Northern croppers have a lot to think about when applying broadleaf herbicides on winter and summer fallows.
Including their effectiveness on weeds, particularly from some traditional options such as plant back intervals; one-pass applications with brews containing grass herbicides and any related antagonism and volatility; application restrictions in sensitive cropping areas; and weather conditions after spraying.
Fortunately, the recent registration of a dual mode of action broadleaf herbicide, including for the popular optical spot spraying of winter and summer fallow weeds, is set to simplify the decision-making for growers and they can take advantage of it leading into summer cropping programs this season.
Monsoon, developed by ADAMA Australia, is a co-formulation of two proven active ingredients, bromoxynil (Group 6) and fluroxypyr (Group 4), that has demonstrated excellent control of a wide range of difficult broadleaf weeds, vines and woody weeds.
It also can be combined with a range of compatible tank-mix partners, with minimal impact on the efficacy of grass herbicides and without the volatility concerns or re-cropping limitations of some alternative options.
ADAMA Australia Southern Queensland market development manager Jim O’Connor, said trials with Monsoon in northern NSW and the Darling Downs region in Queensland had shown strong activity on volunteer cotton, fleabane and saltbush, and he expected it would become another important tool in weed control programs with optical spot sprayers.
He said growers are keen to apply grass herbicides with broadleaf knockdowns for one-pass weed control, and the trials also demonstrate the physical and biological compatibility of Monsoon with grass control chemistry, hence it could be applied in tank mixes with glufosinate, Group 1 herbicides and glyphosate.
“There can be some antagonism when using Group 4 chemistry with grass control herbicides, however it is reduced when using fluroxypyr in combination with bromoxynil. There was no major antagonism,” Mr O’Connor said.
There is also reduced carryover risk associated with these active ingredients, with the re-cropping periods following Monsoon application set at seven days through to 28 days according to application rate and rotation crop type.
“It has a nice rate range with optical spot sprayers up to 4 litres per hectare, so growers can go with a high dose if needed or use a lower rate to further reduce the recropping interval.
“Growers will be able to spray in front of upcoming plantings of major summer cops including cotton, sorghum and mung beans.
“In addition to volunteer cotton and fleabane, Monsoon will also help target hard-to-control broadleaf weeds on summer fallows using optical spot sprayers, and it will be ideal in areas where there are use restrictions on 2,4-D herbicides, including where there are summer plantings of cotton and other crops like grapevines and tree crops. However, growers will still need to employ excellent spray application practices.”
He says the combination of the two active ingredients also had demonstrated success against saltbush, sowthistle and ipomoea vine species, while bromoxynil (Group 6) chemistry was not often used on northern fallows, which would help maximise herbicide efficacy.
“It presents an opportunity to get a different chemical group involved in fallow programs.
“Monsoon applications are also robust in a range of suitable meteorological conditions, whereas alternative herbicide efficacy can vary depending upon conditions.”
Mr O’Connor says growers were having to decide over the use of traditional herbicides, different brews and various products under permit with their fallow weed control applications, so the registration of Monsoon for use with optical spot sprayers was timely.
Monsoon is also registered to be applied in winter cereals, targeting broadleaf weeds in post-emergent applications, and work is under way to add use patterns in sugarcane and sorghum to the product label.
