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Roger has 33 years experience in insect ecology, biological control, and IPM with a background that includes state, university, and federal employment. He joined ARS in 1980 and holds a collateral appointment to the University of Hawaii Graduate Faculty. From 1984 to 1990, he served as Research Leader of the Rearing, Radiation and Genetics Research Unit in Honolulu, where funding increased from $500,000 to $3,000,000. He is the author or co-author of 185 published scientific reports. His research interests include mass rearing, ecology, biological control, SIT and IPM of fruit flies. He has collaborated frequently with agencies such as the Animal Plant Health Inspection Service (APHIS), International Atomic Energy Agency (IAEA), the Secretariat of the Pacific Community (SPC) and Foreign Agricultural Service (FAS). Roger has served consultant and technical assignments in Austria, Mexico, Central America, Japan, Pakistan, the Philippines, Fiji, Mauritius, French Polynesia, Jordan, Israel, Australia, Thailand, the Seychelles, People's Republic of China, Taiwan and Senegal. He developed a research proposal that resulted in the award of over $16.5 million in USDA/ARS AWPM funds to Hawaii (UH, HDOA, ARS) and coordinated the highly successful Hawaii Fruit Fly AWPM program that received seven major awards for IPM excellence. In 2010 he was elected President of the Pacific Branch of the Entomological Society of America.
Hawaii Fruit Fly AWPM
After over 100 years of infestation area-wide control of fruit flies was addressed in Hawaii. From 2002-2010, Roger coordinated a national Area Wide Pest Management program: "Area-Wide Integrated Pest Management of Fruit Flies in Hawaiian Fruits and Vegetables." New technological advances (GF-120 Naturalyte NF Fruit Fly Bait and male annihilation treatments) were incorporated into the area-wide program and generated interest by industry to register new reduced-risk products for AWPM of fruit flies. Implementation of the AWPM program in many cases reduced the use of organophosphate insecticides by 75-90% for fruit fly control in Hawaii. The program was nationally recognized with seven major awards. It also received international attention. Technology transfer and training occurred with Thailand, PRC, Taiwan, French Polynesia, Guam, Northern Marianas, Fiji and various western African countries. Through the AWPM program, GF-120 NF Naturalyte Fruit Fly Bait received an "all crops" and organic label in 2006, Amulet-C-L was registered in 2007 and SPLAT-MAT-spinosad-ME was registered in 2008 for fruit fly control with US EPA.
Development of Reduced Risk Fruit Fly Control Technologies
Roger and coworkers evaluated AWPM fruit fly suppression techniques that included field sanitation, bait sprays, and male annihilation. His laboratory was part of a research team that investigated GF-120 Fruit Fly Bait, a reduced-risk insecticide, as a replacement for malathion bait sprays against Medfly in 1998. This was the first large-scale field test of the bait against fruit flies. More recently, his laboratory, in a partnership with industry, developed and registered a new environmentally friendly male annihilation product (SPLAT-MAT-spinosad-ME) for oriental fruit fly control and registered Fipronil C-L stations for suppression of melon fly in Hawaii. Many scientists suggested fruit fly eradication in Hawaii was too costly financially and environmentally; consequently, an IPM area-wide approach was pursued. GF-120 NF Naturalyte Fruit Fly Bait was demonstrated to be effective not only against Medfly, but also against oriental, melon, and Malaysian fruit flies, the major economic fruit fly pests in Hawaii. Furthermore, an organic "all crops label" was registered through U.S. EPA (Environmental Protection Agency). Likewise, SPLAT-MAT-spinosad-ME/C-L and bucket traps were demonstrated to be safe for suppression of fruit flies in Hawaii. Efficacy and nontarget studies were critical for: 1) obtaining first chemical registrations for ME and C-L for fruit fly control in Hawaii, and 2) developing simple environmentally sound IPM techniques for use in an area-wide program to manage economically important fruit flies without organophosphate insecticides. These 15 years of research formed a technology transfer pipeline for implementation of the Hawaii AWPM Fruit Fly Program.
Roger and colleagues demonstrated a cost effective and sustainable biological control program by introducing and establishing natural enemies into French Polynesia against oriental fruit fly and evaluating their impact. Oriental fruit fly was discovered on Tahiti Island in July 1996 with the most likely source being Hawaii. Eradication programs were conducted from 1997 to 2001, but failed. To suppress oriental fruit fly populations, a classical biological control program was initiated to introduce the two parasitoids, Fopius arisanus and Diachasmimorpha longicaudata into Tahiti from Hawaii. Establishment of F. arisanus reduced oriental fruit fly populations by approximately 75% with average parasitism rates of 50%. From the small laboratory, the French Polynesians have been able to rear parasitoids in the laboratory and release them against oriental fruit fly as it has spread to new islands. Establishment of F. arisanus is the most successful example of classical biological control of fruit flies in the Pacific area outside of Hawaii and serves as a model for introduction into South America and Africa where species of the B. dorsalis complex have recently become established. A second species of parasitoid, D. longicaudata, introduced 3 years ago is currently being evaluated.
