A participatory project was conducted with small-scale coffee growers from Quindío Department, Colombia. In 34 coffee lots in three municipalities, growers implemented an integrated management programme against the coffee berry borer (CBB) Hypothenemus hampei Ferrari, based on improved cultural harvesting and sanitation practices (to remove breeding habitats) and releases of exotic parasitoids. Growers released over 10 million Cephalonomia stephanoderis and 5 million Prorops nasuta (both Hymenoptera: Bethylidae) over 2 years. Populations of the CBB declined from a range of 7–14% infested berries (Quimbaya), 10–13% (Montenegro) and 15–48% (Buenavista) prior to the integrated pest management programme, to an average of 2.1 ± 0.2% infested berries in Químbaya, 3.5 ± 0.2% in Montenegro and 2.8 ± 2.1% in Buenavista, over the following 25 months. Damage to parchment coffee similarly declined during this period. Six months after the final release of parasitoids had been made, we found both parasitoid species established in all three municipalities. However, P. nasuta were recovered more frequently (in 71.4% of lots where they were previously released) compared with C. stephanoderis (recovered in 30.8% of release lots). Average parasitism rates remained low, i.e. 3.7% for P. nasuta and 2.9% for C. stephanoderis. This low rate was probably due to the frequent manual removal of mature berries containing developing parasitoid larvae. In addition, the entomopathogenic fungus Beauveria bassiana was observed on average on 9.5% adult CBB in Montenegro, compared with mean infection rates of 4.3 and 4.4% in Quimbaya and Buenavista, respectively. Cultural harvesting and sanitation is an important component of CBB control, although it may limit the impact of the pest's parasitoids.

Cephalonomia stephanoderis and Prorops nasuta are two bethylid wasps released into several Latin American countries for classical biological control of coffee berry borer, Hypothenemus hampei, the most serious insect pest of coffee worldwide. Recent studies on the host location behaviour of these parasitoids have shown that females of both species are attracted to volatile compounds released by immature stages and dust and frass of H. hampei. In this study, we investigated the role of the contact chemicals present in dust and frass of H. hampei on the behaviour of P. nasuta and C. stephanoderis females. Parasitoids remained longer on patches treated with methanol extracts than on acetone and hexane extracts. Females spent more time on the patch treated with the methanol extract of dust and frass than on the patches treated with the methanol extract of dry coffee and methanol control. The concentration of the methanol extracts from dust and frass influenced the locomotory activity of parasitoids of both species. The time that females spent in the patch tended to increase as the concentration of the methanol extracts increased. A further experiment aimed to identify other behavioural descriptors and gain a deeper understanding of the mechanisms underlying the response of parasitoids to methanol extracts was performed. Females of both species spent more time, covered more distance, turned more (per unit time and per unit distance), and decreased their speed when they contacted patches treated with methanol extracts in comparison to patches treated with methanol control.

The coffee berry borer, Hypothenemus hampei, which originates from Africa, is one of the most serious pests of commercial coffee and is now present in most of the major coffee growing parts of the world. Quite recently, this beetle spread into Mexico and Ecuador and is now causing serious economic losses in these two countries. In 1985, a classical biological control programme was started to control the pest using the bethylid, Prorops nasuta and other hymenopterous natural enemies from Africa. During the programme, various studies were conducted in Kenya on P. nasuta and H. hampei including their field distribution and life history. A technique of rearing and screening P. nasuta against plant diseases was developed and several shipments have now been made to Ecuador and Mexico. In 1988 a continuous laboratory culture of P. nasuta had been established in Ecuador and the wasp was also reported to be reproducing in sleeves cages in the field.