Graham Charles


Graham is a research agronomist and weed scientist specialising in weed management and herbicide damage in cotton. He has been based at the Australian Cotton Research Institute at Narrabri since 1988.

Graham has covered a broad range of research areas over the past 31 years, culminating in the release of WEEDpak, a comprehensive manual for weed management in cotton in 2002, available on the web. He has since revised the manual in 2013 and 2019. He has undertaken research into weed management, weed botany, biology and ecology, farming systems, crop and weed physiology, herbicide resistance, and herbicide damage, documenting damage to cotton from a wide range of the herbicides commonly used in other parts of the farming system. Results from many of these research areas are available on the web. Graham is passionate about the need to develop integrated approaches to weed management (a whole of farming systems approach with a broad range of management tools) as the way to manage the increasing problem of herbicide resistance.

Most recently, Graham has been developing a series of weed control thresholds for high-yielding cotton by defining the critical period for weed control in fully irrigated cotton using three mimic weeds.

In a different role, Graham was recently the joint-leader of a highly successful collaborative project exploring issues around the distribution, taxonomy and botanical classification of the Noogoora burr complex, the development of a bioherbicide for Noogoora burr, and the role of Noogoora burr as a host for Verticillium wilt in cotton.


  • B Rur Sc, University  of New England (1983)
  • M Rur Sc, University  of New England (1989)

Recent projects

  • Developing the weed control threshold (CRDC funded project 2015-2019)
  • Biological control and taxonomic advancement for management in the Noogoora burr complex (Dept Agric & Water Res 2017-2019)

Recent publications

Charles G, Sindel B, Cowie A, Knox O (2019) The value of using mimic weeds in competition experiments in irrigated cotton. Weed Technology doi: 10.1017/wet.2019.35

Charles G, Sindel B, Cowie A, Knox O (2019) Determining the critical period for weed control in high yielding cotton using common sunflower as a mimic weed. Weed Technology

Werth J, Boucher, L, Thornby D, Walker S, Charles G (2013) Changes in weed species since the introduction of glyphosate-resistant cotton. Crop & Pasture Science, 64: 791-798.

Contact details