Cultivar and endophyte effects on a root aphid <i>Aploneura lentisci</i> in perennial ryegrass

Abstract

In a pot trial fungal endophytes (Neotyphodium spp) with different alkaloid profiles were investigated for their effects on numbers of a root aphid (Aploneura lentisci) in perennial ryegrass Some endophytes were also tested in different cultivars (Nui Samson and Impact) Two endophytes AR37 and AR6 strongly suppressed root aphid numbers Wildtype had fewer aphids than endophytefree plants and AR1 Endophytes producing peramine only (AR1 AR12 AR22) and an endophyte producing peramine and lolitrem B (AR23) did not differ from endophytefree There were no cultivar by endophyte interactions but cultivar affected the strength of aphid response to Wildtype Comparisons of alkaloid profiles suggest that ergovaline (in Wildtype and AR6) and epoxyjanthitrems (in AR37) may affect root aphids whereas peramine and lolitrem B do not Differences in herbage dry weight of plants and a significant relationship between herbage dry weight and root aphid numbers indicated this aphid reduces the growth rate of plants