Laboratory and field testing of insecticides against paddy bug, Oebalus poecila (Dallas) and a technique for low-volume drift spraying of paddy for its control
Rai, B.K.
Data on the residual contact toxicity of 35 insecticides to the adult paddy bug, Oebalus poecila at 0.01, 0.003 and 0.001 % w/v concentrations are presented. 17 insecticides were found to be comparatively more toxic than the rest and were thus selected for further testing. With respect to their duration of toxicity on potted rice plants to the paddy bug, monocrotophos 0.04 % and carbaryl 0.04 and 0.1 % sprays were toxic for a longer period. From further field testing it has been recommended that monocrotophos emulsion at 270 gm a.i./ha in 11 litres of spray fluid/ha and carbaryl suspension at 1.4 kg a.i./ha in 22-44 litres of spray fluid/ha gave prolonged control of paddy bug when drift spraying after every 6 m is carried out. Monocrotophos is superior to carbaryl and because it is a systemic insecticide it should not be applied within 15 days of harvest. With respect to the economics of this recommendation, monocrotophos spray costs less than carbaryl and also less than the earlier recommendations of dust. Monocrotophos is ideally suited to low volume drift spraying and by the technique described, it is possible to spray 1 hectare of paddy in 30 mins. with a motorized knapsack sprayer
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