POST-EMERGENT applications of prosulfocarb are not a silver bullet for weed control, according to a trial being run by Imtrade Australia at Latham.
The trial was on show at Liebe Group's Spring Field Day on September 10 with the main aim being to give growers some key data that can help them make informed decisions about their Prosulfocarb use.
The trial investigated key timings to the crop and grass weeds, rates and combinations.
Imtrade national technical manager Michael Macpherson said Liebe Group members had consistently indicated that they would like to see some locally generated data on Prosulfocarb.
"The experience with Prosulfocarb has seen mixed results, especially when it has been used post-emergent in salvage or clean-up situations," Mr Macpherson said.
"Prosulfocarb as a standalone molecule has uses both pre and post-emergence in cereals, however the post-emergent uses have been known to be touchy in relation to environmental conditions and weed growth stage.
"This trial is designed to explore the different timings of use, combinations and rates so that some conclusions on the best use practice for this molecule can be determined for the Liebe area."
In terms of results, the key takeaway was that pre-emergent herbicides are crucial to establishing a vigorous crop, while Prosulfocarb in combination with Trifluralin, such as products like Imtrade's Bolta Duo, had proved useful on the spectrum of weeds present.
Mr Macpherson said no meaningful data had been collected to date, given that the final data was reliant on efficacy and safety following the last application.
"Panicle counts of the grass weeds will be conducted at or around the timing of the seed filling duration (SFD) to determine the potential for seed-set at the completion of the season," he said.
"Visually, the cleanest plots are those that received some form of pre-emergent treatment, with the prosulfocarb blends appearing the most robust, while pre-Trifluralin and post-Prosulfocarb has also yielded good results.
"The one to three leaf post-emergent prosulfocarb treated plots, without pre-Trifluralin, exhibited around 60 per cent control of annual ryegrass numbers.
"However the final determination in efficacy will be if the surviving plants are able to progress to a reproductive phase, or if they have been suppressed by the application."
Some sand blast and furrow-fill was experienced with the first front that passed over in early June, which had some impact on plant establishment in some areas of the site.
However, no noticeable effect of any herbicide treatment to the host crop has been noted to date, with the most noticeable outcome being from the high numbers of weeds present in the site.
Any plot that did not receive a pre-emergent treatment is demonstrated reduced early vigour due to competing weeds.
