Integrated pest management (IPM) has been a major focus of the cotton extension program for the Australian cotton industry. The Australian cotton industry extension model involves Cotton Industry Development Officers (Cotton IDO's) located within each major cotton growing region. A key component of the Cotton IDO role is the adaptation of research at a local level primarily through on-farm trials and demonstrations. The work presented in this paper is the results of a series of on-farm trials carried out across the Australian cotton growing areas in a collaborative effort by researchers and the Australian Cotton Industry Extension Network.

The adoption of dynamic insect pest thresholds has meant a more flexible approach to insect pest management. Consequently, monitoring of crop growth rates and fruit development to avoid excessive crop damage is even more critical. An alternative technique for monitoring crop fruit load is the Fruiting Factor. This technique considers fruit in all fruiting positions. The optimum fruiting factor varies depending on crop development stage. The range of fruiting factor values associated with optimum yield have been identified for each crop development stage. Assessment of fruiting factor during the 7-10 day period after first flower can provide a useful indication of the yield potential of the crop. Monitoring of fruiting factors gives some safety guidelines when using dynamic insect pest thresholds. Interpretation of fruiting factors at first flower can indicate whether there is a significant risk to crop yield and maturity.

The introduction of Bollgard II® technology has raised some issues regarding high retention crops. • Does Bollgard II compensate for early season damage to the same extent as conventional cotton? • What is the impact of the high early retention seen in Bollgard II? • Will fruiting factor ratios also apply to Bollgard II crops? Imposing some damage to Bollgard II crops to simulate early season insect damage eg mirids has been demonstrated to impact on yield to varying extents compared with undamaged treatments. Obviously where damage treatments were severe there was a negative impact on yield. However, in most cases simulating insect damage either through fruit removal or terminal damage improved yield. The impact of different Bollgard II retention levels on fibre quality was also included in this work.