Impact of Elevated CO 2 and Temperature on Brown Planthopper Population in Rice Ecosystem

Influence of elevated CO (570 ± 25 ppm) and elevated temperature (≃3 °C higher than ambient) on rice ( L.) and brown planthopper (BPH), (Stal.) was studied in open top chambers during rainy season of 2013. Elevated CO and temperature exhibited positive effect on BPH multiplication thus enhancing its population (55.2 ± 5.7 hoppers/hill) in comparison to ambient CO and temperature (25.5 ± 2.1 hoppers/hill). Elevated CO + temperature significantly reduced the adult longevity and nymphal duration by 17.4 and 18.5 % respectively, however elevated conditions increased BPH fecundity by 29.5 %. In rice crop, interactive effect of elevated CO and temperature led to an increase in the number of tillers (20.1 %) and canopy circumference (30.4 %), but resulted in a decrease of reproductive tillers (10.8 %), seeds/panicle (10.9 %) and 1000-seed weight (8.6 %) thereby reducing grain yield (9.8 %). Moreover, positive effect of increased CO concentration and temperature on BPH population exacerbates the damage (30.6) which in turn coupled with the plant traits to hampering production.