Our Research
Our lab primarily studies the wheat stem sawfly (Cephus cinctus Norton). This insect causes extensive damage to wheat crops in Colorado and the northern Great Plains region. Adult sawflies lay their eggs within wheat stems, with the resulting larvae feeding on the plants from the inside. Reductions in wheat head size and stem cutting then frequently occur, resulting in yield losses for farmers.
We work alongside wheat breeding specialists, industry experts, and Colorado growers to pursue methods for minimizing the damages this pest causes. This website will be periodically updated to reflect our current research projects.
Our lab primarily studies the wheat stem sawfly (Cephus cinctus Norton). This insect causes extensive damage to wheat crops in Colorado and the northern Great Plains region. Adult sawflies lay their eggs within wheat stems, with the resulting larvae feeding on the plants from the inside. Reductions in wheat head size and stem cutting then frequently occur, resulting in yield losses for farmers.
We work alongside wheat breeding specialists, industry experts, and Colorado growers to pursue methods for minimizing the damages this pest causes. This website will be periodically updated to reflect our current research projects.
Wheat Stem Sawfly (Cephus cinctus Norton)
Photo by Kelsey Dawson
Photo by Kelsey Dawson
Wheat Stem Sawfly Overview
See our fact sheet below for a thorough introduction on this pest:
See our fact sheet below for a thorough introduction on this pest:
| wheat_stem_sawfly_fact_sheet.pdf |
Annual Wheat Stem Sawfly Survey
Every year our lab surveys 15+ Colorado counties for sawfly infestation. This data is then used to monitor sawfly movement, provide a database for use in future projects, and much more! See the images below for our most recent survey. File downloads for previous years are also available:
Every year our lab surveys 15+ Colorado counties for sawfly infestation. This data is then used to monitor sawfly movement, provide a database for use in future projects, and much more! See the images below for our most recent survey. File downloads for previous years are also available:
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Graphic depicting 2022 sawfly infestation
Created by Dr. Erika Pierce
Created by Dr. Erika Pierce
Wheat Stem Sawfly Flight Timing
We conduct sweeps each season to track the timing of when sawfly adults emerge and target wheat crops. The resulting data helps us predict future flight timelines. We've also utilized this information to help guide precision insecticide applications. (See graphic portraying our data below. NOTE: Our data for 2022 was heavily influenced by strong winds and abnormal weather patterns, causing a disparity with the data of previous years.)
We conduct sweeps each season to track the timing of when sawfly adults emerge and target wheat crops. The resulting data helps us predict future flight timelines. We've also utilized this information to help guide precision insecticide applications. (See graphic portraying our data below. NOTE: Our data for 2022 was heavily influenced by strong winds and abnormal weather patterns, causing a disparity with the data of previous years.)
Graphic Depicting WSS Flight Data
Updated by Dr. Erika Pierce
Updated by Dr. Erika Pierce
Solid Stem Assessment Screening
Breeding wheat to have fully solid or semi-solid stems remains one of the major control measures for mitigating sawfly damage. In plants that have these traits, it becomes more difficult for sawflies to lay their eggs. The solid/semi-solid stems are also less suitable for their larvae to develop in than hollow stems. We cooperate with Dr. Esten Mason of the CSU Wheat Breeding and Genetics Program ( People - Wheat Breeding and Genetics Program (colostate.edu) ) to help further this line of research. We perform dissections and record stem solidness for a variety of experimental wheat lines. This data is then utilized to predict a line's resiliency to sawfly infestation, determine how environmental conditions impact solid stem gene expression, etc.
Breeding wheat to have fully solid or semi-solid stems remains one of the major control measures for mitigating sawfly damage. In plants that have these traits, it becomes more difficult for sawflies to lay their eggs. The solid/semi-solid stems are also less suitable for their larvae to develop in than hollow stems. We cooperate with Dr. Esten Mason of the CSU Wheat Breeding and Genetics Program ( People - Wheat Breeding and Genetics Program (colostate.edu) ) to help further this line of research. We perform dissections and record stem solidness for a variety of experimental wheat lines. This data is then utilized to predict a line's resiliency to sawfly infestation, determine how environmental conditions impact solid stem gene expression, etc.
Parasitoid Wasp Studies
Parasitoid wasps are a potential natural control measure for wheat stem sawfly, as the adult wasps will seek out sawfly larvae in wheat stems. After paralyzing a larva, these wasps will then lay their own egg inside the stem. Resulting offspring then consume the sawfly larva, killing it before it has the chance to become an adult. Colorado currently has low populations of two types of parasitoid wasps, Bracon cephi and Bracon lissogaster.
Although these wasps are an effective control measure for sawfly in other states, they have yet to cause a significant decrease in sawfly infestation in Colorado.
