The Interregional Research Project No. 4 (IR-4) and IPM

Keith W. Dorschner, Editor
Entomology Coordinator
IR-4 Project
Rutgers University
New Brunswick, NJ 08903-0231

e-mail Keith Dorschner

Project Overview

Robert Holm, Ph.D.
IR-4 Executive Director
Rutgers University

Established in 1963, the Interregional Research Project Number 4 (IR-4 Project) is funded by the United States Department of Agriculture (Cooperative States Research Education and Extension Service and Agricultural Research Service Departments) to ensure that American farmers have an adequate supply of pest control products registered for minor crops and for minor uses on major crops. IR-4 facilitates the registration of traditional crop protection chemicals, reduced risk products, and biopesticides. Biopesticides include microbials (fungi, bacteria, and viruses), low toxicity biochemicals, pheromones, insect and plant growth regulators, and genetically transformed microbes and plants.

Minor crops are usually small acreage, specialty crops of high monetary value. They are the foods we eat every day such as fruits, vegetables, and nuts. They are also the commercially grown ornamental and floral plants, and the trees and turfgrasses enriching us with their beauty. Minor crops in aggregate comprise over 40% of the value of all crops grown in the United States. In 27 states, the value of minor crops exceeds 50% of the value of all agricultural production. On many levels, minor crops play major roles in our lives and environment. Minor uses on major crops usually involve pests that occur sporadically or pests of limited regional significance.

IR-4 assistance is indicated when the potential market of a chemical for use on a low-acreage crop is insufficient to justify the private investment necessary to obtain a federal registration. This "minor use problem" is not new. Minor crops have historically suffered from a lack of effective crop protection solutions including those which have a natural fit in thoughtful IPM programs. But as the costs associated with crop protection chemical reregistrations and reregistrations have escalated, so have the problems associated with minor crop pest control. IR-4 is the only public or private group that addresses the chemical clearance needs of minor crop farmers. As such, the project prides itself on the high levels of grass-roots support it has earned.

IR-4 receives pesticide clearance requests from the people most knowledgeable of minor crop pest control problems. This includes growers, grower organizations, nurserymen, agricultural scientists, and extension personnel. Essentially, IR-4 will consider a request from any interested party except the crop protection chemical registrant. After receiving a clearance request for a products use on a specific minor crop or group of crops, the request is reviewed and prioritized by external reviewers including growers, researchers, and extension personnel. In setting priorities, the importance of the pest problem, the availability of alternatives, the existence of data gaps (such as chemistry, toxicology, and environmental fate data), and the value to IPM and resistance management programs are all carefully considered. Each request is also reviewed by the U.S. Environmental Protection Agency (USEPA) and the potential registrant prior to final selection.

If a project is selected for research, cooperating scientists carry out field trials to develop crop safety data and collect residue samples. The number, placement, and design of these field trials are carefully considered so that they meet the requirements of the USEPA. The residue samples are analyzed in IR-4 regional or satellite laboratories located at state agricultural experiment stations and ARS analytical laboratories. All work performed by IR-4 is fully compliant with the mandated Good Laboratory Practice (GLP) procedures of the USEPA. These procedures are essential in assuring that the data generated by IR-4 meets the stringent requirements of federal review agencies.

Once all the data have been gathered, IR-4 prepares a data package (petition) which is submitted to the USEPA for approval. The petition must include data to show the amount of residue that will be present from the proposed use as well as toxicology data to demonstrate the safety of that amount of residue. IR-4 petitions almost always contains residue data but generally rely on referenced manufactures’ toxicology data to fulfill the safety requirements.

When the petition is finally approved by the USEPA, a Notice followed by a Final Rule is published in the Federal Register which establishes a tolerance for the particular product on the minor crop. The registrant then labels the product for its intended use by growers once the tolerance has been established by the Final Rule.

The passage of the Food Quality Protection Act (FQPA) in 1996 has dramatically changed the focus of IR-4 programs the past few years. Prior to FQPA, IR-4 devoted a large portion of its resources in reregistering older products. However, it became clear in 1995 that there were many newer, safer (i.e. Reduced Risk) products being developed by the crop protection industry for the major row crops but little effort was being expended to bring these chemistries to minor crop farmers. IR-4 redefined its Strategic Plan and dedicated its efforts to partnering with the registrants at an early stage on the development of the new products so that minor crop uses would be considered along with the major crop markets.

This program has led to over 50% of IR-4's project resources being dedicated to the safer, Reduced Risk chemistries since 1998. These newer products are now becoming available for minor crop growers and serve several critical needs. One of them is to provide replacements for the organophosphate and carbamate insecticides as well as the B2 carcinogen products likely to be restricted in their use on minor crops as the result of FQPA tolerance reviews. Of equal importance is the utilization of these new chemistries in IPM programs. To receive a Reduced Risk classification, these products must be safe to fish, wildlife, avian species as well as little or no impact on surface or groundwater. In addition, the new insecticides have little or no advise effects on beneficial insects allowing them to be fully utilized in IPM programs. Our biopesticide program sponsored 14 projects in 1998 and has resulted in the registering of numerous products over the past few years which fit well into IPM programs.

