HERBICIDE resistance is a major consideration in the weed management program run by Parkes-based farm manager Matthew Burkitt.
Matthew manages a 3700-hectare cropping program on a property owned by Northparkes Mines in Central West New South Wales.
The company’s farming properties operate alongside privately owned farms surrounding the mining lease and in the nearby town of Forbes.
The farm is a total cropping enterprise, comprising canola, wheat, barley and field peas for brown manure.
Matthew has a commercial agronomy background, which saw him providing advice to the farm for a number of years before stepping into the role of farm manager in November 2015.
Subsequently, he has been involved in developing the farm’s weed management program, including the introduction of new herbicides into the rotation and other practices to help manage any potential resistance issues.
“Ryegrass pressure and herbicide resistance have been increasing in the region, particularly over the last five to 10 years for those practicing continual cropping,” Matthew said.
“So while the situation isn’t as bad as it is in some areas, we are tapping in to a lot of the lessons learned by growers in Western Australian and South Australia.”
For the last few seasons, Matthew has been using Factor, from Crop Care, to manage annual ryegrass in selected canola crops and pulses.
Factor is a Group A herbicide using butroxydim as its active ingredient to control grass weeds, including annual ryegrass.
It can also be mixed with other grass selective herbicides for greater weed control in a wide range of broadleaf crops, including summer and winter pulses, oilseeds and pastures.
It’s fast acting, so there is less competition from weeds during the early stages of crop development.
“Crop Care Territory Sales Manager Brett Mawbey is the main reason we use Factor with so much confidence. He was really pro-active in explaining what we can expect from the product and where the product fits,” Matthew said.
“Factor lifts the robustness of our Group A herbicide option. We use it across the odd canola paddock, but its primary use is in our pulse seed crops.
“While we’re doing a brown manure field pea phase, approximately a quarter of our field pea area is kept for seed.
“Factor is one small, albeit vital, tool in an overall diversified program we’re implementing to manage the ryegrass.”
Matthew has been applying a mixture of Factor and Havoc, also from Crop Care and which contains clethodim as its active ingredient.
He said in 2015 they capitalised on the high price of chickpeas, taking the opportunity to sow the pulse phase to chickpeas.
The Factor and Havoc brew played an important role in controlling grass weeds in that rotation.
In pulse crops, Factor is applied at a rate of 150g/ha (with 1% ammonium sulphate and 1% Supercharge Elite) with 500mL/ha of Havoc and 70L/ha of water.
Chemical is sourced through the local AgriWest Parkes store, with the help of Agronomist Luke Wood, and they use contract sprayers with a self-propelled, 36-metre sprayer running nozzles every 25 centimetres.
“We hadn’t been questioning our clethodim performance prior to introducing Factor, but we were getting to that stage where we were over-reliant on it and, with the development of ryegrass resistance in the district, we knew that we needed to change,” Matthew said.
“Our use of Factor was part of our program evolving.”
That program evolution started with the one-in-four-year brown manure phase and now also includes harvest weed seed management tools such as narrow windrow burning and the trialling of a chaff deck.
Matthew said their management of ryegrass had evolved towards the aim of using the Factor/Havoc mix as a clean-up spray, as opposed to being reliant on the Group A herbicides.
“We’re trying to get to the point where we’re exposing those herbicides to only 5-10pc of the ryegrass population, as opposed to 90-95pc of the population.’’
“So we’ve implemented other measures to reduce that pressure prior to having to use the Group A herbicides.
“That’s why we’re seeking the robustness of Factor. We’re looking to minimise any weed seed returning to the seed bank. Our ryegrass control from the Factor and Havoc brew has been outstanding,’’ he said.