KUMAR, N. G.AVINASH, T. G.2020-10-052020-10-052019-05-24Th-12266https://krishikosh.egranth.ac.in/handle/1/5810152378Present investigation was carried out at the University of Agricultural Sciences, GKVK, Bengaluru during 2016-18. Maximum termite damage to bait was noticed in maize followed by sunflower and finger millet ecosystem. Influence of abiotic factors on termite activity was 67.60, 49.30 and 26.20 per cent in maize, sunflower and finger millet ecosystem, respectively. Total rainfall, in situ soil moisture and minimum soil temperature exhibited significant positive impact on the termites activity. Odontotermes obesus constructs conical shaped mound with one or more hollow turrets. The height and circumference of the mound varied based on the age of the colony. Inner mound wall possessed small pin holes distributed more on the top portion. The royal chamber was flat based hard earthen structure located with a mean depth of 27±5.03 cm. Mound height found significant positive correlation with depth, length, breadth and inner height of the royal chamber and length of the queen. Different shaped unilocular fungal combs were distributed 20-40 cm above and below soil surface. Eggs, nymphs, workers, soldiers and alate nymphs were present in the fungal combs. A small supplementary royal chamber with king and queen was also present. Composition of sand, silt and clay content varied in different portion of the mound, royal chamber and earthen sheetings with dominance of clay content. Earthen sheeting soil was slightly acidic with 0.51, 0.01 and 0.01 % of OC, N and K content, respectively. The combination of surrounding soil + mound soil + FYM (75: 10 : 15%) medium supported maximum plant height, pod production and higher soybean yield. Bifenthrin @ 0.05%, chlorpyriphos @ 0.1 % and clothianidin @ 0.075% treated soil protected the baits up to 20 months. Bifenthrin 2.5% EC was found more toxic with the LC50 of 4.35 and 4.93 ppm against O. obesus and O. horni, respectively.EnglishThesis