We conduct a variety of field and lab studies with these wasps, including field releases and genetic studies. Of note, we are investigating the evolutionary compatibility of parasitoid wasps and sawflies from differing parts of the country, in search for an explanation as to why these wasps have yet to become an effective control measure in Colorado.
Parasitoid wasps are a potential natural control measure for wheat stem sawfly, as the adult wasps will seek out sawfly larvae in wheat stems. After paralyzing a larva, these wasps will then lay their own egg inside the stem. Resulting offspring then consume the sawfly larva, killing it before it has the chance to become an adult. Colorado currently has low populations of two types of parasitoid wasps, Bracon cephi and Bracon lissogaster.
Although these wasps are an effective control measure for sawfly in other states, they have yet to cause a significant decrease in sawfly infestation in Colorado.
We conduct a variety of field and lab studies with these wasps, including field releases and genetic studies. Of note, we are investigating the evolutionary compatibility of parasitoid wasps and sawflies from differing parts of the country, in search for an explanation as to why these wasps have yet to become an effective control measure in Colorado.
Parasitoid Wasp (Bracon cephi)
Photo by Paetra Vroman-Lucas
Photo by Paetra Vroman-Lucas
Ancestral Wheat Screening
Over the course of several field seasons, we have searched for novel sources of resistance to sawflies in species of ancestral wheatgrass. Breeding programs are then used to help incorporate these resistances into commercially viable lines of wheat. We test for sawfly infestation rates in these new lines by deliberately exposing them to sawfly adults in the field. We then also evaluate the larval survivorship within the stems. We partner with the Wheat Genetics Resource Center on this project, more information is available at Industry/University Cooperative Research Center | Wheat Genetics Resource Center | Kansas State University (k-state.edu) .
Over the course of several field seasons, we have searched for novel sources of resistance to sawflies in species of ancestral wheatgrass. Breeding programs are then used to help incorporate these resistances into commercially viable lines of wheat. We test for sawfly infestation rates in these new lines by deliberately exposing them to sawfly adults in the field. We then also evaluate the larval survivorship within the stems. We partner with the Wheat Genetics Resource Center on this project, more information is available at Industry/University Cooperative Research Center | Wheat Genetics Resource Center | Kansas State University (k-state.edu) .
Unloading experimental lines for sawfly exposure
Photo by Henrique Vieira
Photo by Henrique Vieira
Evaluating Use of Fusarium spp. Fungi in Sawfly Control
We are planning to evaluate the ability of Fusarium spp. fungi that were discovered in Colorado wheat samples to cause sawfly larvae mortality. Greenhouse assays will be used to expose sawfly-infested wheat to the fungi, with subsequent dissections determining larval survivorship. Project status pending.
We are planning to evaluate the ability of Fusarium spp. fungi that were discovered in Colorado wheat samples to cause sawfly larvae mortality. Greenhouse assays will be used to expose sawfly-infested wheat to the fungi, with subsequent dissections determining larval survivorship. Project status pending.
Fusarium spp. samples on sawfly larvae
Photo by Adam Osterholzer
Photo by Adam Osterholzer
Non-Preference Wheat Cultivars
We are investigating anecdotal reports of herbicide-resistant Clearfield® wheat lines proving less attractive to sawfly adults than other types of winter wheat. Field trials are planned for this upcoming field season, where stem dissections will be used to count sawfly eggs/larvae and compare infestation rates.
We are investigating anecdotal reports of herbicide-resistant Clearfield® wheat lines proving less attractive to sawfly adults than other types of winter wheat. Field trials are planned for this upcoming field season, where stem dissections will be used to count sawfly eggs/larvae and compare infestation rates.
Crop Rotation Impacts Upon Sawfly
We have field experiments planned to evaluate the impacts different crop rotation treatments have upon sawfly infestation and damage in wheat. We will also be collecting various soil attribute and erosion data. This survey will be performed in partnership with the Colorado Wheat Research Foundation ( Colorado Wheat Research Foundation | Colorado Wheat ) .
We have field experiments planned to evaluate the impacts different crop rotation treatments have upon sawfly infestation and damage in wheat. We will also be collecting various soil attribute and erosion data. This survey will be performed in partnership with the Colorado Wheat Research Foundation ( Colorado Wheat Research Foundation | Colorado Wheat ) .
Degree Day Model for Predicting Sawfly Emergence
Our Ph.D student Henrique Vieira will be undertaking this initiative. CoAgMet weather data for New Raymer, Colorado will be used in tandem with historical sawfly infestation to help growers predict future sawfly flights. See more about CoAgMET at Homepage - CoAgMET (colostate.edu) .
Our Ph.D student Henrique Vieira will be undertaking this initiative. CoAgMet weather data for New Raymer, Colorado will be used in tandem with historical sawfly infestation to help growers predict future sawfly flights. See more about CoAgMET at Homepage - CoAgMET (colostate.edu) .
