Application of biochar and vermicompost against the rice root-knot nematode (Meloidogyne graminicola): an eco-friendly approach in nematode management

Abstract

The rice root-knot nematode (Meloidogyne graminicola) is one of the key pests of rice (Oryza sativa L.) in irrigated and upland rice ecosystems inflicting about 20–80% yield loss. While chemical nematicides are widely used to combat this pest, they have a negative impact on the environment as well as on animal and human health. The present study evaluated the efficacy of organic amendments like biochar and vermicompost in managing the rice root-knot nematode (RRKN) at 0.6, 1.2, 2.5, and 5% (w/v) concentrations. Our result showed that biochar and vermicompost exudate neither exhibit any direct killing ability nor altered the infectivity of RRKN second-stage juveniles (J2). Second-stage juvenile hatching was, however, reduced in two higher doses (2.5% and 5%) of vermicompost exudates. When final nematode population was normalized with root weights at 21 days’ post inoculation, a reduction in population build-up was observed with increased doses of vermicompost. A reverse trend was observed for biochar treatments. Overall, our study showed that application of 1.2% biochar and 5% vermicompost could be helpful in mitigating the RRKN stress in rice. Hence, application of biochar and vermicompost could be an effective alternative to toxic chemical nematicides and recommended as eco-friendly management options against M. graminicola in rice.