* Part of the thesis submitted by the senior author for the award of M. Sc. (Ag.) degree of APAU Rajendranaga - Hyderabad-500 030. A. P., India.
Studies on the biology and varietal resistance to white backed planthopper, Sogatella furcifera showed that younger seedlings (15 to 30 days old) were most suitable than old aged seedlings for population build - up. Besides rice, the nymphs could survive and breed only on Chloris barbata while on Echinochloa colonum, Paspalidium geminatum, Leersia hexendra and Panicum sp. they could reach upto adult stage.
Varieties/cultures like IET 6288, IET 4695, ARC 5955, ARC 11208, ARC 11351, ARC 5976, IR 781-144-1-IR 8/2, ARC 10079, Aland T 1426 were identified as resistant in mass screening test. Amongst these IET 6288 followed by ARC 11208 showed distinct nonpre-ference mechanism. Antibiosis test indicated that the insect survival was adversely affectea to a greater extent on ARC 5955 followed by ARC 11351 and IR 781-144-1-IR 8/2. The population build-up in 2 nd generation was distinctly low on resistant varieties as compared to susceptible T (N) 1.
