274 Florida Entomologist 87(3) September 2004 LABORATORY PARASITISM BY PHYMASTICHUS COFFEA (HYMENOPTERA: EULOPHIDAE) UPON NON-TARGET BARK BEETLES ASSOCIATED WITH COFFEE PLANTATIONS ALFREDO CASTILLO1, FRANCISCO INFANTE1, GUILLERMO LÓPEZ1, JAVIER TRUJILLO2, LAWRENCE R. KIRKENDALL3 AND FERNANDO E. VEGA4 1El Colegio de la Frontera Sur (ECOSUR), Carretera Antiguo Aeropuerto km 2.5. Tapachula 30700 Chiapas, Mexico 2Colegio de Posgraduados, Instituto de Fitosanidad, Montecillo, 56230 Edo. de México, Mexico 3Institute of Zoology, University of Bergen, Allégaten 41, N-5007 Bergen, Norway 4Insect Biocontrol Laboratory, U. S. Department of Agriculture, Agricultural Research Service Beltsville, Maryland, 20705-2350, USA ABSTRACT Phymastichus coffea (LaSalle) is an African parasitoid of adults of the coffee berry borer Hy- pothenemus hampei (Ferrari) that has been introduced to Mexico and other Central and South American countries for the biological control of this important pest. The present study assessed the host specificity of this parasitoid in the laboratory. We tested the acceptance and parasitism of P. coffea on five species of bark beetle adults commonly found in coffee plantations of Mexico: Hypothenemus crudiae, H. plumeriae, H. eruditus, Scolytodes borealis and Araptus fossifrons. As a control, we used adults of H. hampei, the natural host. P. coffea parasitized and successfully completed its life cycle in H. crudiae and H. eruditus, as well as in H. hampei. The degree to which bark beetles were attacked by P. coffea was estimated by percent of parasitism, which was 64% for H. hampei, 14% for H. crudiae, and 6% for H. eru- ditus. The risk of potential deleterious effects of the parasitoid on non-target organisms in coffee agroecosystems is discussed. Key Words: Host specificity, Phymastichus, Hypothenemus, Scolytodes, Araptus, Mexico. RESUMEN Phymastichus coffea (LaSalle) es un parasitoide africano de adultos de la broca del café Hy- pothenemus hampei (Ferrari) que ha sido introducido a México y otros países de Centro y Sudamérica para el control biológico de esta importante plaga. El presente trabajo se llevó a cabo con la finalidad de evaluar la especificidad de huéspedes de este parasitoide en el lab- oratorio. Se probó la aceptación y parasitismo de P. coffea sobre adultos de cinco especies de descortezadores comúnmente encontrados en plantaciones de café de México: Hypothenemus crudiae, H. plumeriae, H. eruditus, Scolytodes borealis y Araptus fossifrons. Como control se usaron adultos de H. hampei (hospedero natural). P. coffea parasitó y completó exitosamente su ciclo biológico en sólo dos especies de escolítidos, H. crudiae y H. eruditus, además de H. hampei. El grado en el cual los descortezadores fueron atacados por P. coffea fue estimado por el porcentaje de parasitismo el cual fue de 64% para H. hampei, 14% para H. crudiae, y 6% para H. eruditus. Es discutido el riesgo de los efectos negativos potenciales de este par- asitoide sobre organismos no blanco en agroecosistemas de café. Translation provided by the authors. Phymastichus coffea LaSalle (Hymenoptera: tion, having been collected from east Africa Eulophidae) is a primary parasitoid of the coffee (Kenya) and west Africa (Togo, Benin, Cameroon, berry borer (CBB), Hypothenemus hampei (Fer- Burundi, and Ivory Coast) (Infante et al. 1992). rari) (Coleoptera: Scolytidae), the most devastat- So far, this parasitoid has been introduced to cof- ing pest of coffee throughout the world (Baker fee producing countries, such as Colombia, Guate- 1999). This parasitoid, indigenous to Africa, was mala, Honduras, Jamaica, El Salvador, Ecuador, first recorded in 1987 from Togo parasitizing the India, Brazil and Mexico for biological control CBB (Borbon-Martínez 1989), and subsequently purposes (Castillo, unpublished data). This spe- was described as a new species (LaSalle 1990). cies is the only known parasitoid of adults of CBB, Phymastichus coffea has a pan-African distribu- and is considered to be a potentially useful tool in Castillo et al.: Parasitism by P. coffea upon Non-target Bark Beetles 275 integrated pest management programs against been collected from dozens of host species. The Sc- H. hampei (López-Vaamonde & Moore 1998; olytodes breeds only in fallen Cecropia leaves Baker 1999). (Jordal 1998). Araptus fossifrons Wood, a Me- Eulophidae is one of the largest families in Hy- soamerican species previously collected from vari- menoptera with nearly 4000 described species ous seed pods and lianas (Wood & Bright 1992), (Noyes 1998; Gauthier et al. 2000). The subfamily was captured using CBB traps (Dufour 2002). Tetrastichinae, to which P. coffea belongs, has an extraordinarily wide host range and exhibits a Experimental Procedure great variety of life styles. Members of this sub- family attack over 100 families of insects, as well The host specificity of P. coffea was evaluated as mites, spider eggs, and even nematodes (J. La- in the laboratory in a non-choice test. Fifty