The effect of non-toxic endophytes in tall fescue on two major insect pests

Abstract

In a choice trial in a glasshouse, infection of tall fescue with the endophyte AR542 significantly reduced feeding by adult Argentine stem weevil (ASW) in the cultivar J esup but not in Advance in comparison with the same cultivars without endophyte. Paddocks of Quantum infected with AR542 that were sampled on two Northland farms consistently had fewer tillers damaged by Argentine stem weevil than equivalent paddocks of endophyte-free (Nil) tall fescue. In comparison to Nil plants, AR542 in Jesup and Advance had significantly fewer plants and tillers damaged by adult black beetle in a glasshouse choice trial. Fewer tillers were also damaged by adult black beetle in Advance tall fescue infected with AR501 and AR502 than in Nil Advance in a small plot field trial at Kerikeri. In a similar trial at Ruakura, the occurrence of adult black beetle and signs of larval damage were high in endophyte-free plots and considerably reduced in endophyte-infected plots. It is concluded that the nontoxic endophytes will lessen damage by black beetle and ASW in a range of tall fescue cultivars and that this is likely to contribute to increases in productivity and persistence of this forage grass. Keywords: Argentine stem weevil, black beetle, AR542 endophyte, Neotyphodium, tall fescue