Inhibition of the Growth of Botrytis cinerea by Penicillium chrysogenum VKM F-4876D Combined with Fludioxonil-, Difenoconazole-, or Tebuconazole-Based Fungicides

Abstract

Botrytis cinerea, causing grey mold, is a dangerous plant pathogen able to infect agricultural crops during the whole production cycle, including storage and transportation. A wide set of pathogenicity factors, high ecological plasticity, and universality of propagation and spreading of this fungus significantly complicate the control of this pathogen. A rapid increase in pathogen tolerance to fungicides dictates the necessity of developing antiresistant protection strategies, which include the use of biopreparations based on antagonistic microorganisms or their metabolites. The purpose of the study was to evaluate the antifungal activity of a dry biomass of P. chrysogenum VKM F-4876D (DMP), both individually and in combination with tebuconazole-, fludioxonil-, or difenoconazole-containing compounds recommended to control grey mold, in relation to B. cinerea isolated from grape samples. A water suspension of DMP was added to the PDA medium at a concentration of 1.0, 2.5, 5.0, 7.5, and 10.0 g/L. The pathogen growth inhibition was evaluated after 3, 7, and 14 days of cultivation; fungal cultures grown on DMP-free medium were used as a control. The resulting effective DMP concentration was 2.5 g/L. The effective concentrations of fungicides included in the study were determined to be 0.5 mg/L (tebuconazole), 0.1 g/L (difenoconazole), and 0.04 mg/L (fludioxonil). Combining DMP (2.5 g/L) with tebuconazole, difenoconazole, or fludioxonil (all taken at the effective concentrations) resulted in pathogen growth inhibition after 7 days of incubation by 86.5, 85.6, and 84.6%, respectively. Among all studied variants, the DMP (2.5 g/L) + difenoconazole (1.0 mg/L) combination provided the most efficient control of B. cinerea development under in vitro conditions: even after 14 days of incubation, the pathogen growth suppression remained at the level of 51.3%, whereas the DMP combination with tebuconazole or fludioxonil provided only 28.5 and 37.4%, respectively. The obtained results show good prospects for the efficient control of grey mold development, together with the reduction of pesticide loads on agrobiocoenoses and the prevention of the emergence of new resistant forms of plant pathogens.