The Darling Downs is in full swing with late dryland crops now flowering, most others amid peak flowering/boll accumulation, and to round off, the early planted dryland crops are now cut out. 

The end of January saw a prolonged heat wave affect the Downs region, although for some, it also brought a wave of afternoon storms to temper the impacts. 

Current fruit loads look promising, and it is hoped that the region can experience a dry pick and finally get the quality to match the yield, after the last two seasons wet finishes.   

Approaching cut-out

For some in the region the flowering period is almost over, as the crop approaches cut out. Cut out is a natural physiological stage in cotton plant development when the crop ceases to produce new fruiting sites (squares). This occurs when the demand for carbohydrates by developing bolls exceeds the supply produced by the leaves. An approximation of cut out timing is when a crop reaches an average of 4 nodes above white flower (NAWF). At this point, the crop has attained approximately 95% of its harvestable yield. 

While some crops will reach this point naturally,growers may choose to bring it forward, using application of mepiquat chloride. Some considerations for managing cut out are: 

• Maintaining fibre quality through timely harvest (The timing of cut out directly influences when the crop matures - later cut out = later maturity). 

• Ensuring effective defoliation practices to reduce trash 

• Avoiding excessive immature bolls that may increase neps 

• Is water running short? Should we pull the crop up to preserve what is there? See below for more information.  

Insects – What to Watch For  

As crops on the Downs are spread out in their planting, insect pressure and management may differ widely. Those crops that are currently at peak flowering are in a crucial time and thus it is important to remain vigilant when managing insect pressure. 

Late planted cotton in particular, requires careful management, as it can often have less time to compensate for fruit loss. Insect pressure has been reported to be somewhat persistent this season, with sprays still being conducted into late January.

As boll loads build, understanding boll retention and compensation in current varieties becomes increasingly important (link). Those with more mature crops - bolls older than 20-25 days, are ggenerally not susceptible to feeding damage from sucking pests, as fibre elongation ceases and seed is located deeper within the boll. 

However, insects such as whitefly and their sticky residue can still pose a problem for picking. Key pests to monitor include mirids, green vegetable bugs and whitefly.  

Season so far

Figure 1: CottonTracka for a Cecil Plains trial. Has been monitoring various weather related stats and as assessment are added overlays it for an easy to understand weather overview.

The season so far for the Darling Downs has been a hotter one but has seen frequent storms tempering the damage that this often brings. Looking at the 10-year forecast, this is the hottest year since 2019/20.

There have been more than 20 days above 35°C (Oct 20- 26 Jan) although that’s likely to climb higher as we come out of a heat wave at the end of January. Despite the heatwave, the region is experiencing, the Dalby Post Office and Cecil Plains weather stations have both avoided recording 40°C so far. Night temperatures have also been quite reasonable, depsite the warmer weather. It has been a decent year for rain, despite the drier start in some parts of the region. Over 260mm has fallen in Dalby and this number is similar at Cecil Plains. Summer storms in their typical fashion have delivered both booms and busts, depending on where fields are located.

There is a large spread in the maturity of crops this season. Late dryland crops have just come into flowering, while the early planted dryland crops have cut out. Here is a look at a dryland crop planted early in October, which is fruiting up very quickly. The consequences of this are evident, in how the NAWF of the crops has been affected. The crop did manage to flower for just under 4 weeks, putting on approximately 100 bolls/m, in double skip configuration.

Figure 2: Early planted dryland trial. Sicot 761B3XF. Boll accumulation and NAWF decline was rapid. Retention was above 80%

Figure 3: Irrigated trial of the CSX 1257B3XF. Has been slow to fruit up but NAWF decline has also stalled. Will reassess in the coming weeks and see the effects of the heat wave.

In comparison an irrigated trial planted at the end of October has been slower to accumulate bolls and when this assessment was taken in mid-January, the crop had ample opportunity to add to its yield.

Coming up - events

To showcase the new XtendFlex® varieties, CSD intend to conduct field walks in the region this month, with one planned for 11 February, at Bongeen. CSX 1320B3XF will take centre stage, as it gears up for commercialisation.

There will be another field walk in the region in March, closer to picking, for another look at CSD’s varieties.

In addition to the CSD field walks there will also be a field walk in the ThryvOn™ trial, to showcase the technology and how it has fared through the season. Details will be sent out as they become available.

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 from 10-12 March this year. Currently there is a discount on the course and there are still places available.  

Regards, CSD Extension and Development Agronomist’s Larissa Holland, Chris Barry and Rachel Russell 

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