Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae). II. Other germplasm

2013 ◽  
Vol 93 (6) ◽  
pp. 1169-1177 ◽  
Author(s):  
B. L. Beres ◽  
H. A. Cárcamo ◽  
J. R. Byers ◽  
F. R. Clarke ◽  
Yuefeng Ruan ◽  
...  

Beres, B. L., Cárcamo, H. A., Byers, J. R., Clarke, F. R., Ruan, Y., Pozniak, C. J., Basu, S. K. and DePauw, R. M. 2013. Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae). II. Other germplasm. Can. J. Plant Sci. 93: 1169–1177. The wheat stem sawfly (WSS) Cephus cinctus Norton (Hymenoptera: Cephidae) is an economically destructive insect pest of wheat in the northern Great Plains. Solid stem cultivar selection is one critical component to the integrated management of WSS. A significant resurgence of WSS in the southern prairies of Canada caused substantial economic losses from 1999 through 2007, which was compounded by the low adoption rate of solid-stem cultivars. A study was conducted from 2003 to 2005 in southern Alberta and Saskatchewan, Canada: (1) to characterize resistance levels in solid-stem germplasm derived from S615 and alternate genetic backgrounds, and (2) to determine the impact of host plant tolerance on WSS population dynamics. The tetraploid cultivar Golden Ball and its hexaploid derivative G9608B1-L-12J11BF02 were the most consistent at reducing damage, larval growth (fitness), and fecundity of WSS. The challenge will be to maintain this level of efficacy as the Canada Western Red Spring phenotype is reintroduced into the germplasm. Our study suggests solid-stem cultivars are highly effective but prone to inconsistent performance and should therefore be integrated into a holistic strategy for WSS that includes agronomics and biocontrol.

2013 ◽  
Vol 93 (4) ◽  
pp. 607-617 ◽  
Author(s):  
B. L. Beres ◽  
H. A. Cárcamo ◽  
J. R. Byers ◽  
F. R. Clarke ◽  
C. J. Pozniak ◽  
...  

Beres, B. L., Cárcamo, H. A., Byers, J. R., Clarke, F. R., Pozniak, C. J., Basu, S. K. and DePauw, R. M. 2013. Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars. Can. J. Plant Sci. 93: 607–617. The wheat stem sawfly (WSS) Cephus cinctus Norton (Hymenoptera: Cephidae) is an economically destructive insect pest of wheat in the northern Great Plains. A significant resurgence of the insect pest in the southern prairies of Canada caused substantial economic losses from 1999 through 2007. Solid-stem cultivar selection is critical to the management of WSS but adoption of the use of these cultivars was low, which compounded losses at harvest. A study was conducted from 2001 to 2003 in southern Alberta and Saskatchewan, Canada (1) to establish the range of susceptibility of hollow- and solid-stem varieties representing the major spring wheat classes and (2) to determine the impact of host plant on WSS population dynamics. The solid-stem varieties were generally superior at reducing damage and fitness response of WSS. However, in addition to the durum cultivars AC Navigator and AC Avonlea, the variety McKenzie, which was considered hollow, provided improved efficacy over other hollow-stem cultivars. Our study suggests solid-stem cultivars are highly effective but prone to inconsistent performance and should therefore be integrated into a holistic strategy for WSS that includes agronomics and biocontrol. A companion paper will report on the response of cultivars with novel sources of germplasm.


2020 ◽  
Vol 113 (4) ◽  
pp. 1982-1989
Author(s):  
Buddhi B Achhami ◽  
Gadi V P Reddy ◽  
Jamie D Sherman ◽  
Robert K D Peterson ◽  
David K Weaver

Abstract Host plant traits strongly affect survivorship of insect herbivores, and host suitability is especially important for the wheat stem sawfly, Cephus cinctus Norton, which spends its entire egg, larval, and pupal periods in a single stem. Measuring larval survival inside stems from egg hatch through diapause-mediated dormancy is a potential measure of population size for the next year but is also useful in assessing effects of growing season precipitation and temperature. Larval growth is synchronized with host plant growth, and the larva cannot switch hosts. Thus, incorporating plant physiological time, as growing degree days (GDD), may yield a better prediction of larval survival. Therefore, we assessed wheat stem sawfly survival from early larval growth to the beginning of autumnal diapause in barley cultivars selected from across feed, forage, and two- or six-row malt groups. Field experiments were conducted in Gallatin and Chouteau counties, Montana, in 2016 and 2017. We used Kaplan-Meier estimation to assess larval survival among cultivars. We found that the survival of pre-diapause larvae was greatest in ‘Hockett’ (36.5%) and lowest in ‘Celebration’ (15.4%). Precipitation and temperature during the growing season affected temporal patterns for larval survival across study sites. Adjusting survivorship curves using site-specific GDD accumulation allowed cultivar-specific survivorship to be estimated more precisely for each site, despite differing environmental influences. Our findings suggest that measuring wheat stem sawfly survival across barley cultivars and standardizing by site-specific GDDs may provide better recommendations on barley cultivars that impede wheat stem sawfly population growth and reduce economic losses.


