MOSCAMED-Guatemala An evolution of ideas

Proceedings of 6th International Fruit Fly Symposium 6 10 May 2002, Stellenbosch, South Africa pp. 119 126 MOSCAMED-Guatemala An evolution of ideas Gordon Tween USDA APHIS IS, Regional Medfly Program, Unit 3319, APO AA 34024-3319, U.S.A. E-mail: gtween@aphisguate.com The Moscamed Programme in Guatemala began in 1975 with Medfly pupae imported from Vienna and reared in a vacant aircraft hanger in Guatemala City. From these humble beginnings some 26 years ago, the programme has evolved into the largest Medfly control and eradication effort in the Americas, if not the world. While its present status is of some importance, what needs to be emphasized is the evolution of technologies, ideas, and methodologies that played a major role in the changes that have taken place. Over many years, science and technology has provided the pathways to improve the methods used in insect detection, control, and insect mass-rearing. But it is the operational programme that has facilitated the widespread use and further development of those technologies. Subjecting the technologies to routine usage in field programmes promotes further refinement and a concerted effort to seek other technologies,ideas,and concepts that can be adopted and adapted to the task at hand. The Guatemala Medfly Programme has been a catalyst in the effort to develop and refine fruit fly control and eradication tools. INTRODUCTION It is said that necessity is the mother of invention, and for a Mediterranean fruit fly (Medfly) control and eradication programme,eliminating the pest is the necessity or goal. All on-site efforts are focused on this outcome and the manager must channel field operations,methods development and applied research activities to accomplish the desired result. Off-site long-term research can compliment what is being done by the programme, and is designed to meet some need that has been previously articulated by programme managers. OPTIMIZING ADVANTAGES OF GENETIC SEXING STRAINS An example of science meeting the need of a fruit fly eradication programme would be the development of the genetic sexing ( all male ) strain of Medfly or temperature sensitive lethal (TSL) strain for applying the sterile insect technique (SIT). The TSL strain introduced into the mass-rearing facility in El Pino, Guatemala, in the mid-1990s, was developed in the IAEA laboratory in Seibersdorf, Austria. This promoted the evolution of SIT by making it possible to eliminate the female offspring early on in the mass-production process. Heat-treating the eggs kills the female due to the presence of the recessive temperature lethal gene on the X chromosome that exerts its dominance in the female (XX). This eliminates the female egg from the production process, saving diet, rearing space, and later handling. The absence of sterile females also eliminates sterile male and sterile female copulation after emergence so that 100% of sterile sperm can be dedicated to matings with fertile females, avoids distracting the sterile male in the field, and greatly reduces detection/identification costs and errors. In addition, absence of the female eliminates the damage that results from sterile females stinging the fruit while depositing non-viable eggs. The TSL strain generates some savings in the production process, but the benefits generated in the field greatly outweigh these gains as induced sterility has been shown to be 3 4 times greater than standard (male female) strain releases. The production of the TSL strain has made it necessary to develop a genetic filter to minimize recombination. Recombination, or the tendency to revert back to the normal chromosomal pattern, has to be effectively managed in the mass-rearing process. The filter involves a physical screening of pupae by sexing the adults that emerge from white (normally TSL female) and brown (normally TSL male) pupae to eliminate any recombinants (brown females and white males). The individuals produced from this effort are used to establish small colonies that magnify the numbers of pure offspring that in turn provide pure TSL male and female pupae for the egging colony. A large number of egg-laying females are needed to provide sufficient eggs to produce enough sterile males for release as well as to replenish the colony. A large egging colony requires substantial space and resources to maintain the required number of oviposition cages. Old egging-cage designs, egg production needs, and the required availability of space made it clear that the El Pino production goal of 1.5 to 2.0 billion pupae per week would be difficult to achieve. Through methods development efforts and the use of current engineering, a new cage was

120 Proceedings of the 6th International Fruit Fly Symposium Fig. 1. New cage design and components yields five times the quantity of eggs. designed and built in Guatemala (Fig. 1). Extruded aluminum and injection-molded polycarbonate trays produced a quality unit. The new compact cage produces over three times more eggs than the old cage design. The design change also allowed the required floor space for the egging colony to be reduced by about two-thirds. Less space requires less air-conditioning. The design allows more cage space per ovipositing female, and the photoperiod was greatly reduced without impacting on egg production. Less light also means less electricity, heat generation, air-conditioning, and cost. Maximizing egg production also makes it possible to produce an excess of TSL eggs that can be used by other clients. The mass production of large quantities of TSL eggs (35 60 litres daily) make it necessary to implement an efficient method of heat-treating eggs. Historically, this method involved the use of small plastic bottles of c. 8-litre capacity that contained a small plastic hose for aerating the mixture with air. This bubbling was used to aerate and agitate the egg and water mixture. Using this method with large quantities of eggs would be labour-intensive and inefficient. To address the issue, modern engineering was used to construct a computer-controlled hot-water vat (Fig. 2).The stainless steel vat, with a capacity of Fig. 2. New egg-bubbling vat combines aeration and heat treatment into one step.