This is an exciting time in agriculture with many changes being driven by regulatory and technology forces. IR-4 has positioned itself to be a partner with the crop protection industry, commodity groups, the land grant university system, the USDA and the growers to bring IPM-compatible crop protection solutions to minor crop growers.

The Role of IR-4 in Implementation of IPM for Arthropod Pests

Keith Dorschner, Ph.D.
IR-4 Entomology Coordinator
Rutgers University

Ken Samoil
IR-4 Associate Entomology Coordinator
Rutgers University

Integrated Pest Management (IPM) is a system of pest management which utilizes all suitable control techniques to reduce or maintain pest populations at acceptable levels. It is vitally important that all techniques be integrated into a single coordinated pattern. IPM should not be "chemically dependent" (Frisbie & Smith 1989) but neither should it overlook the judicious use of chemical pesticides for suppression of damaging pest populations. A pesticide's toxicological profile, mode of action, spectrum of activity, and environmental fate should be carefully evaluated for use in IPM. Although certainly not a liability, it is a mistake to assume that a product will always fit into an IPM program just because the active ingredient may be a naturally occurring compound. For example, botanical pesticides such as neem have been promoted as alternatives to synthetic pesticides, but these pesticides can be harmful to beneficial insects and aquatic organisms (see Bottrell 1996 for a summary of the negative effects of neem on non-target organisms). To be acceptable to growers, an IPM program must be effective in maintaining pest populations below levels which cause economic damage to the crop and must have provisions for remedial action should pest populations surge. The thoughtful use of appropriately chosen pesticides is a component of every successful IPM program.

The compatibility of a proposed use for IPM is an important consideration when the IR-4 project receives a pesticide clearance request to initiate research. The effectiveness in controlling the target pest, the toxicity of the product to non-target pests and beneficials, and the effect of the product on the stability of the agroecosystem are all important factors in the decision process. By spreading the exposure of the pest to multiple control tactics, IPM seeks to minimize the pest's exposure to individual control tactics (Smith & van den Bosch 1967) thereby reducing the pest's ability to adapt. Therefore, even if adequate chemical pesticides are available to control a pest, other products with different modes of action or spectrums of activity may be useful for IPM and insecticide resistance management programs. These uses may receive a high priority ranking at IR-4 based solely upon their "fit" into IPM systems. The IR-4 Project serves a vital role in the development of IPM systems for minor crops by securing tolerances for IPM-compatible pesticides.

Examples from the IR-4 Entomology Program

Spinosad is the active ingredient in SuccessR and SpinTorR insecticides from Dow AgroSciences. It is a fermentation product of a soil bacterium and has wide margins of safety to man and the environment. Spinosad is also a highly effective insecticide active against Lepidoptera larvae, thrips, leafminers, and certain other pest species including the Colorado potato beetle. Although very effective against important pests, spinosad applications leave most beneficial species unharmed. Spinosad will become an important chemical component of future IPM programs.

The United States Environmental Protection Agency (EPA) has thoroughly reviewed the toxicological and environmental fate data associated with spinosad and has determined that it is a reduced risk insecticide. Very few pesticides can pass the rigorous screening for reduced risk status. In addition, EPA considers spinosad to be a potential alternative to organophosphates, a class of insecticides currently being scrutinized by the Agency. Extremely low toxicity, low use rates, and a short half-life in sunlight leading to low residues on crops were just a few of the factors EPA used to classify spinosad as reduced risk.

IR-4 has received requests to register this product on almost every crop group and on many miscellaneous crops. Recognizing both the need for spinosad on minor crops and the EPA's level of comfort with the chemistry, IR-4 developed a plan to move spinosad into minor crop agriculture as soon as possible. The plan involved reducing the numbers of crops and field trials compared to what would normally be required for a more toxic chemical pesticide. We then presented our proposal to EPA for consideration.

EPA was very receptive to the plan and saw it as a means to lessen food safety concerns while providing growers an effective control strategy for pest infestations. IR-4 will perform the research required to register spinosad on every minor crop with an identified need during 1999. Between the registrant and IR-4, spinosad will end up being registered for a total of 275 crops by 2001 perhaps ten years ahead of schedule.

In the future, IR-4 will use similar logic to expand the registrations of reduced risk pesticides for minor crops. To do so addresses food safety issues and provides new IPM tools to growers.

Another situation occurred not long ago in which IR-4 interceded on behalf of range grass growers and livestock ranchers to save the registration of permethrin for the control of range caterpillars. The original petition for this use was obtained by IR-4 in 1983 and permethrin was registered for this use in 1984. The range caterpillar not only destroys forage grasses but leaves behind exuviae that contain toxic spines. The toxin causes swelling in the mouths of livestock and they will refuse to graze in the infested area.

