Bioassays developed and extensive screening undertaken between 2007-10 * No changes in resistance factors in cotton from 2007 to 2010 * Elevated resistance factors recorded in horticultural regions for pyriproxyfen (Admiral) emphasise the importance of the cotton IRMS and a maximum one application Admiral per season * No changes recommended to current insecticide resistance management practices in cotton * Registration of spirotetramat (Movento) in the 2010-11 season with a unique mode of action will assist the insecticide resistance management strategy in cotton * Future directions in resistance monitoring need to address correlating resistance factors with field performance

The survey data showed a wide range of irrigation performance and water volume estimation and measurement across the industry. It found the average GPWUIfarm for the cotton industry was 1.14 bales per megalitre. This figure is a representative benchmark for the cotton industry for 2008/2009 and confirmed the previously revealed 40 per cent improvement by NSW DPI, since the last industry estimate 10 years ago.

The widespread adoption of glyphosate tolerant cotton in the last 10 years has substantially modified the weed control practices used in irrigated and dryland cotton crops. Data on changes in the weed populations, infestation levels and flora, and control tactics were compiled from field and industry surveys to compare changes in the weeds and practices used since the introduction of herbicide tolerant cotton. The focus was on three regions: Darling Downs with 36% dryland cotton grown, Gwydir (12%) and Lower Namoi (9%). Across the crop rotations, flaxleaf fleabane had increased dramatically in both dryland and irrigated systems, and there were more residual weeds in dryland than irrigated systems, particularly for bladder ketmia, flaxleaf fleabane, sowthistle and barnyard grass. The main weeds surviving within glyphosate tolerant crops, prior to implementation of remedial actions, were cow vine, flaxleaf fleabane, nut grass, bladder ketmia and barnyard grass, although relative importance differed between the regions. The approach to weed control over the last decade moved from pre-emptive use of residual pre-emergent herbicides to tactics for control of weed seedlings and survivors of glyphosate applications. Weed management practices were similar across the regions but differed somewhat between dryland and irrigated crops. The weed flora shift, threat of glyphosate resistant weeds, and the extent of weeds surviving in the other components of the rotation indicate the need for a more strategic approach to weed management to be applied across the whole cropping system.

Commencing in October 2009, the 12 month pilot program will measure the industry's responsiveness to government funded irrigation modernisation programs aimed at water recovery. Importantly STBBRG will also assist in guiding the development and implementation of future programs in other NSW Murray-Darling catchments

Aphis gossypii Glover (cotton or melon aphid) is an important pest of cotton due to its ability to reduce yield through feeding damage. Until the introduction of Bt-cotton to Australia in the mid 1990s cotton aphids were considered late season secondary pest because they were suppressed by insecticides used against other pests. However, from 1998-1999 season aphids have been more troublesome initially with control failures against pirimicarb (Pirimor) and omethoate (Folimat) making sticky cotton a real possibility and subsequently nearly a decade later more failures with neonicotinoids. Chemical control failures necessitated a complete re think and modification of the aphid IRMS that is still developing and evolving to this day. The strategy is underpinned by resistance monitoring and mitigation methods based on chemical alternation and no sequential use. This is augmented by a series of adjunct methods of aphid control that help put the resistance gene(s) at a selective disadvantage. Although the newly emerged neonicotinoid resistance in cotton aphid is a serous concern the Australian cotton industry is now much better placed to cope with resistance than back in 1998-1999. With the help of good resistance management Pirimicarb (Pirimor) and omethoate (Folimat) now work and from the 2010-2011 season new chemistry called spirotetramat (Movento) will be available

In a trial undertaken to determine the efficacy of selected chemistry for the control of Solenopsis mealybug on cotton picking machinery, Pulse Penetrant provided close to complete control of all lifestages targeted. The remaining treatments provided significantly lower levels of control and were considered unsuitable for minimising the spread of the mealybug. For example, Farmcleanse at 10% v/v provided the next highest level of control at 61.6% overall mortality. The mortality effect varied depending on the lifestages, with adult mortality lower than that of nymphs for all treatments except Pulse

Knowing how you are performing compared to your region or industry, facilitates continuous improvement in management and water use. Unfortunately irrigation benchmarking data has in the past not been well recorded. The performance indicators measured are generally not well defined and calculations have not been standard across the industry. We talk about bales per megalitre, but what do we mean? The cotton industry has been developing an on-going process to capture water use information from growers and consultants. There are currently web-based tools available to collect this information, including the Water Benchmarking Tool (Cotton Catchments Communities CRC (Cotton CRC) and the Cotton Research and Development Corporation (CRDC) 2007) and the commercially available WATERTRACK RAPID. The significance of these tools is that calculations of water use indices are standardised and are defined.

Summary * Pest managers were surveyed to benchmark mirid management practices * Many mirid sprays were applied when mirids were below threshold and fruit retention was high (>85%). * This is largely because pest managers were not allowing for differences between thresholds for visual and beat sheet sampling * Spraying for mirids at below threshold levels provided no yield advantage, but increased costs and the risk of flaring secondary pests * The results therefore validate the recommended thresholds. Emphasis needs to be placed on giving pest managers confidence in mirid thresholds so that they will adjust their interpretation of their counts according to sampling technique.

Maize or corn (Zea mays) is becoming increasingly popular as a summer crop in irrigated cotton rotations. This is largely being driven by anecdotal grower evidence of yield improvements of up to 25 percent in cotton crops grown after maize compared to back-to-back cotton. Cotton growers believe that their soils are in better condition after a maize crop with higher amounts of organic matter observed compared with fields coming out of cotton or wheat. This improved soil structure is thought to be the main driver of the increased yields. Recent research has shown that maize provides more organic matter to upper layers of the soil and extracts less water at depth compared with cotton. It is thought that the following cotton crop can then benefit from increased water availability and better soil health. Another recent study showed that microbial biomass and root density are higher in cotton-based rotations that include maize compared with rotations with wheat or continuous cotton. Maize also provides a number of other benefits to cotton growers including reduced workload in the second half of the season compared with cotton, a refuge option

The results of annual disease surveys in both NSW and Queensland continue to provide useful data on the distribution, incidence and importance of diseases of cotton in Australia. Plant pathologists at Narrabri, Brisbane, Toowoomba, Armidale, Canberra, Melbourne and Sydney are continuing to investigate the relationships between the host, the pathogens and the environment and are continuing to develop and promote strategies for disease control. (See Acknowledgments) Observed trends in disease incidence and severity over time and space are cause for concern. Recent trends in farming practices may also impact on disease incidence and severity. A farming system is a complex assemblage of interacting components and changes to any one component can have significant effects