Efficacy evaluation of synthetic fungicides and biofungicides against Fusarium wilt in blueberry

Abstract

Fusarium wilt poses a significant challenge to blueberry production worldwide and recent reports suggest it is posing a threat to sustainability and expansion of this crop in Serbia. During the survey in 2019 in Sopot, Serbia, symptoms of leaf wilting, reduced plant growth, decreased yield and fruit quality of blueberries were observed. Subsequent morphological and molecular analysis identified Fusarium sporotrichoides as the causal agent of the disease. Addressing this threat, this study aims to evaluate the effectiveness of the widely used synthetic fungicides, trifloxystrobin, metalaxyl+fluazinam, and difenoconazole alongside innovative biological agents comprising of three combinations of lactic acid bacteria (Lactobacillus plantarum, Lactobacillus rhamnosus >103CFU/g), phototrophic bacteria (Rhodopseudomonas palustris >103CFU/g) and yeast sugar molasses (Saccharomyces cerevisiae >103CFU/g), marked as: EM1, EM5 and EM AGRO, using in vitro methods. Minimum inhibitory concentrations (MIC) were determined via microdilution tests in 96-well plates, with spore suspensions adjusted to 5x104 in 100 μl per well, incubated at 25°C for 5 days. MIC values were analyzed using STATISTICA v.7, with Duncan’s multiple range tests to differentiate the means at p<0.05. The highest degree of inhibition for F. sporotrichoides was demonstrated by difenoconazole (MIC: 0.13 μg/ml) and a combination of metalaxyl and fluazinam (MIC: 3.63 μg/ml). Trifloxystrobin showed a moderate inhibition (MIC: 15.00 μg/ml). All three combinations of lactic acid, phototrophic bacteria and yeast sugar molasses showed a significant antifungal effect against F. sporotrichoides (MIC<50.00 μg/ml). The microbial mixture EM5 demonstrated the highest potency (MIC: 38.80 μg/ml). This study not only validates the effectiveness of these antifungal strategies against Fusarium wilt in blueberries, but also encourages a balanced approach to combating this disease. Combining chemical and biological treatments contributes to the preservation of ecosystems and human health by reducing the effect of chemicals and enhancing food safety.