Dynamics of concomitant populations of Tylenchorhynchus mashhoodi and Hoplolaimus indicus in sugarcane fields under crop sequences and pesticide appucation

Population dynamics of Tylenchorhynchus mashhoodi and Hoplolairnus indicus from six fields having sugarcane in rotation and monoculture was studied. T. mashhoodi was the dominant species in all the fields except two, one containing jute and the other sugarcane in rotation where H. indicus was numerically dominant. In general, monoculture supported more numbers than rotations. All the crops under study promoted nematode multiplication except seasame and garlic which depressed it. Two peaks of both the species were observed, one during May and the other in October under sugarcane. Nematode population fluctuations were influenced by crop growth, rainfall and temperature. Under the remaining crops, population showed only one peak which synchronized with the late growth stage of the host. Correlation coefficient calculated between nematode numbers and yield of sugarcane revealed a significant negative relationship. Corm powder of wild arum (Typhonium trilobatum) exerted its nematicidal effect in bringing down population significantly.