New Herbicides for Crops

Several new herbicides are due for release in the coming years. These new herbicide options are focussed on ryegrass control in cereal crops, plus residual control of broadleaf weeds. Thankfully these pre-emergent herbicides have unique modes of action (MOA) which will allow the rotation of active ingredients both new and existing, to maximise the sustainability of all herbicides, while maintaining very good weed control. As most of the following products have not been registered by the APVMA, the characteristics listed are predictions based on trial results and correspondence with chemical company representatives.

Luximax – BASF

•  Pre-emergent herbicide to be registered in wheat (not durum)

• Active ingredient - 750 g/L Cinmethylin

• Due to be registered for the 2020 season with only limited supplies available

• MOA - Group Z (a unique group)

• Claimed 12 week control of ryegrass, plus suppression of brome grass and wild oats

• Application rate is 500 ml/ha applied as an IBS application with knife point and presswheel sowing systems only. Not registered for use with harrows or discs.

• Slightly volatile, incorporation is required within 3 days

• Due to concerns regarding stubble tie-up, it is recommended that stubble cover should be less than 50%

• Taken up via plant roots, so best results are achieved when weed seeds are on the soil surface

• Cultivation is not recommended prior to application. To reduce crop effect, wheat seeds should be sown at least 30 mm below the herbicide band

• Rainfall is required within 10 days post incorporation to activate the herbicide

• Recropping interval is 9 months for barley, oats, canola & winter pulses

• Predicted price $38.50/ha and initially available in 5 litre containers

• Luximax provides an alternative mode of action to Sakura for use in wheat. This will allow the rotation of herbicide groups to manage herbicide resistance. Use of Luximax in wheat would allow for the use of Butisan in canola, which to date has not been ideal given it is the same herbicide group as Sakura

Overwatch – FMC

• Pre-emergent herbicide to be registered in wheat, barley and canola

• Active ingredient - Bixlozone

• Due to be registered for the 2021 season

• MOA - Group Q

• Claimed 10-12 week control of ryegrass, wireweed, sowthistle, fat hen and suppression of wild radish and indian hedge mustard

• Expected application rate 1.25 L/ha applied IBS with knife point and presswheel sowing systems

• Non-volatile, however incorporation is still required within 3 days

• Overwatch is a bleaching herbicide which can cause transient crop yellowing

• Taken up via plant roots so best results are achieved when weed seeds are on the soil surface

• Cultivation is not recommended prior to application. To reduce crop effect wheat seeds should be sown at least 30mm below the herbicide band

• Re-cropping interval is expected to be 9 months to oats, lentils and lupins. Other crops should be less

• Price has not been set but expected to be $35-$40/ha

Bayer - 167 – Bayer

• Pre-emergent or EPE herbicide in wheat (not durum) and barley

• Active - Aclonifen plus other currently undisclosed actives

• Expected to be registered for the 2022 season

• MOA - group undetermined, however it is unique

• Applied either IBS with knife points and presswheels, or as an early post emergent application. Registration in disc systems and barley likely to be EPE only

• Claimed 10-12 week control of ryegrass, wireweed, shepherds purse, fumitory, capeweed and wild radish, plus potential suppression of large seeded grass weeds

• Weeds must be no larger than 1-2 leaf for adequate post emergent control

• Taken up through leaves and shoots

• This product is likely to be registered for IBS use for grass weed control and EPE for broadleaf control

Frequency – BASF

• Early post emergent herbicide applied from 2nd leaf to 2nd node stage in wheat and barley

• Active - 60 g/L Topramezone

• Due to be registered for the 2020 season

• MOA - Group H

• Claimed control of wild radish, capeweed, fleabane, fumitory, shepherds purse, sow thistle, stinging nettle, sub clover, vetch and wireweed, plus suppression of northern strain of wild oats

• Application rate of 200 ml/ha

• Needs to be tank mixed with Bromoxynil or LVE MCPA and requires the addition of 1% Hasten or equivalent MSO adjuvant

• Minimum water rate 80L/ha, good coverage is essential

• Grazing withholding period is 6 weeks

• Cannot be applied during frosty conditions

 Voraxor – BASF

• Knockdown spike with residual control registered in fallow situations and prior to sowing wheat and barley

• Expected to be registered for the 2021 season

• MOA - Group G

• Claimed knockdown control of broadleaf weeds and 1-2 leaf ryegrass, plus residual control of broadleaf weeds

• Expected application rate is 200 ml/ha

• Requires 1% Hasten or equivalent MSO adjuvant

• Application in a tank mix with Gramoxone 250 may provide control of larger Glyphosate resistant ryegrass

ILeVO – BASF

• Seed treatment for control of blackleg in canola

• Active: 380 g/L Fluopyram

• Expected to be available on seed in 2020

• A member of the SDHI group of fungicides

• Claimed suppression of blackleg

• Expected application rate 800 ml/100kg

• Claimed to have no hypocotyl shortening

• A different fungicide group to Jockey and Impact, which will help to manage fungicide resistance in the short term. However, resistance to the SDHI group of fungicides develops quickly, so unless its use is well managed, the benefits may be short lived. 

As none of these chemicals have been released commercially, their fit in current winter cropping systems are still to be determined, however if these new chemicals can replicate the results that are currently being demonstrated in pre-registration trials, there is great potential to control resistant weed populations and drive down the weed seed bank. One potential downside to these pre-emergent products is that they require the application to be made up-front. Therefore growers will be forced to pay the significant cost regardless of seasonal conditions and actual weed population. Also, it is likely that continued widespread use of pre-emergent herbicides will result in selection for later germinating weeds, unless they are controlled via other methods.