An investigation was carried out on Jaya var. rice transplanted in the last week of June 1981–62 and 1982–83 to assess the most suitable growth stage for insecticidal treatment and to determine the avoidable losses caused by whitebacked plant hopper (WBPH)Sogatella furciferaHorv., at Rice Research Station, Kaul, Kurukshetra. Carbofuran 3 G at 1–25 kg a.i./ha during 1981–82 and phorate 10 G at 1.5 kg a.i./ha were applied at three growth stages at 5, 30 and 60 days after transplanting (d.a.t.) either once or with repeated doses at 5 + 30, 5 + 60, 30 + 60 and 5 + 30 + 60 d.a.t. Quinalphos 25 e.c. and monocrotophos 40 e.c. (Nuvacron) at 0.5 kg a.i./ha were applied as foliar spray at 50 and 80 d.a.t. in second and third stage protection respectively. Carbofuran alone or with repeated foliar sprays protected 7.5–23.3% grain losses whereas phorate alone or with combination repeated doses gave 13.9–30.6% increase in grain yield over unprotected check. The crop protected at the third stage (60 d.a.t. until harvest) invariably provided greater pest reduction and higher grain yield. The carbofuran treatments either alone or in combination did not prove economical whereas the net profit by the use of phorate alone or in repeated doses in different combinations ranged from Rs. 967.77–2298.38/ha. Phorate treatment at 60 d.a.t. followed by foliar spray with Nuvacron at 80 d.a.t. gave the highest return of Rs. 2298/ha and a cost/benefit ratio of 3.65. The average yield loss over two years was nearly 20%.