Dosages as low as 0.05 grams per acre of permethrin are highly efficacious compared to the 113 grams of trichlorfon which was previously used. Under IPM, the treatment of incipient populations (usually about 80,000 acres) is effective in preventing the extremely large outbreaks of the past (over 1,000,000 acres treated in New Mexico during 1978) (Huddleston, personal communication).

In 1994, the registrants of permethrin announced that they planned to discontinue the registration of the insecticide on range grasses. IR-4 ascertained that this minor use was still needed for range grass IPM, then contacted the product registrant and requested that they reconsider their cancellation decision. The registrant agreed to retain the use of permethrin on range grasses after considering IR-4's arguments.

References

  • Bottrell, D.G. 1996. The Research Challenge for Integrated Pest Management in Developing Countries: A Perspective for Rice in Southeast Asia. J. Agric. Entomol. 13(3): 185- 193.
  • Frisbie, R.E. & J.W.J. Smith. 1989. Biologically intensive integrated pest management: The future. In: J.J. Mennard & A.L. Steinhauer [Eds.], pp. 151164.
  • Huddleston, E.W. 1995. Personal communication . New Mexico State University, Department of Entomology, Plant Pathology, and Weed Science.
  • Entomological Society of America Centennial National Symposium. Progress and Perspectives for the 21stCentury. Washington, D.C.
  • Smith, R.F. & R. Van den Bosch. 1967. Integrated control, pp. 295-340. In: W.W. Kilgore & R.L. Doutt [Eds.], Pest control-biological, physical, and selected chemical methods. Academic Press, New York.

Regulatory Crop Groupings and IPM: Expediting Registration of IPM Pest Control Agents

G.M. Markle
IR-4 Associate Director
Rutgers University

B.A. Schneider, Ph.D.
Health Effects Division
U.S. EPA

Regulatory crop groupings (including crop definitions) are one of the best avenues to provide a broad base IPM research program which can be rapidly moved into general use. The multiplier concept or improved return-on-investment on research is needed in this age of limited budgets and restricted time periods to advance an IPM program. Especially under the present day FQPA reassessment of all tolerances and exemptions, new pest control tools need to be developed as rapidly as possible for IPM programs.

The growers, extension and research personnel need to address safer (reduced risk, biopesticides, etc.) pest control agents and at the same time reduce or eliminate the use of problem pesticides. The agricultural community cannot be in a position, perceived or not, of not taking advantage of safer materials while still producing safe and copious food supplies for the world. The U.S. agricultural community provides the leadership for a safe food supply. The input of the agrichemical industry, growers, and the federal and state agricultural/environmental community, especially IR-4, provides the necessary partnership of both regulatory affairs and research for registration and food safety purposes. The combining of these aspects under IR-4 continues to provide food safety data and registrations for minor crops and IPM programs.

IR-4 with its broad Good Laboratory Practice (GLP) research knowledge and commodity and pesticide expertise understands the requirements of a safe food supply. In so doing, IR-4 has partnered with the growers, university extension and research personnel, agrichemical industry, and the federal agricultural and regulatory agencies. This partnership helps to address the need for safe pest control materials to facilitate needed IPM programs in an expeditious manner.

For example, IR-4 provided the needed expertise to clear Bacillus thuringiensis (Bt) on all food commodities back in 1976. Since that time, Bt has been used in IPM programs, as well as, biotech crops to help reduce the load of conventional pesticides in our environment.

Prior to 1983, regulatory food crop research was planned on an individual crop basis with little hope from the agrichemical industry of expanding to minor crops because of the time and effort required to register a use. Prior to the 1970's, less than 7% of the edible leafy crops (28 out of 380) grown in the U.S. had any registered insect control materials legally available. This was the reason for the development of the 1971 edition of Food and Feed Crops of the United States book to realize the importance of a crop grouping scheme to include minor crops in the regulatory process as rapidly as possible. With the present day crop group food-use research, the percentage will rise as will the number of safe pesticides in IPM programs. For example, just the new Leafy vegetables crop group # 4 consists of 28 crops as follows:

 Crop Group Representative Crops Crop Group Members
4. Leafy vegetables (except Brassica vegetables) Celery, head lettuce, leaf lettuce and spinach Amaranth (Chinese spinach); arugula (roquette); cardoon; celery; celery, Chinese; celtuce; chervil; chrysanthemum, edible-leaved; chrysanthemum, garland; corn salad; cress, garden; cress, upland; dandelion; dock (sorrel); endive (escarole); fennel, Florence; lettuce, head and leaf; orach; parsley; purslane, garden; purslane, winter; radicchio (red chicory); rhubarb; spinach; spinach, New Zealand; spinach, vine; Swiss chard

