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David K. Weaver
Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA

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Journal article
Published: 22 April 2021 in Environmental Entomology
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Wheat stem sawfly, [Cephus cinctus (Hymenoptera: Cephidae)], females display complex behaviors for host selection and oviposition. Susceptible hollow stem wheat (Triticum aestivum L.) cultivars release a greater amount of attractive compound, (Z)-3-hexenyl acetate and receive a greater number of eggs compared to resistant solid stem wheat cultivars. However, barley (Hordeum vulgare L.) is becoming a more common host for C. cinctus in Montana. Therefore, how do host selection and oviposition behaviors on barley cultivars compare to what happens when encountering wheat cultivars? To answer this question, we carried out greenhouse experiments using two barley cultivars: ‘Hockett’ and ‘Craft’. Between these cultivars at Zadoks stages 34 and 49, we compared host selection decisions using a Y-tube olfactometer, compared oviposition behaviors on stems, and counted the number of eggs inside individual stems. In Y-tube bioassays, we found a greater number of C. cinctus females were attracted to the airstream passing over ‘Hockett’ than ‘Craft’ barley cultivars. Although the frequencies of oviposition behaviors were similar between these cultivars, the number of eggs was greater in ‘Hockett’. Volatile profiles indicated that the amount of linalool was greater in the airstream from ‘Craft’ than in ‘Hockett’ at Zadoks 34 while the amount of (Z)-3-hexenyl acetate was greater in airstream from ‘Hockett’ at both Zadoks 34 and 49. These results suggest that volatiles of barley plants influenced host selection behavior of ovipositing C. cinctus females, while other discriminating behaviors do not differ between cultivars.

ACS Style

Buddhi B Achhami; Gadi V P Reddy; M L Hofland; Jamie D Sherman; Robert K D Peterson; David K Weaver. Plant Volatiles and Oviposition Behavior in the Selection of Barley Cultivars by Wheat Stem Sawfly (Hymenoptera: Cephidae). Environmental Entomology 2021, 1 .

AMA Style

Buddhi B Achhami, Gadi V P Reddy, M L Hofland, Jamie D Sherman, Robert K D Peterson, David K Weaver. Plant Volatiles and Oviposition Behavior in the Selection of Barley Cultivars by Wheat Stem Sawfly (Hymenoptera: Cephidae). Environmental Entomology. 2021; ():1.

Chicago/Turabian Style

Buddhi B Achhami; Gadi V P Reddy; M L Hofland; Jamie D Sherman; Robert K D Peterson; David K Weaver. 2021. "Plant Volatiles and Oviposition Behavior in the Selection of Barley Cultivars by Wheat Stem Sawfly (Hymenoptera: Cephidae)." Environmental Entomology , no. : 1.

Journal article
Published: 01 January 2021 in Journal of Insect Science
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Ground beetles are natural predators of insect pests and small seeds in agroecosystems. In semiarid cropping systems of the Northern Great Plains, there is a lack of knowledge to how ground beetles are affected by diversified cover crop rotations. In a 2-yr study (2018 and 2019), our experiment was a restricted-randomization strip-plot design, comprising summer fallow, an early-season cover crop mixture (five species), and a mid-season cover crop mixture (seven species), with three cover crop termination methods (i.e., herbicide, grazing, and haying). Using pitfall traps, we sampled ground beetles in five 48-h intervals throughout the growing season (n = 135 per year) using growing degree day (GDD) accumulations to better understand changes to ground beetle communities. Data analysis included the use of linear mixed-effects models, perMANOVA, and non-metric multidimensional scaling ordinations. We did not observe differences among cover crop termination methods; however, activity density in the early-season cover crop mixture decreased and in summer fallow increased throughout the growing season, whereas the mid-season cover crop mixture peaked in the middle of the summer. Ground beetle richness and evenness showed a nonlinear tendency, peaking in the middle of the growing season, with marginal differences between cover crops or fallow after the termination events. Also, differences in ground beetle composition were greatest in the early- and mid-season cover crop mixtures earlier in the growing season. Our study supports the use of cover crop mixtures to enhance ground beetle communities, with potential implications for pest management in dryland cropping systems.

ACS Style

Mary E DuPre; David K Weaver; Tim F Seipel; Fabian D Menalled. Impacts of Dryland Cropping Systems on Ground Beetle Communities (Coleoptera: Carabidae) in the Northern Great Plains. Journal of Insect Science 2021, 21, 1 .

AMA Style

Mary E DuPre, David K Weaver, Tim F Seipel, Fabian D Menalled. Impacts of Dryland Cropping Systems on Ground Beetle Communities (Coleoptera: Carabidae) in the Northern Great Plains. Journal of Insect Science. 2021; 21 (1):1.

Chicago/Turabian Style

Mary E DuPre; David K Weaver; Tim F Seipel; Fabian D Menalled. 2021. "Impacts of Dryland Cropping Systems on Ground Beetle Communities (Coleoptera: Carabidae) in the Northern Great Plains." Journal of Insect Science 21, no. 1: 1.

