Dear Grower,

Hope everyone had a Merry Christmas and a Happy New Year! Despite the demands of irrigation, hopefully you all managed a break over the holiday period. Moving into the new year, cotton crops across the Balonne are looking great, though dust in rain gauges continues to accumulate.

Much of the irrigated cotton is now flowering and starting to really stack on bolls, though a drive through the region in late December higlighted a few late planted crops, yet to reach flowering. As water demands increase in peak flowering, we will be watching the skies.

Growth of crops - a quick look out in the field

Most crops are doing their best to load up on fruit and are in the midst of peak flowering and boll fill. It is important to remember that flowering is a critical period of crop development. It is where the yield potential your crop is established. The length of the flowering period, conditions and stresses encountered during this flowering window will determine the production and retention of bolls, and the fibre quality. Other metrics to keep track of over January as the crop progresses is boll numbers. While not always a glamorous task boll counting is a more reliable indicator of yield potential in a cotton crop than retention percentages because it directly measures the number of bolls, which is the primary determinant of yield. Retention percentages, while useful, only provide information about the proportion of fruiting sites that remain on the plant at a given time and don’t reflect the absolute number of developing bolls. It is conceivable that crops can have low retention and high numbers of bolls resulting in excellent yields.

CottonTracka^® is a great CSD tool that can be utilised to monitor and optimise your crops performance. Here are a couple of graphs from CottonTracka of a CSX1320B3XF crop that I have been monitoring as a part of CSD’s trials program.

Here you can see nodes are tracking very close to the trend line, according to our data set, while height progressed rapidly after first flower. Looking at NAWF and bolls, they were initially slow to decline and accumulate respectively but have since caught up. There was low mirid pressure early in the region that may give an explanation as to why this was the case.

Wilt - Fisarium found

As many know Fusarium Wilt is present in fields throughout the Balonne. Though not seeing wider spread incidents or it affecting entire fields, it is important to be vigilant. There have been cases this year of it appearing early and of it outright killing plants even prior to flowering. What is it?  Fusarium is a soil-inhabiting fungus that causes Fusarium wilt, a significant disease affecting cotton crops in Australia. The specific pathogen responsible is Fusarium oxysporum f. sp. Vasinfectum. Once introduced, Fusarium wilt is almost impossible to eradicate and failure to control disease build-up can result in fields becoming unsuitable for cotton production. Key visual indicators are: 

• yellow mottling on leaves
• brown discoloration in the woody part of the stem
• plants may die back from the top and potentially regrow from the base later in the season
• symptoms can appear as individual plants or small patches, often in tail drains or low-lying waterlogged areas.

Photos of Fusarium at St George. Photo 1 (left) a comparison of a healthy plant (left) and an infected plant (right). The infected plant showing wilt from the terminal. Photo 2 (right) shows a plant that has wilted from fusarium.

Prevention is the best course of action with farm hygiene being key: Thoroughly pressure wash machinery on sealed surfaces with waste water retention capacity and implement "Come Clean! Go Clean!" protocols for all farm traffic, including contractors If it is on farm avoiding crop stresses such as over-irrigation and excessive nitrogen application helps reduce its effects and retaining cotton residues on the soil surface as long as possible before incorporation to reduce its effects for the next season. 

Coming up

Field walks

To showcase the new XtendFlex™ varieties, CSD intend to conduct field walks in the region as early as this month, so keep an eye out. CSX1320B3XF will take centre stage, as it gears up for commercialisation. Dates and locations will be finalised over the coming weeks. Keep an eye out for further details or contact me in the New Year to find out more.

Cotton course

If you feel like either you or your staff would benefit from a little bit of extra cotton knowledge in 2026, then it is worth remembering that the new CRDC Cotton Course will be run by the University of Sydney 10-12th March this year. Currently there is a discount available and there are still places.

- Larissa

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