Bio-Management of Soil-Borne Pathogens Infecting Capsicum (Capsicum annum L.) under Protected Cultivation

Repeated in-vivo trials (2019–20) were conducted to manage the concomitant infestation of soil-borne pathogens infecting capsicum (bell pepper) through the application of Bacillus subtilis, Pseudomonas fluorescens and Trichoderma harzianum under protected cultivation system. The initial mean population of soil-borne pathogens,Meloidogyne incognita, Fusarium oxysporum and Rhizoctonia solani was 1.87 J₂/g soil, 2.03×10³ cfu/g soil, and 14.9 propagules/50 cc soil respectively. To manage these pathogens freshly prepared bio-agents were used for soil and drench applications. The combined application of (T. harzianum + B. subtilis + P. fluorescens) caused a significant (P<0.05) reduction (up to 90%) with respect to nematode multiplication in soil and disease severity of all pathogens with significant (P<0.05) enhancement in plant health (up to 54%) at the end of the subsequent second trial followed by chemical controlin comparison to untreated control. The eggs of M. incognita obtained from plant roots treated with all tested bio-agents together showed the least hatching (14.5%) compared to untreated control (90%) when subjected to an in-vitro bioassay test after the termination of each trial. All tested bio-agents showed that they are highly compatible with each other in the rhizosphere under protected cultivation of capsicum. Therefore, T. harzianum, B. subtilis and P. fluorescens are potential biological control agents in plant disease management to overcome serious threats of chemical pesticides under a protected cultivation system.