Endophyte-grass complexes and the relationship between feeding preference and performance in a grass herbivore

Overseeding non-endophytic turfgrass lawns with endophytic turfgrass is considered promising for the development of integrated pest management programs in urban landscapes. In this context, a better understanding of the variability in the preference-performance response of insect herbivores exposed to endophytic grasses could be useful to develop efficient practices. Specifically, while endophytic varieties that are strongly toxic and avoided could provide good control of mobile pests, varieties that are toxic but not avoided could be more suitable for the control of sedentary pests. In this laboratory study, we investigated how the infection of 10 grass varieties by Neotyphodium endophytes affected the feeding performance and preference of newly hatched nymphs of the hairy chinch bug, Blissus leucopterus hirtus Montandon (Heteroptera: Lygaeidae), a common turfgrass pest in north-eastern USA. We found that endophytes generally induced a strong relationship between feeding performance and preference in this herbivore. However, two endophytic varieties did not conform to this relationship, with one variety being highly toxic but not avoided and the other less toxic but highly avoided. These results provide a solid basis to further explore the impacts of endophytic grasses on the dispersal and survival of insect pests in mixed stands of endophytic and non-endophytic plants.