| Abstract: | A voluntary insecticide resistance management strategy for the control of H. armigera was implemented in Australia in 1983 after an outbreak of resistance to synthetic pyrethroids. This strategy restricts the use of pyrethroids to three sprays within a 42-day period in summer. The use of endosulfan is also restricted and rotation of other pesticides is encouraged. The effectiveness of the strategy is monitored by tests on larvae collected from two major cotton areas and from unsprayed crops in northern New South Wales. Research is under way to determine the genetic basis of two of the three mechanisms involved in resistance. One genetic component is associated with the mixed-function oxidases. Selection in the field for this semi-dominant gene (or genes) occurs in larvae 4 days or more old. It is not possible to evaluate directly the success of this strategy because there is no control area where it has not been implemented. While the long-term outcome of the strategy is uncertain, it is likely that resistance will increase in frequency. |
