Studies on Antagonistic Potential of Native Isolates of Trichoderma for the Management of Rice Root Knot Nematode (Meloidogyne Graminicola)

Abstract

Plant parasitic nematodes cause significant damage and yield loss in rice (Oryza sativa L.). It is the staple food of more than three billion people in world. More than 35 genera and 130 species of plant parasitic nematodes are associated with rice. Among them rice root-knot nematode (Meloidogyne graminicola) happens to be the most important pest and it is prevalent in major rice producing countries of the world. Root-knot nematode (Meloidogyne graminicola) has been reported to be a serious pest of paddy, especially in light-textured soil and irrigated upland condition. It causes damage to nurseries and main field. In the present investigation twenty native isolates of the Trichoderma named M-1 to M-20 were isolated from the rice rhizosphere soil at different locations of Meerut, Muzzafarnagar and Hapur districts of western U.P. (India). The isolates were characterized on the basis of their cultural characters such as radial growth, colony colour, pigmentation, sporulation initiation and colony appearance. All Trichoderma isolates were screened for their efficacy against Meloidogyne graminicola under in-vitro conditions through egg hatch inhibition and second-stage juvenile mortality test at 10, 20, 30 and 50% concentrations. Among all tested isolates, minimum (6.67%) egg hatching was recorded in isolates M-1, M-10, M-12, M-17 and maximum (100%) larval mortality was recorded in isolates M-3, M-4, M-5, M-7, M-16 and M-17 after 72 hours of incubation at 50% concentration. Six most efficient isolates were selected based on larval mortality to ascertain their effectiveness under pot condition. These selected Trichoderma isolates were applied as soil application @ 10 g/kg of pot. It was observed that almost all tested isolates significantly reduced the galls/plant. At 60 DAS, minimum (1.78 and 2.11) galls/plant were recorded in isolates M-3 and M-17 as compared to control (5.78 galls/plant). All tested isolates increased the growth parameters (shoot and root length). Plants grown in the control pot without Trichoderma developed more terminal galls on roots and suffered severe reduction in plant growth. However, application of Trichoderma isolates suppressed the negative impact of the nematode and subsequently increased plant growth.