Comparative Demography, Life History, and Survival of Fruit Flies
Through a 10 year series of studies, Roger' laboratory modeled comparative life history, survival, and demographics of wild and laboratory lines of Mediterranean, oriental, melon, and Malaysian fruit flies and their parasitoids. Research demonstrated basic reproductive differences between the more temperate (r-selected) Medfly and the more tropical (k-selected) oriental and melon fruit flies. Statistics for wild lines differed significantly from those calculated for laboratory adapted lines. Research resulted in quantitative predictive models for fruit flies with respect to colonization, development, survivorship, longevity, and reproduction at different temperatures. Demographic methods have diverse applications: analyzing population structure, estimating extinction probabilities, theorizing life history evolution, predicting pest outbreaks, examining the dynamics of colonizing or invading species, and determining risk assessment. Fruit fly demographic methodologies now provide quantitative models (e.g., degree-day models, intrinsic rate of increase, and generation times) for prediction of fruit fly phenology, estimation of age structure in field populations, timing of eradication procedures, and more efficient use of mass?reared sterile fruit flies in SIT programs. More recently, alternative methodologies to the LD-50 risk assessment of insecticides to animal populations were published.
Sterile Insect Technique
Roger and coworkers evaluated area-wide SIT demonstration tests on Kauai Island as part of an "Eight Year Accelerated Eradication Program." One demonstration test undertook Medfly eradication with a 50 million sterile fly maximum. Moderate suppression (56%) was achieved against a large Medfly population infesting a commercial coffee agro-ecosystem. High suppression (91%) was obtained against a small Medfly population infesting mountainous forest. Helicopters were demonstrated to be well suited for sterile fly releases in mountainous areas where terrain and unpredictable weather conditions were unsuitable for fixed-wing airplanes. SIT was shown compatible with a beneficial parasitoid attacking Medfly eggs. Finally, in related studies, Medfly was found to dominate oriental fruit fly throughout a newly planted lowland commercial coffee plantation. Although normally thought to be a parasitoid primarily of the oriental fruit fly, a significant mortality (37%) and a density dependent effect on Medfly were demonstrated for the beneficial wasp, Fopius arisanus. Studies provided quantitative models for dispersal of aerially released sterile flies and length of time sterile flies persisted in the field. Habitat type limited suppression by sterile flies when used as a stand-alone control technology. This information was important in estimating the length of sterile fly survival in the field. Research results demonstrating high mortality of Medfly by F. arisanus supported the benefits of suppressive augmentative parasite releases and were evaluated in expanded field tests not only in Hawaii, but also by scientists in Mexico and Guatemala against Medfly. Most importantly, these studies demonstrated the tremendous cost and commitment required for fruit fly eradication from Hawaii and eventually resulted in an alternative AWPM proposal for fruit fly suppression.
Dr. Vargas's laboratory researched and developed rearing systems (egging, larval recovery, and pupation) implemented in the APHIS Hawaii Sterile Fruit Fly Rearing Facility that produced 300-500 million fruit flies per week for U. S. mainland eradication programs for over 10 years. At the time of the assignment, controversy and confusion existed as to selection of the rearing system producing the highest quality insects. A long-term R&D program resolved the controversy and resulted in Hawaiian-based technology being utilized throughout the facility. Research resulted in a patented cage and egg harvest system capable of providing 1 billion eggs per week. Of key importance, even today, is that this system works not only for Medfly but also for Bactrocera species, which is not the case for other egg collection systems through screen. Similarly, research and development on the "popping" larval recovery procedure established this larval recovery system as the method of choice for not only the Hawaii facility, but also for an annex built in Guatemala and a mass production facility built in Japan to eradicate melon fly. The Hawaii rearing system has provided large numbers of sterile flies used in the battle in California against Medfly. SIT (Sterile Insect Technique) is now the primary eradication procedure used in California and Florida against Medfly where over $500 million has been spent on eradication programs since 1980. Malathion bait sprays have been totally eliminated. Although re-assigned to fruit fly IPM, Dr. Vargas is still called upon to consult on fruit fly rearing systems worldwide.
Service, Leadership and Participation in Professional Activities
Honors, Awards, Achievements and Recognition