The dyeing of cotton is influenced by chemical and physical interactions between dye molecules and the substrate, many of which are not well understood. This project reviews current knowledge of the relationships between the fibre properties of cotton, including surface and structural properties, and dye uptake by cotton fibres. Where available, research specifically pertaining to the dyeing ability of Australian cotton is reviewed.

The aim of this review is to guide the CRDC and researchers in understanding the issues associated with cotton dyeing and the current gaps in knowledge. Understanding and resolving these issues provides better quality, both in terms of breeding fibre with improved dyeing ability and improving dyed quality in mills. Increasing understanding around cotton’s dyeing ability also improves prospects for better water and energy efficiencies associated with dyeing cotton, and thereby the ‘social’ license to use cotton as a textile.

The review has been conducted in response to anecdotal information gathered over time from mills reporting colour appearance and dye uptake differences using Australian cotton (Gordon et al, 2002, Gordon et al, 2004 and Yang and Gordon, 2010).

While a large amount of research has been conducted in this area, there remain questions about the effect of the structural properties of cotton cellulose on dye uptake kinetics and substantivity, i.e. the adherence of the dye molecule to the substrate being dyed. The structural properties in question include the species of wax and associated chromophores on the outer surface of the fibre, the non-cellulosic fractions, e.g. pectins, within the fibre structure and the fine structure of cotton cellulose itself. The review concludes that there remains a gap in understanding how these surface and structural attributes affect dye uptake and dyed appearance in cotton.

Focus is given to research that describes cotton’s structural morphology, its cellulose structure and surface chemistry properties and the physical properties currently used to assess the dyeing ability of cotton. An overview of the dyeing of cotton including the dyestuffs used and procedures for preparing and dyeing cotton is given. This is followed by a review of research on the central issues that affect cotton dyeing. The central issues, as identified, are control of shade variation and water and energy consumption by the dyeing process.

WATERpak is the Australian Cotton Industry’s Compendium of water and irrigation research. Its production was funded by the Cotton Research and Development Corporation and it was first released in August 2004. Since 2004 there has been a significant change in the irrigation management within the industry and new irrigation and water management research findings. Additionally, the myBMP process has been launched with the on-line myBMP process the mechanism by which industry participants can access the latest research findings and recommendations to ensure continued implementation of best management practices with respect to water management within the industry.

In April 2008, grains related information was incorporated as part of the Irrigation Knowledge Management Project. In 2009, a meeting was held to determine a strategy for updating WATERpak, details of which have been included in the final report of the recently completed CRDC project “Water Smart Cotton and Grains”.

It is now opportune to look at updating WATERpak with the latest research information and including new information that has been identified in irrigation and water research since the first edition was published. This is particularly relevant given the improved water supply situation within the industry, the impending changes in water availability that may result from the proposed Murray Darling Basin Plan and the myBMP process now being promoted within the industry. An update process has been flagged by the Industry D&D team as a desirable step in improving the integration of water research and the myBMP program.

Information about farming practices used in cotton production, yields obtained and fibre quality are

of enormous value in planning research and extension efforts, in industry activities and in telling the

industry’s ‘story’. Without regular surveys there is relatively limited information about current

practices used on farm or changes over time. Survey findings are used to evaluate research and

development uptake and identify areas for further research to help improve cotton production.

The Cotton Growing Practices 2013 survey was conducted in late winter 2013, focusing on the 2012-

13 cotton crop.The hot, dry 2012-13 season produced the second biggest Australian cotton crop on

record with the highest yet, average yield of 10.2 bales/ha. 4.384 million bales were produced from

405,000 ha of irrigated cotton. Dry conditions restricted the dryland plantings to 36,880 ha producing

132,300 bales.

Latest weather and climate news Observed rainfall analysis (Dec 2014): Summary of climate indicators: Rainfall and temperature guidance summary: Madden-Julian Oscillation (MJO): Australian Sea Surface Temperatures: Tasman Sea Atmospheric Blocking

Silverleaf whitefly (SLW) is a major insect pest of the cotton industry. It is a pest because it excretes honeydew that contaminates cotton lint, causing problems during textile processing. Honeydew contaminated lint may receive price penalties or in extreme cases may be rejected from sale. Insecticides are an integral part of whitefly IPM, particularly products like Admiral® (pyriproxyfen) which are soft on natural enemies. However, SLW can rapidly develop resistance to insecticides as seen overseas (Israel and USA: Arizona) where resistance to pyriproxyfen has been reported. An insecticide resistance management strategy (IRMS) has been developed by the Australian cotton industry for SLW to prolong the life of insecticides like Admiral®. This project collected SLW insecticide resistance data so the performance of the IRMS can be evaluated and if necessary the IRMS can be adjusted to reduce the likelihood of SLW developing resistance to insecticides used against it. During 2010-13, the insecticide resistance status of silverleaf whitefly populations in cotton growing regions (Emerald, Theodore, St George, Mungindi, Moree and Narrabri) was monitored. Insecticides tested included pyriproxyfen, diafenthiuron, bifenthrin, spirotetramat and clothianidin. Silverleaf whiteflies populations in each of these cotton regions remain susceptible to these products. A small increase in the LC50 for bifenthrin at Narrabri was detected in the 2010–11 season, but this has decreased in the subsequent seasons. Limited data on clothianidin indicate potential for resistance at Emerald but further testing over coming seasons is required. The elevated levels of resistance to clothianidin are likely to be the result of widespread usage of neonicotinoids in the form of seed coat dressings at planting as only minor amounts of clothianidin are utilised in foliar crop applications.

Correct species ID and the SLW threshold matrix

Research and trials on the real cost of N application

Ginning update, MyBMPVerticillium wilt, Volunteer cotton trials soil health workshops, Reniform nematode rotation trial at Theodore

Latest weather news Observed rainfall analysis (for the week ending 14 Dec): Summary of climate indicators: Rainfall and temperature guidance summary: Madden-Julian Oscillation (MJO): Australian Sea Surface Temperatures: El Niño-Southern Oscillation (ENSO) outlook for 2015

First irrigation timing, Researchers and consultants thoughts