Trichoderma-Mediated Suppression of Red Rot of Sugarcane Under Field Conditions in Subtropical India

Abstract

Thirty-eight isolates of Trichoderma spp. established from the rhizosphere of sugarcane were characterized using a multiplex PCR assay and further assessed for the production of hydrolytic enzymes chitinase and cellulase. The results of multiplex PCR assay successfully identified 29 isolates and revealed T. harzianum to be the predominant species (21 isolates) in sugarcane rhizosphere followed by T. longibrachiatum (8 isolates). In enzymatic assays, chitinase production was recorded in 18 isolates and cellulase production observed in 17 isolates. However, there was a considerable variability in both chitinase and cellulase production potential across the isolates. Three T. longibrachiatum isolates (STr-52, STr-83 and STr-108) exhibited high production of both chitinase and cellulase. Talc formulation of two promising isolates (STr-83 and STr-108) was prepared and evaluated in the field conditions for their potential to suppress red rot under three different delivery systems, viz. sett treatment, soil application and their combination. All Trichoderma treatments resulted in considerable reduction in red rot (29.5–56.3%) over untreated control. However, the level of reduction accorded was much higher when the Trichoderma isolates were applied as a combination of sett and soil treatment (> 53% reduction) as compared to soil application (43–49% reduction) or sett treatment alone (< 35% reduction). Delivery of Trichoderma isolates as a combination of sett and soil treatment also exhibited highest NMCs and yield over untreated control. The application methods of talc formulations of these two isolates offer a feasible and effective option for large-scale application of these isolates for the management of red rot disease in sugarcane growing regions.