Seed Systemics for Control of Aphids on Oats and Barley 1

Eleven organophosphorous compounds in carbon formulation were tested as seed systemics for phytotoxicity to barley and oats, and control of aphids on oats. Ph orate, Bayer 25198 ( O, O -dimethyl- O-p -(methylsulfinyl)phenyl phosphorothioate), Di-Syston®( O, O -diethyl S -2 (ethylthio)ethyl phosphorodithio-ate), dimethoate, and phosphamidon were promising. Phorate and Di-Syston did not. prevent transmission of barley yellow-dwarf virus to small plots of oats by migrating alate aphids.