A network meta-analysis provides new insight into fungicide scheduling for the control of Botrytis cinerea in vineyards
Résumé
BACKGROUND Control of Botrytis bunch rot (BBR) is currently based on the application of fungicides at four timings corresponding to specific growth stages of vines: end of flowering (A), pre-bunch closure (B), veraison (C) and before harvest (D). The current research provides a network meta-analysis of 116 studies conducted between 1963 and 2016 in nine countries, in which 14 strategies (based on combinations of 1, 2, 3, or 4 sprays applied in A, B, C, and/or D) were compared.
RESULTS When a one-spray strategy was applied, BBR control was more effective with sprays applied in A, C, or D than B. With a two-spray strategy, strategy AC provided similar control as strategy BC; strategy CD also provided good control. For a 3-spray strategy, the best disease control was consistently obtained with strategy ACD. Four-spray strategy ABCD provided the best control but often involved needless sprays so that the routine application of four sprays is not justified.
CONCLUSIONS Spraying at timing A seems to be very important for achieving efficient and flexible disease control. Flexibility is reduced by spraying at timing B rather than A.