cscap-usb partnership report 2013

This publication is produced as part of a regional collaborative project supported by the USDA-NIFA, Award No. 2011-68002-30190 “Cropping Systems Coordinated Agricultural Project: Climate Change,

Mitigation, and Adaptation in Corn-based Cropping Systems.” The 11 institutions comprising the project team include: Iowa State University, Lincoln University, Michigan State University, The Ohio

State University, Purdue University, South Dakota State University, University of Illinois, University of Minnesota, University of Missouri, University of Wisconsin, and USDA-ARS Columbus, Ohio.

Publication No. CSCAP-0151-2013

Integrated Pest Management

Research Report to

The United Soybean Board

A Partnership of Climate & Corn-based Cropping Systems CAPand the United Soybean Board

April 2013

Table of Contents

CSCAP & USB Partnership Overview ....................................................................... 2-4

Research Network and IPM Data Overview ....................................................................... 5-6

Research Spotlight: Ed Zaworski, Iowa State University Graduate Student ........................ 7Research Spotlight: Gang Han, Iowa State University Graduate Student ........................ 8Research Spotlight: Rebecca Redline, University of Wisconsin Graduate Student .............. 9Research Spotlight: Mike Dunbar, Iowa State University Graduate Student ...................... 10

Going Forward ........................................................................ 11

Integrated Pest Management Team Members

Name Position University E-Mail

Entomologists

Mike Dunbar*Mary GardinerAaron Gassmann*Andy MichelMatt O’Neal

PhD Graduate StudentAssistant ProfessorAssistant ProfessorAssistant ProfessorAssociate Professor

Iowa State UniversityThe Ohio State UniversityIowa State UniversityThe Ohio State UniversityIowa State University

[email protected]@[email protected]@[email protected]

Plant Pathologists

*Nate Bestor*Marty Chilvers*Darin Eastburn*Paul Esker*Gang Han*Leonor Leandro*Dean MalvickDaren Mueller*Alison Robertson*Greg Tylka*Kiersten Wise*Ed Zaworski

Assistant CoordinatorAssistant ProfessorAssociate ProfessorAffiliateMS Graduate StudentAssociate ProfessorAssociate ProfessorAssistant ProfessorAssociate ProfessorProfessorAssociate ProfessorMS Graduate Student

Iowa State UniversityMichigan State UniversityUniversity of IllinoisUniversidad de Costa RicaIowa State UniversityIowa State UniversityUniversity of MinnesotaIowa State UniversityIowa State UniversityIowa State UniversityPurdue UniversityIowa State University

[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@[email protected]@iastate.edu

Weed Scientists

*Kevin Bradley*Vince Davis*Rebecca Redline

Associate ProfessorAssistant ProfessorMS Graduate Student

University of MissouriUniversity of WisconsinUniversity of Wisconsin

[email protected]@[email protected]

* Funded by the United Soybean Board. Others are funded by Climate and Corn-based Cropping Systems

CAP.

2

Climate scientists widely agree the global climate is changing. This is evidenced by variations in temperature and precipitation, as well as seasonality shifts; these changes are expected to continue. There is a lack of research and subsequent information regarding how these global climate changes will impact local and regional cropping systems. As such, the US agricultural base needs to be strengthened and made more resilient to potential changes. One of the first steps is to identify adaptive and mitigative strategies that have the potential for implementation by farmers and industry and that will be supported through policy.

The team seeks to investigate complex carbon, nitrogen, and water cycles to increase the efficiency and productivity of corn- and soybean-based cropping systems while simultaneously decreasing the environmental footprint under extreme and variable long-term weather conditions. An integrated approach is used across research locations to capture crop and environmental responses under a suite of management practices including: corn-soybean rotation, cover crops within a corn-soybean rotation, extended crop rotations, organic management, drainage water management, nitrogen fertilizer management, tillage management, and landscape position. Within this diverse set of practices, team members measure carbon, nitrogen, greenhouse gas, water quality and flow, pest populations, and agronomic indicators.

A set of local, regional, and national scale models utilize the field research data to examine current and predicted implications of the various practices on carbon, nitrogen, and water under different climate conditions. Additionally, the social and economic behavior of farmers, as related to climate change, is examined. This includes their perceptions of impacts to their production systems. This unique research and analysis drives the team’s education and extension components as information is distributed outward to empower and equip students and citizens with greater knowledge and ways to actively engage.

A changing climate will impact the Midwest environment and is expected to influence pest populations, migration patterns, severity, and farmer recommendations. Climate changes that will impact insects, diseases, and weeds include:

• Longer growing season (shifted frost dates)

• Warmer winters

• Warmer nights

• More frequent severe precipitation events

• Increased humidity within canopy

Integrated Pest Management EffortThe IPM team supported through CSCAP funding includes three faculty and a graduate student. This limited number of personnel could not adequately address the complex challenges facing pest management in corn and soybean systems. Significant funding by the United Soybean Board allowed for the addition of 12 faculty and 3 graduate students. The combined IPM team has developed standardized protocols for use across 8 Midwestern states and are collecting soil-borne pests, foliar disease incidence and severity, insect populations, and weed populations.