Physiology
Published: 11 September 2020 in PLOS ONE
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Accurately estimating cause-specific mortality for immature insect herbivores is usually difficult. The insects are exposed to abiotic and biotic mortality factors, causing cadavers to simply disappear before cause of mortality can be recorded. Also, insect herbivores are often highly mobile on hosts, making it difficult to follow patterns for individuals through time. In contrast, the wheat stem sawfly, Cephus cinctus Norton, spends its entire egg, larval, and pupal period inside a host stem. Therefore, with periodic sampling stage-specific causes of mortality can be ascertained. Consequently, we examined C. cinctus mortality in eight barley, Hordeum vulgare L., cultivars in two locations in Montana from 2016 to 2018 by collecting stem samples from stem elongation to crop maturity at weekly intervals, and collecting overwintered barley stubs the following spring and summer from the same plots. If larvae were present, we examined larval status—dead or alive—and categorized dead individuals into one of 5 mortality categories: plant defense, cannibalism, parasitism, pathogens, and unknown factors. We used multiple decrement life tables to estimate cause-specific mortality and irreplaceable mortality (the proportion of mortality from a given cause that cannot be replaced by other causes of mortality). Plant defense (antibiosis) caused 85.7 ± 3.6%, cannibalism (governed by antixenosis) caused 70.1 ± 7.6%, parasitism caused 13.8 ± 5.9%, unknown factors caused 38.5 ± 7.6%, and pathogens caused 14.7 ± 8.5% mortality in the presence of all causes of mortality. Similarly, irreplaceable mortality due to plant defense was 22.3 ± 6.4%, cannibalism was 29.1± 4.2%, unknown factors was 6.2 ± 1.8%, pathogens was 0.9 ± 0.5%, and parasitism was 1. 5 ± 0. 6%. Antibiosis traits primarily killed newly emerged larvae, while other traits supported more favorable oviposition decisions by females, increasing mortality by obligate cannibalism. Our results suggest that breeding barley for resistance to C. cinctus targeting both categories of traits (antibiosis and antixenosis) is a highly valuable tactic for management of this important pest.

ACS Style

Buddhi B. Achhami; Robert K. D. Peterson; Jamie D. Sherman; Gadi V. P. Reddy; David K. Weaver. Multiple decrement life tables of Cephus cinctus Norton (Hymenoptera: Cephidae) across a set of barley cultivars: The importance of plant defense versus cannibalism. PLOS ONE 2020, 15, e0238527 .

AMA Style

Buddhi B. Achhami, Robert K. D. Peterson, Jamie D. Sherman, Gadi V. P. Reddy, David K. Weaver. Multiple decrement life tables of Cephus cinctus Norton (Hymenoptera: Cephidae) across a set of barley cultivars: The importance of plant defense versus cannibalism. PLOS ONE. 2020; 15 (9):e0238527.

Chicago/Turabian Style

Buddhi B. Achhami; Robert K. D. Peterson; Jamie D. Sherman; Gadi V. P. Reddy; David K. Weaver. 2020. "Multiple decrement life tables of Cephus cinctus Norton (Hymenoptera: Cephidae) across a set of barley cultivars: The importance of plant defense versus cannibalism." PLOS ONE 15, no. 9: e0238527.

Journal article
Published: 01 August 2020 in Journal of Insect Science
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Wheat stem sawfly, Cephus cinctus Norton, is an economically serious pest of cereals grown in North America. Barley cultivars were previously planted as resistant crops in rotations to manage C. cinctus, but due to increasing levels of injury to this crop, this is no longer a valid management tactic in Montana. Therefore, we aimed to understand antixenosis (behavioral preference), antibiosis (mortality), and potential yield compensation (increased productivity in response to stem injuries) in barley exposed to C. cinctus. We examined these traits in eight barley cultivars. Antixenosis was assessed by counting number of eggs per stem and antibiosis was assessed by counting infested stems, dead larvae, and stems cut by mature larvae. Potential yield compensation was evaluated by comparing grain yield from three categories of stem infestation: 1) uninfested, 2) infested with dead larva, and 3) infested cut by mature larva at crop maturity. We found the greatest number of eggs per infested stem (1.80 ± 0.04), the highest proportion of infested stems (0.63 ± 0.01), and the highest proportion of cut stems (0.33 ± 0.01) in ‘Hockett’. Seven out of eight cultivars had greater grain weight for infested stems than for uninfested stems. These cultivars may have compensatory responses to larval feeding injury. Overall, these barley cultivars contain varying levels of antixenosis, antibiosis, and differing levels of yield compensation. Our results provide foundational knowledge on barley traits that will provide a framework to further develop C. cinctus resistant or tolerant barley cultivars.

ACS Style

Buddhi B Achhami; Gadi V P Reddy; Jamie D Sherman; Robert K D Peterson; David K Weaver. Antixenosis, Antibiosis, and Potential Yield Compensatory Response in Barley Cultivars Exposed to Wheat Stem Sawfly (Hymenoptera: Cephidae) Under Field Conditions. Journal of Insect Science 2020, 20, 1 .

AMA Style

Buddhi B Achhami, Gadi V P Reddy, Jamie D Sherman, Robert K D Peterson, David K Weaver. Antixenosis, Antibiosis, and Potential Yield Compensatory Response in Barley Cultivars Exposed to Wheat Stem Sawfly (Hymenoptera: Cephidae) Under Field Conditions. Journal of Insect Science. 2020; 20 (5):1.

Chicago/Turabian Style

Buddhi B Achhami; Gadi V P Reddy; Jamie D Sherman; Robert K D Peterson; David K Weaver. 2020. "Antixenosis, Antibiosis, and Potential Yield Compensatory Response in Barley Cultivars Exposed to Wheat Stem Sawfly (Hymenoptera: Cephidae) Under Field Conditions." Journal of Insect Science 20, no. 5: 1.

Journal article
Published: 29 July 2020 in Environmental Entomology
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The leaf beetle Diorhabda carinulata Desbrochers (Coleoptera: Chrysomelidae) was introduced into the United States in 1999 for classical biological control of the exotic woody invader saltcedar (Tamarix spp. L. [Caryophyllales: Tamaricaceae]). The recent southern expansion of the range of D. carinulata in the United States has precipitated conflict between proponents of biological control of Tamarix and those with concerns over habitat conservation for avian species. Several semiochemicals that mediate aggregations by this species have been reported, but no repellent compounds have been recorded thus far. We now report a repellent compound, 4-oxo-(E)-2-hexenal, induced by adult D. carinulata feeding on saltcedar foliage. Collection of headspace volatiles, gas chromatography mass spectrometry, and electroantennographic analyses identified 4-oxo-(E)-2-hexenal as an insect-induced compound that is antennally active. Behavioral and exposure assays were conducted to test for repellency and toxicity in adults and larvae. Headspace volatiles were also collected from adult males exposed to 4-oxo-(E)-2-hexenal to determine the impact exposure might have on the emission of the aggregation pheromone. 4-Oxo-(E)-2-hexenal elicited electrophysiological responses in adults of both sexes. Behavioral responses indicated repellency across multiple doses for reproductive D. carinulata adults but not in nonreproductive adults. Exposure assays indicated altered behaviors in first instar larvae and adults, but not in third instar larvae. Collection of headspace volatiles indicated that exposure to 4-oxo-(E)-2-hexenal did not alter emission of the D. carinulata aggregation pheromone by adult males. The continued development and field deployment of this repellent compound may provide a new tool for the management of D. carinulata.