The U.S. EPA crop grouping regulations enable the establishment of tolerances and exemptions for groups of crops based on residue data for certain representative or indicator commodities. The U.S. EPA established crop group regulations in 1983 (40 CFR 180.34(f)) and expanded them with more crops and the use of subgroups in 1995 (40 CFR 180.41). Each subgroup is a smaller and more closely related grouping of commodities included in the crop groups. These crop subgroups subdivide the crop group into commodities within the group with similar growth characteristics and residue potential, such as Crop Group 4 leafy vegetables (except Brassica vegetables) has two subgroups: the leafy greens subgroup with head and leaf lettuce and spinach as the representative commodities and the leaf petioles subgroup with celery as the representative commodity. Subgroups will increase the utility of the crop groups for growers, registrants, and dietary surveys. Crop groups also are useful in determining and expanding crop rotational and chemical rotation possibilities, since closely related crops with similar pest spectrums are in the same group. Representative commodities for which magnitude-of-residue (MOR) GLP food use research is conducted, provide the necessary basis to expand this research to crops in the group(s). This flexibility is further enhanced with the use of crop definitions (40 CFR 180.1(h)) and EPA Opinion letters addressing crop definitions. IR-4 understands these crop concepts and budgets its research to reflect the highest or best return-on-investment by utilizing U.S. EPA regulations concerning crop groups. IR-4 continues to support Section 18 exemptions with its crop grouping database (Dorschner).

IR-4 continues to evaluate the existing crop grouping/definition schemes to improve the concept. Recently, IR-4 requested the expansion as research tolerance definitions of certain tropical/subtropical crops grown in the U.S. In 1998, U.S. EPA accepted the concept to utilize representative crops to secure tolerances on various groups of tropical/subtropical crops (Lurvey et. al.). These crops are orphan minor crops when it comes to the availability of legal plant health materials which has hampered the expansion of the U.S. tropical crop industry.

One of the new tropical/subtropical fruit crop regulatory definitions is as follows:

Representative Crop Commodities included in definition
Papaya Papaya; black sapote; canistel; mamey sapote; mango; sapodilla; and star apple

With the recent publication of the second edition of Food and Feed Crops of the United States, information on further developments and expansions of new or additions to crop groups/definitions is possible. In addition, information on grouping commodities for applicator risk, as well as new developing commodities is provided. The new publication also stimulates the development of international harmonization between crop groups, residue levels, and trade, since scientific names are updated using USDA-ARS Germplasm Resources Information Network (GRIN) and links to Codex and geographical growing locations are provided in the text. This book has also facilitated the development of the EPA Master Tolerance Vocabulary which consolidated commodities listed in 12 different databases with over 16,000 terms to about 1,000 preferred terms. This vocabulary will be the standardized commodity vocabulary to establish tolerances, and exemptions from tolerances for pest control agents.

Another advantage of IR-4 completing GLP food-use research on crop groupings under good agricultural practices is that this public sector residue database will become more extensive for decision-making purposes. This will help address the residue data voids and further enhance our research programs by extending the food safety database to more minor crops or by reducing the number of tests to register a needed use. This will help minimize the burden of developing data in support of minor crop uses, as well as facilitating the development of IPM programs in minor crops by ensuring that pest control tools are available for the grower’s use.

The concept of crop grouping is legally, scientifically and economically sound, especially for the regulatory side of IPM research, and the future development of IPM research which puts growers in a proactive position. The ability to register pest control agents on minor crops will enable the U.S. to remain competitive with world agricultural markets.

References

  • Dorschner, K.W. 1998. Section 18's and IR-4 Data. In IR-4 Newsletter. G.M. Markle, editor. Rutgers University, New Brunswick, NJ. 29:3 p. 19.
  • Lurvey, E.L. and B.A. Schneider. 1998. The First Step Towards the Establishment of Tropical/Subtropical Crop Definitions. In IR-4 Newsletter. G.M. Markle, editor. Rutgers University, New Brunswick, NJ. 29:3 p.16.
  • Magness, J.R., G.M. Markle, and C.C. Compton. 1971. Food and Feed Crops of the United States, 1st edition. NJAES Bulletin 828. New Brunswick, NJ. 255pp.
  • Markle, G.M., J.J. Baron, and B.A. Schneider. 1998. Food and Feed Crops of the United States., 2nd edition. Meister Publishing Company, Willoughby, Ohio. 517 pp.
  • Markle, G.M. (Editor). 1998. IR-4 Newsletter. Rutgers University, New Brunswick, NJ. 29:2, 23pp.
  • Markle, G.M. 1970. Edible Land - Habitat Herbaceous Leafy Crops Grown in the United States of America and its Territories. Rutgers University, New Brunswick, NJ. 466 pp.
  • Schneider, B.A. 1990. Use of Crop Rotations in Pest Control. U.S. EPA. Washington, D.C. 23pp.
  • U.S. EPA. 1998. Title 40 - Protection of Environmental Parts 150-189, CFR, Office of Federal Register. U.S. Government Printing Office, Washington, D.C. 732 pp.

