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.

Keywords: cold-hardiness, novel solid wheat germplasm, supercooling, wheat stem sawfly, winter survivorship

Correspondence: ^a hector.carcamo@agr.gc.ca, ^b brian.beres@agr.gc.ca, ^c carolyn.herle@agr.gc.ca, ^d hugh.mclean@agr.gc.ca, ^e sean.mcginn@agr.gc.ca, *Corresponding author

Editor: JP Michaud was Editor of this paper.

Received: 18 November 2010 | Accepted: 26 April 2011 | Published: 30 September 2011

Copyright: This is an open access paper. We use the Creative Commons Attribution 3.0 license that permits unrestricted use, provided that the paper is properly attributed.  

ISSN: 1536-2442 | Volume 11, Number 129

Cárcamo HA, Beres BL, Herle CE, McLean H, McGinn S. 2011. Solid-stemmed wheat does not affect overwintering mortality of the wheat stem sawfly, Cephus cinctus. Journal of Insect Science 11:129 available online: insectscience.org/11.129