Parasitism of the Wheat Stem Sawfly (Hymenoptera: Cephidae) in Montana

Morrill, Wendell L.; Kushnak, G. D.; Gabor, Jámes W.

doi:10.1006/bcon.1998.0629

Cited by 43 publications

(41 citation statements)

References 23 publications

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“…Previous studies have also shown that the presence of braconid parasitoids can lead to a decrease in WSS populations in Canada and Montana (Ainslie 1929;Holmes et al 1963;Morrill 1998;Morrill et al 1994;Nelson and Farstad 1953). However, the occurrence and abundance of these parasitoids, and therefore their effectiveness in acceptable management of the WSS, has been highly variable.…”

Section: Discussionmentioning

confidence: 99%

“…Two congeneric parasitoids, the larval idiobionts, Bracon cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae), can suppress WSS populations in wheat in Montana, USA (Morrill 1998;Runyon et al 2002;Weaver et al 2005). These solitary ectoparasitoids attack WSS larvae feeding within various hosts, including feral grasses and cultivated wheat, by inserting their ovipositor through the stem wall to sting and paralyze the endophagous late-instars.…”

Section: Introductionmentioning

confidence: 99%

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Parasitism and the demography of wheat stem sawfly larvae, Cephus cinctus

et al. 2011

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Previous research has suggested that insect herbivores in protected environments have higher mortalities from biotic factors such as parasitism compared to herbivores in less protected situations, although overall mortalities in protected environments are often lower. However, this has not been examined using life table approaches. In this study, we used demographic methods to characterize the mortality dynamics of parasitism for pre-diapause wheat stem sawfly larvae, Cephus cintus Norton (Hymenoptera: Cephidae), a stem-mining wheat pest. Larvae were intensively sampled from commercial wheat fields at two locations in Montana, USA from 2005 through 2008. The feeding larvae present in the summer succumbed to only two mortality categories: parasitism and unknown factors. In Conrad, a location with relatively high densities of the parasitoids, mortality by parasitism was largely irreplaceable. In contrast, in Amsterdam, where parasitism did not occur to any appreciable degree, overall mortality remained relatively low.Keywords Multiple decrement life table Á Mortality risk Á Biological control Á Parasitoid Á Bracon cephi Á Bracon lissogaster

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Parasitism and the demography of wheat stem sawfly larvae, Cephus cinctus

et al. 2011

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“…Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. (Morrill, Kushnak, and Gabor 1998).…”

Section: Please Scroll Down For Articlementioning

confidence: 99%

First record of Bracon lissogaster (Hymenoptera: Braconidae) in Canada – a potentially important parasitoid of Cephus cinctus (Hymenoptera: Cephidae) in the prairies

Cárcamo

Weaver

Meers

et al. 2012

Biocontrol Science and Technology

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“…Two native parasitoid wasps, B. cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae) attack C. cinctus (Morrill et al, 1998). In wheat crops, these two species represent the only important insect natural enemies of C. cinctus, with B. cephi generally dominating (Runyon et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…In wheat crops, these two species represent the only important insect natural enemies of C. cinctus, with B. cephi generally dominating (Runyon et al, 2002). These beneficial enemies can reach high densities and reduce economic damage by C. cinctus (Morrill et al, 1998;Buteler et al, 2008), but populations are highly variable across wheat fields and regions (Shanower and Waters, 2006) and causes of their population fluctuations are not well understood. The only documented host of the braconid parasitoids is C. cinctus, which is attacked during the larval stage regardless of whether host plants are crop or non-crop grasses.…”

Section: Introductionmentioning

confidence: 99%

Increased area of a highly suitable host crop increases herbivore pressure in intensified agricultural landscapes

Rand

Waters

Blodgett

et al. 2014

Agriculture, Ecosystems & Environment

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Landscape simplification associated with agricultural intensification has important effects on economically important arthropods. The declining cover of natural and semi-natural habitats, in particular, has been shown to reduce natural-enemy attack of crop pests, but also in some cases reduced crop colonization by such pests. In this study, we examined the influence of changes in two elements of landscape composition, natural grassland cover and cover of a highly suitable crop host, on infestation by a generalist insect pest in wheat, and parasitism of this pest by its dominant natural enemies. Surprisingly, we found no significant influences of increasing natural grassland habitat, at either local or landscape scales, on infestation by the wheat stem sawfly, Cephus cinctus, or parasitism of this pest by the native parasitoid wasps, Bracon cephiand Bracon lissogaster. In contrast, we found significant increases in levels of C. cinctus infestation with increasing wheat cover at the landscape scale. This pattern was consistent across six study regions spanning three states in the northern Great Plains of North America, despite large differences in cropping systems and pest population densities across regions. Regional variation in pest infestation was best explained by long-term averages in precipitation, with higher C. cinctus infestation rates found in drier regions. Results suggest that landscape-mediated variation in pest pressure in this system is better explained by a direct response of pest insects to increasing cover of a highly suitable crop rather than an indirect response via reductions in natural enemies as natural habitat declines. The implication is that habitat diversification at the landscape scale could play a role in suppressing agricultural pest populations via reductions in area of suitable crop hosts. RightsWorks produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted. b s t r a c tLandscape simplification associated with agricultural intensification has important effects on economically important arthropods. The declining cover of natural and semi-natural habitats, in particular, has been shown to reduce natural-enemy attack of crop pests, but also in some cases reduced crop colonization by such pests. In this study, we examined the influence of changes in two elements of landscape composition, natural grassland cover and cover of a highly suitable crop host, on infestation by a generalist insect pest in wheat, and parasitism of this pest by its dominant natural enemies. Surprisingly, we found no significant influences of increasing natural grassland habitat, at either local or landscape scales, on infestation by the wheat stem sawfly, Cephus cinctus, or parasitism of this pest by the native parasitoid wasps, Bracon cephi and Bracon lissogaster. In contrast, we found significant increases in levels of C. cinctus infestation with increasing wheat cover at the landscape scale. Thi...

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Parasitism of the Wheat Stem Sawfly (Hymenoptera: Cephidae) in Montana

Cited by 43 publications

References 23 publications

Parasitism and the demography of wheat stem sawfly larvae, Cephus cinctus

Parasitism and the demography of wheat stem sawfly larvae, Cephus cinctus

First record of Bracon lissogaster (Hymenoptera: Braconidae) in Canada – a potentially important parasitoid of Cephus cinctus (Hymenoptera: Cephidae) in the prairies

Increased area of a highly suitable host crop increases herbivore pressure in intensified agricultural landscapes

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