Preharvest sampling plan for larvae of the wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae), in winter wheat fields

2005 ◽  
Vol 137 (5) ◽  
pp. 602-614 ◽  
Author(s):  
Christian Nansen ◽  
Mark E. Payton ◽  
Justin B. Runyon ◽  
David K. Weaver ◽  
Wendell L. Morrill ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Insect Pest ◽  
Sampling Plan ◽  
Sampling Effort ◽  
Infestation Level ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Explanatory Variables ◽  
Increased Risk ◽  
Harvest Efficiency

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.

Rearing the wheat stem sawfly on an artificial diet

2005 ◽  
Vol 137 (4) ◽  
pp. 497-500 ◽  
Author(s):  
Tuilo B. Macedo ◽  
Paula A. Macedo ◽  
Robert K.D. Peterson ◽  
David K. Weaver ◽  
Wendell L. Morrill
Keyword(s):  
Great Plains ◽  
Cropping Systems ◽  
Insect Pest ◽  
The United States ◽  
Northern Great Plains ◽  
Yield Losses ◽  
Canadian Prairies ◽  
Wheat Stem Sawfly ◽  
Head Weight ◽  
Harvest Efficiency

The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), is an insect pest in dryland wheat cropping systems in the southern Canadian Prairies and the northern Great Plains of the United States (Morrill 1997). Yield losses caused by C. cinctus are due to reduced head weight (Holmes 1977; Morrill et al. 1992) and lodging, which decreases harvest efficiency. Estimates of yield losses in Montana alone are about US$25 million per year.

Host plant interactions between wheat germplasm source and wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) I. Commercial cultivars

2013 ◽  
Vol 93 (4) ◽  
pp. 607-617 ◽  
Author(s):  
B. L. Beres ◽  
H. A. Cárcamo ◽  
J. R. Byers ◽  
F. R. Clarke ◽  
C. J. Pozniak ◽  
...  
Keyword(s):  
Host Plant ◽  
Insect Pest ◽  
Economic Losses ◽  
Plant Interactions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Wheat Germplasm ◽  
Commercial Cultivars ◽  
Solid Stem ◽  
The Impact

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.

Within-field spatial distribution of Cephus cinctus (Hymenoptera: Cephidae) larvae in Montana wheat fields

2005 ◽  
Vol 137 (2) ◽  
pp. 202-214 ◽  
Author(s):  
Christian Nansen ◽  
David K. Weaver ◽  
Sharlene E. Sing ◽  
Justin B. Runyon ◽  
Wendell L. Morrill ◽  
...  
Keyword(s):  
Edge Effect ◽  
Great Plains ◽  
Insect Pest ◽  
The United States ◽  
Northern Great Plains ◽  
Infestation Level ◽  
Cephus Cinctus ◽  
Wheat Field ◽  
Management Procedures ◽  
High Level

AbstractThe wheat stem sawfly, Cephus cinctus Norton, is a major insect pest in dryland wheat (Triticum L. spp.; Poaceae) fields in the northern Great Plains of the United States and in southern regions of the prairie provinces of Canada. Field infestations by this pest commonly show a distinct “edge effect”, with infestation levels highest at the field edge and declining inwards. In this study, we characterized the edge effect of C. cinctus infested wheat fields in Montana at four locations in two separate years. "Infestation level" refers to the average proportion of wheat stems infested with C. cinctus in samples collected in a given wheat field. The gradual decrease in C. cinctus infestation towards the centre of wheat fields is referred to as the “infestation slope”, and it was presented as a proportion of infestation level at field edges. We showed that (i) for most of the fields bordering grassland or fallow wheat, a simple exponential decline curve provided a significant fit to the infestation slope; (ii) the infestation slopes in different fields and in different directions within fields were similar and appeared to be independent of the overall infestation level; and (iii) the relationship between infestation level and the proportion of samples infested followed an asymptotic curve, which indicates a high level of dispersal of ovipositing C. cinctus females. The general perception has been that the edge effect of C. cinctus infestation is a result of ovipositing C. cinctus females being both weak flyers and short-lived, but our results do not fully corroborate this perception. Currently, the only reliable way to detect C. cinctus infestations is to dissect individual stems and look for developing instars. However, this type of sampling is extremely time consuming and labor intensive and therefore impractical for wheat growers. Increasing the understanding of the spatial patterns in C. cinctus infestations is a first step towards development of an optimal sampling plan for this important field pest. Thus, the results presented are relevant for researchers involved in sampling designs and integrated pest management procedures for field pests. We discuss behavioral and evolutionary factors that may contribute to the edge effect of C. cinctus infestations.

