Submitted to: Acremonium Grass Interactions International Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/1996
Publication Date: N/A
Technical Abstract: Feeding behaviour of fall armyworm (Spodoptera frugiperda Smith) larvae was investigated using novel grass-endophyte (Neotyphodium) associations with previously characterized alkaloid spectra. Larvae were presented with a choice between excised leaf blades of endophyte (Neotyphodium)-infected (E+) and endophyte-free (E-) grasses. Aggregation of larvae and damage to the leaf blade were determined at 24h. Leaf age did not play a role in determination of feeding damage but did influence aggregation of the larvae. Novel associations in perennial ryegrass which contained peramine but no other known alkaloids had variable effects on larval location and feeding damage (ranging from attraction to E- to attraction to E+). Larvae preferentially aggregated on E+ blades from a perennial ryegrass-endophyte association which produces no known alkaloids, but there was no significant reduction of feeding due to endophyte infection. Larval feeding was not affected by any endophyte tested in tall fescue. Larvae presented with blades from meadow fescue infected with its natural endophyte had no preference for either E+ or E- blades. Novel meadow fescue-Neotyphodium associations contained unique spectra of the alkaloids which are associated with E+ tall fescue and perennial ryegrass; all novel associations resulted in a deterrence of larval feeding but not all influenced aggregation. In this study, ergovaline, loline and lolitrem B were not necessary for deterrence of fall armyworm; peramine, however, was present in all E+ plants in which there was reduced feeding, but presence of peramine did not necessarily result in deterrence. For two separate endophyte strains, associations with tall fescue and meadow fescue resulted in host-specific behaviour differences.