Differential sensitivity of Pyrenophom teres to organomercury formulations

Abstract

SUMMARYIn agar plate tests, all 45 isolates ol Pyrenophora teres Drechsler tested were less sensitive to methoxyethyl mercury acetate (MEMA) as ‘Panogen M’ than to phenyl mercury acetate (PMA) as‘Agrosan D’, In further tests with eight isolates selected at random, mean ED50 values (p.p.m. Hg) for inhibition of mycelial growth at 17°C were 0.620 for MEMA, 0.098 for PMA, 0.070 for ethyl mercury phosphate and 0.060 for phenyl mercury chloride.In field trials on spring barley in 1980 at seven different sites throughout England and one in Scotland, mean seedling infection of 5.8 percent was reduced to 1.2 per cent by PMA and to 1.9 per cent by MEMA.