Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/30/2018
Publication Date: 5/9/2018
Citation: Kostromytska, O.S., Rodriguez-Saona, C., Alborn, H.T., Koppenhofer, A.M. 2018. Role of plant volatiles in host plant recognition by Listronotus maculicollis (Coleoptera: Curculionidae). Journal of Chemical Ecology. 44(6):580-590. doi:10.1007/s10886-018-0964-y.
DOI: https://doi.org/10.1007/s10886-018-0964-y

Interpretive Summary: The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby, is an economically important pest of short cut turfgrass. ABW females prefer annual bluegrass, Poa annua L., for oviposition, and this grass species is also a more suitable host for larvae compared to bentgrasses (Agrostis spp.). A scientist at the USDA-ARS Gainesville, FL Chemistry Research Unit in collaboration with Rutgers University colleges investigated the involvement of odors from the grasses in the ABW host plant preference. Odors emitted by P. annua and six cultivars of three bentgrass species (A. stolonifera, A. capillaris and A. canina) were collected, identified and compared. In laboratory and field tests it was determined that the oviposition preference for annual bluegrass was due to odors that attracted female ABW. Specifically, the combination of the compounds (Z)-3-hexenyl acetate and phenyl ethyl alcohol were found to comprise most of the ABW female attraction. However, the usefulness of these two compounds, alone or in combination with additional odors, for field monitoring of weevil populations needs further investigation. The discovery of odors that attract insect pests are important for understanding plant-insect interactions, and how these interactions, once understood, can be used to control insect pests of agricultural commodities.

Technical Abstract: The annual bluegrass weevil (ABW), Listronotus maculicollis Kirby, is an economically important pest of short cut turfgrass. ABW females prefer annual bluegrass, Poa annua L., for oviposition, and this grass species is a more suitable host for larvae compared to bentgrasses (Agrostis spp.). We investigated the involvement of grass volatiles in ABW host plant preference under laboratory and field conditions. First, ovipositional and feeding preferences of ABW adults were studied in a sensory deprivation experiment. Clear evidence of involvement of olfaction in host recognition by ABW was demonstrated. Poa annua was preferred for oviposition but weevils with blocked antennae did not exhibit any preferences. Following, ABW behavioral responses to different bentgrass species and cultivars and P. annua emitted volatiles were examined in Y- tube olfactometer assays. Headspace volatiles emitted by P. annua and six cultivars of three bentgrass species (A. stolonifera, A. capillaris and A. canina) were extracted, identified and compared among grass species and cultivars. Poa annua was attractive to ABW females and preferred to bentgrass cultivars in Y-tube assays. Mostly quantitative differences were found in the headspaces of P. annua and bentgrasses. No P. annua specific volatiles were found, but bentgrasses tended to have larger quantities of terpenoids than P. annua. Combination of two compounds attractive to ABW females were tested as trap baits in field experiments. Although (Z)-3-hexenyl acetate, phenyl ethyl alcohol and their combination were the most attractive compounds to ABW females in laboratory Y-tube assays and in the field, their usefulness for monitoring weevil populations need further investigation.