IR-4, IPM, and Weed Control

Fred Salzman, Ph.D.
IR-4 Herbicide Coordinator
Rutgers University

The concept of Integrated Pest Management (IPM), though more likely known for application to insect control, also has application to weed control. In the past, herbicides that were developed for field crop use were generally applied as a prophylactic treatment. The goal was one application of a herbicide or herbicides, preferably at planting. Ideal characteristics for these herbicides included soil residual activity that would provide season-long weed control. Since a grower could predict to a certain extent the weed species that would be present in a given field, based on past knowledge and the history of the field, this type of program become accepted. However, the past history of a field did not always accurately predict the specific weed control problems in a given year. Other factors, particularly weather and cultural practices, could influence weed problems later in the growing season.

In recent years, many of the newer herbicides that have come to market have been developed for postemergence (POST) use. Residual activity from these compounds has been seen as a desired, but not necessarily a required, characteristic for development. The POST activity of these compounds has been touted as a desirable characteristic because the grower would only have to choose, purchase, and apply the herbicide once the weed infestation had materialized and specific species identified. The disadvantage is that there can be only a short time period during which the herbicide can be applied. If the weather during this time is unfavorable for application, the alternatives for control may not be as effective. This has led to a weed control program in many crops that includes a residual, usually soil-applied, herbicide at planting followed by a POST-applied herbicide(s) to control the remaining weed species present. Whether the increased use of POST herbicides was a conscience decision by growers to follow IPM practices, or rather a decision driven by the economics and the herbicides available, is open to debate. However, in general the trends in weed control practices have come to reflect the IPM ideal of using pesticides only as needed. Growers of major crops have a large number of compounds from which to make decisions on weed control; therefore, weed spectrum, residual activity, price, toxicity, and personal preference can all be incorporated in the final decision of a weed control program. In other words, major crop growers have a number of tools from which to choose for weed control.

Growers of minor crops are at a disadvantage compared to growers of major field crops. Industry develops herbicide candidates based on their projected ability to generate profits, and the fit in major crop markets. Characteristics of a herbicide under development, such as carry over to minor crops, or the applicability of use on minor crops, receives a small if any consideration in the rush for registration and marketing. This has left growers of minor crops with only a small number of herbicides, or maybe no herbicides, registered for weed control for a particular crop. Often the herbicides that are registered are older, and less desirable for use. With so few herbicides registered on a specific crop, there may be significant gaps in the control of key weed species. The gaps in weed control become greater over time, characterized by a weed species shift in response to repeated applications of a limited number of herbicides. The weeds that are not controlled by herbicides must then be controlled by cultural or mechanical means, which are labor intensive and can be expensive.

Growers of minor crops also face a major problem related to herbicide use that is not present from fungicides or insecticides. Since herbicides are designed to kill plants, the susceptibility of crop plants is a primary concern. Minor crops are generally high-value crops and the tolerance for crop injury among growers may be low. Concern must not only be paid to the effect of the herbicide on yield, but also any effect on the part of the plant that is harvested. However, the effect of the herbicide on the target crop is only the first thing to consider.

Residual activity of a herbicide is generally seen as a desirable characteristic. Ideally, the residual activity of a herbicide would last as long as the target crop is grown. However, a rate of herbicide that is effective for use and safe for one crop, may result in soil residues that adversely affect the growth of subsequent crops. In some cases, a crop can be so sensitive to a herbicide that an application 24 months or more prior to planting will cause unacceptable injury. Rotations that have been developed over the years may preclude the use of a certain herbicide so growers are faced with the choice of using a herbicide or changing crop rotation practices.

When viewed from an IPM perspective, herbicides that have been developed in recent years have a significant advantage over their older counterparts. Many of these new compounds are active at only a tenth or less the rate of existing compounds. This means that there is less of a pesticide load on the environment, and even smaller amounts of residues that may potentially exist. They have a better environmental profile; for example, less likely to leach in the soil. Many of the newer herbicides have lower toxicity and may fall under the guidelines for reduced risk pesticides, making their registration a priority.

In the past, the IR-4 project has sought to register pre-existing herbicides on minor crops, or in other words, expand the label of a herbicide to include minor crops. However, as explained elsewhere in this chapter, the interest in newer compounds and the benefits they have under new regulations has changed the focus of IR-4 in approaching new registrations. For example, IR-4 is currently conducting the work needed to register halosulfuron, a recently developed herbicide, for use on cucumbers, cantaloupe, and squash (winter and summer) because it controls purple and yellow nutsedge, perennial weed species for which there is no control alternative other than mechanical removal. In addition to providing control of the nutsedge species, and some broadleaf weeds, the use rate of halosulfuron is approximately 10 to 100 times less than the use rates of the herbicides currently registered for these crops. Ideally, in the future, given cooperation between IR-4 with industry and growers, IR-4 could develop data packages on minor crops at the same time that the registrant is developing the packages on major crops. With coordination of the work, the data on both major and minor crops could be submitted as one package to the benefit of both the registrant and the growers.