ACS Style

Alexander M Gaffke; Sharlene E Sing; Jocelyn G Millar; Tom L Dudley; Daniel W Bean; Robert K D Peterson; David K Weaver. An Herbivore-Induced Plant Volatile From Saltcedar (Tamarix spp.) Is Repellent to Diorhabda carinulata (Coleoptera: Chrysomelidae). Environmental Entomology 2020, 49, 1063 -1070.

AMA Style

Alexander M Gaffke, Sharlene E Sing, Jocelyn G Millar, Tom L Dudley, Daniel W Bean, Robert K D Peterson, David K Weaver. An Herbivore-Induced Plant Volatile From Saltcedar (Tamarix spp.) Is Repellent to Diorhabda carinulata (Coleoptera: Chrysomelidae). Environmental Entomology. 2020; 49 (5):1063-1070.

Chicago/Turabian Style

Alexander M Gaffke; Sharlene E Sing; Jocelyn G Millar; Tom L Dudley; Daniel W Bean; Robert K D Peterson; David K Weaver. 2020. "An Herbivore-Induced Plant Volatile From Saltcedar (Tamarix spp.) Is Repellent to Diorhabda carinulata (Coleoptera: Chrysomelidae)." Environmental Entomology 49, no. 5: 1063-1070.

Journal article
Published: 19 May 2020 in Journal of Economic Entomology
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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.

ACS Style

Buddhi B Achhami; Gadi V P Reddy; Jamie D Sherman; Robert K D Peterson; David K Weaver. Effect of Precipitation and Temperature on Larval Survival of Cephus cinctus (Hymenoptera: Cephidae) in Barley Cultivars. Journal of Economic Entomology 2020, 113, 1982 -1989.

AMA Style

Buddhi B Achhami, Gadi V P Reddy, Jamie D Sherman, Robert K D Peterson, David K Weaver. Effect of Precipitation and Temperature on Larval Survival of Cephus cinctus (Hymenoptera: Cephidae) in Barley Cultivars. Journal of Economic Entomology. 2020; 113 (4):1982-1989.

Chicago/Turabian Style

Buddhi B Achhami; Gadi V P Reddy; Jamie D Sherman; Robert K D Peterson; David K Weaver. 2020. "Effect of Precipitation and Temperature on Larval Survival of Cephus cinctus (Hymenoptera: Cephidae) in Barley Cultivars." Journal of Economic Entomology 113, no. 4: 1982-1989.

Journal article
Published: 10 September 2019 in Scientific Reports
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The northern tamarisk beetle Diorhabda carinulata (Desbrochers) was approved for release in the United States for classical biological control of a complex of invasive saltcedar species and their hybrids (Tamarix spp.). An aggregation pheromone used by D. carinulata to locate conspecifics is fundamental to colonization and reproductive success. A specialized matrix formulated for controlled release of this aggregation pheromone was developed as a lure to manipulate adult densities in the field. One application of the lure at onset of adult emergence for each generation provided long term attraction and retention of D. carinulata adults on treated Tamarix spp. plants. Treated plants exhibited greater levels of defoliation, dieback and canopy reduction. Application of a single, well-timed aggregation pheromone treatment per generation increased the efficacy of this classical weed biological control agent.

ACS Style

Alexander M. Gaffke; Sharlene Sing; Tom L. Dudley; Daniel W. Bean; Justin A. Russak; Agenor Mafra-Neto; Robert K. D. Peterson; David K. Weaver. Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp. Scientific Reports 2019, 9, 1 -9.

AMA Style

Alexander M. Gaffke, Sharlene Sing, Tom L. Dudley, Daniel W. Bean, Justin A. Russak, Agenor Mafra-Neto, Robert K. D. Peterson, David K. Weaver. Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp. Scientific Reports. 2019; 9 (1):1-9.

Chicago/Turabian Style

Alexander M. Gaffke; Sharlene Sing; Tom L. Dudley; Daniel W. Bean; Justin A. Russak; Agenor Mafra-Neto; Robert K. D. Peterson; David K. Weaver. 2019. "Field demonstration of a semiochemical treatment that enhances Diorhabda carinulata biological control of Tamarix spp." Scientific Reports 9, no. 1: 1-9.

Original article
Published: 22 August 2019 in Physiological Entomology
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Knowledge of the life‐history traits that influence the reproductive success of parasitoids could provide useful information to enhance their effectiveness as biological control agents. The wheat stem sawfly Cephus cinctus Norton (Hymenoptera: Cephidae) is a major pest of wheat in the Northern Great Plains of North America. The bivoltine, sympatric and specialist parasitoids Bracon cephi (Gahan) and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae) are the only species known to attack C. cinctus in wheat. In the present study, we quantify the body size, longevity, egg load and egg volume of B. cephi and B. lissogaster aiming to test whether these life‐history traits differ among adult females developing from overwintering and summer generation larvae. We also investigate the effect of sucrose supplementation on the same reproductive parameters. The results obtained show no differences between life‐history traits of B. cephi developing from the overwintering and summer generations. By contrast, the egg load of B. lissogaster is significantly different between generations, with overwintered females producing 1.2‐fold more eggs than summer individuals. Sucrose feeding has a strong positive effect on life‐history traits of both parasitoid species and generations. The longevity of sucrose‐fed females of B. cephi is increased three‐fold, whereas the survival of B. lissogaster is increased almost nine‐fold. Females of B. cephi treated with sucrose have four‐fold more mature eggs, whereas the egg load of B. lissogaster is increased 1.15‐ to 1.25‐fold with sugar feeding. Only B. cephi females increase egg volume with sucrose. The present study provides valuable insights on the life‐history and nutritional requirements of these two important parasitoid species.

