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Integrated Pest Management (IPM) is the practice of integrating methods (chemical, cultural, biological, genetic, etc.) and disciplines (entomology, plant pathology, weed science, etc.) into a systematic approach to pest management decision making. IPM targets optimization of net return in crop production while minimizing environmental impact. As a management practice, IPM decision making is based on information collected from the field in a systematic manner. As a result, IPM depends on field monitoring of pest populations and crop development which is often referred to as field scouting.
Application of IPM procedures to soybean production may be executed by (1) growers scouting fields themselves, (2) contracting the services of a field scout or consultant, or (3) commercial ag service personnel including field scouting as part of their service to clients. IPM decision making may be done by anyone if procedures are clearly understood and field information is collected and recorded in an accurate and timely manner.
An IPM program applied to soybeans may include one or more of the following features:
Depending on the pests targeted in an IPM program, field scouting may include observations from planting time to harvest. The average time span of soybean crop development in Ohio is illustrated in Figure 1. Soybean planting peaks in mid May and early June. The early planted soybeans require close monitoring for overwintering pests such as the bean leaf beetle (BLB). Based on the planting dates illustrated, weed scouting for determination of post-emergence weed control may range from mid May to early July. Prior to pod set, late June and early July are critical periods for monitoring defoliating pests, potential pod damaging pests, and completing weed surveys. In general, the early summer period of late June and July is the most important time to scout soybeans, since key decisions can be made regarding prediction of pest impact and determining weed management strategies for the forthcoming year. Once pods begin to set in late July, attention should focus on detection of pod injury by BLB. The yellowing stage of soybean development that occurs from late August through September is a critical period for detection of pod injury, since at this point the pods tend to be more succulent than the foliage and serious pod injury may occur if BLB populations are abundant at this point in the crop's development. By mid September and October, the crop is maturing and field scouting may focus on a final assessment of yield and quality if time permits.
Figure 1. Ohio soybean development and peak activity of key pests.
Field scouting for weeds in an IPM program is a routine practice during the early stages of corn development, especially when such observations may influence the application of post-emergence herbicides. A comprehensive survey and assessment of weeds in a field is generally conducted prior to closure of the soybean canopy to identify the weed complex in a field and assess its relative abundance. Such a weed survey provides the basis for determining the forthcoming herbicide program, which represents a primary pesticide expenditure in soybean production.
Accurate recording of field observations is fundamental to providing information on which pest management decisions are based. The Ohio IPM Program has developed a series of field data forms, which have been used by many field scouts and modified over time to enable practical recording of field observations. The soybean survey form displayed in Figure 2 can be used throughout the growing season. The form is printed in a pressure sensitive 3-copy format allowing 1 copy for the grower, 1 copy for the field scout, and 1 copy for a third party that may be providing advise on pest management decisions. A multi-field version of this survey form is also available. Computer software has also been developed to enable organization and analysis of date collected from multiple sites and numerous farms.
Figure 2. Ohio IPM Program Soybean Survey Single Field Record.
Effective field scouting in an IPM program requires skills in pest identification (insects, diseases & weeds), familiarity with life cycles, recognition of plant injury per pest, understanding the development of the crop, and knowledge of methods used to measure various types of pest activity. The party making the management decisions must understand the criteria and logic included in decision makings applicable to different pests. In addition, the decision making party must be familiar with alternative control measures available and procedures for selecting appropriate pesticides.
Pest management is not a simple job and years of experience are often required to develop a full comprehension of the process and the variables that influence a pest management decision. As a result, the IPM field scout and decision making party must invest time and effort studying materials available plus achieve a significant amount of field experience to be effective.
Study materials on soybean pest management recommended by the Ohio IPM Program include the following sources of information:
Copyright 1993, The Ohio State University
OPMS Circular # FC-21 SOYBEAN IPM
Prepared by: Harold R. Willson, Dept. of Entomology
May 1990
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
TDD No. 800-589-8292 (Ohio only) or 614-292-1868