S.T. PrabhuBasavaraj Ashokappa H.T.2016-11-122016-11-122011http://krishikosh.egranth.ac.in/handle/1/85252Studies on bioecology and management of rice earhead bug, Leptocorisa oratorius, Fabricius (Hemiptera: Alydidae) were undertaken during kharif, 2010 in rainfed ecosystem of Uttara Kannada district. Uttara Kannada district represents three distinct rice ecosystems, namely; ’upghat’ drill sown paddy, ’upghat’ transplanted paddy and coastal transplanted paddy. The roving survey taken up in these ecosystems revealed the two species belonging to the genus Leptocorisa, viz., L. oratorius, and L. lepida. Assuming that all rice earhead bugs were L. oratorius, it was confirmed by observing the characteristic black ventrolateral spots on the abdominal segments of this species. Among the two species L. oratorius was of high abundance and noticed in almost all places of surveyed. The highest incidence of rice earhead bug was recorded at reproductive stage of crop during kharif season than rabi. The maximum population of 3.04 nymphs and adults per hill was recorded, during October (kharif-2010) in Mundgod and least in Sirsi (1.97/hill). Whereas, in rabi (2011) maximum population of 2.04 nymphs and adults per hill was recorded during May in Mundgod and least in Kumta (1.08/hill). The preadatory spiders, coccinellids, ground beetles, dragonflies, damselflies, bugs and roberflies were recorded during both the seasons. Seven alternate hosts of rice earhead bug were observed during survey which included Echinocloa crusagalli (L.), Echinocloa colonum (Link.), Eleusina indica (L.) Gaertn, Digitaria sanguinalis (L.), Cyperes rotundus (L.), Cyperes iria (L.) and Brachiria mutica (Stapf.). Among the various botanicals, entomopathogenic fungi and synthetic insecticides evaluated for the management of rice earhead bug, imidacloprid 17.8 SL @ 0.25 ml/l was found very effective in reducing rice bug population and was at par with thiamethoxam 25 WG @ 0.3 g/l and malathion 5D @ 20 kg/ha. Next best treatments included azadirachtin 3000 ppm @ 3 ml/l and Acorus calamus aqueous rhizome extract @ 10%.Agricultural EntomologyThesis