Bait matrix for novel toxicants for use in control of fruit flies (Diptera: Tephritidae)

The notion of geographical isolation as a protective barrier for a nation's agricultural assets is going fast by the wayside as agricultural trade expands globally. Barriers are breaking down in the interests of export or import of agricultural products and with expanded trade the probabilities of moving undesirable pests from one locality to another are increasing. The notion of invading pest species may be, in great part, the movement of people that facilitate the movement of exotic insects. The dilemma to a receiving state or country is what to do to do prevent the entry of, detect, or eliminate a new pest species. If the pest can not be eliminated, then, what is the risk and cost of living with it and manage its numbers. The first line of defence should be regulatory based on evidence provided by science. The second should be an active response that curtails the survival of the new pest. An insecticidal spray strategy has worked well time and time again against the Mediterranean fruit fly (Ceratitis capitata) and the oriental fruit fly (Bactrocera dorsalis) each time these fruit flies have invaded California in the past. The insecticide strategy is still being used against B. dorsalis but is being replaced against C. capita with continual releases of sterile flies. The action embodies the concept that the continued presence of sterile flies will nullify the reproductive capability of incoming feral flies due to shear competition for mates. The continual release of sterile flies appears to work very well in the Los Angeles basin area and targets only the species in question. However, such a technique is not available for a number of fruit fly species. Consequently, reliance on an insecticidal strategy will continue. But, if novel toxins with little or no contact toxicity are used, more attention must be given to the carriers of such toxins to ensure that they attract flies to spray deposits and entice them to consume the residues. (author)