Effectiveness of fungicides and an essential-oil-based product in the control of grey mould disease in raspberry

M. Kostic, M. Mihajlovic, J. Hrustic, D. Indic, G. Delibasic, M. Grahovac, B. Tanovic

Abstract: Field experiments were conducted in two commercial raspberry fields to evaluate effectiveness of some fungicides and an essential oil based product in the control of Botrytis fruit rot. The experiments consisted of four fungicides - fenhexamid, vinclozolin, benomyl, and pyrimethanil, two essential oil product treatments (0.5% and 1% emulsion) and untreated control, in randomized block design with four replicates per treatment. Afterwards, the pathogen was isolated from infected fruits and identified based on colonial and conidial morphology. Sensitivity of 10 randomly chosen isolates to all mentioned fungicides and tea tree oil was determined in radial growth assay on PDA supplemented with a range of concentrations of the relevant product. At both localities, the highest efficacy was achieved by pyrimethanil (97.4% and 98.2%) and fenhexamid (93.6% and 97.6%), while the efficacy of tea tree oil, applied at both concentrations, was less than satisfactory and ranged from 13.3% to 55.9% compared to the control. In vitro sensitivity of B. cinerea was determined based on EC-50 values which ranged between: 0.14 mg/l and 0.20 mg/l for vinclozolin, 0.16 mg/l and 0.46 mg/l for benomyl, 0.22 mg/l and 3.81 mg/l for pyrimethanil, 0.06 mg/l and 0.19 mg/l for fenhexamid, and 383.3 mg/l and 1500.6 mg/l for tea tree oil product.

Keywords: Botrytis cinerea; disease control; fungicide efficacy; fungicide resistance; raspberry

Date published: 2019-07-26