The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is historically one of the most important economic insect pests in the northern Great Plains of North America. Within this geographical region, the areas subjected to greatest attack are southern Alberta and Saskatchewan, southwestern Manitoba, eastern and northern Montana, North Dakota, northern South Dakota, and western Minnesota. Cumulative grain-yield losses and annual economic losses associated with this pest can exceed 30% and $350 million, respectively. Solid-stemmed cultivars of common wheat, Triticum aestivum L. (Poaceae), tolerant of infestation, are critical for C. cinctus management, but outbreaks of this pest continue to occur even after six decades of cultivar development. Furthermore, chemical control (a primary control option for other cereal (Poaceae) insect pests) has proven ineffective; this underscores the need to integrate resistant cultivars into a comprehensive integrated pest management program. We provide overviews of wheat stem sawfly biology, recent advances in applied research, the efficacy and integration of cultural and biological management strategies, and future directions for global research activities to manage wheat stem sawfly.

The inclusion of winter cereals in spring-annual rotations in the northern Great Plains may reduce weed populations and herbicide requirements. A broad range of spring and winter cereals were compared for ability to suppress weeds and maximize grain yield at Lacombe (2002 to 2005) and Lethbridge (2003 to 2005), Alberta, Canada. High seeding rates (≥ 400 seeds/m2) were used in all years to maximize crop competitive ability. Spring cereals achieved high crop-plant densities (> 250 plants/m2) at most sites, but winter cereals had lower plant densities due to winterkill, particularly at Lethbridge in 2004. All winter cereals and spring barley were highly effective at reducing weed biomass at Lacombe for the first 3 yr of the study. Weed suppression was less consistently affected by winter cereals in the last year at Lacombe and at Lethbridge, primarily due to poor winter survival. Grain yields were highest for spring triticale and least for spring wheat at Lacombe, with winter cereals intermediate. At Lethbridge, winter cereals had higher grain yields in 2003 whereas spring cereals had higher yields in 2004 and 2005. Winter cereals were generally more effective at suppressing weed growth than spring cereals if a good crop stand was established, but overlap in weed-competitive ability among cultivars was considerable. This information will be used to enhance the sustainable production of winter and spring cereals in traditional and nontraditional agro-ecological zones.

According to the UN-FAO, agricultural production must increase by 50% by 2050 to meet global demand for food. This goal can be accomplished, in part, by the development of improved cultivars coupled with modern best management practices. Overall, wheat production on farms will have to increase significantly to meet future demand, and in the face of a changing climate that poses risk to even current rates of production. Durum wheat [Triticum turgidum L. ssp. durum (Desf.)] is used largely for pasta, couscous and bulgur production. Durum producers face a range of factors spanning abiotic (frost damage, drought, and sprouting) and biotic (weed, disease, and insect pests) stresses that impact yields and quality specifications desired by export market end-users. Serious biotic threats include Fusarium head blight (FHB) and weed pest pressures, which have increased as a result of herbicide resistance. While genetic progress for yield and quality is on pace with common wheat (Triticum aestivum L.), development of resistant durum cultivars to FHB is still lagging. Thus, successful biotic and abiotic threat mitigation are ideal case studies in Genotype (G) × Environment (E) × Management (M) interactions where superior cultivars (G) are grown in at-risk regions (E) and require unique approaches to management (M) for sustainable durum production. Transformational approaches to research are needed in order for agronomists, breeders and durum producers to overcome production constraints. Designing robust agronomic systems for durum demands scientific creativity and foresight based on a deep understanding of constitutive components and their innumerable interactions with each other and the environment. This encompasses development of durum production systems that suit specific agroecozones and close the yield gap between genetic potential and on-farm achieved yield. Advances in individual technologies (e.g., genetic improvements, new pesticides,

The wheat stem sawfly [Cephus cinctus Norton (Hymenoptera: Cephidae)] (WSS) has been a serious pest of wheat (Triticum aestivum L.) since the late 19th century. Adoption of solid‐stemmed cultivars, which are available only in the spring bread wheat class in Canada, can mitigate damage but the trait that confers resistance tends to be variable. Five other classes of wheat are grown within the geographical range of C. cinctus and are vulnerable to WSS infestation, and the entire production area for durum (T. turgidum L.) in western Canada, Montana, and western North Dakota lies within the geographic range of C. cinctus. Our objective was to test the hypothesis that the response of hollow‐ and solid‐stemmed cultivars to sowing density (150, 250, 350, or 450 seeds m−2) would differ and subsequently affect infestation patterns of WSS and an endemic parasitoids. The lowest rates of infestation occurred in the hollow‐stemmed durum cultivar AC Avonlea and declined with increased sowing density. Wheat pith expression was optimized at the lowest sowing density but the same level produced low and variable grain yield. In the solid‐stemmed cultivar Lillian, pith expression was most stable at 250 or 350 seeds m−2. For all cultivars, grain yield was optimized at the higher seeding rates of 350 and 450 seeds m−2. Solid‐stemmed wheat should be seeded at low to moderate density to maximize resistance to WSS, but hollow‐stemmed cultivars should be seeded at higher seeding rates to optimize yield, lower WSS infestation, and to increase overall crop competitiveness.