Antagonistic microorganisms inhibited Botrytis cinerea of tomatoes in vitro and in vivo

Tomato (Solanum lycopersicum) is one of the most widely cultivated and extensively consumed horticultural crops globally. This fruit is nutritious and beneficial for human consumption as it contains lycopene and carotenoids with antioxidant properties. The main antioxidants in tomato are carotenoids, ascorbic acid, and phenolic compounds. Tomatoes have a short shelf life and are highly perishable, resulting in infections by plant pathogens causing mechanical damage before and/or after harvest. This research aimed to isolate antagonistic microorganisms and evaluate their in vitro and in vivo antagonistic activity against B. cinerea of tomato. Antagonistic microorganisms were isolated from different plant parts and tested for inhibitory effects against B. cinerea of tomatoes both in vitro and in vivo. A total of 48 antagonistic microorganisms were screened in vitro against B. cinerea on potato dextrose agar and incubated at 25°C. The mycelial growth of B. cinerea was measured post-inoculation after days 3, 5 and 7. Serratia marcescens, Bacillus pumilus and Bacillus safensis inhibited B. cinerea in vitro by 54, 52 and 51%, respectively. These isolates were further characterized and identified as the best performing antagonistic isolates. In vivo screening of S. marcescens, B. pumilus and B. safensis inhibited grey mould incidence on ‘Jam’ tomato cultivar by 83, 75 and 75%, respectively, after 7 days at 25°C. The results obtained from this study showed that biological control agents inhibited grey mould and are potential alternatives against B. cinerea of tomato.