CSCAP Vision

3

USB Funding: 2012 & 2013

4

Graduate Student

Salary

$105,946

Undergraduate

Student Salary

$55,978

Staff Salary

$23,942

Materials &

Supplies

$23,310

Travel

$37,173

Other Direct

Costs

$17,251

Total Funding: $263,600

Research Network

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Decagon Soil Moisture Sensors

Measuring Greenhouse Gas Emissions with Photoacoustic Spectroscopy

Measurements and Samples Collected

IPM Measurements Nathan BestorDr. Daren Mueller

Iowa State University

The CSCAP research network is leveraged with pest management data collected from plots that also have a suite of agronomic, soil, and water measurements taken. Pest data were collected from field locations in 7 states in 2012. Pests were assessed visually in corn and soybean fields.

Corn

• Foliar disease was visually assessed as a percentage of total leaf areainfected.Ten to 15 plants per plot were rated by assessing the ear leaf and the second leaf above the ear leaf.• Nine to 15 ears in each plot were rated for ear rots by visually assessing the percentage of the total ear infected.• Stalk rots were assessed on 5 consecutive plants in three rows using the push test (30 degrees). Incidence of lodging and type of stalk rot also were recorded. • Insects populations were assessed using sticky traps, pit fall traps, and sweep netting. Mike Dunbar, graduate student at Iowa State University, is currently identifying insects collected from each location.

Soybean

• Foliar disease was visually assessed as a percentage of total leaf area infected. Twenty to 25 leaves in the upper and lower canopy were rated in each plot.• Stem diseases such as white mold and sudden death syndrome were assessed at the plot level when present.• Insects populations were assessed using sticky traps, pitfall traps, and sweep netting. Mike Dunbar is currently identifying insects collected from each location.

Observations from 2012 Data

• Disease levels were extremely low (<5% severity) throughout the region for both soybean and corn. • Diseases expected to be seen in drought conditions such as Aspergillus ear rot and charcoal rot did occur, but were not as problematic as expected in a drought year.• Insects collected from traps are still being identified by Mike Dunbar (see

page 10).

Looking Forward

The value of collecting pest data to complement the larger project is two-fold. First, if any damaging pests are present at a particular location, the subsequent impacts on yield may be taken into account in crop models. Second, if any pest trends do occur in the multistate scouting, these may trigger specific modeling efforts. However, because the plots are set up to address non-pest related research, the pest data collected by the IPM team will most likely be used for identifying possible pest outbreaks at each location.

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Research Spotlight Ed ZaworskiDr. Greg Tylka and Dr. Daren Mueller


Research Description

Discoveries To-Date


Soybean cyst nematode (SCN) is a major concern for soybean farmers. It is likely that with imminent global climate change, the frequency of extreme weather patterns such as drought could increase. Thus, it becomes important to understand how the lifecycle of major diseases such as SCN might be affected during these extreme weather conditions. In order to examine lifecycle changes, I am altering the amount of water a soybean receives under greenhouse settings. I am also looking at a new seed treatment and how it will affect SCN and sudden death syndrome (SDS). Data from the seed treatment study are not presented here.

The first of two experiments conducted examines the difference in SCN reproduction between plants watered daily with two different amounts of water (10 and 20 ml). The second experiment explores SCN reproduction between plants watered daily and plants watered only when they begin to wilt. To measure soybean cyst nematode reproduction, females are collected from soil or roots. Eggs of SCN are also counted by releasing the eggs from cysts.

In the first experiment, 20 ml of water was applied per day to half of the plants and 10 ml was applied to the other half. There was no significant difference in SCN eggs among these two watering regimes. However, a trend existed in which the number of SCN eggs was higher for plants receiving the 20 ml treatment. This was opposite of what we expected to see. Thus, for the second experiment, the protocol was changed to increase water stress on plants, rather than only reducing water amount. This was accomplished by applying 10 ml water per day to half of the plants, watering the others only when they began to wilt. In this experiment, SCN eggs were significantly higher for plants allowed to reach wilting than for those with water applied daily. These results may indicate that soil moisture is a less important factor in SCN reproduction than is plant stress. Re-testing for confirmation of results will occur; however, it appears water stress to a soybean plant can influence SCN reproduction.