ACS Style

Dayane A. Reis; Megan L. Hofland; Robert K. D. Peterson; David K. Weaver. Effects of sucrose supplementation and generation on life‐history traits of Bracon cephi and Bracon lissogaster , parasitoids of the wheat stem sawfly. Physiological Entomology 2019, 44, 266 -274.

AMA Style

Dayane A. Reis, Megan L. Hofland, Robert K. D. Peterson, David K. Weaver. Effects of sucrose supplementation and generation on life‐history traits of Bracon cephi and Bracon lissogaster , parasitoids of the wheat stem sawfly. Physiological Entomology. 2019; 44 (3-4):266-274.

Chicago/Turabian Style

Dayane A. Reis; Megan L. Hofland; Robert K. D. Peterson; David K. Weaver. 2019. "Effects of sucrose supplementation and generation on life‐history traits of Bracon cephi and Bracon lissogaster , parasitoids of the wheat stem sawfly." Physiological Entomology 44, no. 3-4: 266-274.

Journal article
Published: 19 June 2019 in PeerJ
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Loss of crop protection products when agricultural spray applications drift has economic and ecological consequences. Modification of the spray solution through tank additives and product formulation is an important drift reduction strategy that could mitigate these effects, but has been studied less than most other strategies. Therefore, an experimental field study was conducted to evaluate spray drift resulting from agricultural ground applications of an insecticide formulated as a suspension concentrate (SC) and as a wettable powder (WP), with and without two adjuvants. Droplet sizes were also measured in a wind tunnel to determine if indirect methods could be substituted for field experimentation to quantify spray drift from these technologies. Results suggest that spray drift was reduced by 37% when comparing the SC to the WP formulation. As much as 63% drift reduction was achieved by incorporating certain spray adjuvants, but this depended on the formulation/adjuvant combination. The wind tunnel data for droplet spectra showed strong agreement with field deposition trends, suggesting that droplet statistics could be used to estimate drift reduction of spray solutions. These findings can be used to develop a classification scheme for formulated products and tank additives based on their potential for reducing spray drift.

ACS Style

Collin J. Preftakes; Jerome J. Schleier; Greg R. Kruger; David K. Weaver; Robert K.D. Peterson. Effect of insecticide formulation and adjuvant combination on agricultural spray drift. PeerJ 2019, 7, e7136 .

AMA Style

Collin J. Preftakes, Jerome J. Schleier, Greg R. Kruger, David K. Weaver, Robert K.D. Peterson. Effect of insecticide formulation and adjuvant combination on agricultural spray drift. PeerJ. 2019; 7 ():e7136.

Chicago/Turabian Style

Collin J. Preftakes; Jerome J. Schleier; Greg R. Kruger; David K. Weaver; Robert K.D. Peterson. 2019. "Effect of insecticide formulation and adjuvant combination on agricultural spray drift." PeerJ 7, no. : e7136.

Review
Published: 11 June 2019 in Sustainability
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Covering about 40% of Earth’s land surface and sustaining at least 38% of global population, drylands are key crop and animal production regions with high economic and social values. However, land use changes associated with industrialized agricultural managements are threatening the sustainability of these systems. While previous studies assessing the impacts of agricultural management systems on biodiversity and their services focused on more diversified mesic landscapes, there is a dearth of such research in highly simplified dryland agroecosystems. In this paper, we 1) summarize previous research on the effects of farm management systems and agricultural expansion on biodiversity and biodiversity-based ecosystem services, 2) present four case studies assessing the impacts of management systems on biodiversity and ecosystem services across highly simplified dryland landscapes of the Northern Great Plains (NGP), USA, 3) discuss approaches to sustain biodiversity-based ecosystem services in drylands, and 4) present a conceptual framework for enhancing agricultural sustainability in the drylands through research, policy, economic valuation, and adaptive management. An analysis of the land use changes due to agricultural expansion within the Golden Triangle, a representative agricultural area in the NGP, indicated that the proportion of land conversion to agriculture area was 84%, 8%, and 7% from grassland, riparian, and shrubland habitats, respectively. Our results showed this simplification was associated with a potential reduction of pollination services. Also, our economic analysis projected that if 30% parasitism could be achieved through better management systems, the estimated potential economic returns to pest regulation services through parasitoids in Montana, USA alone could reach about $11.23 million. Overall, while dryland agroecosystems showed a significant loss of native biodiversity and its services, greater pest incidence, and a decrease in plant pollinator networks, these trends were moderately reversed in organically managed farming systems. In conclusion, although land use changes due to agricultural expansion and industrialized farming threaten the sustainability of dryland agroecosystems, this impact can be partially offset by coupling ecologically-based farming practices with adaptive management strategies.

ACS Style

Subodh Adhikari; Arjun Adhikari; David Weaver; Anton Bekkerman; Fabian Menalled. Impacts of Agricultural Management Systems on Biodiversity and Ecosystem Services in Highly Simplified Dryland Landscapes. Sustainability 2019, 11, 3223 .

AMA Style

Subodh Adhikari, Arjun Adhikari, David Weaver, Anton Bekkerman, Fabian Menalled. Impacts of Agricultural Management Systems on Biodiversity and Ecosystem Services in Highly Simplified Dryland Landscapes. Sustainability. 2019; 11 (11):3223.

Chicago/Turabian Style

Subodh Adhikari; Arjun Adhikari; David Weaver; Anton Bekkerman; Fabian Menalled. 2019. "Impacts of Agricultural Management Systems on Biodiversity and Ecosystem Services in Highly Simplified Dryland Landscapes." Sustainability 11, no. 11: 3223.

