Farming system and wheat cultivar affect infestation of, and parasitism on, Cephus cinctus in the Northern Great Plains

2018 ◽  
Vol 74 (11) ◽  
pp. 2480-2487 ◽  
Author(s):  
Subodh Adhikari ◽  
Tim Seipel ◽  
Fabian D Menalled ◽  
David K Weaver
Keyword(s):  
Great Plains ◽  
Wheat Cultivar ◽  
Farming System ◽  
Northern Great Plains ◽  
Cephus Cinctus

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.

Durum Spring Wheat Susceptibility to Wheat Stem Sawfly (Hymenoptera: Cephidae)

2007 ◽  
Vol 42 (2) ◽  
pp. 133-138 ◽  
Author(s):  
H.B. Goosey ◽  
A.W. Lenssen ◽  
G.D. Johnson ◽  
S.L. Blodgett ◽  
G. R. Carlson ◽  
...  
Keyword(s):  
Triticum Aestivum ◽  
Great Plains ◽  
Spring Wheat ◽  
Field Trials ◽  
Northern Great Plains ◽  
Wheat Stem Sawfly ◽  
Hard Red Spring Wheat ◽  
Cephus Cinctus ◽  
Rotational Crop ◽  
Arthropod Pest

The wheat stem sawfly, Cephus cinctus Norton, is the primary arthropod pest of wheat, Triticum aestivum Thell, in the Northern Great Plains. Yet, information is unavailable on wheat stem sawfly infestation potential of currently grown spring durum cultivars. Field trials were conducted in 1998 and 1999 to determine wheat stem sawfly susceptibility of 13 spring durum cultivars and one hard red spring wheat. Preharvest infestations ranged from 2–55%. Postharvest larval infestations of stubble ranged from 1–9.5%. Three durum cultivars ‘Lloyd’, ‘Plenty’, and ‘Sceptre’ appear to offer potential, as a rotational crop, for management of wheat stem sawfly.

Dynamic Cropping Systems for Sustainable Crop Production in the Northern Great Plains

2007 ◽  
Vol 99 (4) ◽  
pp. 904-911 ◽  
Author(s):  
D. L. Tanaka ◽  
J. M. Krupinsky ◽  
S. D. Merrill ◽  
M. A. Liebig ◽  
J. D. Hanson
Keyword(s):  
Great Plains ◽  
Crop Production ◽  
Cropping Systems ◽  
Northern Great Plains ◽  
Sustainable Crop Production
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