Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. Reserve aQL527 .A5F68 1996 FOURTH ANNUAL PROGRESS REVIEW OF THE 5-YEAR NATIONAL RESEARCH AND ACTION PLAN FOR DEVELOPMENT OF MANAGEMENT AND CONTROL METHODOLOGY FOR SILVERLEAF WHITEFLY SAN ANTONIO, TEXAS FEBRUARY 4-6, 1996 An Interagency Effort of: USDA/Agricultural Research Service USDA-Cooperative State Research, Education, and Extension Service State Agricultural Experiment Stations USDA/Animal and Plant Health Inspection Service USDA-Extension Service Agricultural Services and Commodities Industries National Agricultural Library EDITORS’ COMMENTS The multi-agency silverleaf whitefly, Bemisia argentifolii Bellows and Perring (formerly sweetpotato whitefly, Bemisia tabaci Gennadius Strain B) research and action plan is a continuing effort of federal and state agencies, and agricultural industries to develop tools for effective whitefly management. A vital facet of the plan is the annual review process. Program formats for the review focus on reports of research progress, information exchange, development of cooperative efforts, and reassessment of research priorities. Informative and productive reviews of the research and action plan were conducted in Tempe, AZ in 1993, Orlando, FL in 1994, and San Diego, CA in 1995. This publication presents a compilation of abstracts, whitefly bibliography addendum, and other information gathered at the fourth annual review, February 4-6, 1996 at San Antonio, TX. The editors appreciate the contributions of all attendees and participants. The research abstracts are intended as reports of current research and the contents remain the sole responsibility of the authors. Minor editing was done only to conform to camera-ready format requirements. Sweetpotato whitefly Strain B was described as a new species, B. argentifolii Bellows and Perring. In the present publication, both names appear at the discretion of the authors. The editors assume the names are synonymous. Sections of this document other than the abstracts are the combined effort of the meeting participants and other interested contributors. Tables A through F of the “5-Year National Research and Action Plan Priority Tables” have been reproduced and included in the present supplement. This is for the reader's orientation and relevance of the fourth year review to the plan in its entirety. Also included in the present publication is an addendum to the whitefly bibliography published by Butler et al. (1995) in "Silverleaf Whitefly 1995 Supplement to the 5-Year National Research and Action Plan,” USDA-ARS, 1995-2, National Technical Information Service, Springfield, VA. Editors: T. J. Henneberry, N. C. Toscano, R. M. Faust and J. R. Coppedge PROGRESS REVIEW ORGANIZATIONAL TEAM USDA Sweetpotato Whitefly Research, Education and Implementation Coordinating Group Robert M. Faust, Chair, ARS, Beltsville, MD; James R. Coppedge, Alternate, ARS, College Station, TX; Robert Riley, Dennis D. Kopp and Michael Fitzner (Alternate), CSREES, Washington, DC; Harold Browning, University of FL, State Agricultural Experiment Station, Lake Alfred, FL; Dale E. Meyerdirk, Robin Huettel and Norman C. Leppla (Alternate), APHIS, Riverdale, MD Annual Review Program Chairs: T. J. Henneberry, USDA-ARS-Westem Cotton Research Laboratory, Phoenix, AZ, and N. C. Toscano, Department of Entomology, University of California, Riverside, CA Local and State Coordinator: James R. Coppedge, ARS, College Station, TX Technical Working Group: J. Amador, TX A&M J. Brown, Univ. AZ D. Byrne, Univ. AZ R. Carruthers, ARS D. Kopp, CSREES J. Coppedge, ARS J. Duffus, ARS R. Faust, ARS T. Henneberry, ARS L. Lacey, ARS N. Leppla, APHIS R. Mayer, ARS D. Meyerdirk, APHIS S. Naranjo, ARS L. Osborne, Univ. FL R. Riley, CSREES J. Sanderson, Cornell Univ. C. Schwalbe, APHIS N. Toscano, Univ. CA, Riverside I. Wedderspoon, E. I. Dupont De Nemours, Miami, FL Acknowledgment: The USDA SPW Coordinating Group, Annual Review Program Chairs, Section Chairs, Local and State Coordinators and the Technical Committee sincerely appreciate the contributions of all the participants and those who have helped in organizing the meeting. We especially thank Lisa Arth, Cindy Giorgio, and Lynn Jech for their help in assuring the success of the meeting. -li- CONTENTS Editors' Comments. i Progress Review Organizational Team. ii Contents. iii Foreword . iv Executive Summary. v Annual Review Objectives. vii Research Progress on the Silverleaf Whitefly 5-Year National Research and Action Plan.viii Reports of Research Progress A. Ecology, Population Dynamics, and Dispersal. 1 Abstracts. 2 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan. 11 B. Fundamental Research, Behavior, Biochemistry, Biotypes, Morphology, Physiology, Systematics, Virus Diseases and Vector Interactions. 12 Abstracts. 13 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan. 43 C. Chemical Control, Biorationals and Pesticide Application Technology. 45 Abstracts. 46 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan. 92 D. Biocontrol. 93 Abstracts. 