A pilot sterile insect release programme to suppress codling moth in South African apple and pear orchards

Full text: A local pilot codling moth sterile insect release (SIR) programme was proposed in 2002. The purpose of the pilot programme is to demonstrate the method and to establish its economic feasibility in commercial apple and pear orchards in South Africa. Due to financial constraints, the programme was limited to a total area of 150 ha. The pilot programme was launched in 2004 and is due to continue until March 2006. Initial efforts involved the establishment of a codling moth colony from field-collected insects during 2002. The colony was expanded during 2003 and codling moth eggs were imported from Canada. The insects were reared on an agar-based diet in small containers enclosed in paper bags. The colony was subsequently expanded in preparation for field releases in 150 ha during the 2004/05-season. The orchards selected for the pilot programme are planted in close proximity to each other and the area is semi-isolated. All orchards are treated with pheromone mediated mating disruption in combination with insecticide applications. The orchards are situated on two neighbouring farms, and both farms have extensive pest and disease monitoring programmes, thus historic data is available for all orchards. A monitoring method involving the weekly inspection of 24 trees per orchard is used. The monitored trees are marked and their position recorded using a global positioning system (GPS). All data generated during monitoring are recorded on a hand held computer and analysed using software developed in conjunction with Stellenbosch University. The software allows for the spatial and temporal analysis of pest and disease distribution and associated damage in the monitored orchards. Current research and development needs include the development of improved culture methods and the assessment of the overall fitness of laboratory cultured moths in the field. Irradiated and non-irradiated have been assessed under field condition using mark and recapture methods. The distribution of laboratory-reared moths, in conventional and pheromone treated orchards has been assessed over a period of 20 weeks. Results indicate that locally produced moths are competitive. The determination of the costs and benefits associated with the integrated use of SIT is central to the pilot programme. Initial estimates of production costs indicate that the treatment of an orchard with sterile moths is comparable to the cost of codling moth pheromone disruption. The benefits accrued by the use of SIT over a number of seasons will be determined. The programme is financially supported by the South African Apple and Pear Producers Association, the IAEA and the participating farms. The total costs for the first year of operation are approximately USD 100,000. The local fruit industry has insisted on the rapid commercialization of the programme if it proves to be financially viable. (author)