Crop growers are generally pragmatic and realize that using pesticides, including herbicides, only as needed is beneficial to all including themselves. Increasing the choice of registered herbicides available for use, particularly newer, reduced-risk herbicides, increases the tools from which a grower can choose, which in turn will assure that the objectives of IPM are met.

Interdisciplinary IPM

The three disciplines that study and incorporate IPM principles into pest control management tend to view themselves as distinct and separate from each other. However, it can pay to step back and examine if interactions exist between the weeds, insects, and diseases within a crop situation.

An example is on-going work conducted by Dr. Peter Shearer of Rutgers, The State University of New Jersey and colleagues (1). Dr. Shearer, an entomologist, has found that the populations of tarnished plant bug are influenced by the plant species that grow in the row middles of peach orchards. These insects preferentially feed on broadleaf weeds, and if the broadleaf weeds are removed the insect population decreases. White clover, a broadleaf weed that grows in the middle of rows in orchards, attracts the tarnished plant bugs. The weed species also attracts honeybees, a beneficial insect; and acts as a repository for plant viruses that can be spread by insects. By controlling the white clover, along with other broadleaf weeds, the population of insect pests is reduced, reducing the need for insect control measures; helps protect a beneficial insect species; and reduces the spread of plant viruses. By maintaining grass species for orchard row middles, along with mowing, both insect and disease pressure can be reduced.

Reference

  • Shearer, P.W., B. Majek, D. Polk, R. Belding, N. Lalancette, and J. Halbrendt. 1997. Orchard ground cover management affects peach insect damage. Proceedings of the Cumberland-Shenandoah Fruit Workers Conference 73rd Annual Meeting. Nov. 20-21, 1997. Winchester, VA. 278-279.

The IR-4 Biopesticide Program and its Role in IPM

W.L. Biehn, Ph.D.
IR-4 Biopesticide Coordinator
Rutgers University

In 1982, IR-4 initiated a program to assist in the development and registration of biopesticides, regulated under FIFRA, for minor uses. Biopesticides include:

  • Microbial pest control agents (MPCA) including viruses, bacteria and fungi.
  • Biochemical pest control agents (BPCA) which are characterized by their natural origin and non-toxic mode of action and include mating disruptant pheromones, repellants, insect and plant growth regulators.
  • Transgenic plants with pesticidal activity.

IR-4 works closely with state and federal scientists, growers, registrants and EPA to develop and register biopesticides for minor uses. IR-4 provides both research funds and regulatory assistance to further the development and registration of biopesticides. Specifically IR-4:

  1. Aids in developing approved research protocols.
  2. Funds small or large scale field efficacy and crop safety trials.
  3. Assists in the development of safety and toxicology data to the level of Tier 1 as defined by EPA.
  4. Funds magnitude-of-residue studies if required.
  5. Assists in obtaining Experimental Use Permits from EPA.
  6. Prepares and submits petitions to EPA to support clearances.
  7. Develops data to expand existing registrations for additional crop uses.
  8. Provides assistance in meeting the requirements of Good Laboratory Practice for data submitted to EPA.
  9. Assists in preparing registration documents for submission to EPA.

IR-4 has a Biopesticides Grants program in which research proposals requesting funding have to be submitted to IR-4 by November 15. IR-4 can assist in funding research leading to the first registration or research on currently registered biopesticides to expand the label. Instructions for proposal content, format, and submission can be obtained from IR-4 Headquarters or the Regional Offices.

Biopesticides and IPM

Biopesticides along with traditional chemical pesticides and reduced risk pesticides are important tools that can be used in integrated pest management (IPM) programs. The advantage of many biopesticides is that they target a narrow range of pests and therefore minimize unintended adverse effects on beneficials. Most biopesticides are compatible with IPM programs, because they allow natural enemies (beneficials) to exist.

In contrast, many traditional pesticides which are broader spectrum, eliminate natural enemies and thus induce some pest problems not controlled by one pesticide. Biopesticides are also considered to pose fewer risks to the environment and human health than traditional chemical methods of control. Many biopesticides are also effective at very low use rates (e.g. mating disruptant pheromones).

One of the criteria IR-4 uses in selecting biopesticide projects for funding is the compatibility of the biopesticide in an IPM program.

A good example of what can be accomplished in the area of IPM with biopesticides is the research supported by IR-4, the cranberry growers and 3M Canada to label the pheromone mating disruptant (E)-11-tetradecen-1-yl acetate for the management of the sparaganothis fruitworm in cranberries. In large scale field studies, it was determined that two applications at 50 to 125 mls/acre (10-25 grams ai/A) are effective in the control of the sparaganothis fruitworm. The use of the sparaganthosis mating disruptant pheromone in cranberries has many advantages including reduced use of organophosphate insecticides, reduced risk to workers and applicators and reduced risk to the environment.

