KALITA, RINKI MANI2022-02-262022-02-262017-07https://krishikosh.egranth.ac.in/handle/1/5810182906An experiment entitled “Identification and mass production of entomopathogenic nematodes” was conducted in the laboratory of Department of Nematology, Assam Agricultural University, Jorhat. A systematic survey was undertaken in Assam Agricultural University, Jorhat Campus for the occurrence of entomopathogenic nematodes during the year 2015-16. A total of 200 soil samples were collected randomly during the period November, 2015 to March, 2016 from four habitats (vegetation type) viz., Instructional-cum-Research (ICR) Farm, Experimental farm of Department of Horticulture, Experimental farm for plantation crops and Fallow land. From each habitat 50 numbers of samples were collected. Survey data revealed that out of 200 soil samples, eight samples were positive for entomopathogenic nematodes (4%), with containing 4 isolates were assigned the genus Steinernema (2%), 2 isolates were assigned to the genus Heterorhabditis (1%) and 2 isolates were assigned to the genus Oscheius (1%). Steinernematid isolates were designated as EPN-S-J-1, EPN-S-J-2, EPN-S-J-3. The isolates were found from rhizosphere of mung bean, arahar and cowpea respectively from ICR Farm, AAU, Jorhat. Another isolate of steinernematid (designated as EPN-S-J-4) was found from rhizosphere of citrus from the Experimental farm of the Department of Horticulture. One heterorhabditid isolate (designated as EPN-H-J-1) was found from rhizosphere of citrus and one isolate of Oscheius (designated as EPN-O-J-1) was found from rhizosphere of coconut in the Experimental farm of the Department of Horticulture. One heterorhabditid isolate (designated as EPN-H-J-2) and another isolate of Oscheius (designated as EPN-O-J-2) were found from tea garden of Experimental farm for plantation crops of AAU, Jorhat. Entomopathogenic nematodes were not recovered from the fallow land. EPN species were identified as Heterorhabditis bacteriophora, Steinernema aciari, Oscheius chongmingensis based on their morphological and morphometrical study of different life stages (infective juveniles, adults of both generations). The mass multiplication of three isolates Heterorhabditis bacteriophora, Steinernema aciari, Oscheius chongmingensis were done on different artificial media (plant and animal origin media). In plant origin media consisted of nine treatments including a control with three replications were laid out in a Completely Randomized Designs. The treatments were T1 (Wheat flour and sunflower oil), T2 (Wheat flour and soya oil), T3 (Wheat flour and coconut oil), T4 (Soya flour and sunflower oil), T5 (Soya flour and soya oil), T6 (Soya flour and coconut oil), T7 (Green gram flour and sunflower oil), T8 (Green gram flour and soya oil), T9 (Green gram flour and coconut oil) and control (Soya flour and corn oil). Among these treatments, T9 containing green gram flour and coconut oil which was found to be highest multiplication rate in all EPN specis viz., Heterorhabditis bacteriophora, Steinernema aciari, Oscheius chongmingensis 97.92 x 105, 114.17 x 105, 104.10 x 105 IJs/flask, respectively. Out of these EPNs spp. Steinernema aciari was found to be more yield (114.17x105) in T9. The medium containing wheat flour and sunflower oil (T1) recorded lowest multiplication rate for Oscheius chongmingensis (3.68 x105) and the medium containing wheat flour, soya oil (T2) recorded lowest multiplication rate for Heterorhabditis bacteriophora (5.19x105) and Steinernema aciari (2.67 x105). In animal origin media comprising of varied sources of proteins and lipids of animal origin and consisted of three treatments including a control with five replications were laid out in a Completely Randomized Designs. Treatments were T1 (Dog biscuit), T2 (Goat waste homogenate), T3 (Pork homogenate) and control (Chicken offal homogenate). Among these treatment, T3 containing pork homogenate which was found to be highest yield in three isolates viz., Heterorhabditis bacteriophora, Steinernema aciari, Oscheius chongmingensis were 6.54x105, 17.24x105, 5.99x105 IJs/100 flask respectively and more yield was found Steinernema aciari. T2 containing goat waste homogenate recorded the least multiplication rate of all three isolates viz., Heterorhabditis bacteriophora, Steinernema aciari, Oscheius chongmingensis were 3.67x105, 6.75x105, 3.47x105 IJs/100 flask, respectively.EnglishThesis