94 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan.143 E. Crop Management Systems and Host Plant Resistance .144 Abstracts.145 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan.158 F. Integrated Techniques, Approaches and Philosophies.159 Abstracts.160 Summary of Research Progress in Relation to Year 4 Goals of the 5-Year Plan.165 FOREWORD This publication is the fourth annual report of progress of the 5-Year National Research and Action Plan for Control and Development of Management Strategies for the Sweetpotato, Bemisia tabaci (Gennadius) and Silverleaf whiteflies, Bemisia argentifolii Bellows and Perring. In 1991 and 1992, USDA agencies. State Agricultural Experiment Stations and commodity-involved industries in a cooperative effort formulated the original 5-year National Research and Action Plan that focused on developing methodology for control and management of the sweetpotato whitefly. Six high priority research and action areas were established during a series of meetings in Atlanta, GA, Reno, NV, and Houston, TX. The sweetpotato whitefly has been a worldwide economic pest for many years, but was of little concern in the United States until the late 1970's when epidemic outbreaks began to occur at sporadic intervals through the 1980’s. In the late 1980's, the expanded host range involved in whitefly outbreaks, as well as biological, geneuc and vector differences and the occurrence of unique adverse plant physiological disorders in some cultivated crops, led several scientists to propose the occurrence of a new sweetpotato biotype (Strain B). Subsequently, sweetpotato Strain B was described as a new species B. argentifolii Bellows and Pemng, and renamed the silverleaf whitefly. Silverleaf whitefly terminology has not been formally accepted as a common name by the Entomological Society of America's committee on common names of insects. However, repetitive use of the name within the scientific and agricultural community prompted the USDA coordinating group to retitle the 5-year plan substituting silverleaf whitefly for sweetpotato whitefly in its 1994 report and subsequent reports of annual progress. The transition from sweetpotato to silverleaf whitefly dominated agricultural systems in Arizona, California, Texas and Florida has not been clearly defined, but appears to have occurred during the mid to late 1980's. Economic losses from silverleaf whitefly have involved cotton and a wide range of ornamentals and vegetable crops. Conservative estimates suggested that in 1991 and 1992 losses in the agricultural communities exceeded $200 and $500 million, respectively. Crop yield losses attributable to silverleaf whitefly in the Imperial Valley, CA over a 4 year period (1991 to 1995) have been estimated to be about $100 million per year. The success of the 5-Year National Research and Action Plan and the annual progress reviews in 1993, 1994, 1995 and 1996 have resulted from the combined efforts of participating Federal and State agencies and the agricultural industries. The urgent need for short-term technologies and the groundwork for long-term management have been established. Losses in agricultural communities where the silverleaf whitefly is a factor in crop and horticultural production have been reduced. Significant research progress has been made and a number of management tools adopted in crop production systems. More importantly, a huge base of new knowledge on biology, physiology, biochemistry, morphology, genetics, and other fundamentals of the silverleaf whitefly have been assessed. Long-term ecology based, socially and environmentally acceptable management systems will be drawn from this knowledge base. USDA Sweetpotato Whitefly Research, Education and Implementation Coordinating Group (two members from ARS, two members from APHIS, two members from CSRS/SAES, and one member from ES) was formed in 1992 to coordinate the USDA interagency activities. The USDA Coordinating Group and partner State Agricultural Experiment Stations help ensure a unified effort for the plan and provide for an annual review to exchange research information, plan cooperative work, and evaluate research progress. The Coordinating Group deeply appreciates the contributions of all of the individuals who have made the progress reviews and 5- Year Research and Action Plan a successful endeavor. Special appreciation this year is accorded to T. J. Henneberry, N. C. Toscano, T. Perring, L. Arth, C. Giorgio, Annual Review Program Co-Chairs and committees, the Silverleaf Whitefly Technical Working Group, the National, State and local Coordinators, and the Program Chairs for their substantial efforts in this process. We particularly appreciate the effort of Dr. James R. Coppedge and his staff for local arrangements. Robert M. Faust James R. Coppedge Chair, USDA SPW Coordinating Group USDA SPW Coordinating Group ARS National Program Staff Areawide Pest Management Research Laboratory Beltsville, Maryland College Station, Texas -IV- EXECUTIVE SUMMARY The silverleaf whitefly 5-year national research and action plan has been a focal point for coordination and cooperative research involving federal and state agencies, state agricultural experiment stations and commodity industries. It provides open lines of communication, strong research linkages and information exchange. The plan has been used as a model for similarly developed activities