Overview

Established in 1963, the Interregional Research Project Number 4 (IR-4 Project) is a federally funded program designed to ensure that American farmers have an adequate supply of pest control products registered for minor crops and for minor uses on major crops. IR-4 facilitates the registration of traditional chemical pesticides, reduced risk products, and biopesticides. Biopesticides include microbials (fungi, bacteria, and viruses), low toxicity biochemicals, pheromones, insect and plant growth regulators, and genetically transformed microbes and plants.

Minor crops are usually small acreage, speciality crops of high monetary value. They are the foods we eat every day such as fruits, vegetables, and nuts. They are the commercially grown ornamental and floral plants, and the trees and turfgrasses enriching us with their beauty. Minor crops in aggregate comprise approximately 42% of the value of all crops grown in the United States. In 27 states, the value of minor crops exceeds 50% of the value of all agricultural production. On many levels, minor crops play major roles in our lives and environment. Minor uses on major crops usually involve pests that occur sporadically or pests of limited regional significance.

IR-4 assistance is indicated when the potential market of a pesticide for use on a crop is insufficient to justify the private investment necessary to obtain a federal registration. This "minor use problem" is not new. Minor crops have historically suffered from a lack of effective pesticides including those which have a natural fit in thoughtful IPM programs. But as the costs associated with pesticide registrations and reregistrations have escalated, so have the problems associated with minor crop pest control. IR-4 is the only public or private group that addresses the pesticide clearance needs of minor crop farmers. As such, the project prides itself on the high levels of grass-roots support it has earned.

IR-4 receives pesticide clearance requests from the people most knowledgeable of minor crop pest control problems. This includes growers, grower organizations, nurserymen, agricultural scientists, and extension personnel. Essentially, IR-4 will consider a request from any interested party except the pesticide registrant. After receiving a clearance request for a pesticide use on a specific minor crop or group of crops, the request is reviewed and prioritized by external reviewers including growers, researchers, and extension personnel. In setting priorities, the importance of the pest problem, the availability of alternatives, the existence of data gaps (such as chemistry, toxicology, and environmental fate data), and the value to IPM and resistance management programs are all carefully considered. Each request is also reviewed by the US Environmental Protection Agency (USEPA) and the potential registrant prior to final selection.

If a project is selected for research, cooperating scientists carry out field trials to develop crop safety data and collect residue samples. The number, placement, and design of these field trials are carefully considered so that they meet the requirements of the USEPA. The residue samples are analyzed in IR-4 regional or satellite laboratories located at state agricultural experiment stations and federal analytical laboratories. All work performed by IR-4 is fully compliant with the mandated Good Laboratory Practice Procedures (GLP) of the USEPA. These procedures are essential in assuring that the data generated by IR-4 meets the stringent requirements of federal review agencies.

Once all the data has been gathered, IR-4 prepares a data package (petition) which is submitted to the USEPA for approval. The petition must include data to show the amount of residue that will be present from the proposed use as well as toxicology data to demonstrate the safety of that amount of residue. IR-4 petitions almost always contain residue data but generally rely on referenced manufacturers' toxicology data to fulfill the safety requirements.

When the petition is finally approved by the USEPA, a Notice followed by a Final Rule is published in the Federal Register which establishes a tolerance for the particular pesticide on the minor crop. The pesticide manufacturer may label the product for its intended use by growers once the tolerance has been established by the Final Rule.

The Role of IR-4 in Implementation of IPM for Arthropod Pests

Integrated Pest Management (IPM) is a system of pest management which utilizes all suitable control techniques to reduce or maintain pest populations at acceptable levels. It is vitally important that all techniques be integrated into a single coordinated pattern. IPM should not be "chemically dependant" (Frisbie & Smith 1989) but neither should it overlook the judicious use of chemical pesticides. A pesticide's toxicological profile, mode of action, spectrum of activity, and environmental fate should be carefully evaluated for use in IPM. It is a mistake to assume that a product will fit into an IPM program just because the active ingredient may be a naturally occurring compound. For example, although botanical pesticides such as neem have been promoted as alternatives to synthetic pesticides, these pesticides can be harmful to beneficial insects and aquatic organisms (see Bottrell 1996 for a summary of the negative effects of neem on non-target organisms). To be acceptable to growers, an IPM program must be effective in maintaining pest populations below levels which cause economic damage to the crop and must have provisions for remedial action should pest populations surge. The thoughtful use of appropriately chosen pesticides is a component of every successful IPM program.

