Reducing Damage Caused by Root-knot Nematodes by Applying Methane-fermentation Liquid from Livestock Waste Slurry to Soil

Abstract

The effect of methane fermentation liquid obtained from livestock waste slurry (MFL) on the activity of root-knot nematodes (Meloidogyne spp.) was evaluated. On the day after preparation, MFL contained 1.86 g L^–1 of ammonium nitrogen which is reported to have nematocidal activity. However, the ammonium nitrogen content decreased with the lapse of storage time. More than 90% of the population of M.incognia was immobilized by adding the five-times-diluted MLF solution to a suspension of M.incognita. This immobilization effect was also observed in other Meloidogyne spp.: M. arenaria Honshu-type, M. arenaria Okinawa-type, M.hapla, M.javanica and M.microcephalus. The population of M.incognita in soil was significantly reduced by addition of 120 mL kg^–1 (equivalent to 60% of maximum water-holding capacity) MLF to soil in Sand-dune Regosol infested with M.incognita. However, this effect was not observed clearly in Gray Lowland soil and Andosol. The amount of egg masses produced by M.incognita was reduced to less than 25% of that in the control by applying 70 mL kg^–1 MLF (containing 200 mg NH₄⁺-N) to the soil of nematode-infected Sand-dune Regosol in the pot experiment with tomato seedling.