Assessment of impact of climate change with reference to elevated CO2 on rice brown planthopper, Nilaparvata lugens (Stal.) and crop yield

Abstract

Impact of elevated CO2 on the rice brown planthopper (BPH), Nilaparvata lugens (Stal.) population and rice yield was assessed in open-top chambers during kharif 2010 and 2011. Brachypterous females laid more eggs (324.3 ± 112.3 eggs/female) on the rice plants exposed to elevated CO2 (570 ± 25 ppm) than 380 ppm ambient CO2 (231.7 ± 31.8 eggs). Elevated CO2 exhibited positive effect on BPH multiplication and resulted in morethan a doubling of its population (435.4 ± 62.0 hoppers/ hill) at peak incidence compared to ambient CO2 (121.4 ± 36.8 hoppers/hill) during kharif 2010; corresponding populations being 113.0 ± 11.5 and 47.0 ± 8.1 hoppers/hill during kharif 2011 respectively. Besides, honeydew excretion was observed to be 74.41% more under elevated CO2 (187.6 ± 44.8 mm2/5 females) than ambient CO2 (48 ± 20.1 mm2/5 females). On the other hand, high CO2 exhibited nutritive effect on uninfested rice crop through 21.6%, 15.3% and 14.1% increase in the number of tillers, reproductive tillers and seeds/panicle respectively, and as a consequence increased grain by 11.1% compared to ambient CO2. However, despite the nutritive effect, crop under elevated CO2 suffered higher yield loss (26.5%) due to higher BPH population as well as sucking rate compared to ambient CO2 (12.4%).