Proceedings of 6th International Fruit Symposium 6–10 May 2002, Stellenbosch, South Africa pp. 245–249

SIT and biological control of fruit in

D. Orozco*, J. Domínguez, J. Reyes, A. Villaseñor & J.M. Gutiérrez Campaña Nacional Moscas de la Fruta, SAGARPA-IICA, Metapa, Chiapas, México

After the success of the Moscamed programme in stopping the northward spread of the Mediterra- nean fruit fly and eradicating it from southern Mexico in the early 1980s, Anastrepha spp. fruit flies became the most important pest for the fresh fruit industry in the country. Basic research on species’ distribution, host preferences, ecology and behaviour of these flies was initiated. Soon, it was evident that the sterile technique (SIT) and augmentative biological control (ABC) were feasible control alternatives for the integrated management of some of the most important species. Methods of mass-rearing the three most important species (A. ludens, A. obliqua and A. serpentina) and the parasitoid Diachasmimorpha longicaudata, were developed. By the early 1990s the Mexican National Fruit Fly Campaign was initiated with the goal of having fruit fly-free areas in the north of the country, areas of low prevalence in particular agroecological regions, and integrated management of fruit flies in other fruit-growing areas.Because SIT and ABC were chosen as the main control methods, a mass-rearing facility was built near the Moscamed facility, in Metapa, to produce 50 million sterile A. ludens and A. obliqua and 30 million parasitoids per week. Today,the northern states of Sonora,Chihuahua and Coahuila are recognized as fruit fly-free areas. Sterile flies and parasitoids are being sent to the states of Nuevo León, Tamaulipas, Baja , BajaCaliforniaSur,SinaloaandAguascalientesforpopulationsuppression.Themass-rearingfacility has been able to maintain the production of high-quality A.ludens,A.obliqua and D.longicaudata for more than six years,with an increasing level of efficiency,and therefore cost reduction.In collabora- tion with the California Department of Food and Agriculture,sterile flies are being sent to California for the control of A.ludens in the state of California.The current status of the National Campaign,as wellasdataonthemassproductionofinsects,indicatesthatSITandABCarefeasiblealternativesfor the control of these fruit flies, and if a long-term cost–benefit analysis is made, this area-wide approachcouldresultamuchmoreefficientoptionthanfarm-by-farmcontrolbasedoninsecticides.

INTRODUCTION THE PROBLEM Fruit production in Mexico is one of its most In Mexico there are over 30 species of Anastrepha important economic activities. However, fruit flies fruit flies. Because of their distribution, hosts, and represent a limiting factor for further development damage caused, only four of these species are of this industry,with damage estimated at approxi- considered of economic importance: A. ludens, A. mately US$2350 million (Anon. 1991). obliqua, A. striata (guava fruit fly) and A. serpentina Technologies currently available for the integrated (zapote fruit fly). management of pests offer sound strategies that The distribution of these four species is along the are economically feasible and have minimal or no Pacific and Gulf coasts, with greater abundance effect on non-target organisms.The strategy of the and diversity in the tropical areas of southern Mexican National Fruit Fly Campaign is based on an Mexico.There are some specific areas in the central area-wide pest management approach with the highlands where these species are reported as use of sterile flies Anastrepha ludens (Mexican fruit important pests. In the more dry and arid regions fly) and A. obliqua (West Indian fruit fly), and with of northern Mexico, A. ludens is the most common augmentative releases of the highly selective and species, mainly attacking and crops, effective parasitoids Diachasmimorpha longicaudata and occasionally, A. obliqua is found infesting (Aluja 1982). mango fruits (Anon. 1986). The (SIT) requires the mass production and release of millions of sterile MOSCAFRUT MASS-REARING AND flies in order to gradually reduce pest populations. STERILIZATION FACILITY To be effective, detailed information on pest The mass-rearing methods used at the Moscafrut population density and distribution is needed, as facility were initially derived from the Medfly well as the capacity produce high-quality at mass-rearing facility (Moscamed) and the methods a competitive cost. used at the USDA Mexican fruit fly mass-rearing

*To whom correspondence should be addressed. laboratory in Monterrey, Nuevo León. Later, these E-mail: [email protected] methods were adapted to local conditions and 246 Proceedings of the 6th International Fruit Fly Symposium

Table 1. Average weekly production of sterile Anastrepha spp. fruit fly pupae and Diachasmimorpha longicau- data parasitoids at the Moscafrut facility from 1994 to 2001.

