Endophytes improve ryegrass persistence by controlling insects

Abstract

Fungal endophytes reduce populations and damage by several different insect pests which alone or in combination with each other can reduce ryegrass persistence. AR1, AR37, the Standard endophytes and two endophytes in tetraploid ryegrasses, NEA2 in cv. Bealey and Endo5 in cvs. Quartet II and Banquet II, are available to the New Zealand farmer. Their effects on insects depend on the spectrum and concentration of alkaloids they produce. Argentine stem weevil is controlled by all endophytes except perhaps Bealey NEA2; black beetle is controlled by all endophytes except AR1; pasture mealybug are controlled by AR1, AR37 and Standard and likely to also be controlled by Endo5 and NEA2; porina and root aphid are controlled by AR37. Increased persistence of ryegrass infected with endophyte is reflected in increases in endophyte infection rates in pasture, higher yields and tiller densities and reduced weed invasion, particularly where climatic stress is also present. AR37, with the protection it provides against a range of insect pests, is the most effective endophyte for improving persistence. Keywords: alkaloids, Argentine stem weevil, black beetle, insect damage, Neotyphodium