Tween: MOSCAMED-Guatemala An evolution of ideas 121 Fig. 3. Central air-conditioning provides greater environmental control over rearing processes. 150 300 gallons of eggs and water, can treat the entire daily egg production. The unit provides for the entire treatment 24 h at ambient temperature, 12 h at 33 34 C, and an additional 12 h at ambient temperature. The treatment involves gentle agitation and the introduction of a measured amount of pure oxygen or a clean mix of air instead of contaminated compressed air. The unit is capable of monitoring temperature, oxygen levels, contaminants, and conducts the entire treatment cycle unaided. Loading the unit with the ratio of eggs and water used for seeding diet, could facilitate the mixture being applied directly to the diet from the vat. NEW STRAINS LEAD TO NEW FACILITY DESIGN REQUIREMENTS The high production levels, and the dependency of the programme on a consistent supply of quality flies, requires a well-controlled environment. For this reason the new modules in El Pino were designed and constructed with a central air-conditioning system (Figs 3&4).The system can produce the desired temperatures and humidity within the Fig. 4. HVAC installed in a service corridor for easier access. A computerized system provides the means of monitoring and modifying environmental conditions to suit the insect. Conditions can be monitored remotely via the Internet or by using a pager.

122 Proceedings of the 6th International Fruit Fly Symposium Fig. 5. The new Packing, Handling and Eclosion Facility located at Retalhuleu includes sizeable emergence rooms, washdown ramps, cold rooms, and a kitchen for preparing adult diet used to feed flies prior to release. different rearing spaces. York components were selected due to the company s previous interest, involvement, and experience in insect rearing. York personnel conducted a study of air-conditioning needs for insect-rearing facilities and toured many of the current facilities in operation. This IAEA-sponsored study led to the system design and equipment currently installed in El Pino. It is likely that further improvements will be made to the fruit fly strain, and dependable environmental control will continue to play a big part in the success of the rearing process. When a production level of 2 billion pupae per week is reached at El Pino, the air-conditioning system must not be a limiting factor. Air management also eliminates acid and other contaminants in the air, protecting personnel, equipment, and Medfly production. With current Medfly production levels at or above 1.5 billion pupae per week, the new packing and eclosion centre in southern Guatemala was a necessary addition (Fig. 5). This facility has c. 7000 m 2 under roof. The facility is currently using the familiar plastic PARC box to contain the pupae for eclosion,but testing is underway to designa tower that will increase the capacity of the facility. A modified adult egging cage and other systems are being tested to determine if other, more efficient units can be used. When the egging-cage trays and parts were designed, the design allowed for this potential dual application. Replacing the PARC box could lead to more efficient use of floor space, sufficient to accommodate 2 billion pupae per week.the warehouse and kitchen,in the modular design, were also insulated and air conditioned to maximize the use of all space for Medfly eclosion. The six cold rooms allow the timely preparation of the 140 170 million flies being distributed daily via aerial release. GREATER CAPACITY OF FACILITIES LEADS TO INCREASED RELEASE CAPACITY To maintain the quality of Medfly being produced in the packing centre, new aerial release equipment is being built. The new unit is designed to eliminate many troublesome mechanical, electrical, and air-conditioning components. The emphasis is on precise temperature/humidity control, simplicity, reliability, durability, and ease of handling. The current design will allow the unit to be used with a variety of moving platforms, including motor vehicles, promoting further flexibility. The new equipment, using cryogenics for cooling, will greatly reduce the electrical load on the aircraft or vehicle selected for the task. Also, the cartridge design will allow the release of varying quantities of fruit flies, parasites, and/or other insects simultaneously. The current aerial platform of choice,a turboprop Cessna Caravan (Fig. 6), was chosen out of necessity. The selection criteria dictated that the aircraft must be dependable, economical, and have a high degree of utility (high-altitude performance, safe slow-flight characteristics, long range, short and rough field capability, low maintenance, a large clear cabin area, and capable of being operated safely by one pilot). This aircraft is currently releas-

Tween: MOSCAMED-Guatemala An evolution of ideas 123 Fig. 6. Aircraft that accommodate two release machines can transport five times more sterile insects per flight with less ferry time and lower release costs. ing 40 million medfly per flight, a factor that results in a very reasonable cost per million flies released. NEW TOOLS FOR POPULATION SUPPRESSION To augment the SIT programme an organic fruit fly bait was selected to lower populations for effective application of SIT (Fig. 7). The stringent regulations applied to environmental protection, human health, food safety, endangered species, and impact of chemicals on beneficial species, greatly restricts the use of non-specific baits and broad-spectrum insecticides. Aerial application of insecticides and fruit fly baits is more restrictive depending on the material of choice. SUCCESS 0.02CB (GF-120; active ingredient = spinosad) is being used in Guatemala and Mexico and is now registered for use in most countries of the Americas. Spinosad has recently acquired an organic registration. This bait is being applied by air and ground methods using large-droplet ULV application. The viscous formulation that is used in the dry season is being used as a base to develop a formu- Fig. 7. SUCCESS 0.02 CB is used to lower wild Medfly populations. This new environmentally-friendly bait kills medflies without adversely effecting non-target organisms such as honey bees, parasitic hymenoptera, birds or mammals. It is non-persistent in the environment.