The compatibility of a proposed use for IPM is an important consideration when the IR-4 project receives a pesticide clearance request to initiate research. The effectiveness in controlling the target pest, the toxicity of the product to non-target pests and beneficials, and the effect of the product on the stability of the agroecosystem are all important factors in the decision process. By spreading the exposure of the pest to multiple control tactics, IPM seeks to minimize the pest's exposure to individual control tactics (Smith & van den Bosch 1967) thereby reducing the pest's ability to adapt. Therefore, even if adequate chemical pesticides are available to control a pest, other products with different modes of action or spectrums of activity may be useful for IPM and insecticide resistance management programs. These uses may receive a high priority ranking at IR-4 based solely upon their "fit" into IPM systems. The IR-4 project serves a vital role in the development of IPM systems for minor crops by securing tolerances for IPM-compatible pesticides and biologically-based pest control products.

A good example of what can be accomplished by the IR-4 program in the area of IPM and chemical insecticides can be found with our work to register imidacloprid on tomatoes and peppers. The introduction of the silverleaf whitefly into southern Florida had a devastating effect on tomato and pepper production. Growers were making up to 20 applications per crop cycle of non-specific chemical pesticides in order to obtain any whitefly suppression and produce a crop. Such a massive use of pesticide is very disruptive and makes the implementation of IPM problematic. IR-4 data helped secure a registration for imidacloprid on tomatoes and peppers which resulted in whitefly insecticide applications being reduced from a maximum of 20 per crop to only one. The use of imidacloprid for pepper and tomato growers has numerous advantages including reduced pesticide use, reduced risk to workers and consumers, increased selectivity, and reduced risk to the environment.

IR-4 has an imidacloprid petition currently under review at the USEPA which will have a similar impact on cucurbit (melon, squash, and cucumber) production. Although imidacloprid will be widely used by growers to control the silverleaf whitefly on these crops, the resultant reduction in pesticide use over current practices will be substantial and will allow for less disruption of the biotic forces which maintain other pest species below damaging levels. As a result, IPM system development on cucurbits will become practicable in areas with heavy whitefly pressure.

Another situation occurred not long ago in which IR-4 interceded on behalf of range grass growers and livestock ranchers to save the registration of permethrin for the control of range caterpillars. The original petition for this use was obtained by IR-4 in 1983 and permethrin was registered for this use in 1984. The range caterpillar not only destroys forage grasses but leaves behind exuviae that contain toxic spines. The toxin causes swelling in the mouths of livestock and they will refuse to graze in the infested area.

Dosages as low as 0.05 grams per acre of permethrin are highly efficacious compared to the 113 grams of trichlorfon which was previously used. Under IPM, the treatment of incipient populations (usually about 80,000 acres) is effective in preventing the extremely large outbreaks of the past (over 1,000,000 acres treated in New Mexico during 1978) (Huddleston, personal communication).

In 1994, the registrants of permethrin announced that they planned to discontinue the registration of the insecticide on range grasses. IR-4 ascertained that this minor use was still needed for range grass IPM, then contacted the product registrant and requested that they reconsider their cancellation decision. The registrant agreed to retain the use of permethrin on range grasses after considering IR-4's arguments.

The IR-4 Project would like to hear from you. If you need assistance in the registration of a pest management product that may be compatible with an IPM program on minor crops, please contact one of the IR-4 Regional Field Coordinators listed below:

  • Northeastern Region: Ms. Edith Lurvy, Analytical Laboratories, Dept. of Food Science. & Tech., NYSAES, Cornell University, Geneva, NY 14456 (315) 787­2308, FAX# 315­787­2397, e-mail Edith Lurvey
  • North Central Region: Dr. Satoru Miyazaki, IR­4 Regional Coordinator, Pesticide Res. Center., Michigan State Univ., East Lansing, MI 48824­1311, (517) 353­9497, FAX# 517­353­5598, e-mail Satoru Miyazaki
  • Southern Region: Dr. Charles Meister, Food & Env. Tox. Lab., Dept. of Food Science & Human Nutrition, IFAS, Univ. of Florida, P.O. Box 110720 S.W. 23rd Drive, Gainesville, FL 32811­0720, (352) 392­2399, FAX# 352­392­1988, e-mail Charles Meister
  • Western Region: Ms. Becky Sisco, IR-4/PIAP, Dept. of Environmental Tox., Univ. of California, Davis, CA 95616­8588, (916) 752­7633, FAX# 916­752-2866, e-mail Becky Sisco

References

  • Bottrell, D.G. 1996. The Research Challenge for Integrated Pest Management in Developing Countries: A Perspective for Rice in Southeast Asia. J. Agric. Entomol. 13(3): 185- 193.
  • Frisbie, R.E. & J.W. J. Smith. 1989. Biologically intensive integrated pest management: The future. In: J.J. Mennard & A.L. Steinhauer [Eds.], pp. 151164. Entomological Society of America Centennial National Symposium. Progress and Perspectives for the 21stCentury. Washington, D.C.
  • Smith, R.F. & R. Van den Bosch. 1967. Integrated control, pp. 295-340. In: W.W. Kilgore & R.L. Doutt [Eds.], Pest control-biological, physical, and selected chemical methods. Academic Press, New York.