speci- Salle, pers. comm.). Despite the fact that P. coffea mens of each species were placed individually in has already been imported and released in vari- 40 × 10 mm glass vials and immediately after- ous countries of the Americas, it is important to wards, a P. coffea female was introduced. The in- determine whether this parasitoid can attack sects were observed for five hours under a 20W non-target scolytids. fluorescent lamp. We considered oviposition to The objective of this study was to test the host have occurred when the female parasitoid specificity of P. coffea in the laboratory with six adopted a characteristic ovipositing position on bark beetles species commonly found in coffee the elytra of the scolytids (López-Vaamonde & plantations of Mexico, with H. hampei serving as Moore 1998). Hosts attacked by P. coffea were the control. A previous study in Colombia reported transferred individually into vials containing that P. coffea was able to parasitize H. obscurus, CBB diet (Villacorta & Barrera 1996) and para- H. seriatus, and Araptus sp. in the laboratory (Ló- sitization was assessed based on the emergence of pez-Vaamonde & Moore 1998). We included differ- the progeny, or by dissecting the hosts that did ent species than those examined in Colombia; not yield parasitoids. We also recorded the time thus, this study serves to further elucidate the po- required for the encounter (defined as the time tential risk of P. coffea for non-target scolytids. elapsed between the release of the parasitoid in the arena until it assumed the characteristic ovi- positing position on the beetle), and the handling MATERIALS AND METHODS time (defined as the time elapsed between the en- Parasitoids counter and the end of parasitization). Environ- mental conditions of the laboratory during the We used mated females of P. coffea, which were development of parasitoid’s progeny were 26 ± less than 1h old from the time they emerged from 2°C and 70-80% RH. CBBs. The parasitoids were obtained from a col- ony established in the laboratory in March of Taxonomy 2000. The colony was initiated with insects im- ported from Guatemala with methodology de- Samples of the species used were compared by scribed by Infante et al. (1994). Adult CBB Kirkendall with type material, or with specimens females obtained from the field were used for par- in his collection or in the S. L. Wood collection asitoid rearing. The insect colony is normally which had been compared with type material. maintained at 26 ± 2°C, 75 ± 10% RH and 8:16 Vouchers for all species are in Kirkendall’s collec- (L:D) photoperiod. tion at University of Bergen, Norway. Hosts RESULTS We offered six species of bark beetles collected Oviposition attempts by P. coffea were ob- as adults in coffee plantations near Tapachula, served on all scolytid species tested, but parasiti- Chiapas to adults of P. coffea in the laboratory. The zation and development of progeny was parasitoid was never released in the plantations completed on only two species of bark beetles, in where we collected the bark beetles. To minimize addition to H. hampei (Fig. 1). The percentage the risk, the CBBs were obtained by dissecting parasitism for H. hampei, H. crudiae, and H. eru- infested coffee fruits from the field, while we ditus was 64%, 14% and 6%, respectively (Table collected Hypothenemus eruditus Westwood, 1). We did not detect any oviposition by P. coffea in Hypothenemus crudiae (Panzer), Hypothenemus S. borealis, H. plumeriae, and A. fossifrons, nor plumeriae (Nordlinger), and Scolytodes borealis did we find adult or immature stages of the para- Jordal from petioles of Cecropia sp. leaves. The sitoid after hosts were dissected. Sex ratio of three Hypothenemus species we used are wide- progeny produced by P. coffea in the three species spread and co-occur with Coffea spp. where the was 1:1. The shortest encounter time was be- latter are native (Wood 1982; Wood & Bright tween P. coffea and H. hampei (mean = 23 min). 1992). They are extremely polyphagous, and have Encounter time was 5-6 times longer when para- 276 Florida Entomologist 87(3) September 2004 Fig. 1. Adults of three species of scolytids parasitized by Phymastichus coffea in the laboratory, showing the hole made by the emerging wasp adult: (A) H. hampei (B) H. eruditus and (C) H. crudiae. sitization was on H. crudiae or H. eruditus. How- demonstrated in the field later on (Barron et al. ever, the handling time was shorter (1.5 min) in 2003; Babendreier et al. 2003b). Accordingly, par- H. eruditus than in the other hosts. In most cases asitism by P. coffea on H. crudiae and H. eruditus P. coffea allocated more than two eggs per host af- in the laboratory does not necessarily mean that ter a single attack. Development of immature these beetles will be attacked by this parasitoid in stages of the parasitoid ranged from 39 to 42.6 the field. Careful observations under field condi- days (Table 1). tions should be carried out before concluding that these beetles are alternative hosts of P.