Abstract

                                The biology of Nephotettix virescons (Distant) was studied on 4 rice (Oryza sativa L.) varieties viz. TKM 9, IR 8. IR 50 and PY 3 having differential reaction to green leafhopper (GLH) and rice tungro virus (RTV) and on an alternate weed host Cyperus rotundus L. Among the rice varieties, TKM 9, the variety susceptible to GLH and RTV was more suitable for the development of N virescens favouring higher fecundity, fesser pre-oviposition and incubation period, lower mortality and nymphal duration, prolonged adult longevity and higher sex ratio than IR 8, IR 50 and PY 3. Differential influence was exhi- bited by IR 8 (resistant to GLH but susceptible to RTV), IR 50 (moderately resistant to GLH but resistant to RTV) and PY 3 (resistant to both GLH and RTV) on various aspects of life history of N. virescens. Weed host C. rotundus offered more resistance than rice varieties and had not favoured the population build up though it aided in sustaining GLH.

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