The present study on the plant nematodes associated with Bt cotton crop growth in northern Karnataka, India covered several aspects like a nematode random survey in Bt cotton-growing areas of the state, nematode community analysis, pathogenicity and biology of a dominant nematode and reaction of Bt cotton cultivars and hybrids to that nematode. A random survey undertaken in the Bt cotton-growing districts of northern Karnataka for the associated nematodes in