The registration of Infinity Ultra in Australia this season allowed some growers to become the world’s first users of the new herbicide for post-emergent broadleaf weed control in cereals.
Growers were pleased with its performance, and agronomists have also recognised its flexibility to be safely mixed with herbicide tank mix partners to broaden the weed control spectrum, as well as with fungicides.
Developed by Bayer to help Australian growers address local broadleaf weed control challenges, Infinity Ultra comprises a complementary co-formulation of Groups 27 and 12 (formerly Groups H and F) herbicides, pyrasulfotole and diflufenican.
Bayer NSW market development agronomist Gus MacLennan says Infinity Ultra had mainly been used to target wild radish, sowthistle and wireweed and it had been applied in mixes with other broadleaf and grass selective herbicides to achieve wider weed control.
“MCPA LVE has been a popular partner, as well as bromoxynil and clopyralid, to provide robust control and broaden the spectrum to include other weeds such as fumitory, volunteer pulses and larger wild radish and sowthistle,” Mr MacLennan said.
Plot trials across the country last year revealed a strong performance by Infinity Ultra, showing it was equal to standard commercial herbicides for control of the specific weed spectrum in the different regions.
Trials in wheat, barley and oats this season have evaluated Infinity Ultra in various tank mix combinations and in fallow situations.
Bayer northern NSW and Queensland market development agronomist Richard Jackman said Infinity Ultra offers a new herbicide mode of action for targeting sowthistle in fallows, and has been highly effective against the hard-to-control weed applied alone or in mixes with glyphosate.
“Infinity Ultra is an ideal mixing partner with glyphosate for sowthistle compared with alternative partners such as 2,4-D and fluroxypyr. It is less antagonistic to glyphosate, and there is reduced risk of volatilisation and off-target damage to sensitive surrounding crops such as cotton in northern areas,” Mr Jackman said.
Plot trials showed almost 100 per cent control of sowthistle and bladder ketmia when tank mixes of Infinity Ultra and glyphosate were applied, compared with about 15 per cent reduced control where glyphosate was applied alone or in mixes with fluroxypyr. He said there was some confirmed resistance to glyphosate in sowthistle populations in the northern region, however trials had shown when mixed with Infinity Ultra, resistant sowthistle was controlled.
Importantly, Infinity Ultra also offers a favourable re-cropping profile compared with alternatives, especially with its short plant-back period for following pulse and other winter crops.
“Depending upon rainfall patterns, one to two knockdown applications can be required on northern fallows and Infinity Ultra and glyphosate tank mixes could be applied at various timings.
“Typically, it has a big fit after winter pulse crops, including chickpeas, faba beans and canola, where there won’t be carryover from picloram and aminopyralid herbicide applications,” Mr Jackman said.
He says latest development trials also were exploring further fallow use patterns for Infinity Ultra, including its use with optical spot spraying technology and its activity on additional weeds such as flaxleaf fleabane.
Following development trials, registration for Infinity Ultra was anticipated to be expanded including with more tank mix partners and control of additional weed species.
