Laboratory Evaluation of Insecticides for Ovicidal Activity Against the Rice Brown Planthopper. IRRI Laboratory, 1977

Five gravid brown planthoppers were caged and allowed to oviposit on potted 30-day-old rice seedlings for 24 hours. One day later the cages were removed, the potted plants were placed on a turntable and sprayed, and the plants were recaged. Hatching nymphs were recorded daily from 7-14 days after spraying. Thereafter, the plants were dissected under the microscope (eggs are injected into the leaf sheath tissue) to determine the number of unhatched eggs. Percent ovicidal activity was computed by dividing the number of hatched nymphs by the sum of hatched nymphs and unhatched eggs and multiplying times 100.