Journal article
Published: 01 June 2019 in G3 Genes|Genomes|Genetics
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The wheat stem sawfly (WSS) (Cephus cinctus Norton) is a major yield-reducing pest of wheat (Triticum aestivum L.). Varieties with pith-filled, or solid, stems provide a measure of resistance by inhibiting larval survival inside the stem. Durum wheat (Triticum turgidum L.) has resistance to the wheat stem sawfly even in the absence of known genes for stem solidness. To determine the genetic basis of resistance in durum wheat, a susceptible durum wheat, PI 41353, was identified from among 1,211 landrace accessions from around the world screened in WSS-infested sites. A recombinant inbred line (RIL) population of 105 individuals was developed from a cross of PI 41353 with a typically resistant variety, Pierce. The RIL were screened in a total of three WSS-infested locations in Montana over a two year period. A genetic map was constructed with 2,867 SNP-based markers. A quantitative trait locus (QTL) analysis identified six QTL associated with resistance. An allele from resistant cultivar Pierce at a QTL on chromosome 3A, Qss.msub-3AL, caused a 25% reduction in stem cutting. Assessment of near-isogenic lines that varied for alleles at Qss.msub-3AL showed that the Pierce allele was also associated with higher stem solidness as measured early in stem development, which is a critical stage for WSS oviposition and larval development. Stem solidness of Pierce and other resistant durum wheat lines largely disappeared later in plant development. Results suggest a genetic mechanism for WSS resistance observed in durum wheat, and provide an additional source of WSS resistance for hexaploid bread wheat.

ACS Style

Andrea C. Varella; Hongtao Zhang; David K. Weaver; Jason P. Cook; Megan L. Hofland; Peggy Lamb; Shiaoman Chao; John M. Martin; Nancy K. Blake; Luther E. Talbert. A Novel QTL in Durum Wheat for Resistance to the Wheat Stem Sawfly Associated with Early Expression of Stem Solidness. G3 Genes|Genomes|Genetics 2019, 9, 1999 -2006.

AMA Style

Andrea C. Varella, Hongtao Zhang, David K. Weaver, Jason P. Cook, Megan L. Hofland, Peggy Lamb, Shiaoman Chao, John M. Martin, Nancy K. Blake, Luther E. Talbert. A Novel QTL in Durum Wheat for Resistance to the Wheat Stem Sawfly Associated with Early Expression of Stem Solidness. G3 Genes|Genomes|Genetics. 2019; 9 (6):1999-2006.

Chicago/Turabian Style

Andrea C. Varella; Hongtao Zhang; David K. Weaver; Jason P. Cook; Megan L. Hofland; Peggy Lamb; Shiaoman Chao; John M. Martin; Nancy K. Blake; Luther E. Talbert. 2019. "A Novel QTL in Durum Wheat for Resistance to the Wheat Stem Sawfly Associated with Early Expression of Stem Solidness." G3 Genes|Genomes|Genetics 9, no. 6: 1999-2006.

Journal article
Published: 30 May 2019 in Environmental Entomology
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Industrialized farming practices result in simplified agricultural landscapes, reduced biodiversity, and degraded species-interaction networks. Thus far, most research assessing the combined effects of farming systems and landscape complexity on beneficial insects has been conducted in relatively diversified and mesic systems and may not represent the large-scale, monoculture-based dryland agriculture that dominates many regions worldwide. Specifically, the effects of farming systems on forbs, bees, and their interactions are poorly understood in highly simplified dryland landscapes such as those in the Northern Great Plains, United States, an area globally important for conventional and organic small grain, pulse, forage, and oilseed production. During a 3-yr (2013-2015) study, we assessed 1) the effects of dryland no-till conventional and tilled organic farming on forbs, bees, and bee-flower networks and 2) the relationship between natural habitat and bee abundance. Flower density and richness were greater in tilled organic fields than in no-till conventional fields, and forb community composition differed between farming systems. We observed high bee diversity (109 taxa) in this highly simplified landscape, and bee abundance, richness, and community composition were similar between systems. Compared with tilled organic fields, bee-flower interactions in no-till conventional fields were poorly connected, suggesting these systems maintain relatively impoverished plant-pollinator networks. Natural habitat (11% of the landscape) did not affect small-bodied bee abundance in either farming system but positively affected large-bodied bees within 2,000 m of crop-field centers. In highly simplified agricultural landscapes, dryland organic farming and no-till conventional farming together support relatively high bee diversity, presumably because dryland organic farming enhances floral resources and bee-flower networks, and no-till management in conventional farming provides undisturbed ground-nesting habitats for wild bees (Hymenoptera: Apoidea).

ACS Style

Subodh Adhikari; Laura A Burkle; Kevin M O’Neill; David K Weaver; Casey M Delphia; Fabian D Menalled. Dryland Organic Farming Partially Offsets Negative Effects of Highly Simplified Agricultural Landscapes on Forbs, Bees, and Bee-Flower Networks. Environmental Entomology 2019, 48, 826 -835.

AMA Style

Subodh Adhikari, Laura A Burkle, Kevin M O’Neill, David K Weaver, Casey M Delphia, Fabian D Menalled. Dryland Organic Farming Partially Offsets Negative Effects of Highly Simplified Agricultural Landscapes on Forbs, Bees, and Bee-Flower Networks. Environmental Entomology. 2019; 48 (4):826-835.

Chicago/Turabian Style

Subodh Adhikari; Laura A Burkle; Kevin M O’Neill; David K Weaver; Casey M Delphia; Fabian D Menalled. 2019. "Dryland Organic Farming Partially Offsets Negative Effects of Highly Simplified Agricultural Landscapes on Forbs, Bees, and Bee-Flower Networks." Environmental Entomology 48, no. 4: 826-835.