2005 ◽  
Vol 137 (5) ◽  
pp. 602-614 ◽  
Author(s):  
Christian Nansen ◽  
Mark E. Payton ◽  
Justin B. Runyon ◽  
David K. Weaver ◽  
Wendell L. Morrill ◽  
...  

AbstractThe wheat stem sawfly, Cephus cinctus Norton, is the most important insect pest of dryland wheat, reducing both harvest efficiency and head weight. When wheat lodged (flattened) by C. cinctus is straight-cut, harvest efficiency is affected in three ways: (1) lodged stems are difficult to collect with the combine, so mature wheat is lost; (2) the combine has to operate more slowly to collect as many of the lodged stems as possible; and (3) there is increased risk of damage to the combine due to lowering of the combine header to recover lodged stems. An alternative harvest method is to swath the wheat before lodging occurs and place it in windrows prior to combining. When swathing is used, harvest efficiency is not affected by the C. cinctus infestation level; however, this type of harvesting is more expensive and labor-intensive than straight- cutting. Thus, swathing should be used only when the crop is heavily infested by C. cinctus, while straight-cutting should be used when the level of C. cinctus infestation is lower. Adapting harvesting practices to the C. cinctus infestation level requires a sampling plan that can reliably and cost-effectively predict the infestation level in a given field. In this study, we (i) evaluate the relationship between sampling effort along field edges and precision of the estimated average infestation level in 6 wheat fields, and (ii) generate a Gaussian regression analysis of the infestation level up to 200 m into 18 wheat fields using two variables, distance from the edge and average infestation level at the edge, as explanatory variables. We conclude that little additional precision for estimates of infestation level is gained by collecting more than 10 samples along field edges. We also conclude that the average C. cinctus infestation level along field edges can be used successfully to predict infestation levels up to 200 m into winter wheat fields. The proposed sampling should be implemented about one month before harvest to provide growers with enough time to make logistical preparations for harvest.


2021 ◽  
Author(s):  
Shouyin Li ◽  
Hui Li ◽  
Jingting Wang ◽  
Cong Chen ◽  
Dejun Hao

Abstract The resistance mechanisms evolved by insects to overcome host-plant allelochemicals are a key consideration in pest management. Camphor oil (EO) and its main component (i.e., D-camphor) form a specific terpenoid-defensive system in camphor trees, Cinnamomum camphora. However, an emerging insect pest, Pagiophloeus tsushimanus, has recently caused serious damage to this intractable plant species and is largely elusive. Here, we used feeding bioassays and RNA-seq to investigate the mechanism underlying the resistance of the beetle to host-specific terpenoid defences. First, a hormetic response in both larval weight and developmental time, which is a highly generalized dose-response phenomenon in toxicology but occurs infrequently in the context of insect-plant interactions, was observed in terpenoid-feeding individuals. Then, comparative transcriptome analysis between terpenoid-feeding and control groups indicated that both CYP450-mediated metabolic resistance and CP-mediated cuticular resistance were jointly employed to cope with terpenoid-induced stress. In addition, a small portion of genes involved in the glucose transport pathway were upregulated at the low D-camphor dose, suggesting that an extra intake of glucose used for larval growth may contribute to a hormetic response. These findings suggested that the dual terpenoid resistance mechanisms in this specialist are an essential precondition for the hormetic response in larval growth, ultimately contributing to the widespread successful colonization of host camphor trees. Overall, our study will open new avenues for understanding insect-plant coevolutionary adaptation and developing durable pest control strategies.


2000 ◽  
Vol 35 (4) ◽  
pp. 478-482 ◽  
Author(s):  
Wendell L. Morrill ◽  
David K. Weaver

The size of male Cephus cinctus Norton (Hymenoptera: Cephidae) adults did not significantly increase with the size of host stems in which larvae developed. Larger adult male sawflies had higher longevity. There was no statistically significant relationship between wing length and the emergence date, mating success, or dispersal from overwintering sites. The relation of host plant quality and sawfly fitness was less apparent for male adults than that which we previously reported for females.


2002 ◽  
Vol 42 (7) ◽  
pp. 995 ◽  
Author(s):  
P. A. McGee

More than 13 morphospecies of fungal endophyte were isolated from leaves of cotton collected from eastern New South Wales, Australia. Of the fungi tested, methanol extracts of 4 morphospecies offered with a food source reduced the larval growth rate of the insect pest Helicoverpa armigera. Extracts of different isolates of 1�common morphospecies had varying effects on growth rates of H. armigera and H. punctigera. The impact of the endophytes after inoculation to leaves of cotton also differed. Five of 10 selected isolates were associated with reduced feeding from leaf discs in a feeding-choice experiment with H. armigera. The data are consistent with the view that some fungal endophytes benefit their host through reduced herbivory of the plant.


