Endophyte effects on consumption of seed and germinated seedlings of ryegrass and fescue by grass grub (Costelytra zealandica) larvae

Abstract

Tall fescue, meadow fescue and ryegrass seeds with and without endophyte infection were fed to third-instar grass grub to determine the relative effects of different endophytes on consumption. Treatments were: tall fescue without endophyte or infected with four novel endophytes (AR514, AR542, AR584, ES), meadow fescue without endophyte or infected with Neotyphodium uncinatum and perennial ryegrass infected with a novel endophyte AR37. Grass grub larvae were initially given hard seed but when they failed to eat this, moist soil was added to allow seed to soften and germinate. After 7 days, all endophytes had reduced feeding compared to their endophytefree counterparts. At the completion of the trial, 15 days after adding moist soil, only AR37 in perennial ryegrass had no effect on damage to the seed. Of the endophytes in tall fescue, seeds containing AR542 were significantly more damaged than other endophyte treatments. Composition of loline alkaloids may be important in reducing feeding. Keywords: tall fescue, meadow fescue, ryegrass, endophytes, loline alkaloids, seed damage, grass grub, Costelytra zealandica