Abstract & Overview
Rice Brown Planthopper, Nilaparvata lugens (Stal) (BPH) along with White-backed Planthopper, Sogatella furcifera (Horvath) (WBPH) have co-evolved along with rice plant during its domestication of thousands of years. These plant hoppers are small insects. The adults measure about 4-6 mm in length and 3-4 mm in width. The nymphs as well as adults suck plant sap from phloem and occasionally from xylem. Enormous draining of sap results in drying of plants in circular patches called “hopper-burn”. Adults have two morphologically distinct forms1) macropterous i.e. those with fully developed wings and 2) brachypterous i.e. those with half developed wings. Macropterous forms can move up to few thousands of kilometers and settle in favorable areas. The progeny develops into brachypterous forms capable of laying 300-400 eggs/female facilitating very rapid population build up. This process of morpho-form development is under hormonal regulation and genetically controlled. Distribution of BPH in the field is patchy or clumped i.e. “negative binomial distribution”. East Asian, South-east Asian, and South Asian biotypes of BPH with distinct virulence patterns for host resistance exist. Long range migration of East Asian biotype from southern tip of China to Japan and Korea and back has been well documented. Possibility of such migration in South Asian biotype from Sri Lanka up to Punjab is hypothesized. South-east Asian biotype can possibly move from Indo-China countries up to tip of Indonesia and back .