Module 8: Pests and Integrated Pest Management

Goals

• The goals of the first part of this module are for students to learn the types of major agricultural insect pests, the benefits of insects, challenges associated with pest control, how trophic interactions can contribute to pest control, and the scientific basis for IPM to control agricultural pests over the long term.
• The goals of the second part of this module are for students to understand weed and pathogen pests; how integrated pest and weed management can contribute to long-term successful weed and pest management, and some transgenic pest management technologies and their impact.

Learning Objectives

After completing this module, students will be able to:

• Describe characteristics of insect pests and factors that make them successful pests, as well as beneficial characteristics of insects
• Explain some history of agricultural pesticides
• Describe factors that contribute to pests evolving resistance to pest control strategies
• Discuss what IPM is and why it is effective and enhances agricultural resilience
• Interpret how to apply pest scouting data and distinguish if pests have reached an economic threshold
• Analyze IPM management scenarios and interpret the agroecosystem benefits of IPM
• Describe and compare the characteristics of natural ecosystems and agroecosystems, and explain how trophic level interactions and biodiversity may contribute to pest control
• Describe characteristics of weed pests and factors that make them successful pests, as well as beneficial characteristics of weeds
• Describe categories of weed management tactics with example weed control practices
• Explain what organisms and factors contribute to crop diseases
• Explain some recent transgenic pest management technologies
• Analyze and interpret scientific data about transgenic technologies
• Differentiate pest control approaches that are likely to be effective in the long term based on IPM principles, and generate or formulate IPM approaches to enhance pest control

This "pests and IPM "module is designed to introduce undergraduate students to insect, weeds and disease pests, integrated pest management, and the dominant transgenic crop pest management technologies. This module was designed to follow modules of this course that introduce crops and cropping system concepts. It can however be used in other courses, provided that students have been introduced to some concepts of crop management.

This two-part module is designed for one week of classroom sessions, or blended online course or an online class; it could also be taught over two weeks because of the amount of information presented includes multiple characteristics of insects and weeds, integrated pest management and some transgenic crop pest management technologies. We piloted the module in blended course in which students read the material and completed the activities and a formative assessment of the first part of the module online. Students then read the second part of the module online, took a quiz online and then met with the instructors for one classroom session. In the classroom, we discussed the students' completed formative assessments, quiz questions they had difficulty with, and briefly reviewed important course themes with. Then students worked on the summative assessment in the classroom with a classmate, and instructors offered assistance and answered questions.

This module introduces the major crop pests (insects, weeds and pathogen) and integrated pest management. The first part of the module introduces broad differences between natural ecosystem and agroecosystems, insects, the challenges of pest management, integrated pest management. In the second part of the module, weeds, weed survival characteristics, weed control practices, herbicide resistance, transgenic crops, insect resistant Bt crops, and herbicide resistant crops are discussed. The module is designed for a one week module, but could be covered over two weeks due to the extent of the material presented. Students engage with the module concepts through:

• Reading the course pages online and watching the online embedded videos
• Completing the embedded activities for students to check their understanding
• Some outside reading on websites that are linked into the course pages
• A formative assessment activity in which students to watch a video about grain IPM in Australia and learn how to interpret an economic threshold table and make decisions to manage the alfalfa pest: the potato leafhopper.
• A summative assessment that asks students to analyze and critique herbicide resistant crop technologies introduced to manage herbicide resistance weeds.

Students can complete this module in the classroom, online, or in a blended format. If used for a class that meets two or three times a week, students can initiate the formative and summative assessment towards the end of class with or without a classmate, and completed assessments can be the basis for discussion and clarification in a following classroom meeting.

• Student Materials - Module 8: Agroecology: Pests and IPM

What works best for the module

Consistent coursework expectations and due dates for the online quiz and assessments can help students get into a routine and complete the readings and assignments to get the most out of classroom meeting time or online discussions. If the module is used in a classroom, the formative and summative assessments can provide activities with real world data to engage students in higher order active learning with classmates and with assistance from the instructor. In the piloted blended course format, the online quiz and formative assessments were due prior to attending the class that met once a week. In class, we discussed and clarified topics that students found confusing from the online quiz and formative assessment. Because this module covers multiple pest topics, we briefly reviewed integrated pest management and discussed the differences between the two case-study transgenic pest management crop traits (Bt and glyphosate-tolerance). Discussing some of the issues raised in the summative assessment as a class before the students begin working in groups is recommended to ensure that all students have a clear understanding of the multiple issues associated with transgenic crop technologies. Then students can work in pairs or groups of three on the summative assessment in class to share ideas and questions; and the instructor can offer factors for students to consider.

