Endophyteinfected meadow fescue and loline alkaloids affect Argentine stem weevil larvae

Abstract

In a meadow fescue plant assay a lower percentage of tillers on endophyteinfected (E) than endophytefree (E) plants on which eggs had been laid were damaged by Argentine stem weevil (ASW) larvae There were indications of endophytemediated toxicity to young larvae The percentage of damaged tillers on E and E plants without ASW eggs was similar when they were planted alongside a plant with eggs but severity of damage was less on E plants In an artificial diet experiment eggs took 23 days longer to hatch on an alkaloidfree diet than on diets containing either of two loline alkaloids produced by E meadow fescue Growth and development of larvae was reduced by up to 36 at two higher concentrations of Nformyl loline (NFL) relative to the lowest concentration and to a lesser extent by Nacetyl norloline Larval survival declined with increasing concentrations of both alkaloids with the highest mortality occurring at the two higher concentrations of NFL