Evaluation of 'Jackal' AR601 (Avanex) and Kentucky-31 endophytic tall fescues for suppressing types of invertebrates that contribute to bird strike hazard at airports

Use of endophyte-infected (E+) grasses to deter vertebrate grazers such as geese, and invertebrates attractive to insectivorous birds, has been proposed as a means to reduce bird strike hazard at airports. 'Jackal' tall fescue (Lolium arundinaceum) with the endophyte strain AR601, branded Avanex Unique Endophyte Technology and marketed as a bird-deterrent grass, purportedly expresses inordinately high levels of both ergovaline to induce bird avoidance behavior and loline alkaloids for insect resistance. We tested the hypothesis that Avanex is more effective than Kentucky-31 (KY-31), a common tall fescue with wild-type endophyte, for suppressing types of invertebrates fed on by birds. Bioactivity of Jackal AR601 and KY-31, with or without their endophytes, was compared in insect feeding trials, and against macroinvertebrate communities in field plots. Presence of viable endophyte was confirmed by immunoblot and alkaloid analyses. Alkaloid concentrations varied seasonally but were no higher in Jackal AR601 than in E+ KY-31. Both E+ grasses suppressed an endophyte-sensitive aphid, but effects on grass-feeding caterpillars were more subtle, with similar and some cases better larval growth and survival on Avanex than on KY-31. Neither E+ grass reduced populations of earthworms, white grubs, or aboveground macroinvertebrates. This study suggests that suppression of invertebrates by Avanex or E+ KY-31 is probably too weak to significantly reduce the food supply for insectivorous birds at airports.