Control of powdery mildew of grape in Greece using Sporodex® L and Milsana®

Abstract

Six field trials were conducted in Greece to study the efficacy of two formulations of Reynoutria sachalinensis extract (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.