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.

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.

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.

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.

VARIATION IN PATHOGENICITY BETWEEN ISOLATES OF CLAVICEPS PURPUREA

1977 ◽  
Vol 57 (3) ◽  
pp. 729-733 ◽  
Author(s):  
L. C. DARLINGTON ◽  
D. E. MATHRE ◽  
R. H. JOHNSTON
Keyword(s):  
Great Plains ◽  
Triticum Aestivum L ◽  
The United States ◽  
Northern Great Plains ◽  
Claviceps Purpurea ◽  
Male Sterile ◽  
Hordeum Vulgare L ◽  
Clear Cut ◽  
Weakly Virulent ◽  
Grass Hosts

Isolates of Claviceps purpurea (Fr.) Tul. originally isolated from many different grass hosts in the northern Great Plains and several other areas in the United States and England were tested for their pathogenicity to selected cultivars or lines of male-sterile wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.). While there was a great range in the level of virulence, no clear-cut evidence of specific races was obtained. A few isolates were weakly virulent on two cultivars of male-sterile spring wheat but were highly virulent on the other two cultivars tested. Wheat and barley breeders are advised to use a mixture of isolates in screening germ plasm for resistance to ergot.

scholarly journals Physiologic Specialization of Puccinia triticina on Wheat in the United States in 2013

Plant Disease ◽  
2015 ◽  
Vol 99 (9) ◽  
pp. 1261-1267 ◽  
Author(s):  
J. A. Kolmer ◽  
M. E. Hughes
Keyword(s):  
United States ◽  
Winter Wheat ◽  
Leaf Rust ◽  
Great Plains ◽  
Puccinia Triticina ◽  
The United States ◽  
Northern Great Plains ◽  
Ohio River ◽  
Ohio Valley ◽  
Red Winter Wheat

Collections of Puccinia triticina were obtained from rust-infected leaves provided by cooperators throughout the United States and from wheat fields and breeding plots by USDA-ARS personnel and cooperators in the Great Plains, Ohio River Valley, and southeastern states in order to determine the virulence of the wheat leaf rust population in 2013. Single uredinial isolates (490 total) were derived from the collections and tested for virulence phenotype on 20 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes. In 2013, 79 virulence phenotypes were described in the United States. Virulence phenotypes MBTNB, TNBGJ, and MCTNB were the three most common phenotypes. Phenotypes MBTNB and MCTNB are both virulent to Lr11, and MCTNB is virulent to Lr26. MBTNB and MCTNB were most common in the soft red winter wheat region of the southeastern states and Ohio Valley. Phenotype TNBGJ is virulent to Lr39/41 and was widely distributed throughout the hard red winter wheat region of the Great Plains. Isolates with virulence to Lr11, Lr18, and Lr26 were common in the southeastern states and Ohio Valley region. Isolates with virulence to Lr21, Lr24, and Lr39/41 were frequent in the hard red wheat region of the southern and northern Great Plains.

scholarly journals Phytoplankton productivity across prairie saline lakes of the Great Plains (USA): a step toward deciphering patterns through lake classification models

2009 ◽  
Vol 66 (9) ◽  
pp. 1435-1448 ◽  
Author(s):  
Courtney R. Salm ◽  
Jasmine E. Saros ◽  
Sherilyn C. Fritz ◽  
Christopher L. Osburn ◽  
David M. Reineke
Keyword(s):  
Primary Production ◽  
Nutrient Limitation ◽  
Great Plains ◽  
Saline Lakes ◽  
Information Criterion ◽  
The United States ◽  
Northern Great Plains ◽  
Classification Models ◽  
Phytoplankton Productivity ◽  
P Limitation

We investigated patterns of primary production across prairie saline lakes in the central and northern Great Plains of the United States. Based on comparative lake sampling in 2004, seasonal predictors of algal primary productivity were identified within subsets of similar lakes using a combination of Akaike’s information criterion (AIC) and classification and regression trees (CART). These models indicated complex patterns of nutrient limitation by nitrogen (N), phosphorus (P), and iron (Fe) within different lake groups. Nutrient enrichment assays (control, + Fe, + N, + P, + N + P) were performed in spring and summer of 2006 to determine if phytoplankton in selected lakes followed predicted patterns of nutrient limitation. Both the comparative lake sampling and experimental results indicated that N limitation was widespread in these prairie lakes, with evidence for secondary P limitation in certain lakes. In the experiments, iron did not stimulate primary production. Our results suggest that given the diverse geochemical nature of these lakes, classification models that separate saline lakes into subsets may be an effective method for improving predictions of algal production.

scholarly journals Regional uptake and release of crop carbon in the United States

