Efficacy of Trichlorfon Plus Fipronil 50% EC and Several Other Insecticides Against Cnaphalocrocis medinalis

Trichlorfon plus fipronil 50% EC provided excellent control of Cnaphalocrocis medinalis in field demonstra- tion trials. When applied at 1200 ml/ha during peak activity of 2-instar larvae, trichlorfon plus fipronil provided 90.2% and 94.1% insect control 3 and 7 d after application, respectively, while leaf protection efficacy was 82.0% and 87.7%, respectively. These results were better than those provided by chlorpyrifos plus triazophos 30% EC at 1050 ml/ha and by triazophos 40% EC at 1200 ml/ha. trichlorfon plus fipronil at 1500 ml/ha during peak activity of 3-instar larvae provided 80.1% insect control 4 and 6 d after treatment.