Eco-friendly management of red rot disease of sugarcane with Trichoderma strains

Eighty strains of Trichoderma harzianum and T. viride occurring in sugarcane rhizosphere soil of sub-tropical zone were isolated on Trichoderma specific medium and tried screened in vitro against Colletotrichum falcatum. Highly potent ones (Th 37 & Th 38) were tried to manage red rot disease under field conditions. Healthy setts were treated by applying Trichoderma mixed culture (TMC) of T. harzianum strains grown in sterilized maize bran (2 kg) and subsequently mixed with sterilized press mud or FYM (20 kg) / ha. The treatment was also compared with spore suspension containing 10⁶ conidia / ml and metabolites (2.5% culture filtrate). Combinations were also tried for improving efficiency. The trials were repeated thrice in CoLk 7701, a highly susceptible variety / genotype. Disease management was ascertained by inoculation challenged with potent Colletotrichum falcatum pathotype (Cf 09). Infection of C. falcatum was protected in 45–55% plants. There was no infection in such plants as against 97–100% infection in check. Red rot infection was also considerably suppressed in 20–25% plants. Where grade of infection was reduced to 2–4 in 0–9 scale. Testing was made at an appropriate temperature (300 C) and high relative humidity (90%) during July–August. The protection offered might be due to direct parasitic action of T. harzianum on C. falcatum and also systemic resistance induced in sugarcane. Application of T. harzianum is useful for management of red rot and cultivation of moderately resistant varieties for several years. It is also useful for reducing the economical losses in susceptible varieties. The yield was also enhanced by 15–20 t / ha due to improved germination and shoot biomass. Application of Trichoderma biopesticide is eco-friendly, economical and efficient for improving soil health also.