Happy New Year !

We hope you had the chance to relax and enjoy some time with family and friends over the holiday period.

As we move into mid-summer, the Namoi Valley cotton crop is entering a critical phase of development. January brings both opportunity and challenge, with heat, irrigation management, pest pressure and crop nutrition all requiring close attention to support strong boll development and protect fibre quality.

Warmer conditions through December have lifted crop momentum across much of the valley, with many crops recovering well from the early-season stresses experienced in November, from Walgett through to the Upper Namoi. With first flower occurring in late December, or fast approaching for many crops in January, the focus now turns to fruit retention, irrigation scheduling and the management decisions that will shape crop performance through January and February.

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Upper Namoi - how the crops are tracking?

Crop development across the Upper Namoi has been slower than average, largely due to cooler conditions through October and November that held back early growth. December brought a welcome shift to warmer temperatures, and crops have responded well.

Many growers undertook inter-row cultivation, fertiliser applications and prepared for first irrigations leading into Christmas. As the heat arrived, crops grew away from early thrips damage and are now looking significantly healthier. While some areas benefited from summer storm rainfall, others missed out, and a number of paddocks were unfortunately impacted by hail.

Despite these early-season challenges, crops are now catching up and setting up for a strong season ahead. Trial sites are also progressing steadily.

Heading into the new year, key focus areas include in-crop irrigation scheduling, pest monitoring, and tackling persistent weeds ahead of row closure.

Lower Namoi - where are we up to?

First flowers seen in December on many crops, and irrigation well and truly underway. Storm activity across the region brought welcome rain in dryland systems, but also hail for some resulting in severe damage to crops.

Plenty of inter-row cultivation and fertiliser applications occurring heading towards the critical growth period of flowering to cut out.

Dryland cotton fields have benefit from the patchy storm activity and are approaching squaring. With hot weather conditions into January, careful moisture management will be essential to support crop momentum.

CSD trial sites are progressing well, with some differences between the various varieties starting to appear. We are looking forward to seeing how they progress towards the end of the season.

Focus areas for January and beyond are flowering and irrigation, pest monitoring and weed control ahead of row closure.

Growth management - a slower start tells a story

Looking at the cumulative day degrees for the season so far tells an interesting story moving into January. Many areas of the valley are currently tracking behind long-term averages in terms of accumulated day degrees given the extensive period of cool weather experienced in the weeks after planting, which has influenced crop development and, in some cases, delayed flowering.

This is a timely reminder that flowering may be occurring later than expected in some crops. Below is an example from CSD’s Day Degree Calculator showing that locally, we are slightly up on the average accumulation of DD for the period 10/10/2025 to 15/12/2025, but we’ve had a mix of more cold and hot conditions to achieve this, which explains the delay in flowering.

CSD’s Day Degree Calculator is a useful tool designed to assist growers, agronomists and industry professionals in determining day degree accumulation and other essential climatic metrics relevant to growth and development.

Figure 1. Narrabri (Mollee) Day Degrees (Period 10/10/2025 to 15/12/2025)

Irrigation Through Flowering

Maintaining adequate soil moisture through flowering and into cut-out is critical to minimise plant stress and support fruit retention. This period represents the highest water demand for cotton and plays a major role in determining yield potential and fibre quality. The duration of flowering, prevailing conditions and any stress experienced during this window will directly influence boll retention and final yield.

With temperatures increasing and crops establishing deeper root systems, irrigation is now underway across the valley. Current dam levels across the Namoi system remain high, providing confidence for irrigation planning through the critical flowering and boll-setting period.

Current Dam levels (source:

• Copeton Dam – 79%
• Split Rock Dam – 99%
• Keepit Dam – 99%
• Chaffey Dam – 100%

While individual allocations and on-farm storage will vary, these levels provide a positive backdrop as crops move into their peak water-use phase.

Technologies such as soil moisture probes and canopy temperature sensors can assist in identifying crop stress and refining irrigation timing.

