This proposal builds on many years of weeds work supported by CRDC and aims to value add to the earlier work, while providing strategic information to cotton growers in support of MyBMP, based around updating WEEDpak, the Guide to Integrated Weed Management in Cotton.The project aims to develop and expand strategic areas of WEEDpak, providing:• Up-to-date guidelines for Integrated Weed Management in the Roundup Ready Flex system,• Up-to-date information on key weed questions in MyBMP,• More and better information on the potential for damage issues from herbicides used in other parts of the farming system, and• An improved, more user-friendly and more robust weed control threshold for cotton.

The project uses a combination of field and glasshouse experiments, laboratory studies and observations in commercial cotton fields, in collaboration with the weeds work undertaken by researchers at QDPI, Toowoomba.

Work will continue on the weed threshold, with analysis of 8 years of data to re-develop a weed biomass-based threshold, improving on the current density based threshold which doesn’t adequately allow for staggered weed germination. This work will be written up in a series of scientific papers and submitted as a PhD by the Principal Researcher. The work will be supplemented by experiments to validate the weed control threshold using the background weed population, supplemented to ensure strong weed pressure, manipulated with a range of timings and number of applications of glyphosate. An infra-red sensor (GreenSeeker ™) is used to estimate weed biomass.

The weed growth and development information will be validated using a large number of 200 L drums at ACRI, which will be filled with soil and flood irrigated according to normal practices. The drums closely mimic field conditions, but allow individual weeds to be studies without the complications of competition and other field issues. The work will be undertaken as a PhD, supervised through UNE, Armidale, with assistance from the field staff in this project for much of the initial work. The work will complement work by the QDPI team at Toowoomba, who will use at number of large, controlled environment chambers to examine the seasonal requirements for weed emergence, and additional work at ACRI using our 4 germination cabinets. The research will examine 18 weeds which have been identified as being at high risk of developing herbicide resistance (analysis from the QDPI group) and are weeds which are showing up in the Monsanto weed audits as being problematic in Roundup Ready Flex crops. This weed set will be covered in both the QDPI and this project. The project will also cover additional species which are currently in the WEEDpak Weed Growth & Development Guide.

The field experiments will be conducted at the ACRI, Narrabri, with treatments applied at various crop growth stages. Experiments will use detailed crop measurements to assess the post-treatment impact of treatments on cotton plants, monitoring plant height and development, leaf number and area, squares, flowers and bolls throughout the season, and crop yield, fibre quality and time to maturity. The research will expand the Herbicide Damage Guide to cover 29 different herbicides, including information on the identification of herbicide damage and detailed information on the likely consequences of damage on subsequent crop growth and development. Additional detailed work will also be undertaken on 2,4-D damage, and the crop’s response to post-damage management.

Work will continue on the weed threshold, with analysis of 8 years of data to re-develop a weed biomass-based threshold, improving on the current density based threshold which doesn’t adequately allow for staggered weed germination. This work will be written up in a series of scientific papers and submitted as a PhD by the Principal Researcher. The work will be supplemented by experiments to validate the weed control threshold using the background weed population, supplemented to ensure strong weed pressure, manipulated with a range of timings and number of applications of glyphosate. An infra-red sensor (GreenSeeker ™) is used to estimate weed biomass.

The weed growth and development information will be validated using a large number of 200 L drums at ACRI, which will be filled with soil and flood irrigated according to normal practices. The drums closely mimic field conditions, but allow individual weeds to be studies without the complications of competition and other field issues. The work will be undertaken as a PhD, supervised through Dr. Brian Sindel at UNE, Armidale, with assistance from the field staff in this project for much of the initial work. The work will complement work by the QDPI team at Toowoomba, who will use at number of large, controlled environment chambers to examine the seasonal requirements for weed emergence, and additional work at ACRI using our 4 germination cabinets. The research will examine 18 weeds which have been identified as being at high risk of developing herbicide resistance (analysis from the QDPI group) and are weeds which are showing up in the Monsanto weed audits as being problematic in Roundup Ready Flex crops. This weed set will be covered in both the QDPI and this project. The project will also cover additional species which are currently in the WEEDpak Weed Growth & Development Guide.

The field experiments will be conducted at the ACRI, Narrabri, with treatments applied at various crop growth stages. Experiments will use detailed crop measurements to assess the post-treatment impact of treatments on cotton plants, monitoring plant height and development, leaf number and area, squares, flowers and bolls throughout the season, and crop yield, fibre quality and time to maturity. The research will expand the Herbicide Damage Guide to cover 29 different herbicides, including information on the identification of herbicide damage and detailed information on the likely consequences of damage on subsequent crop growth and development. Additional detailed work will also be undertaken on 2,4-D damage, and the crop’s response to post-damage management.

In addition to the research highlighted in this application, the project will allow the researcher to continue his role in advising cotton growers on weed issues, giving expert technical advise to the TIMS Herbicide Tolerant Crop Technical Panel and continuing to review pesticide applications on behalf of NSW DPI for the APVMA that involve the cotton farming system.