GIS/GPS based survey on incidence and distribution of rice root-knot nematode (Meloidogyne graminicola) in Southern transition zone of Karnataka

Abstract

A survey was conducted during Kharif -2016 in Southern transition zone districts of Karnataka to know the level of incidence and distribution of Meloidogyne graminicola with respect to soil types, types of cultivar, and geographical location. The survey indicated that, there is incidence of rice root- knot nematode in all the surveyed villages. But their level of incidence varies with respect to cultivar, soil type and geographical location. Maximum nematode population was found in Chikadadkatte of Davanagere district, Tuduru, Beguvalli, Hasudi of Shivamogga, Karagunda and Lakkavalli of Chickmagaluru district (586.33 to 841.00 J2/100 cc of soil) with root knot indices varying from 3 to 4. The lowest incidence was observed in Kumsi of Shivamogga and Vadeyarhatturru of Davanagere district. Interestingly it was observed that where the places recorded highest nematode population having sandy loam soil and Jyothi was predominant cultivated variety it is highly susceptible to rice root-knot nematode. M. graminicola is soil borne in nature it is adapted to congenial condition favored in these districts and continuous growing of susceptible cultivar Jyothi results in spreading throughout all rice growing areas of Southern transition zone districts