Distinguishing adults of Bracon cephi and Bracon lissogaster (Hymenoptera: Braconidae), parasitoids of the wheat stem sawfly (Hymenoptera: Cephidae)

2001 ◽  
Vol 133 (2) ◽  
pp. 215-217 ◽  
Author(s):  
J.B. Runyon ◽  
R.L. Hurley ◽  
W.L. Morrill ◽  
D.K. Weaver
Keyword(s):  
North Dakota ◽  
Great Plains ◽  
Life Histories ◽  
Insect Pest ◽  
Northern Great Plains ◽  
Similar Species ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus

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.

Spatiotemporal distributions of wheat stem sawfly eggs and larvae in dryland wheat fields

2005 ◽  
Vol 137 (4) ◽  
pp. 428-440 ◽  
Author(s):  
Christian Nansen ◽  
Tulio B. Macedo ◽  
David K. Weaver ◽  
Robert K.D. Peterson
Keyword(s):  
Spatial Distribution ◽  
Great Plains ◽  
Insect Pest ◽  
Management Strategies ◽  
The United States ◽  
Northern Great Plains ◽  
Flight Period ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Eggs And Larvae

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.

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 ◽  
...  
Keyword(s):  
Host Plant ◽  
Insect Pest ◽  
Larval Growth ◽  
Economic Losses ◽  
Plant Interactions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Wheat Germplasm ◽  
Solid Stem ◽  
The Impact

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.

Effect of Time of Seeding Apex Wheat on Infestation and Sex Ratio of the Wheat Stem Sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae)

1952 ◽  
Vol 84 (3) ◽  
pp. 90-92 ◽  
Author(s):  
L. A. Jacobson ◽  
C. W. Farstad
Keyword(s):  
Sex Ratio ◽  
Field Experiment ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus

In 1945 a field experiment was designed at the Lethbridge laboratory to augment data on the effect of the time of seeding on infestation by the wheat stem sawfly, Cephus cinctus Nort. At that time one of the recommendations for the control of this insect was to delay seeding wheat until after May 15. The resulting crop escaped infestation because of the retarded plant during the period of the sawfly flight.

Survey of Wheat Stem Sawfly (Hymenoptera: Cephidae) Infesting Wheat in Eastern Colorado

2021 ◽  
Author(s):  
Darren M Cockrell ◽  
Terri Randolph ◽  
Erika Peirce ◽  
Frank B Peairs
Keyword(s):  
Triticum Aestivum ◽  
Wheat Variety ◽  
Triticum Aestivum L ◽  
The State ◽  
Economic Effects ◽  
Management Decisions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Growing Region

Abstract From 2012 through 2020, a survey of wheat stem sawfly, Cephus cinctus Norton, was conducted in wheat (Triticum aestivum L.) fields in Eastern Colorado. In 2013, results showed sawfly infestations concentrated in the northern part of the state with only a few highly infested sites, with 38 of the 94 sampled sites having any infestation (five of which had >50% infestation levels). By 2020 sawfly had been found in all eastern counties sampled, and 72 of the 106 sites sampled were found to contain sawfly (11 of which had >50% infestation levels). The spread of this pest across the Colorado wheat-growing region will have lasting economic effects. The information gathered from this and future surveys will inform wheat variety development and aid in management decisions made by growers across the state.

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