Search

Substrate supplementation and co-cultivation approaches were used to enhance activity of biofungicide Trichoderma viride. Biopesticides were produced using corn cobs (T), corn cobs + 1% keratin (K), corn cobs + 5% lignin (L), and corn cobs + 1% keratin + 5% lignin (K+L). Also, biopesticides were produced through co-culturing with Bacillus subtilis MTCC8142, by sequential inoculation (B+T) and simultaneous inoculation (T3+B2) (B2+T3). The highest spore count was produced by (T3+B2) of 6.25x108 spores/g of substrate, followed by (T) of 6.20x108 spores/g of substrate. GC-MS characterization of ethyl acetate extract of biopesticides revealed different metabolites produced under different conditions. The zone of inhibition of extract was greatest for (T) of 21 mm, followed by (K) of 20.7 mm and for (B2+T3) of 18 mm at 10 mg/mL concentration. (K) and (B2+T3) did not affect antifungal properties; however, other substrate-supplemented and co-cultivated biopesticides decreased them. Competition between two microbes prevented (T3+B2) from producing antimicrobial metabolites; hence, no zone of inhibition was observed. The biopesticides (K), (L) and (B2+T3) significantly enhanced growth of chili plants (Capsicum frutescens L.), outperforming other biopesticides. The production of phthalates, also known as phytotoxins, by B+T resulted in a decrease in plant growth. Adding 1% keratin to corn cobs (K) and (B2+T3) sequential inoculation are best ways to boost plant growth promoting activity of T. viride without affecting its biocontrol activity. [ABSTRACT FROM AUTHOR]

The present study reports the production of Trichoderma viride spores in an earthen vessel using corn cobs. Using 4 kg of corn cobs, spore-based biopesticide was produced after 21 d with a maximum spore count of 2.50 × 10 9 spores/g of substrate and a moisture reduction from 70.80% w/v to 8.10% w/v. The gas chromatography-mass spectrometry analysis of its ethyl acetate extract revealed that it had 20 secondary metabolites, of which 13 were known to be antimicrobial, one was plant growth-promoting, and one performed both functions. Dried extract dissolved in methanol showed the minimum fungicidal concentration of 5-10 mg/ml against Rhizoctonia solani on potato dextrose agar plate. Plate assays and pot experiments on Rhizoctonia solani-infected potato plants exhibited good antifungal and plant growth-promoting activities. The biopesticide showed 71.28% viability over 10 m of storage in the same earthen vessel at 30 ± 2 °C. Thus, a simple, robust technology was developed with good potential for farm deployment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)