectiveness on leaves that became apparent after the sixth application. This was correlated with a shift of the B. cinereapopulation (not previously exposed to anilinopyrimidines) towards reduced sensitivity, probably due to the development of a low level of resistance (RL= 7.7). Pyrimethanil delayed the onset of the disease but it did not reduce the infection rate.