Comparing fungicides and biologicals for grey mould control in semi-hydroponic strawberry cultivation

Abstract

Biologicals and fungicides were evaluated for the control of grey mould in detached fruit in semi-hydroponic strawberry cultivation. Bacillus subtilis (Serenade, Bio-Baci, Bio-Imune), B. amyloliquefaciens (No-Nema), B. pumilus, B. velezensis (Bombardeiro, BTP 11–19 and BTP 135–19) were compared to the fungicide fluazinam in detached fruit assays. After treatment, fruits were inoculated with 30 μL of a 10⁵ spores mL⁻¹ suspension and incubated in a growth chamber. The relative risk for symptom expression in the treatments in relation to the control was estimated by survival analysis. In the field experiment, Serenade, No-Nema, Bio-Imune, Bombardeiro and BTP 11–19, the fungus Clonostachys rosea, procymidone, boscalid, fluazinam, pyrimethanil and cyprodinil + fludioxonil were tested. Biological products were sprayed every 7 days and fungicides at intervals of 14 days. Disease incidence (field and postharvest) and yield were evaluated. In the detached fruit assay, the fungicide fluazinam, followed by the biological products No-Nema and Bio-Imune, reduced the relative risk for symptom expression. In the field, cyprodinil + fludioxonil was the most efficacious at harvest. However, no differences in yield were observed. In postharvest, all fungicides in addition to C. rosea, No-Nema and Bombardeiro reduced the incidence compared to the control during the main production peak (second), and cyprodinil + fludioxonil mixture was the most effective during the season. However, some biological products can be incorporated into an integrated management to reduce postharvest losses.