2011 ◽  
Vol 8 (8) ◽  
pp. 2037-2046 ◽  
Author(s):  
T. O. West ◽  
V. Bandaru ◽  
C. C. Brandt ◽  
A. E. Schuh ◽  
S. M. Ogle
Keyword(s):  
Great Plains ◽  
Carbon Budget ◽  
Supply And Demand ◽  
The United States ◽  
Northern Great Plains ◽  
Agricultural Crops ◽  
Biomass Storage ◽  
The Us ◽  
Import And Export ◽  
Crop Biomass

Abstract. Carbon fixed by agricultural crops in the US creates regional CO2 sinks where it is harvested and regional CO2 sources where it is released back to the atmosphere. The quantity and location of these fluxes differ depending on the annual supply and demand of crop commodities. Data on the harvest of crop biomass, storage, import and export, and on the use of biomass for food, feed, fiber, and fuel were compiled to estimate an annual crop carbon budget for 2000 to 2008. With respect to US Farm Resource Regions, net sources of CO2 associated with the consumption of crop commodities occurred in the Eastern Uplands, Southern Seaboard, and Fruitful Rim regions. Net sinks associated with the production of crop commodities occurred in the Heartland, Northern Great Plains, and Mississippi Portal regions. The national crop carbon budget was balanced to within 0.3 to 6.1 % yr−1 during the period of this analysis.

scholarly journals A Unified Effort to Fight an Enemy of Wheat and Barley: Fusarium Head Blight

Plant Disease ◽  
2012 ◽  
Vol 96 (12) ◽  
pp. 1712-1728 ◽  
Author(s):  
Marcia McMullen ◽  
Gary Bergstrom ◽  
Erick De Wolf ◽  
Ruth Dill-Macky ◽  
Don Hershman ◽  
...  
Keyword(s):  
United States ◽  
Fusarium Head Blight ◽  
Great Plains ◽  
Plant Disease ◽  
Management Strategies ◽  
The United States ◽  
Export Market ◽  
Northern Great Plains ◽  
Head Blight ◽  
Food And Feed

Wheat and barley are critical food and feed crops around the world. Wheat is grown on more land area worldwide than any other crop. In the United States, production of wheat and barley contributes to domestic food and feed use, and contributes to the export market and balance of trade. Fifteen years ago, Plant Disease published a feature article titled “Scab of wheat and barley: A re-emerging disease of devastating impact”. That article described the series of severe Fusarium head blight (FHB) epidemics that occurred in the United States and Canada, primarily from 1991 through 1996, with emphasis on the unparalleled economic and sociological impacts caused by the 1993 FHB epidemic in spring grains in the Northern Great Plains region. Earlier publications had dealt with the scope and damage caused by this disease in the United States, Canada, Europe, and China. Reviews published after 1997 further described this disease and its impact on North American grain production in the 1990s. This article reviews the disease and documents the information on U.S. FHB epidemics since 1997. The primary goal of this article is to summarize a sustained, coordinated, and collaborative research program that was put in place shortly after the 1993 epidemic, a program intended to quickly lead to improved management strategies and outreach implementation. This program serves as a model to deal with other emerging plant disease threats.

scholarly journals Primary Atmospheric Drivers of Pluvial Years in the United States Great Plains

2018 ◽  
Vol 19 (4) ◽  
pp. 643-658 ◽  
Author(s):  
Paul X. Flanagan ◽  
Jeffrey B. Basara ◽  
Jason C. Furtado ◽  
Xiangming Xiao
Keyword(s):  
United States ◽  
Great Plains ◽  
Heavy Precipitation ◽  
The United States ◽  
Precipitation Variability ◽  
Northern Great Plains ◽  
Southern Great Plains ◽  
The Public ◽  
Moisture Fluxes ◽  
Precipitation Events

Abstract Precipitation variability has increased in recent decades across the Great Plains (GP) of the United States. Drought and its associated drivers have been studied in the GP region; however, periods of excessive precipitation (pluvials) at seasonal to interannual scales have received less attention. This study narrows this knowledge gap with the overall goal of understanding GP precipitation variability during pluvial periods. Through composites of relevant atmospheric variables from the ECMWF twentieth-century reanalysis (ERA-20C), key differences between southern Great Plains (SGP) and northern Great Plains (NGP) pluvial periods are highlighted. The SGP pluvial pattern shows an area of negative height anomalies over the southwestern United States with wind anomalies consistent with frequent synoptic wave passages along a southward-shifted North Pacific jet. The NGP pattern during pluvial periods, by contrast, depicts anomalously low heights in the northwestern United States and an anomalously extended Pacific jet. Analysis of daily heavy precipitation events reveals the key drivers for these pluvial events, namely, an east–west height gradient and associated stronger poleward moisture fluxes. Therefore, the results show that pluvial years over the GP are likely driven by synoptic-scale processes rather than by anomalous seasonal precipitation driven by longer time-scale features. Overall, the results present a possible pathway to predicting the occurrence of pluvial years over the GP and understanding the causes of GP precipitation variability, potentially mitigating the threats of water scarcity and excesses for the public and agricultural sectors.

Sign in / Sign up

Export Citation Format

Share Document