Preprint
Published: 30 July 2018
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The wheat stem sawfly, Cephus cinctus, is a major pest of wheat and key ecological player in the grasslands of western North America. It also represents a distinctive lineage of sawflies that appeared early during the hymenopteran radiation, but after the clade of Eusymphyta sawflies that is the sister lineage of all other Hymenoptera. We present a high-quality draft genome assembly of 162 Mbp in 1,976 scaffolds with a scaffold N50 of 622 kbp. Automated gene annotation identified 11,210 protein-coding gene models and 1,307 non-coding RNA models. Thirteen percent of the assembly consists of ~58,000 transposable elements partitioned equally between Class-I and Class-II elements. Orthology analysis reveals that 86% of Cephus proteins have identifiable orthologs in other insects. Phylogenomic analysis of conserved subsets of these proteins supports the placement of the Cephidae between the Eusymphyta and the parasitic woodwasp superfamily Orussoidea. Manual annotation and phylogenetic analysis of families of odorant, gustatory, and ionotropic receptors, plus odorant binding proteins, shows that Cephus has representatives for most conserved and expanded gene lineages in the Apocrita (wasps, ants, and bees). Cephus has also maintained several insect gene lineages that have been lost from the Apocrita, most prominently the carbon dioxide receptor subfamily. Furthermore, Cephus encodes a few small lineage-specific chemoreceptor gene family expansions that might be involved in adaptations to new grasses including wheat. These comparative analyses identify gene family members likely to have been present in the hymenopteran ancestor and provide a new perspective on the evolution of the chemosensory gene repertoire.

ACS Style

Hugh M. Robertson; Robert M. Waterhouse; Kimberly K. O. Walden; Livio Ruzzante; Maarten J. M. F. Reijnders; Brad S. Coates; Fabrice Legeai; Joanna C. Gress; Sezgi Biyiklioglu; David K. Weaver; Kevin W. Wanner; Hikmet Budak. Genome sequence of the wheat stem sawfly, Cephus cinctus, a primitive hymenopteran and wheat pest, illuminates evolution of hymenopteran chemoreceptors. 2018, 380873 .

AMA Style

Hugh M. Robertson, Robert M. Waterhouse, Kimberly K. O. Walden, Livio Ruzzante, Maarten J. M. F. Reijnders, Brad S. Coates, Fabrice Legeai, Joanna C. Gress, Sezgi Biyiklioglu, David K. Weaver, Kevin W. Wanner, Hikmet Budak. Genome sequence of the wheat stem sawfly, Cephus cinctus, a primitive hymenopteran and wheat pest, illuminates evolution of hymenopteran chemoreceptors. . 2018; ():380873.

Chicago/Turabian Style

Hugh M. Robertson; Robert M. Waterhouse; Kimberly K. O. Walden; Livio Ruzzante; Maarten J. M. F. Reijnders; Brad S. Coates; Fabrice Legeai; Joanna C. Gress; Sezgi Biyiklioglu; David K. Weaver; Kevin W. Wanner; Hikmet Budak. 2018. "Genome sequence of the wheat stem sawfly, Cephus cinctus, a primitive hymenopteran and wheat pest, illuminates evolution of hymenopteran chemoreceptors." , no. : 380873.

Correction
Published: 07 July 2018 in Functional & Integrative Genomics
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The original version of this article contained a mistake. The word "RefSeq v.1" was incorrectly inserted on page 7. The correct sentence should be: To identify the differentially regulated transcripts, clean RNA-Seq reads were mapped onto the T. aestivum Chinese Spring chromosome 3B pseudomolecule.

ACS Style

Sezgi Biyiklioglu; Burcu Alptekin; B. Ani Akpinar; Andrea C. Varella; Megan L. Hofland; David K. Weaver; Brian Bothner; Hikmet Budak. Correction to: A large-scale multiomics analysis of wheat stem solidness and the wheat stem sawfly feeding response, and syntenic associations in barley, Brachypodium, and rice. Functional & Integrative Genomics 2018, 18, 611 -611.

AMA Style

Sezgi Biyiklioglu, Burcu Alptekin, B. Ani Akpinar, Andrea C. Varella, Megan L. Hofland, David K. Weaver, Brian Bothner, Hikmet Budak. Correction to: A large-scale multiomics analysis of wheat stem solidness and the wheat stem sawfly feeding response, and syntenic associations in barley, Brachypodium, and rice. Functional & Integrative Genomics. 2018; 18 (5):611-611.

Chicago/Turabian Style

Sezgi Biyiklioglu; Burcu Alptekin; B. Ani Akpinar; Andrea C. Varella; Megan L. Hofland; David K. Weaver; Brian Bothner; Hikmet Budak. 2018. "Correction to: A large-scale multiomics analysis of wheat stem solidness and the wheat stem sawfly feeding response, and syntenic associations in barley, Brachypodium, and rice." Functional & Integrative Genomics 18, no. 5: 611-611.

Research article
Published: 24 April 2018 in Annals of Applied Biology
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Linaria vulgaris, common or yellow toadflax, and Linaria dalmatica, Dalmatian toadflax (Plantaginaceae), are Eurasian perennial forbs invasive throughout temperate North America. These Linaria species have been the targets of classical biological control programmes in Canada and the USA since the 1960s. The first effective toadflax biological control agent, the stem‐mining weevil Mecinus janthinus (Coleoptera: Curculionidae) was introduced from Europe in the 1990s. This weevil has become established on L. dalmatica and L. vulgaris in both countries, although it has shown greater success in controlling the former toadflax species. Genetic and ecological studies of native range M. janthinus populations revealed that weevils previously identified as a single species in fact include two cryptic species, now recognised as M. janthinus, associated with yellow toadflax, and the recently confirmed species Mecinus janthiniformis, associated with Dalmatian toadflax. The results of a comprehensive study characterising haplotype identities, distributions and frequencies within M. janthinus s.l. native range source populations were compared to those populations currently established in the USA and Canada. The presence of both Mecinus species in North America was confirmed, and revealed with a few exceptions a high and consistent level of host fidelity throughout the adopted and native ranges. Genetic analysis based on mitochondrial cytochrome oxidase subunit II gene (mtCOII) defined the origin and records the subsequent North American establishment, by haplotype, of the European founder populations of M. janthinus (northern Switzerland and southern Germany) and M. janthiniformis (southern Macedonia), and provided population genetic indices for the studied populations. This analysis together with existing North American shipment receipt, release and rearing records elucidates probable redistribution routes and sources of both weevil species from initially released and established adopted range populations.

