Biological control of Fusarium wilt of pigeonpea by Pantoea dispersa, a field assessment

Fusarium wilt is one of the major yield and growth-limiting factors of pigeonpea (Cajanus cajan). For an eco-friendly and sustainable management of such a disease, a novel mycolytic strain Pantoea dispersa was evaluated against fungal pathogen Fusarium udum that is known to be infecting the susceptible variety of pigeonpea (T-15-15), commonly prevalent in India. To study the efficacy of P. dispersa as a biocontrol agent in comparison with chemical fungicide Bavistin and antifungal biocontrol agent Trichoderma Monitor WP was studied in both pot and field experiments. In vitro, P. dispersa inhibits the growth of F. udum. In the pot experiment, P. disPersa the treated pigeon pea (T-15-15) seeds showed higher percentage of seed germination and decreased wilt incidence as compared to chemical fungicide; Bavistin and antifungal biocontrol agent Trichoderma Monitor WP treatments. Moreover, the root, shoot lengths and growth were also found to be higher. Due to high impact of P. dispersa in in vitro condition on controlling the F. udum growth, further study was conducted in field in a wilt-stricken plot. These studies were repeated for three cropping seasons (2004/2007). The seed dressing by P. dispersa reduced wilt incidence (47%) during field trials, which is greater than Bavistin (41%) and Trichoderma Monitor WP (36%) treatments. Hence P. dispersa was proven superior to Trichoderma Monitor WP and Bavistin; which are used as commercial Fusarium wilt control agents.