Impact of Elevated CO₂ and Temperature on Brown Planthopper Population in Rice Ecosystem

Influence of elevated CO₂ (570 ± 25 ppm) and elevated temperature (≃3 °C higher than ambient) on rice (Oryzasativa L.) and brown planthopper (BPH), Nilaparvata lugens (Stal.) was studied in open top chambers during rainy season of 2013. Elevated CO₂ and temperature exhibited positive effect on BPH multiplication thus enhancing its population (55.2 ± 5.7 hoppers/hill) in comparison to ambient CO₂ and temperature (25.5 ± 2.1 hoppers/hill). Elevated CO₂ + 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 CO₂ 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 CO₂ concentration and temperature on BPH population exacerbates the damage (30.6) which in turn coupled with the plant traits to hampering production.