Characterization of cool- and warm-season turfgrass host suitability to annual bluegrass weevil (Listronotus maculicollis, Kirby)

The annual bluegrass weevil, Listronotus maculicollis Kirby, is considered the most destructive insect pest of short-mown turfgrasses in northeastern North America. Poa annua L. is the preferred host plant, though the weevil can develop in other cool-season (C3) turfgrasses such as bentgrasses (Agrostis spp. L.) and perennial ryegrass (Lolium perenne L.). Recently, damaging populations have been reported in midwestern and southeastern United States, where cool- and warm-season (C4) turfgrasses are grown. However, it is unknown whether L. maculicollis can establish and develop within common warm-season turfgrasses such as zoysiagrasses (Zoysia matrella L.) and hybrid bermudagrasses (Cynodon dactylon Pers. × transvaalensis Davy). Larvae reared on Agrostis stolonifera ‘Penncross’, an older cultivar, experienced a significant reduction in survivorship and longer development periods compared to a newer cultivar (Penn-A4) and P. annua. Agrostis stolonifera ‘Penncross’ possessed significantly greater quantities of carotenoids and flavonoid content, which may explain differences in host suitability among C3 turfgrasses. No larvae were recovered from C4 hosts in no-choice ovipositional assays, suggesting Z. matrella and C. dactylon × transvaalensis are nonviable hosts of L. maculicollis. Further investigation into the morphological and physiological defense mechanisms in Z. matrella and C. dactylon × transvaalensis may broaden our understanding of tolerance mechanisms not observed in C3 cool-season turfgrasses and provide guidance for future breeding efforts.