Looking Forward

As my research progresses, I will begin to examine the combined effect of SCN and SDS infection on soybean grown in various moisture regimes under greenhouse settings. This will be challenging, as both pathogens require slightly different optimal environmental conditions for development, making it difficult to get both to infect a plant substantially. Another graduate student will be continuing the above mentioned SCN water regime research as I focus on the combined SCN/SDS experiment.

Main Effect Watering RegimeEggs (per gram wet root); Run #2

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Research Spotlight Gang HanDr. Daren Mueller and Dr. Leonor Leandro



Discoveries To-Date


Soybean root rot and seedling diseases can lead to significant stand loss and yield reduction. Several soil microorganisms are able to infect soybean plants early in the season, especially in soils with excessive soil moisture. My research, which started in May 2012, mainly focuses on how drainage systems and cover crops affect soil microorganisms over time, specifically focusing on soybean soilborne pathogens such as Fusarium spp., Alternaria spp., and Aspergillus spp. My hypothesis is that drainage systems and cover crops do not have long-term effects on soil microbial activity.

Four drainage regimes (conventional, controlled, shallow, and no drainage) and four cover crop regimes (tillage-cover crop [T-C], tillage-no cover crop [T-NC], no tillage-cover crop [NT-C], and no tillage-no cover crop [NT-NC]) were examined in this study. Root rot severity of V2 stage soybean seedlings was visually evaluated and root pieces were plated to determine frequency of root pathogens. Diseased and healthy root pieces were plated onto water agar, V8 agar, and corn meal agar. Root pieces on water agar were incubated under continuous light, and V8 and corn meal agar were incubated under dark. Fungi were identified to genus based.

Root rot severity was not significantly different amongdrainage regimes. Frequency of pathogen isolation differed among drainage regimes, but repetitiveness was poor. The severe drought in Iowa in 2012 may explain the lack ofdrainage effects in this trial. Among cover crop regimes, the most severe root infection occurred in the NT-NC treatment based on root ratings. T-C and T-NC treatments had the least severe symptoms, while the T-NC treatment had the largest disease rating variance among four replications. The mostfrequently isolated fungi in both experiments were Fusarium spp.

As 2013 approaches, I am very interested in examining these drainage and cover crop regimes under non-drought conditions, as well as to determine treatment consistency from year to year. In addition, greenhouse work is ongoing to investigate how soils from different drainage regimes affect root rots at three moisture gradients.

Looking Forward

Photographs L to R: Plants showing root rot; fungi growing on media; fungal growth used for identification

Severity Rating on Roots

Germination Rate on V8 Plates

Fusarium spp. Ratio

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I am in the preliminary stages of the experiment and have not begun data analysis, but I can share the hypothesis being testing and what I expect to find. Research on N2O emissions from weeds is extremely limited. However, there are similarities between the utilization of N and water between cover crops and weed management in POST herbicide control systems. Cover crops reduce N2O emissions because they uptake excess soil N and reduce soil moisture. When cover crops are terminated, their residues break down and release N, and their presence on the surface generally increases soil moisture. This favors denitrification and the release of N2O. Using what is known about cover crops as a framework, my hypothesis is that treatments with growing weeds will have reduced N2O emissions compared to treatments without weeds. However, once the weeds are killed they will create surface residues before they start to break down and therefore generate higher N2O emissions as weed densities increase. Overall, I expect that total N2O emissions will be comparable for plots with the same N treatment (independent of weed density), but the magnitude and timing of N2O fluxes will differ.

I’m excited to analyze the data from this greenhouse study and compare the results to a similar non-crop field study I’ll be conducting this summer. Additionally, I’ll have a field study investigating how N2O emissions are affected by weed competition for N and soil moisture with corn, and another study measuring N2O emissions in soybean plots with different row spacings and levels of weed management.

Research Spotlight Rebecca RedlineDr. Vince Davis

University of Wisconsin-Madison


Looking Forward

Discoveries To-Date


My research will determine how nitrogen (N) use and early-season weed management influence nitrous oxide (N2O) emissions in Midwest corn and soybean production. Weeds compete with these crops for water and soil available nitrogen, and soil moisture and N fertility are major contributors to N2O emissions in crops. Moreover, plant residues on the soil surface encourage N cycling and emissions. My research seeks to answer to following questions: What effect does early-season weed competition have on N2O emissions? Do dead weed residues in crops increase N2O emissions? Are cumulative emissions (before and after postemergence weed control) the same for a given rate of N independent of weed density?

A non-crop greenhouse study is underway that compares the effects of N rate and weed density on N2O emissions. Nitrogen is applied when the weeds are seeded, and when weeds are 10-15 cm tall they are killed with glyphosate and residue is left on the soil surface. Gas samples and soil moisture data are collected starting at the time of weed seeding until four weeks after the glyphosate application. Static gas chambers are used in each treatment and four gas samples are removed from each chamber over the course of one hour twice each week. Samples are analyzed with gas chromatography to determine the concentration of N2O and gas fluxes for each treatment are determined by regression analysis over the four sample timings.

