Continuous wet conditions and saturated soils affecting crop establishment and growth across large areas of Northern Queensland.
Reduced and uneven plant stands are common, particularly where young cotton was unable to withstand prolonged moisture stress. Waterlogging, combined with reduced solar radiation during the early growth phase, has significantly slowed cotton development.
January has remained too wet for field operations in the Bowen region, preventing growers from starting their intended planting programs. Under normal seasonal conditions, planting would be underway in January, but with paddocks still holding too much moisture, growers are waiting for a suitable drying window during February.
The December–January period at Dimbulah was milder and slightly wetter than average, but the defining feature of the season has been the severe waterlogging following planting, in early December.
Total rainfall recorded was 462 mm, only slightly above the long‑term average, but the timing and frequency of rainfall events kept soils saturated for extended periods. This has caused major establishment stress, with cotton showing poor early growth, shallow roots, reduced nitrogen availability, and uneven plant stands.
Temperatures were mild - with no days above 35°C, radiation was slightly lower , and degree‑day accumulation was 4–5% below average. While these conditions would normally support steady early growth, the persistent soil saturation has slowed crop recovery and limited the benefits of the mild weather.
Overall, the 2025–26 season to date has been shaped far more by waterlogging than by heat or temperature extremes, and current crop performance reflects the ongoing impacts of prolonged saturated soils.
Despite the tough start, there is still plenty of opportunity in North Qld for cotton crops to finish strong.
Above average‑ rainfall (60–70% chance) across parts of Queensland, NSW and the tropical north.
Neutral rainfall outlook for large parts of Australia, meaning roughly equal chances of wetter, drier or average conditions between February and April.
The period aligns with the northern wet season, when high impact‑ rainfall events are common.
Increased chance of above average rainfall‑ in March across the tropical north.
Above average‑ maximum temperatures are less likely across much of northern Australia in March due to expected higher cloud cover.
Nutrition management
Recent high rainfall events have left many cotton crops inundated for prolonged periods and exposed to persistent overcast conditions. The timing coincided with planting through to squaring — a developmental stage particularly vulnerable to waterlogging stress.
Waterlogging immediately restricts oxygen exchange between roots and the soil atmosphere. When oxygen levels fall too low, root respiration declines, resulting in reduced nutrient uptake, limited root growth and slower overall crop development.
Nitrogen (N)
Managing nitrogen remains challenging during the wet season due to risks of leaching, volatilisation and denitrification.
Key points:
More than 65% of applied N can be lost in the first 30 days after planting if heavy rainfall occurs before the root system is established.
Denitrification may continue to reduce available N even after waterlogging subsides.
Foliar N can improve yields in waterlogged crops when applied one day before irrigation under hot, sunny conditions.
Around two thirds‑ of fertiliser N should ideally be applied 25–50 days after planting, in one or multiple applications.
Wet soils may delay in crop‑ applications, increasing the risk of N deficiency during peak demand (e.g., flowering).
Late N applications can increase disease pressure (e.g., boll rots), delay maturity and complicate defoliation.
Avoid N applications after mid flowering‑ unless the crop is severely deficient.
Potassium (K)
Potassium demand peaks from early to peak flowering.
Soil applied potassium offers the most sustained benefit but moves only short distances in soil.
Waterlogging limits root access to soil bound K, increasing the risk of K related leaf disorders.
Soil potassium applied after flowering is less impactful if it is not positioned near active roots, particularly when waterlogging restricts root function and limits uptake.
Applications during or after waterlogging can improve plant water status, photosynthesis and recovery.
Combined soil + foliar K provides the strongest response; foliar K alone has short term benefits.
Flowering remains a critical yield‑defining period. Conditions and stresses encountered during this window determine boll set, retention and fibre quality. Your agronomist or consultant can assist with:
Disease and insect surveillance
Vegetative growth rate assessments
Plant height management
Fruit retention tracking
Disease update
Wet, humid weather continues to promote foliar disease development. Leaf spot symptoms caused by Alternaria, Cercospora and Stemphylium spp. may appear, with infection favoured by temperatures between 20–30°C, particularly at the lower end of this range. Potassium deficiency can exacerbate symptoms as plants remobilise K from leaves to fruit during boll fill.
