Vol. 9, Issue 6 (2020)

Author(s):
Niranjanadevi Jeevanandham and Ganapathy N

Abstract:
The insecticidal treatments differed considerably in their persistence, period of efficacy and index of persistent toxicity. At 48 hours of treatment, high mortality was observed with chlorpyriphos 2000 ml/ha (95.83%) and 79.17% with chlorpyriphos 1500 ml/ha and the persistent toxicity (PT) values were 4600.0, 3800.0 respectively. The higher dose of chlorpyriphos 20 EC treatments were the most persistent and Dursban 20 EC, lower dose of chlorpyriphos was the least. Contact toxicity results showed that, Chlorpyriphos 20 EC 1000 ml/ha registered 100 per cent mortality and chlorpyriphos 20 EC 750 ml/ha (100%) followed by chlorpyriphos 20 EC 500 ml/ha (96.67%) and Dursban 20 EC 500 ml/ha (93.33%), dimethoate 30 EC 500 ml/ha (90.00%) and chlorpyriphos 20 EC 250 ml/ha (86.67%). Higher Mortality of the psyllids in adult feeding experiments was recorded with chlorpyriphos 20 EC at 1000 ml/ha (100%) and chlorpyriphos 20 EC at 750 ml/ha (100%) The other effective treatments were; chlorpyriphos 20 EC at 500 ml/ha (96.67%) and Dursban 20 EC at 500 ml/ha (93.33%) dimethoate 30 EC at 500 ml/ha (90.00%) and chlorpyriphos 20 EC at 250 ml/ha (86.67%).