Field studies of a Schizaphis on pangola grass in North Queensland

Abstract

Studies were conducted in 1971 and 1972 on the aphid Schizaphis sp. of the graminum group attacking pangola grass (Digitaria decumbens) on the wet tropical coast of North Queensland. In a small plot trial, populations of the aphid were found to significantly reduce yields of pangola grass. A screening trial showed that dimethoate, omethoate and methidathion applied at 280 g a.c./ha and demeton-s-methyl at 140 g a.c./ha were effective treatments. Diaizinon, maldison and carbaryl at 280 g a.c./ha were much less effective. A comparison of aphid numbers on six pasture grasses showed that pangola grass carried the largest populations.