Insect pest control newsletter. No. 61

In the past years it has often been pointed out that the name of the Insect and Pest Control Subprogramme of the Joint FAO/IAEA Division, and the name of this newsletter (Insect and Pest Control Newsletter) create confusion and expectations for control of rats, birds, weeds and other non-insect pests but which are not within our mandate. All work within the Subprogramme has been on insect pests, and in 1999 an external review recommended a change to Insect Pest Control Subprogramme since this is simpler, reduces confusion and retains the good recognition and high reputation that already exists. The IAEA management implemented this recommendation and consequently, as of this issue this newsletter is entitled Insect Pest Control Newsletter. There was a very constructive consultant's meeting recently held in Vienna on the development of genetic sexing strains for the codling moth, for which the demand for SIT application is significantly increasing. Based on the discussions during this meeting a real opportunity seems now to exist to move the field of Lepidoptera genetic sexing forward. The possibility of using an allele of a dominant lethal mutation, such as the temperature sensitive Notch, in the development of a genetic sexing system for codling moth is very exciting. As emerged during the meeting, if an appropriate allele of this mutation can be inserted onto the female determining chromosome of codling moth, through transformation, then it may be possible to kill female embryos with a cold temperature treatment. Another approach could be to translocate an autosomal insertion of the gene onto the female determining chromosome. If the insert of the dominant lethal mutation also included a gene expressing a fluorescent protein then the strain would also have a visible marker for the sexing procedure. This latter is very important for any use of a sexing strain in mass rearing. There appear to be few technical constraints to demonstrating 'proof of principle' for this sexing system, which could be a model for other moth pest insects. Germ-line transformation is quite efficient in the codling moth and the appropriate Notch allele has already been shown by Lisa Neven at ARS/USDA in Wapato, Washington State to express correctly in transformed codling moth lines. If such a sexing system could be developed in codling moth then it would have several advantages, a) only the females would be transgenic, the sterile males to be released as part of SIT operations would carry a completely normal genome, b) as the Notch gene is dominant, any recombinant individuals would also be killed by the temperature treatment and not be accidentally released, c) the fluorescent marker would be very tightly linked to Notch, resulting in strain stability, d) stockpiles of diapausing mass reared males would require only half the storage space, and e) the system should probably be easily transferable to other economically important lepidopteran pests. I would also like to report developments related to medfly control in Europe. Currently, medfly control requires intensive insecticide applications during the whole fruit maturation period. This is also the case of southern Spain, where the largest citrus production areas in Europe are located. Nevertheless, as a result of the detection of medfly-infested cargo at US ports of entry over a year ago, the US phytosanitary authorities banned temporarily the large citrus exports from Valencia, Spain. As the US has expensive programmes in operation to remain medly-free, including various preventive SIT programmes, it cannot tolerate the import of infested fruit. In view of these developments, and in order to reduce insecticide use to protect the environment, the authorities of the Autonomous Province of Valencia decided in 2002 to gradually shift their medfly control strategy from conventional large scale aerial insecticide spraying to an integrated pest control approach including the SIT. In March 2002, FAO/IAEA-trained staff initiated aerial releases of sterile medflies over two pilot areas to assess the feasibility of the technology under the specific conditions of Valencia. The Autonomous Government of Valencia is currently purchasing sterile medfly pupae from the mass rearing and sterilization facility located in Mendoza, Argentina, from where weekly shipments are sent to Valencia. Approximately US $500,000 have been invested in asterile fly emergence facility where sterile male flies are emerged and prepared for aerial release. The construction of a mass rearing facility in Spain is under consideration in view of the potential expansion of the approach to major citrus production areas