Figure. Anticipated results of N2O fluxes over time for various N rates and weed densities based on our stated hypothesis. This graph does not represent actual date, just our hypothetical expectation.

Powell amaranth in our static gas sampling chambers, just prior to glyphosate application, at equivalent field density of 100 plants m-2. At the glyphosate application timing, weeds are harvested in one chamber to determine biomass accumulation and gas samples are continually collected over the dead weed residue in the second chamber following the application.

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Research Spotlight Mike DunbarDr. Aaron Gassmann and Dr. Matthew O’Neal



Discoveries To-Date


I investigate how different farm management practices, including the use of cover crops and extended rotations, will impact arthropod communities. Arthropods are sampled multiple times throughout the growing season and are also sampled at different locations within the crops (i.e., at ground and canopy level). Captured arthropods are identified and then classified into categories such as beneficial or pest taxa. I expect that increasing levels of polyculture will foster increasing abundance and/or diversity of beneficial arthropod taxa while decreasing pest taxa abundance.

Arthropod communities are measured monthly throughout the growing season. To capture arthropods at the ground level, pitfall traps are placed within fields. Arthropods that move throughout or above the crop canopy are captured with sticky traps and sweep nets. Once captured, arthropods are identified to their taxonomic family (though in some cases individuals may be identified to species) and categorized as being beneficial, harmful (pests), or neutral to the cropping system. Once all the arthropods are identified, different ecological indices can be calculated which measure the characteristics of the arthropod communities of interest.

I’ve focused on better understanding the influence of farm management practices including cover crops over the last two years. Differences between abundance of beneficial and pest arthropod communities have rarely been observed between fields planted with cover crops and fields where cover crops are absent. However, abundance data only tells one part of the story; how many individuals were classified as beneficial, pest or neutral taxa is also important. Understanding what taxa make up communities of arthropods found in soybean fields grown with cover crops compared to soybean fields grown in the absence of cover crops will hopefully yield more interesting results. It could be that arthropod communities in more diverse planting schemes are themselves more diverse in arthropod taxa than more conventional monoculture. I plan to answer some part of that question as I move forward with my research.

Mean species richness (or more accurately, family richness) of research plots grown at the Iowa State University Ag Research Site, Ames, IA 2012. These data are taken from pitfall traps, and only include taxa that are considered beneficial. Throughout the season it appears that species richness is similar between plots where cover crops were planted and where they were not.

Looking Forward

I hope to see similar trends from our ecological indices over all three years of sampling (2011-2013). Hopefully, regardless of an extreme drought year, increasing levels of polyculture will correspond to increasing levels of beneficial arthropod diversity.

Overall June July Aug Sept

Spec

ies R

ichne

ss (±

SEM)

0

2

4

6

8

10

SB SB(Rye) Corn Corn(Rye)

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Going ForwardThe highlights of the first two years of funding are the three graduate student projects funded entirely by USB. The students have been incorporated into the larger CSCAP project, gaining an important awareness of transdisciplinary research. The IPM team also is collecting data to supplement Mike Dunbar’s graduate research and pest-related data to complement the larger CSCAP project.

With three more years of funding from CSCAP, we will continue to leverage USB’s funding with the $20 million from USDA-NIFA.

The vision moving forward is to build on the activities that currently exist – complementing the CSCAP project with pest data and adding graduate students to answer peripheral questions related to the larger project and IPM. With the next three years of funding, the existing three graduate students will finish and we plan to add several more graduate students. As more faculty see the value in being part of the larger CSCAP project, several graduate student projects have been discussed. These include:

• Understanding how changing climate may play a role in the distribution of charcoal rot on soybean• Studying the effect of extreme weather events on green stem syndrome • Studying how strobilurin fungicides will affect root growth, thus affecting how crops can survive

drier-than-normal growing conditions• Study the impact of water management on weeds• Continue to look at the effect of soil moisture on soybean cyst nematode• Continue to investigate the effect of weeds on greenhouse gas emissions• Effect of soybean on carbon and nitrogen footprint [Note: not IPM related, but can be incorporated

in the next three years.]

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Please contact us with your questions or areas of interest:

Dr. Daren MuellerAssistant Professor, Iowa State [email protected] | 515.460.8000

Lori AbendrothProject Manager, CSCAP

[email protected] | 515.294.5692

Dr. Lois Wright MortonProject Director, CSCAP

Professor, Iowa State [email protected] | 515.294.2843

Climate and Corn-based Cropping Systems Coordinated Agricultural Projectwww.sustainablecorn.org

Design Assistance from Gabrielle GlenisterCSCAP Project Management Undergraduate Assistant

cscap-usb partnership report 2013

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