Relationship between Rotylenchulus reniformis densities and host damage with reference to tolerance levels1 Varaprasad K.S.*, HeadHead, Sud U.C., Swarup G. Division of Nematology, Indian Agricultural Research Institute, New Delhi-110012, India. * Present address: Plant Quarantine Regional Station, (NBPGR), Rajendranagar Hyderabad-500 030 (A.P.). Abstract Relationship between logarithmic densities of the reniform nematode, Rotylenchulus reniformis and damage to castor, cotton, cowpea, greengram, okra and tomato was fitted to Seinhorst's equation Y = m + (l-m) ZP-T. Tolerance limits of cotton, cowpea, greengram and tomato, at two different stages of crop growth and at one stage of okra (60 days) and castor (100 days) were calculated separately for shoot and root weights and total plant weights with. the help of computer programme. Host root parameter had lower tolerance limits (1.6 to 10.0/1000-cm3 of soil). Castor and cotton had higher tolerance limits (10.12 and 14.35/1000 cm3 of soil) and better multiplication rates (372 and 83 times) suggesting advanced relationship and suitability for culturing the nematode on these hosts. Top Key words Reniform nematode, host tolerance levels. Top |