2001 ◽  
Vol 133 (2) ◽  
pp. 215-217 ◽  
Author(s):  
J.B. Runyon ◽  
R.L. Hurley ◽  
W.L. Morrill ◽  
D.K. Weaver

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), has been the most economically important insect pest of wheat in the northern Great Plains since cultivation began (Weiss and Morrill 1992). The wheat stem sawfly was first reported from wild grasses where populations were often highly parasitized by a number of parasitoids, including Bracon (= Microbracon) cephi (Gahan) (Hymenoptera: Braconidae) (Criddle 1923; Ainslie 1929). A similar species, Bracon lissogaster Muesebeck, was later reported to also attack C. cinctus larvae (Muesebeck 1953; Somsen and Luginbill 1956). These parasitoids are now prevalent in wheat in some regions of Montana (Morrill et al. 1994, 1998; Morrill 1997). The life histories and phenologies of these sympatric idiobiont ectoparasitoids are similar. The ability to distinguish B. cephi from B. lissogaster is essential in elucidating their effects on populations of C. cinctus. We examined 159 females and 123 males of B. cephi from Chouteau, Hill, Stillwater, Teton, and Toole counties in Montana; Burke, Burleigh, Rolette, and Williams counties in North Dakota; Rock County in Minnesota; and southem Alberta (Rockyford and Consort). The 254 females and 215 males of B. lissogaster examined were from Chouteau, Hill, Teton, and Toole counties in Montana. Holotypes were compared to verify identifications.


2005 ◽  
Vol 137 (4) ◽  
pp. 428-440 ◽  
Author(s):  
Christian Nansen ◽  
Tulio B. Macedo ◽  
David K. Weaver ◽  
Robert K.D. Peterson

AbstractThe wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is the most serious insect pest of dryland wheat (Triticum aestivum L.; Poaceae) in the southern Canadian Prairies and the northern Great Plains of the United States. We characterized the spatial distribution pattern of C. cinctus eggs and larvae throughout the adult flight period in three dryland winter wheat fields in Montana. Cephus cinctus females laid eggs in wheat stems until a few weeks before wheat maturity, and most wheat stems received only one egg. Wheat stem samples collected along the field edges represented 12%–16% of the samples but 40%–95% of the infested stems. The highest numbers of C. cinctus eggs and larvae found in a single wheat stem were 16 and 4, respectively. On a field scale, both C. cinctus eggs and larvae were significantly aggregated along field edges in most of the sampling events. A comparison of indices of aggregation revealed that C. cinctus larvae were significantly more spatially aggregated than C. cinctus eggs. Based on our spatiotemporal analysis, we speculate that the majority of the eggs are initially laid along field edges, and ovipositing C. cinctus females do not distinguish between previously infested and uninfested wheat stems. Gradually, these eggs hatch and the larvae begin feeding; at the same time, the later emerging C. cinctus females oviposit farther into the wheat fields. One explanation is that ovipositing C. cinctus females avoid stems containing feeding larvae. The analysis of the temporal changes in the spatial distribution patterns of C. cinctus eggs and larvae is discussed in the context of possible integrated pest management strategies.


2019 ◽  
Vol 99 (4) ◽  
pp. 560-567
Author(s):  
Y. Ruan ◽  
A.K. Singh ◽  
R.M. DePauw ◽  
R.E. Knox ◽  
R.D. Cuthbert ◽  
...  

AAC Stronghold durum wheat [Triticum turgidum L. subsp. durum (Desf.) Husn.] is adapted to the durum production area of the Canadian prairies. Averaged over 3 yr, AAC Stronghold yielded significantly more grain than AC Navigator. AAC Stronghold had a protein concentration significantly less than Strongfield but significantly more than Brigade. AAC Stronghold had a plant height significantly shorter than Brigade, Strongfield, and AAC Cabri, with a lodging score significantly less than Strongfield and AAC Cabri. AAC Stronghold has a solid stem, which confers resistance to cutting by the wheat stem sawfly (Cephus cinctus Norton). AAC Stronghold had low grain cadmium concentration and stronger gluten than Strongfield. AAC Stronghold is eligible for grades of Canada Western Amber Durum.


2020 ◽  

This specially curated collection features three reviews of current and key research on climate change, insect pests and invasive species. The first chapter reviews the impact of climate change on insect pests and how it has affected insect pest development and population dynamics, activity and abundance, diversity and geographical distribution. It also assesses insect-host plant interactions and the effectiveness of crop pest management techniques. The second chapter discusses the literature on the potential impact of climate change on the principal insect pests of wheat, including cereal aphids, Hessian fly, orange wheat blossom midge, cereal leaf beetle and cotton bollworm. It assesses the different methods used to assess likely impacts as well climate change effects on biological control in wheat systems. The final chapter surveys what we know about the ecology of invasive species and potential management strategies. In particular, it assesses how integrated pest management (IPM) needs to evolve to deal with invasive species, particularly in focussing more on monitoring, prevention and rapid response.


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