Evaluating winter wheat varieties to determine suitability in trap cropping to protect spring wheat against the wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae)
Micaela Buteler, email@example.com, David K. Weaver, firstname.lastname@example.org, and Robert K. D. Peterson, email@example.com. Montana State University, Department of Entomology, Bozeman, MT
Nine varieties of winter wheat grown in Montana were studied to determine suitability in trap cropping to protect spring wheat against the wheat stem sawfly. Attractive and repellent volatile compounds emitted by the wheat plants were determined and the amounts produced by the varieties were compared. In addition, agronomic characteristics that would affect their attractiveness to sawfly: height, developmental rate and stem diameter, were also compared for these varieties.
Using these results, the varieties were ranked and two thought to be most attractive, ‘Norstar’ and ‘Neeley’, and one thought to be less attractive, ‘Rampart’ were selected for behavioral trials to validate the rankings.
Oviposition preferences were evaluated in laboratory cage trials. Experiments performed evaluated relative preferences among these winter wheat varieties and the spring wheat variety being protected. In comparisons among the winter wheat varieties, sawflies laid more eggs in ‘Norstar’, fewer were deposited in ‘Neeley’, and ‘Rampart’ received the least. In comparisons between winter wheat in a more advanced stage than spring wheat, more eggs were deposited in the winter wheat. This simulates the field situation because winter wheat is planted earlier than spring wheat. Ongoing research is evaluating the suitability of these varieties for trap cropping in a field experiment.