Summer Fallow Weed Control – Rainfall Outlook, New Weeds
Key Points
Recent storm events in WA – have played havoc with harvest and also brought about a germination of weeds that will need to be controlled as soon as possible. The ability to “store” this summer rain, by controlling weeds presents an opportunity to set up the 2020 season – a strategy which has well proven yield advantages
Changing Rainfall Patterns
The recent rainfall events through Summer have become increasingly common over the past 10 years. This has re-inforced the shift from a predominant winter dominant Mediterranean climate to declining winter and increasing summer rain events (see figure 2).
Changing Weed Types
In the previous decade summer weed control used to focus almost exclusively on broadleaves like melons, caltrop and wireweed. “Tropical” type grasses such as button grass, windmill grass and kerosene grass were really only a problem in northern cropping areas – whilst broadleaves like fleabane and matricaria were rare – they are now becoming the dominant weed in much of the wheatbelt.
Agrion Crop Solutions’s Research on Newly Emerging Fallow Weeds
Over the last five summers Agrion Crop Solutions has built on it’s decades of research into making herbicides work more effectively, by focusing its field research program on new, difficult to control fallow weeds where matching the correct adjuvant to the most important herbicide mode of action in the tank mix is critical. In addition, new herbicide mode of actions have also been evaluated, to ensure that growers are well informed on how to match the right adjuvant with the right herbicide mode of action. For example with some new actives such as Sharpen – the use of acidifying adjuvant such as a soyal phospholid can cause the herbicide to be inactivated.
Get the Most out of Summer Fallow Herbicides
Using an adjuvant that:
- Increases droplet size – to reduce drift whilst still providing good coverage
- Increases droplet survival – to allow herbicides to penetrate through leaves
- Improves the mixing compatibility of multiple products in poor quality water
- Is matched to the most important mode of action in the mix – generally targeted at the most dominant/difficult to kill weed in the paddock
- Always add AMS to the mix particularly with glyphosate
(Source: David Stephens ‘South-west Western Australia is losing its Mediterranean Climate’ GRDC update 2016).
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(Source: Agrion Crop Solutions)
ANTIEVAP & ENHANCE
Agrion Crop Solution’s mineral oil based adjuvants ANTIEVAP® and ENHANCE® have become the fallow spraying adjuvants of choice in many cropping areas. In addition to the above benefits they also offer;
- Flexibility to mix with all herbicides including glyphosate and paraquat for the double knock
- Over twenty years of proven results under local Australian conditions
- Ongoing product support including up to date information on new weeds and actives
- Made in Australia, by a fully Australian owned, agriculture focused
The Facts
Agrion Crop Solutions’s research program uses a combination of in-house and external resources to produce fully replicated and statistically sound information which is highly regarded in the industry for its integrity and relevance to current agronomic programs.
Results on Grasses
% Eragrostis Control – Quiarading
Chart 1: Eragrostis – Quairading (Source: T.Boyes AgVivo agronomy, Quairading)
Button Grass Control – Mullewa
Chart 2: Button grass control – Mullewa (Source: Agrion Crop Solutions/ADAMA/Elders -March 2017)
Windmill Grass Control – Mullewa
Chart 3: Windmill Grass Control – Mulle- wa
Button Grass Control – Meckering
Chart 4: % Button Grass Control – Meckering (Source: T.Boyes AgVivo Agrono- my, Meckering)
Fleabane Control – York
Chart 5: Fleabane Control – York (Source: T.Boyes AgVivo Agronomy, York)
Fleabane Control – Quiarading
Chart 6: Fleabane Control – Quairading (Source: T.Boyes AgVivo Agronomy, Quairading)
Melon Control – Quiarading
Chart 7: Melon Control – Quairading (Source: T.Boyes AgVivo Agronomy, Quairading)
Matricaria Control – Wyalkatchem
Chart 8: Matricaria Control Wyalatchem (Source: Agrion Crop Solutions internal trial Wyalkatchem)
Takeaway Messages
ENHANCE® and ANTIEVAP® proved superior to other adjuvant types, particularly soyal phospholipids and non-ionic surfactants across a range of broadleaf and grass weeds at multiple replicated trial sites. Improvement in performance was observed with all actives tested including glyphosate, paraquat, triclopyr, and GRP A
grass selectives with no evidence of compatibility issues or antagonism even on grasses. Clear rate responses between ENHANCE® 0.5% and ENHANCE® 1.0% were observed at all sites, with Glyphosate mixes being most rate responsive.
Importance of Correct Boomspray Setup
The final piece of summer fallow weed control is to ensure the herbicide mix goes out correctly. Summer spraying often produces some of the worst conditions for herbicides to work – therefore having the right nozzles, operating pressures, Delta T, travel speed & water volumes to minimise drift and maximise target coverage is critical to achieving the best results. Every boomspray and situation is different so use tools like water sensitive paper & snapcard (see figure 4) to ensure that herbicides get to where they need to be and always add AMS to every mix.
References
- GRDC – Group A herbicides for control of grass weeds in fallow
- https://grdc.com.au/Resources/ Factsheets/2014/10/Group-A- Herbicides-in-Fallow
- GRDC – Summer Fallow Spraying
Disclaimer and Copyright
This document should act as a guide only and no purchase or usage decisions should be made based on the information provided without obtaining independent, expert advice. Agrion Crop Solutions and contributors do not necessarily recommend or endorse any products or manufacturers referred to. Agrion Crop Solutions Pty Ltd will not be liable for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the information contained in this document. More information is available from Agrion Crop Solutions via agrion.com.au or 1800 778 247, or by contacting your local reseller.
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