in other states and internationally. Much of the research information has provided tools to extension and education, and action agencies for use in whitefly management programs. Active participation and attendance of representatives from ten foreign countries has occurred at the annual plan reviews. The six high priority research areas that were developed during formulation of the plan have served as effective guidelines for orientation and direction of the research. The mandated annual reviews have effectively resulted in information exchange, analyses and restructuring of priorities and identification of research needs. The original 5-year plan in 1991 and 1992 targeted the sweetpotato whitefly as the pest of significance. With increasing study and accumulated evidence showing expanded host range, biological, genetic and vector differences and the occurrence of unique adverse plant physiological disorders occurring in some cultivated crops, several authors proposed a new sweetpotato whitefly biotype (Strain B). Strain B has been described as a new species Bemisia argentifolii Bellows and Perring and provisionally designated a common name of the silverleaf whitefly. An overview of the plan progress reviews in 1993, 1994, 1995 and 1996 shows that extensive achievements have been made in all of the research priority areas. A complete effective management system for silverleaf is a goal for the future, but at present, is in the early formative stages and much of the accomplished research is being implemented in control programs. Extensive ecological, biological and fundamental research on the silverleaf whitefly and its natural enemies is revealing many additional potential components for incorporation into an ecologically-based management system. Some crop management and community-oriented farm practices are being implemented in an effort to provide overall whitefly population reduction. The extensive host range cultivated crops including wild weeds and urban ornamentals has been identified. These combine to provide spatial and temporal continuum of host biomass that provide silverleaf whitefly food, shelter and reproductive requirements throughout the year. The knowledge of these complex interrelationships of types of cultivated crops, crop growing sequences and urban community hosts have brought an awareness that the entire farm community must concern itself with whitefly population suppression programs. Areawide community-involved approaches have emerged as having the best possible chance of success. For example, the cotton grower in a farming community must give careful consideration to the status of winter¬ spring cultivated crop sequences in proximity to prospective cotton planting locations. Although, low whitefly populations occur on vegetable crops such as broccoli, lettuce and cole crops during October through February and March, populations developing in early spring melons increase dramatically in April to May and high numbers move to cotton. Thus, early harvest and melon crop residue destruction and plowdown is an essential SLW management component for the cotton grower. An early and uniform cotton plant dating scheduling may escape high, early-season infestation levels. Planting upwind of infested or potentially infested cultivated crop hosts is a further precaution to managing early-season infestations. Smoothleaf cottons support lower whitefly population levels than hairy-leaf cottons. Also, short-season cotton types for early harvest and crop destruction are effective measures to reduce overall population densities in areawide farming community programs. Water and fertilizer management are important factors in whitefly management. Although the mechanisms involved in the complex interaction of the host plant condition and whitefly population dynamics are largely unknown, populations increase dramatically when cotton plants become stressed. Thus, frequent and adequate irrigation during the season delay the occurrence of high population densities. These effects have been studied primarily in cotton production and information is much needed on other crop production systems. -v- Several insecticides alone or in combination have been found to provide adequate control on major cultivated crops. Particular attention must be given to good coverage, particularly to underleaf surfaces. Insecticide resistance management is a particularly important factor in control. It is important to avoid using materials in the same chemical class for extended periods. Frequent population monitoring of the adult and immature populations on leaves is critical to assess effectiveness of control strategies. Definitive economic threshold values have not been established, but high population levels cause severe defoliation and reduced yield as well as sticky cotton and significant losses in vegetable, ornamental and nursery crops. Community action programs involving research, extension, industry, growers and urban community are essential to provide the framework for whitefly population management systems. T. J. HENNEBERRY N. C. TOSCANO USDA-ARS, Western Cotton Research Laboratory Department of Entomology Phoenix, Arizona University of California Riverside, California ■vi