What students found difficult

• Interpreting the economic threshold table in the formative assessment can be challenging to some students. If students complete this activity in class, the instructor can highlight that the table values represent the threshold, and that once pest populations are above the threshold it is profitable to take action. It can also be helpful to ask students to explain to each other how to read the economic threshold table.
• Although many students understand that organisms can develop resistance (such as pathogens to antibiotics), planting a refuge area of the crop without the pest-resistance trait is often a new and foreign idea to most students whom aren't familiar with this topic. Explaining how the refuge is designed to maintain susceptible individuals in the population to breed with individuals with resistance traits is highly recommended. Instructors who aren't familiar with the regulatory refuge requirements additional reading about Bt resistance management and refuge requirements in corn from the University of Wisconsin that is embedded in the insect resistance page is recommended. See: http://corn.agronomy.wisc.edu/Management/pdfs/A3857.pdf

Reflection

This module introduces a wide range of crop pest topics; for those whom aren't familiar with these concepts, it can be daunting. Instructors may want to increase opportunities to discuss and interact with students about the information presented in the module; it could also be taught over the course of more than one week. This module is an opportunity to highlight that integrated pest management integrates multiple pest control factors, including beneficial species and other processes that can provide additional soil quality and crop production benefits in the agroecosystem; an opportunity to encourage systems thinking.

• Formative Assessment: Australian grain crop Integrated Pest Management video and Determining the Economic Threshold of Potato Leafhoppers in Alfalfa Pests and IPM Formative Assessment
• Formative Assessment Grading Key (for instructors only:
  Pests and IPM Formative Assessment Grading Key -- private instructor-only file
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• Summative Assessment: Herbicide Resistant Weed Interpretation and Management of Multiple Pest Types
  Pests and IPM Summative Assessment
• Summative Assessment Grading Key (for instructors only:
  Pests and IPM Summative Assessment Grading Key -- private instructor-only file
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Readings that students are directed to read in the course pages through embedded links.

• Pesticide Development: A Brief Look at the History. 
Taylor, R. L., A. G. Holley and M. Kirk. March 2007. Southern Regional Extension Forestry. A Regional Peer Reviewed Publication SREF-FM-010 (Also published as Texas A & M Publication 805-124)
• "Use and Impact of Bt Maize 
" by: Richard L. Hellmich (USDA–ARS, Corn Insects and Crop Genetics Research Unit, and Dept of Entomology, Iowa State Univ, IA) & Kristina Allyse Hellmich (Dept. of Biology, Grinnell College, IA). 2012 Nature Education
• The Integrated Pest Management (IPM) Concept. D. G. Alston. July 2011. IPM 014-11. Utah State University Extension and Utah Plant Pest Diagnostic Laboratory
• IPM Pest Management Decision-Making: The Economic-Injury Level Concept. (link is external)
D. G. Alston. July 2011. IPM 016-11. Utah State University Extension and Utah Plant Pest Diagnostic Laboratory: Plant Pathogens NCAT ATTRA Sustainable Agriculture

References

Benbrook. C. 2014. Impacts of genetically engineered crops on pesticide use in the U.S. -- the first sixteen years. Environmental Sciences Europe 2012, 24:24 doi:10.1186/2190-4715-24-24

Duke. O. S. and S. B. Powles. 2009. Glyphosate-Resistant Crops and Weeds: Now and in the Future AgBioForum, 12(3&4): 346-357

Georghiou. G. P. 1986. The Magnitude of the Resistance Problem. Chapt 1. 14-44. In Pesticide Resistance: Strategies for the Management. Eds. Committee on of Pest Populations; Board of Agriculture, National Research Council.

Gunsolus, L. J. Weed Science, Department of Agronomy and Plant Genetics. Herbicide resistant weeds. http://www.extension.umn.edu/agriculture/crops/weed-management/herbicide...

International Survey of Herbicide Resistant Weeds. http://weedscience.org

Liebman, M. and E. R. Gallandt. 1997. Many little hammers: ecological management of crop-weed interactions. Pages 291–343 in L. E. Jackson, ed. Ecology in Agriculture. San Diego, CA: Academic.

Odum, E. P. 1997. Ecology: A Bridge Between Science and Society. Snauer Associates: Sunderland, MA.

Stern, V. M., Smith, R F, van den Bosch, K. & Ragen, K. S. 1959. The integration of chemical and biological control of the spotted alfalfa aphid: the integrated control concept. Hilgardia 29:81-101.

Tabashnik B., Brevault, T., Carriere, Y. 2013. Insect resistance to Bt crops: lessons from the first billion acres. Nature Biotechnology 31: 510-521.

Additional Reading:

1. FAO UN More About IPM: http://www.fao.org/agriculture/crops/thematic-sitemap/theme/pests/ipm/en/
2. Cornell University's; Pesticide Safety Education Program (PSEP) Part of the Pesticide Management Education: https://psep.cce.cornell.edu/
3. Cullen, E., and R. Proost, D. Volenberg. 2008. Insect Resistance Managment and Refuge Requirements for Bt Corn University of Wisconsin Extension. Pest and Nutrient Management Program. http://corn.agronomy.wisc.edu/Management/pdfs/A3857.pdf