UNDERSTANDING how herbicides work and which ones to use in which environments were the key take-aways learnt by agronomists and interested growers at a series of workshops presented by the Grains Research and Development Corporation.
The Herbicide Behaviour Workshops have been running around the country since last year, with the Western Australian series wrapping up last week with sessions in Narrogin and Perth.
The aim of the workshops was to provide agronomists with a thorough understanding of how herbicides work to maximise their performance when confronted with a range of weed problems and environmental conditions.
Independent Consultants Australia Network weed specialist Mark Congreve, who delivered the workshops, said it was about understanding how the different products worked, which then allowed users to think about how to use them in order to get the best out of them.
"The key thing is understanding that there is a big difference between the products that we're using and some of them are very different in how we should be applying them best," Mr Congreve said.
"As a user, it's important to understand what's the right way to use each of the products and how they're going to behave in the environment we're putting them into, so we can get the best level of performance each time we make a decision to use one of those products."
Throughout the workshops, attendees learnt what the advantages and disadvantages of combining two products might be.
"Quite often there are disadvantages but we will still make those decisions even if it's a negative situation because of the efficiency on the farm," Mr Congreve said.
"But I want the agronomists to understand we might be making a compromise and while those compromises might be for a valid reason, at least they understand what they're doing and know they might be able to slightly change how they employ things, so they can get the best result of the mix they're putting out."
Other topics discussed included the differences in effectiveness of post-emergent and pre-emergent herbicides.
"When it comes to post-emergents, we spent a lot of time talking about climatic conditions," Mr Congreve said.
"In particular, extremely hot conditions affect some of our herbicides, especially something like glyphosate, while in the middle of winter, with a lot of frost, something like clethodim doesn't work particularly well in that environment.
"In pre-emergents, things like soil type and the amount of rainfall are going to be highly influencing how the product is going to behave and perform, so if we know what properties affect what herbicides, we can have a lot more confidence in how we use those products."
When the majority of herbicides were new 20 years ago, they worked well and developed use patterns which were relatively full proof, however resistance in populations that didn't exist before is now an issue which needs to be combated.
"What we can do is make sure we're applying the product right and that may be the difference between getting a successful job and an unsuccessful job on some of these populations which have relatively weak levels of resistance," Mr Congreve said.
"If they've got really high levels of resistance, we're not going to be able to turn that around, but in some populations by doing things right you can potentially get a better job and it may be good enough, but if you're cutting a few corners it might end up as a failure."
While the workshops were targeting agronomists, there were plenty of growers with a keen interest in attendance.
"I don't have enough hours in the day to talk to every grower," Mr Congreve said.
"But if I can get the agronomists to understand all of the principles, then they're dealing with the growers on a daily basis and it's the best way for me to get the necessary information out to everyone."
The next workshops to be presented by the GRDC are on sprayer calibration and application and will be delivered by application specialist Bill Campbell throughout February and March.
