title: Solid-stemmed wheat does not affect overwintering mortality of the wheat stem sawfly, Cephus cinctus.
abstract: The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is a key pest of wheat in the northern Great Plains of North America. Host plant resistance in the form of solid-stemmed wheat cultivars is the main control strategy for C. cinctus. This study investigated the effect of novel and traditional solid wheat hosts on the overwintering mortality and cold-hardiness of C. cinctus. Field conditions from 2003-2005 showed that overwintering mortality in various wheat cultivars averaged 8% and was not related to the type of wheat cultivar. Similarly, supercooling points (-22° C) were not influenced by wheat host type. C. cintus are cold-hardy; up to 80% survive 10 days at -20° C and 10% survive 40 days. Its overwintering microhabitat near the crown area of the plant is well insulated for temperatures above -10° C and remains ~ 20° C above ambient minima. These data suggest that winter mortality is a minor factor in the population dynamics of wheat stem sawfly, and despite clear detrimental effects on larval weight and adult fitness, solid-stemmed cultivars do not reduce the ability of larvae to survive winters.
authors.affiliation: Agriculture and Agri-Food Canada, Lethbridge Research Centre, 5403-1st Avenue South, Lethbridge, Alberta, Canada T1J 4B1. hector.carcamo@agr.gc.ca
authors.forename: Héctor A
authors.initials: HA
authors.lastname: Cárcamo
authors.forename: Brian L
authors.initials: BL
authors.lastname: Beres
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Herle
authors.forename: Hugh
authors.initials: H
authors.lastname: McLean
authors.forename: Sean
authors.initials: S
authors.lastname: McGinne
mesh_terms: D000064:Acclimatization; D000818:Animals; D003080:Cold Temperature; D005260:Female; D006790:Host-Parasite Interactions; D006927:Hymenoptera / Q000502:physiology*; D007814:Larva / Q000502:physiology; D012621:Seasons; D014908:Triticum / Q000469:parasitology*