Average weekly production of pupae (millions) Year Anastrepha ludens Anastrepha obliqua D. longicaudata

1994 152.173 – 24.645 1995 106.501 1.012 23.415 1996 142.361 12.994 20.057 1997 122.215 8.153 16.757 1998 94.136 2.179 7.019 1999 113.919 0.629 10.167 2000 106.259 0.585 24.925 2001 97.326 5.051 27.187 locally available materials at the Methods Develop- the reduction in production yields. The number ment Department of the Moscamed programme. and type of tests for diet ingredients was increased Modifications have continued to achieve produc- and new quality parameters were established. tion goals and to make the process more efficient. Currently,and because of field needs,two modules The Moscafrut facility was build as a modular of the facility are dedicated to the production of system with the goal of producing 50 million sterile A.ludens,withanaverageweeklyproductionof150 A.ludens,50 million sterile A.obliqua and 30 million million sterile pupae per module. D. longicaudata parasitoids per week. Anastrepha obliqua Anastrepha ludens From 1993 to 1995 several studies were conducted From 1998 to 2001 problems with the diet ingre- to optimize production of this fruit fly. During 1996 dients were encountered that were responsible for and 1997, production was increased to implement Table 2. Average weekly quality of Anastrepha spp. (a, b) and Diachasmimorpha longicaudata (c)atthe Moscafrut facility from 1994 to 2001. a. Quality of Mexican fruit fly, pre-irradiation

Parameters 1995 1996 1997 1998 1999 2000 2001

Pupation in 24 h (%) 57 87 87 81 82 64 79 Pupal weight (mg) 16.25 16.50 16.50 17.80 17.70 17.71 18.36 Emergence (%) 88 95 95 93 93 91 91 Fliers (%) 86 92 92 91 91 90 89 b. Quality of West Indian fruit fly, pre-irradiation

Parameters 1994 1995 1996 1997 1998 1999 2000 2001

Pupation in 24 h (%) 84 89 83 92 80 79 75 84 Pupal weight (mg) 13.63 15.61 15.39 14.31 14.00 14.01 14.09 14.23 Emergence (%) – – 90 92 84 84 80 79 Fliers (%) – – 86 85 76 76 75 73 c. Quality of Diachasmimorpha longicaudata ready for release

Parameters 1996 1997 1998 1999 2000 2001

Larval weight (mg) 22.90 22.90 24.49 24.90 23.76 24.86 Emergence 1st exposure (%) 56 56 69 67 62 69 Emergence 2nd exposure (%) 56 56 68 65 64 62 Orozco et al.: SIT and biological control of Anastrepha fruit flies in Mexico 247

Fig. 1. Release areas of sterile West Indian fruit fly.

SIT in the northwestern part of Mexico in the state Field results of Baja California Sur. From 1998 to 2000 only a The goal of the Mexican National Fruit Fly maintenance colony was kept (no releases), and in Campaign was to establish fruit fly-free areas in the 2001 production was increased to enable sterile northern states, low prevalence areas in some releases in Baja California Sur and Sinaloa. specific isolated fruit-growing regions,and areas of integrated fruit fly management in other areas Diachasmimorpha longicaudata where ecological conditions were more complex The production goal since 1994 has been 20 and isolation was not feasible. Actions to prevent million per week. However, due to funding limita- the introduction of exotic fruit fly species were tions,from 1997 to 1999 only a maintenance colony simultaneously maintained. was kept. In 2000 the strategies of the National The strategy for integrated management included Campaign changed and the goal became the the following action sequence: fruit sampling and production of 30 million parasitoids per week. trapping, determining the time for lowest popula- tions under natural conditions,further reduction of Quality control populations at this time by cultural practices, The quality of the sterile flies and parasitoids is application of insecticide baits only when it was continually evaluated through quality control tests strictly necessary, release of parasitoids together under laboratory and field conditions (Boller et al. with or followed by releases of sterile flies, estab- 1981;Orozco et al.1983;Cancino et al.1996).Table 1 lishment of quarantine stations, and permanent shows the average weekly production and Table 2 monitoring of wild fruit fly populations, even after the average quality control parameters obtained control or eradication was achieved. At the same from 1994 to 2001. time, post-harvest treatments were developed for The most dramatic changes in the quality of non-traditional crops, so that export to fruit fly- some parameters, such as pupation of Mexican free countries was possible. fruit fly, were attributed to environmental condi- For strategic purposes the country was divided in tions. In the case of West Indian fruit fly, quality three zones: parameters largely depend on the quality of the Free zone. Areas where fruit flies were eradicated larval diet ingredients. For example, high levels of and no wild fruit flies are detected. These include coliforms on corn cobs were considered the main the states of Baja California, Baja California Sur, problem in 2000.The emergence of D.longicaudata Sonora, Chihuahua, Coahuila and north of Sinaloa. depends directly on the quality of the fruit fly larval Low prevalence zone. Fruit flies might be present, host,so if the weight of the fruit fly larvae increases, but at a level at which they do not represent a pest the emergence of parasitoids also increases. risk for fruit marketing. This zone includes the 248 Proceedings of the 6th International Fruit Fly Symposium

