Darren and Leanne Eather have been growing cotton east of Narrabri for some 20 years. Speaking to their CottonInfo Regional Extension Officer, Darren Eather outlined how they are managing the threat of resistant weeds.
Darren encounters a range of weeds each season, particularly fleabane, windmill grass, liverseed, barnyard grass, turnip, milk thistle and volunteer cotton.
Darren’s approach to weed management varies between his irrigated and dryland cotton, and is tailored field by field and crop by crop.
In his dryland crop, he strategically uses rotations to control weeds, along with different chemical modes of action. He applies a pre-plant residual herbicide, followed by an at-plant residual and glyphosate as a pre-emergent knock down.
“For grass control, Group D chemicals were our preferred option in order to rotate chemistries. However, we’ve found that windmill grass in particular is not consistently controlled and we get some escapees, which is why we’ve moved towards Group As as an alternative. We’re finding it is providing good control,” Darren said.
In his irrigated country, he combines cultivations with two or three applications of post-emergent glyphosate. He aims to meet with his consultant each year following picking to discuss his approach.
Darren tends not to apply a layby residual, due to the long-lasting effects and subsequent reduction of options. He believes weed control in non-crop areas of his farm is very important, and actively manages this.
“We purchased a farm around a decade ago where we had a very serious issue with black oat and black bindweed,” Darren said. “As a result, we were unable to grow chickpeas on that farm. Now, 10 years later, with a good strategy of weed control and careful crop selection we have controlled the weeds in our system to the stage where we can now grow chickpeas.”
Darren and Leanne Eather
Total hectares: 3,000 ha.
Cotton: 400 ha irrigated and 300 ha dryland
Vary from deep black soils to river loams and some hard setting soils
Two-year rotation: Irrigated – cotton (summer); wheat (winter); long fallow (summer and winter); cotton (summer)
Dryland – Cotton (summer); chickpeas, canola, wheat (winter); long fallow (summer and winter); cotton (summer)