Efficacy of Certain Pesticides in the Control of Thrip Retithrips Syriacus on Cassava

Tests wee performed with 24 pesticides during 1976–78 against thrip, Rctithrips syriacus (Mayet) a pest of cassava. Manihot esculenta Crantz in Kerala. Amongst 21 pesticides tested during 1975, pomising 15 were revualated during 1977. Eleven pesticides found promising were retested during 1978. Final results showed that monocrotophos and leptophos at 0.03 per cent and metasystox and fenthion at 0.05 percent were superior in controlling R. syriacus and were found to be most promising. The pesticides from the view point of effectiveness based on 3 years systematic study, can be arranged serially as follows: monocrotophos, leptophos, metasystox, fenthion, formothion, dictotophos, hexinphos, thiometon, dimethoate, phosalone and dictotophos.