Nightly catches of Scirpophaga nivella (F.) in light traps in rice plots in West Bengal, India, showed two discrete peaks of abundance in each trap-year corresponding to congenial weather and abundance of summer (mid-March-mid-June) and autumn (mid-July-mid-November) rice plants. Estimated generation times showed many overlapping generations in each trap a year. Variations in summer catches were significantly correlated (P < 0.01–0.05) with maximum temperature and minimum relative humidity of the day, and minimum temperature and wind speed of the night; whereas those in autumn catches were significantly associated with maximum temperature and minimum relative humidity of the night (P < 0.01–0.05). Autumn crops had more infestations, and sustained greater larval density than summer ones. Females were twice as heavy as males (2.1:1) and adults were heavier in October than in May. Catches of immature and mature females were consistently maximum at full moon and new moon, respectively.