ACS Style

I. Toševski; S.E. Sing; Rosemarie De Clerck-Floate; Alec McClay; D.K. Weaver; M. Schwarzländer; O. Krstić; J. Jović; A. Gassmann. Twenty‐five years after: post‐introduction association of Mecinus janthinus s.l. with invasive host toadflaxes Linaria vulgaris and Linaria dalmatica in North America. Annals of Applied Biology 2018, 173, 16 -34.

AMA Style

I. Toševski, S.E. Sing, Rosemarie De Clerck-Floate, Alec McClay, D.K. Weaver, M. Schwarzländer, O. Krstić, J. Jović, A. Gassmann. Twenty‐five years after: post‐introduction association of Mecinus janthinus s.l. with invasive host toadflaxes Linaria vulgaris and Linaria dalmatica in North America. Annals of Applied Biology. 2018; 173 (1):16-34.

Chicago/Turabian Style

I. Toševski; S.E. Sing; Rosemarie De Clerck-Floate; Alec McClay; D.K. Weaver; M. Schwarzländer; O. Krstić; J. Jović; A. Gassmann. 2018. "Twenty‐five years after: post‐introduction association of Mecinus janthinus s.l. with invasive host toadflaxes Linaria vulgaris and Linaria dalmatica in North America." Annals of Applied Biology 173, no. 1: 16-34.

Journal article
Published: 14 March 2018 in Annals of the Entomological Society of America
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Scott L Portman; Stefan T Jaronski; David K Weaver; Gadi V P Reddy. Advancing Biological Control of the Wheat Stem Sawfly: New Strategies in a 100-yr Struggle to Manage a Costly Pest in the Northern Great Plains. Annals of the Entomological Society of America 2018, 111, 85 -91.

AMA Style

Scott L Portman, Stefan T Jaronski, David K Weaver, Gadi V P Reddy. Advancing Biological Control of the Wheat Stem Sawfly: New Strategies in a 100-yr Struggle to Manage a Costly Pest in the Northern Great Plains. Annals of the Entomological Society of America. 2018; 111 (3):85-91.

Chicago/Turabian Style

Scott L Portman; Stefan T Jaronski; David K Weaver; Gadi V P Reddy. 2018. "Advancing Biological Control of the Wheat Stem Sawfly: New Strategies in a 100-yr Struggle to Manage a Costly Pest in the Northern Great Plains." Annals of the Entomological Society of America 111, no. 3: 85-91.

Article
Published: 23 February 2018 in Pest Management Science
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Semiochemicals for monitoring, attracting or repelling pest and beneficial organisms are increasingly deployed in agricultural and forest systems for pest management activities. However, the use of aggregation pheromones and host plant attractants for the express purpose of increasing the efficacy of classical biological control agents of weeds has not been widely reported. Therefore, we conducted field-based assays to determine if a specialized wax based matrix impregnated with an aggregation pheromone of the northern tamarisk beetle Diorhabda carinulata (Desbrochers) or host plant volatiles could increase the efficacy of D. carinulata. The aggregation pheromone and host plant volatiles were formulated for field application using a wax based matrix. Reported release rates suggest this matrix is a viable formulation for enhancing D. carinulata aggregations under field conditions. Pheromone-treated saltcedar plants (Tamarix spp.) not only had higher densities of adult and larval D. carinulata, but also sustained greater levels of foliar damage than control plants. Increased damage from the focused feeding of D. carinulata caused an increase in foliar dieback and decrease in live canopy volume of semiochemical-treated plants. Field deployment of these semiochemical formulations could be useful in directing populations of D. carinulata for increased impact on Tamarix spp.

ACS Style

Alexander M. Gaffke; Sharlene Sing; Tom L. Dudley; Daniel W. Bean; Justin A. Russak; Agenor Mafra-Neto; Paul A. Grieco; Robert K. D. Peterson; David K. Weaver. Semiochemicals to enhance herbivory byDiorhabda carinulataaggregations in saltcedar (Tamarixspp.) infestations. Pest Management Science 2018, 74, 1494 -1503.

AMA Style

Alexander M. Gaffke, Sharlene Sing, Tom L. Dudley, Daniel W. Bean, Justin A. Russak, Agenor Mafra-Neto, Paul A. Grieco, Robert K. D. Peterson, David K. Weaver. Semiochemicals to enhance herbivory byDiorhabda carinulataaggregations in saltcedar (Tamarixspp.) infestations. Pest Management Science. 2018; 74 (6):1494-1503.

Chicago/Turabian Style

Alexander M. Gaffke; Sharlene Sing; Tom L. Dudley; Daniel W. Bean; Justin A. Russak; Agenor Mafra-Neto; Paul A. Grieco; Robert K. D. Peterson; David K. Weaver. 2018. "Semiochemicals to enhance herbivory byDiorhabda carinulataaggregations in saltcedar (Tamarixspp.) infestations." Pest Management Science 74, no. 6: 1494-1503.