CSD decision-support tools, including CottonTracka, can also help growers and agronomists better understand crop development, anticipate peak demand periods and support timely irrigation decisions throughout the season.

Keeping an eye on soil moisture levels throughout the flowering period is critical to minimise stress to the plants and ensure the fruit load can be adequately sustained. Flowering (through to cut out) is the biggest period of water requirement for cotton and where the yield potential is established. The length of the flowering period, conditions, and stress encountered during this window will determine the production and retention of bolls and the fibre quality.

Utilising technology such as soil moisture probes and canopy temperature sensors can assist in assessing crop stress and predicting the next irrigation. This season, eight canopy sensors will be placed across trial sites. In some cases, canopy temperatures will be compared between Siokra 253B3XF and a normal leaf variety in both dryland and irrigated systems to gain further insights from this technology.

Helpful reference articles:

Verticillium wilt - stay alert!

Cool, wet conditions from irrigation and storm events over the past month have created favourable conditions for Verticillium Wilt infection. Unfortunately, Verticillium Wilt pressure is high across many parts of the Namoi Valley, and while some symptoms are already evident, the disease is expected to become more noticeable in coming weeks.

Early symptoms to watch for include discolouration of lower leaves, leaf wilting and vascular browning. Continued monitoring is recommended, particularly in higher-risk paddocks.

Figure 2. Verticillium wilt starting to show leaf symptoms 15/12/2025

Weather outlook

Looking ahead into January, outlooks from the Bureau of Meteorology, DPIRD and Eric Snodgrass suggest NSW is going to be drier than average. QLD, in the north and south east of the state, might be in for some above average rainfalls. How these patterns develop locally will be important to monitor, particularly in relation to irrigation scheduling and managing crop stress during flowering.

Insects – What to Watch For

As crops move into peak flowering and early boll fill, continued vigilance is essential. Insect pressure is expected to remain high this season, based on early-season activity and prevailing weather patterns. As flowering progresses and boll load builds, understanding boll retention and compensation in current varieties becomes increasingly important.

Key pests to monitor include mirids, green vegetable bugs and whitefly.

In mid-December, Crop Capsules shared footage of whitefly nymphs found on milk thistle near Walgett, a timely reminder that pest populations are active and ready to move into cotton crops. With ongoing hot conditions, pest pressure across the Namoi and surrounding regions is likely to increase.

So when we throw weather and insects into the mix, understanding boll retention and compensation in the current varieties might be of interest to you?  

Flowering progression field inspections

Join us in mid-January for flowering progression inspections at selected Variety Trial sites across the valley. These visits aim to provide a snapshot of varietal performance at a critical stage of the season.

Dates and locations will be finalised over the coming weeks. Keep an eye out for further details or contact one of us in the New Year to find out more.

Did you miss it?

Recently, CSD and Bayer hosted a field walk at the ThryvOn™ Cotton trial site at Locharba, Narrabri. There was a fantastic turnout on the day with great information and feedback shared.

Since then, the crop has continued to develop, with early insights emerging between ThryvOn™ and non-ThryvOn™ cotton. Currently, retention is tracking around 10% higher in the ThryvOn™ plots, based on assessments taken on the 16/12/25. It’s important to note, this is from a small number of counts taken, but still an interesting insight early in the picture. Ongoing monitoring will focus on how this translates through flowering and ultimately into yield at the end of the season.

If you missed the field walk and would like a walkthrough of the site, please contact us or Jack Sharp, Territory Business Manager, Bayer.

Figure 3. Non-ThryvOn™ cotton (left), and ThryvOn™ Cotton (right) taken 16/12/2025.

Final Note 

As we move through January and into peak flowering, conditions will continue to test crops and management decisions. 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.

We wish you a safe, productive and successful month ahead and look forward to seeing how the season unfolds across the Namoi Valley.

Nat & Emma 
Upper and Lower Namoi and Western Valley Extension Team 

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