The potential of entomopathogenic fungi to control the lettuce root aphid,<Emphasis Type="Italic">pemphigus bursarius</Emphasis>

The lettuce root aphid,Pemphigus bursarius, is a commercially important pest of lettuce and occupies a niche amenable to the action of entomopathogenic fungi. As the first stage of a biological control programme, a bioassay was developed against adult apterousP. bursarius. An isolate ofMetarhizium flavoviride was pathogenic toP. bursarius and sporulated abundantly upon aphid cadavers. However, two isolates ofVerticillium lecanii, pathogenic against glasshouse whitefly and aphids, were only weakly pathogenic toP. bursarius.