124 Proceedings of the 6th International Fruit Fly Symposium Fig. 8. New ground application equipment mounted on tractors, all-terrain vehicles and trailers apply measured amounts of insecticide bait to host plants with greater precision. lation suited for wet, humid conditions. Encapsulation in gelatin balls, and wax and jellied bait station formulations, are under development to combat Medfly populations in the high mountain valleys and deep canyons, and to provide extended field life during the unseasonal and seasonal rainy periods. Special application equipment has been designed to apply the bait material (Figs 8 & 9). Ground application equipment is mounted on ATVs for rough terrain,on tractors and trailers to accomplish orchard treatments, and on trucks to address a variety of urban and rural treatment situations. All mobile units can be equipped with computers to insure a precise dosage is applied, an important consideration if the treatment is to be used for quarantine certification purposes. Backpack units are also under review to determine the best design for the rugged areas where coffee is grown. Motor-driven, CO 2 -powered and handpump designs are in daily use. Aerial application equipment was fabricated to provide a cost-effective and safe method of applying the bait at high altitudes (Figs 10, 11, 12). Fig. 9. Novel ways to apply baits include the use of paint balls, gel formulations, wax-impregnated matrices, or motorized backpack sprayers with metered spray guns and nozzles.

Tween: MOSCAMED-Guatemala An evolution of ideas 125 Fig. 10. Aircraft with greater capacity to apply bait sprays result in larger areas being covered at lower cost. Twin-engine turboprop aircraft, Czech LETs, are employed to carry loads of 500 gallons of the heavy bait material to altitude. The large tank capacity avoids frequent ferry flights back to the base, thus reducing cost. The twin-engine aircraft also provides a measure of safety in the mountainous regions, along with the presence of a co-pilot who manages the spray equipment, GIS, and other aircraft systems. Air-tractors, other single engine turboprop aircraft, and turbine helicopters are also used as an integral part of the aerial applications. CONTINUOUS REFINEMENT LEADS TO GREATER EFFICIENCY All facets of the programme are subject to continuous refinement, an evolutionary process critical to the efficient and effective application of fruit fly control and eradication technologies. But more importantly, the refinement process serves to introduce a wide range of engineering technology that makes way for further improvements in the biological systems being employed. Fruit fly control or eradication is a global problem, with Medfly representing only one of many fruit Fig. 11. A variety of aircraft allow greater flexibility in working over mountainous and broken terrain, deep canyons, or relatively flat coastal areas.

126 Proceedings of the 6th International Fruit Fly Symposium Fig. 12. Satellite guidance and flight recorder instruments help pilots avoid ecologically sensitive sites, sources of water and under- or over-treating areas. They also provide programme managers with useful analytical data that can be compared with weekly fruit fly detection data. fly pests needing attention. An all-male strain of Mexican fruit fly (Mexfly), Anastrepha ludens, would facilitate the more effective application of SIT for this economic pest.the use of organic toxins in jellied baits when mixed with methyl eugenol and other attractants would aid the use of male annihilation techniques for Bactrocera and other species. Efficient and cost-effective ground control applications of organic baits, and long-lasting bait stations,can reduce people problems in urban areas. Preventative release programmes (PRPs) and fruit fly control/eradication programmes applying the systems approach, can be more affordable and environmentally friendly with more efficient and effective technologies. While the primary focus of the Guatemala Moscamed programme is Medfly control and eradication, it is also a unique opportunity to improve fruit fly management techniques.the evolutionary changes taking place in the Moscamed programme are influenced by the changing global attitudes toward the environment. Stewardship of the environment and food safety are synonymous with plant protection. These changes in thinking have brought about modifications in the organization of the programme. It is not business as usual, but a concerted effort to set new performance standards for programmes of its kind. It is clear that new biological techniques need the support of new engineering technologies to take full advantage of the scientific development. The synergy resulting from this combination will help programme management accomplish published goals in a cost-effective and efficient manner, conform to more stringent regulations, and meet the expectations of the clients they serve. REFERENCE McINNIS, D.O., TAM, S., GRACE, C. & MIYASHITA, D. 1994. Population suppression and sterility rates induced by variable sex ratio sterile insect releases of Ceratitis capitata (Diptera: Tephritidae) in Hawaii. Annals of the Entomological Society of America 87: 231 240.