Is herbicide resistance starting to direct your clients’ rotations and management strategies? What advice will you be giving on glyphosate-resistant ryegrass, brome grass, windmill grass and fleabane? What about control of broadleaf weeds resistant to multiple modes of action? These will be among the questions posed to Victorian grains industry advisers at a Herbicide Resistance Technical Update on Friday, July 25, at Bendigo.

Sponsored by the Grains Research and Development Corporation (GRDC) and the Australian Glyphosate Sustainability Working Group, the Technical Update is designed to place advisers on the “front foot” in terms of herbicide resistance knowledge and understanding.

A range of experts from across Australia will be presenting and discussing strategies in detail. They include Chris Preston, University of Adelaide, looking at multiple resistance in broadleaf weeds; Andrew Storrie, Australian Glyphosate Sustainability Working Group, on how Western Australian farmers are dealing with multiple resistant wild radish; and Pingrup (WA) farmer Doug Smith who will give his thoughts on narrow windrow burning of high-yielding crops.Five tonne per ha barley crop successfully windrow burnt, March 2014

St Arnaud farmer Roy Postlethwaite and Jaron Bennett of AgriVision Consulting, Swan Hill, will discuss living with glyphosate resistance for 15 years; Peter McInerney, of 3D-Ag, Wagga Wagga (NSW), will delve into the role of manuring in farming systems in the southern grain region; Sam Kleemann, University of Adelaide (SA), will advise on understanding and managing glyphosate resistant brome grass; and Sally Peltzer, Department of Agriculture and Food WA, will explore decision support systems such as Weed Seed Wizard and RIM.

The Technical Update will be from 8:30am to 4 pm at the Bendigo Racecourse. For further information or to register, contact Andrew Storrie on 0428 423 577 or email andrew@agronomo.com.au.

For further information

Andrew Storrie, AGSWG
Phone 0428 423 577

Contact

Sharon Watt, Porter Novelli
Phone 0409 675100

 

Here is a valuable article from the latest E-weed newsletter by Sally Peltzer and Alex Douglas, DAFWA.

Despite the rain in September in many areas of WA and southern Australia, there are still dry conditions in many regions.

It is tempting to stop any harvest weed management in the dry years. “There doesn’t seem to be many seeds on those annual ryegrass plants”, I can hear you say. That’s where you may be wrong.

 Research by AHRI has shown that annual ryegrass seed numbers can still be relatively high in poor seasons (Table 1). These can carry over to the following year and reduce yields. Note the comparative ryegrass seed yields for the two seasons. Not much of a yield penalty for ryegrass in a drought year when compared with wheat.

 Table 1: Wheat yield and annual ryegrass seeds produced over 2 years.

Year	Wheat yield	Annual ryegrass
	(t/ha)	(plants/m2)	(seed/m2)
2011	4.0	19	12,000
2012	0.6	29	7,000

Cut your crop lower in a dry year to catch more ryegrass seeds.

In a good year with a big crop, there will be less light penetration and the annual ryegrass tillers will be upright and easier to catch. In a low-yielding year with a light crop and an open canopy, the ryegrass tillers will be also shorter. The work done by AHRI showed that at 40cm harvest height in 2011 (high yielding crop) collected about 60 per cent ryegrass seed at crop maturity compared to about two per cent in 2012 (low yielding crop).

 The more seeds dropped in one year, the less crop yield in the following year.

To illustrate the difference in cutting height in a dry year, The Weed Seed Wizard has simulated wheat yields in 2013 after 7,000 annual ryegrass seeds/m² were set in 2012. If the crop was cut at 10 cm, only 1250 ryegrass seeds/m² are returned to the seedbank with a resulting 400 kg/ha of wheat yield loss the next season. This compares to a yield loss of 1.4 t/ha when the crop is cut at 40 cm and most of the ryegrass seeds are dropped.

Fig. 1 Effect of weed seed management strategy on crop yield and
weed seed numbers modelled with the Weed Seed Wizard.

Also in dry years where wheat yield is low, it is possible to burn narrow windrows in wheat.  For wheat crops of 2 to 2.5 t/ha or less it is possible to burn just the windrows. Cutting low is imperative to keep the fire in the windrow.