Argentine stem weevil response to variable endophyte infection in Grasslands Greenstone ryegrass

In three screenhouse trials three categories of endophyte infection of Grasslands Greenstone ryegrass plants were identified; viz.fully infected with the endophyte Neotyphodium lolii, partially infected with N. lolii, or completelyN.lolii-free but infected with a Gliocladium-like endophyte.Damage by Argentine stem weevil larvae was higher on plants partially infected with N. lolii than on fully infected plants but in two trials was not as high as damage to N. lolii-free plants.Occurrence of partially infected plants appears to be variable and may be environmentally induced.The presence of the Gliocladium-like endophyte in some plants in one trial significantly increased larval damage to those plants, except where N. lolii was also present.