Antagonistic potentials of Trichoderma Spp. against fruit rot of custard apple caused by Phoma ligam
Context: Custard-apple (Annona squamosa Linn.) is a popular tropical fruit and fruit-rot disease caused by Phoma lingam leads to considerable qualitative and quantitative damages to the fruit in the area under study.
Objective: Studies were conducted to investigate the antagonistic potential of five Trichoderma spp. namely, T. harzianum, T. hamatum, T. lignorum, T. reesei and T. viride against in vitro growth of the pathogen followed by field experiments.
Materials and Methods: Dual culture plate, closed petriplate and food poisoning technique were followed in order to ascertain the antagonistic potential of the five species of Trichoderma. Hyphal interaction between the pathogen and T. viride was studied by collecting mycelial samples from the interaction zone of dual culture plate and was processed for scanning electron microscope. Plants with infected fruits were sprayed with spore suspension of T. viride and two commercial bioformulations of T. viride viz. Trichofix and Trichoguard for three times at a dose of 0.1, 0.5 and 1.0% prepared in distilled water.
Results: All the Trichoderma species more or less effectively inhibited the growth of the pathogen through mycoparasitism, production of volatile and non-volatile metabolites. Scanning electron microscopic (SEM) micrographs revealed that hyphal interaction between P. lingam and T. viride leads to lysis of the pathogenic mycelium by the antagonist. Field experiments with spore suspension of T. viride and Trichofix and Trichoguard significantly reduced fruit rot incidence of custard-apple.
Conclusion: The results of the current study indicate that adoption of biocontrol based disease management programmes can be effectively utilized against similar fruit diseases.
J. bio-sci. 19: 15-21, 2011