Journal article
Published: 21 February 2018 in Journal of Economic Entomology
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Most barley cultivars have some degree of resistance to the wheat stem sawfly (WSS), Cephus cinctus Norton (Hymenoptera: Cephidae). Damage caused by WSS is currently observed in fields of barley grown in the Northern Great Plains, but the impact of WSS damage among cultivars due to genetic differences within the barley germplasm is not known. Specifically, little is known about the mechanisms underlying WSS resistance in barley. We characterized WSS resistance in a subset of the spring barley CAP (Coordinated Agricultural Project) germplasm panel containing 193 current and historically important breeding lines from six North American breeding programs. Panel lines were grown in WSS infested fields for two consecutive years. Lines were characterized for stem solidness, stem cutting, WSS infestation (antixenosis), larval mortality (antibiosis), and parasitism (indirect plant defense). Variation in resistance to WSS in barley was compared to observations made for solid-stemmed resistant and hollow-stemmed susceptible wheat lines. Results indicate that both antibiosis and antixenosis are involved in the resistance of barley to the WSS, but antibiosis seems to be more prevalent. Almost all of the barley lines had greater larval mortality than the hollow-stemmed wheat lines, and only a few barley lines had mortality as low as that observed in the solid-stemmed wheat line. Since barley lines lack solid stems, it is apparent that barley has a different form of antibiosis. Our results provide information for use of barley in rotation to control the WSS and may provide a basis for identification of new approaches for improving WSS resistance in wheat.

ACS Style

Andrea C Varella; Luther E Talbert; Buddhi B Achhami; Nancy K Blake; Megan L Hofland; Jamie D Sherman; Peggy F Lamb; Gadi V P Reddy; David K Weaver. Characterization of Resistance to Cephus cinctus (Hymenoptera: Cephidae) in Barley Germplasm. Journal of Economic Entomology 2018, 111, 923 -930.

AMA Style

Andrea C Varella, Luther E Talbert, Buddhi B Achhami, Nancy K Blake, Megan L Hofland, Jamie D Sherman, Peggy F Lamb, Gadi V P Reddy, David K Weaver. Characterization of Resistance to Cephus cinctus (Hymenoptera: Cephidae) in Barley Germplasm. Journal of Economic Entomology. 2018; 111 (2):923-930.

Chicago/Turabian Style

Andrea C Varella; Luther E Talbert; Buddhi B Achhami; Nancy K Blake; Megan L Hofland; Jamie D Sherman; Peggy F Lamb; Gadi V P Reddy; David K Weaver. 2018. "Characterization of Resistance to Cephus cinctus (Hymenoptera: Cephidae) in Barley Germplasm." Journal of Economic Entomology 111, no. 2: 923-930.

Journal article
Published: 05 August 2016 in Plant Breeding
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Andrea C. Varella; Luther E. Talbert; Megan L. Hofland; Micaela Buteler; Jamie D. Sherman; Nancy K. Blake; Hwa-Young Heo; John M. Martin; David K. Weaver. Alleles at a quantitative trait locus for stem solidness in wheat affect temporal patterns of pith expression and level of resistance to the wheat stem sawfly. Plant Breeding 2016, 135, 546 -551.

AMA Style

Andrea C. Varella, Luther E. Talbert, Megan L. Hofland, Micaela Buteler, Jamie D. Sherman, Nancy K. Blake, Hwa-Young Heo, John M. Martin, David K. Weaver. Alleles at a quantitative trait locus for stem solidness in wheat affect temporal patterns of pith expression and level of resistance to the wheat stem sawfly. Plant Breeding. 2016; 135 (5):546-551.

Chicago/Turabian Style

Andrea C. Varella; Luther E. Talbert; Megan L. Hofland; Micaela Buteler; Jamie D. Sherman; Nancy K. Blake; Hwa-Young Heo; John M. Martin; David K. Weaver. 2016. "Alleles at a quantitative trait locus for stem solidness in wheat affect temporal patterns of pith expression and level of resistance to the wheat stem sawfly." Plant Breeding 135, no. 5: 546-551.

Journal article
Published: 14 August 2015 in Environmental Entomology
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This study investigated the dynamics of parasitism, host plant resistance, pathogens, and predation on the demography of wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), developing in susceptible (hollow stem) and resistant (solid stem) wheat hosts. This study is also the first to investigate the prevalence and impact of cannibalism on wheat stem sawfly mortality. Wheat stem sawflies were sampled in two commercial wheat fields over 4 yr from the egg stage through adult emergence, and multiple decrement life tables were constructed and analyzed. Cannibalism, host plant resistance, or unknown factors were the most prevalent factors causing egg mortality. Summer mortality of prediapause larvae ranged from 28 to 84%, mainly due to parasitism by Bracon cephi (Gahan) and Bracon lissogaster Muesebeck, cannibalism, and host plant resistance. Winter mortality ranged from 6 to 54% of the overwintering larvae, mainly due to unknown factors or pathogens. Cannibalism is a major cause of irreplaceable mortality because it is absolute, with only a single survivor in every multiple infested stem. Subsequent to obligate cannibalism, mortality of feeding larvae due to host plant resistance was lower in hollow stem wheat than in solid stem wheat. Mortality from host plant resistance was largely irreplaceable. Irreplaceable mortality due to parasitoids was greater in hollow stem wheat than in solid stem wheat. Host plant resistance due to stem solidness and parasitism in hollow stems cause substantial mortality in populations of actively feeding larvae responsible for all crop losses. Therefore, enhancing these mortality factors is vital to effective integrated pest management of wheat stem sawfly.

ACS Style

Micaela Buteler; Robert K. D. Peterson; Megan L. Hofland; David K. Weaver. A Multiple Decrement Life Table Reveals That Host Plant Resistance and Parasitism Are Major Causes of Mortality for the Wheat Stem Sawfly. Environmental Entomology 2015, 44, 1571 -1580.

AMA Style

Micaela Buteler, Robert K. D. Peterson, Megan L. Hofland, David K. Weaver. A Multiple Decrement Life Table Reveals That Host Plant Resistance and Parasitism Are Major Causes of Mortality for the Wheat Stem Sawfly. Environmental Entomology. 2015; 44 (6):1571-1580.

Chicago/Turabian Style

Micaela Buteler; Robert K. D. Peterson; Megan L. Hofland; David K. Weaver. 2015. "A Multiple Decrement Life Table Reveals That Host Plant Resistance and Parasitism Are Major Causes of Mortality for the Wheat Stem Sawfly." Environmental Entomology 44, no. 6: 1571-1580.