Fig. 2. Release areas of sterile Mexican fruit fly. states of Aguascalientes, Durango, Nuevo León, released every week in the states of Baja California North and Central Tamaulipas and central and Sur and Sinaloa (Fig. 1). Up to 100 million sterile south Sinaloa. A. ludens flies are produced per week for release in Zone under phytosanitary control. This zone is the states of Nuevo León, Tamaulipas, Sinaloa, represented by the rest of the country, where the ZacatecasandNayarit(Fig.2)andCalifornia(U.S.A.), pests are widely distributed and control actions and 25 million parasitoids per week are released in are taken to suppress natural populations, so the states of Nayarit, Michoacán, Sinaloa, Chiapas fruits can be sold in local markets or exported and Nuevo León. (Fig. 3). following specific protocols thatinclude integrated The establishment of free areas, low prevalence management practices and the use of post-harvest areas, and areas under phytosanitary control has treatments. resulted in benefits for fruit growers, transporters, Currently, four million sterile A. obliqua flies are traders and consumers due to the production of

Fig. 3. Release areas of the parasitoid Diachasmimorpha longicaudata. Orozco et al.: SIT and biological control of Anastrepha fruit flies in Mexico 249 non-infested fruits. During 2001, new markets , C.A. were opened for citrus, , guavas and ANON. 1986. Planta de Producción de Moscas de la Fruta Estériles y Parasitoides. Secretaria de Agricultura y , with an estimated value of US$1500 mil- Recursos Hidráulicos. Grupo Grafico Romo, Rome. lion in the local markets and US$142 million in ANON. 1991. Estudio Beneficio/Costo de la Campaña de international markets. Erradicación de las Moscas de la Fruta. Secretaria de Agricultura y Recursos Hidráulicos, Subsecretaria de ACKNOWLEDGEMENTS Agricultura. BOLLER, E.F., KATSOYANNOS, B.I., REMUND, U. & The authors wish to express their gratitude to CHAMBERS, D.L. 1981. Measuring, monitoring and Martin Aluja who initiated basic research work improving the quality of mass reared fruit flies, Cera- in order to develop integrated management titis capitata Wied. 1. Rapid quality control system for approaches for the control of Anastrepha spp. We early warning. Zeitschrift für Angewandte Entomo- logie 92: 67–83. thank W. Enkerlin (International Atomic Energy CANCINO, D.J.L., DE LA TORRE, S., RUIZ, S., MORENO, F. DE Agency, Vienna) and all staff at the Dirección MA., HERNÁNDEZ, E. & ZENIL, M. 1996. Estableci- General de Sanidad Vegetal, fruit growers associa- miento de la producción masiva de Diachasmimorpha tions, and federal and state authorities who have longicaudata en Metapa de Domínguez, Chiapas, supported the National Campaign. We also thank México. Proceedings of the 2nd Meeting of the Working Group on Fruit Flies of the Western Hemisphere. PabloLiedoforreviewingearlydraftsofthispaper. Viña del Mar, Chile. OROZCO, D., SCHWARZ, A. & PEREZ, A. 1983. Manual de REFERENCES Procedimientos de Control de Calidad Utilizado para ALUJA, M. 1982. Perspectivas futuras para el manejo Evaluar la Mosca Producida en el Laboratorio de integrado de las moscas de la fruta (Diptera- Producción y Esterilización de la Mosca del Mediter- ) en ecosistemas tropicales de América ráneo. DGSV-SARH. Talleres Gráficos de la Nación, Latina. I Congreso de Manejo Integrado de Plagas en Mexico.