Target Spot (Corynespora cassiicola)
Significant target spot pressure has historically been observed in Tropical FNQ following canopy closure under prolonged humidity and cloudy weather.
Fungicides may be required for foliar disease and excessive vegetative growth management.
Best results occur when fungicides are applied before or very early in disease development, and before canopy closure.
High water volumes and adequate spray pressure are needed to reach lower canopy zones.
Current APVMA Minor Use‑ Permits:
PER95141 — Belanty Fungicide (Group 3)
Apply prior to infection when conditions favour disease development.
While there are numerous products registered for the control of various cotton pests; many insecticides, if used at the wrong time, can cause more problems than they solve by disrupting the balance of natural pest enemies (‘beneficials’). This can subsequently flare secondary pests, which may then require further, often harsher methods of control. It is particularly important to avoid the use of broad spectrum non-selective products where possible.
In the past, repetitive application of dimethoate at various locations in Northern Australia has resulted in cotton-melon aphid (𝘈𝘱𝘩𝘪𝘴 𝘨𝘰𝘴𝘴𝘺𝘱𝘪𝘪) outbreaks during boll opening. Several seasons of testing have revealed catastrophic levels of resistance to organophosphate insecticides in cotton-melon aphids in Western Australia and North Queensland.
The cotton-melon aphid, Aphis gossypiiGlover, has a wide host range and the levels of resistance present are likely the result of long-term usage of these products across various crops. Where possible, use the most targeted insecticide, particularly between emergence and crop cut-out.
In Northern Australia, managing weeds in cotton requires a strategy tailored to a tropical environment where rapid growth and high moisture levels can quickly lead to heavy weed pressure.
TACKLING WEEDS HEAD ON
Key guidance from Gus MacLennan (Bayer Technical Solutions, Northern Australia)
For those growers who have planted XtendFlex cotton this season, the option of using glufosinate and XtendiMax 2 (dicamba) for over-the-top weed control can prove to be extremely useful particularly on difficult to control weeds such as peach vine, fleabane and barnyard grass.
To obtain maximum efficacy from your herbicides there are a few factors to consider to help you achieve incremental gains in your weed control:
Target small weeds early on in crop development, glufosinate is a contact herbicide so coverage and weed size is important, small weeds and limited shading from the crop will assist in better levels of control.
Relative humidity plays a key role in glufosinate efficacy. Data shows that the relative humidity at 9am compared to 3pm is on average 5-10% higher for the Bowen and 10-15% higher for the Atherton tablelands. Higher humidity means longer droplet survival on the leaf and improved uptake from the plant.
Double knock where necessary. Trials have demonstrated that the highest levels of control from glufosinate are when it is utilised as a sequential application, for example glufosinate followed by glufosinate (minimum 14-day interval) or glyphosate followed by glufosinate (7–14-day interval). This strategy is best applied when weed pressure is high and weeds have become “robust”.
Each of the chemistries available for over-the-top use have their own strengths and weaknesses. For weeds such as Peach Vine (Ipomoea lonchophylla) where the efficacy of glyphosate has declined in recent years the best approach is to target plants early or double knock following either glyphosate or dicamba with glufosinate 7-10 days later, this approach is also every effective on Fleabane (Conyza bonariensis) and Barnyard Grass (Echinochloa crus-galli).
Follow the label. For dicamba there is only one registered product, XtendiMax 2. There are several label restrictions which majorly limit the opportunities to utilise this chemistry over the top of XtendFlex cotton so follow the label closely.
For more information regarding your weed control options call Gus MacLennan, Bayer Technical Solutions Agronomist for Northern Australia: 0407 641 320
Supporting future capabilites
The FastStart™ Cotton Pathways Program for early career agronomists will be running again this year. This program continues to offer valuable development opportunities for those at the beginning of their careers, helping participants build technical confidence, expand industry networks, and gain practical, infield experience.
