NGA Chickpea herbicide trials 2014


Take home message

  1. Factor® (butroxydim) was not effective as a knockdown for wild oats in chickpeas.
  2. Mixtures of Verdict® (haloxyfop) plus Status® (clethodim) or 500 ml/ha of Status proved the most effective brews for knockdown control of wild oats
  3. Clethodim (as Status) benefited from the addition of Liase® even when rain water was used as the carrier

The issue

In reviews of the 2013 winter season agronomists and farmers had raised managing resistant populations of wild oats as a major issue for the region. Wild oats are a key weed of winter crops throughout the region and for the past 30 years growers and agronomists have relied on Group A herbicides for control.

Haloxyfop a “fop” herbicide is perhaps the most widely used herbicide in the region for knockdown of wild oats in chickpeas and other pulse crops, however resistance to this herbicide is becoming increasingly frequent.  Many agronomists, where they have concerns about the Group A resistance status of wild oats in a paddock, will mix haloxyfop (eg Verdict 520) with a “dim” herbicide (most commonly clethodim), other agronomists might use clethodim alone. NGA was questioned as to what was the best strategy to use.

Butroxydim (eg Factor) is another “dim” group A that although registered for wild oat control in many broadleaf crops has not been widely used in the Northern NSW/Sth Qld region. Reports have filtered up from southern Australia that in some situations butroxydim is the last group A herbicide effective against annual ryegrass. The question was asked “Could butroxydim have similar attributes against wild oats in our region?”

What was done?

In 2014 the NGA team conducted 4 small plot replicated trials looking at control of wild oats in chickpeas with knockdown herbicides.

Trials were situated in commercial chickpea paddocks near Mungindi, North Star, Bowenville and Edgeroi. The Mungindi and North Star sites were known to have wild oats with resistance to haloxyfop.

Aims of the trials were:

  1. Does mixing haloxyfop with clethodim give an advantage in wild oat control compared to either product applied alone?
  2. Can we get equal benefit by just increasing the herbicide rate?
  3. Can butroxydim also work in a similar way to clethodim? i.e. a “resistance buster”
  4. Is there an advantage in adding ammonium sulphate (as Liase) to the herbicides?

Table 1. Spray dates, growth stage of wild oats and water quality of trials conducted in 2014

Site

Spray date

Wild Oat Growth stage at spraying

Water source

Bicarb ppm

Mungindi

July 1 2014

2 – 4 leaves

Goondiwindi Town water

104

North Star

June 26 2014

3 – 5 leaves

Goondiwindi town water

104

Bowenville

August 11 2014

Up to 3 tillers

Rain water

18

Edgeroi

September 4 2014

Up to 7 tillers

Gunnedah Town water

low

Table 2. Products used in trials

Trade name

Active ingredient

Formulation

Adjuvant use 

Verdict® 520

Haloxyfop

520 g/L

 

Status®

Clethodim

240 g/L

 

Factor®

Butroxydim

250 g/kg

 

Uptake®

Paraffin oil +

Non-ionic surfactants

582 g/L +

240 g/L

Adjuvant

Supercharge®

Paraffin oil

471 g/L

Adjuvant

Liase®

Ammonium sulphate

417 g/L

Adjuvant

Applications were made with quadbike mounted booms. In all cases using AIXR110015 nozzles at 50 cm spacing and a water volume of 70 L/ha.

Uptake was added to all tank mixes containing Verdict or Status at a rate of 0.5%

Supercharge was added at 1% to treatments of Factor (But not when tank-mixed with Verdict)

Results

Trial RN1419 Mungindi

Figure 1. Surviving wild oats per square metre at 43 days after application at Mungindi trial 

Figure 1. Surviving wild oats per square metre at 43 days after application at Mungindi trial

Uptake 0.5% added to all treatments containing Verdict or Status, Supercharge 1% added to all treatments ONLY containing Factor.    DAA = days after application

Summary
  • Verdict applied alone failed to give effective control
  • Addition of 250 ml/ha of Status improved efficacy compared to verdict applied alone
  • Factor applied alone or as a tank-mix with Verdict failed to give effective control
  • Status was the most effective herbicide
  • There was a non-significant rate response for Status.
  • Addition of Liase trended to improve the performance of Status in low bicarb water

Trial RN1420 North Star

Figure 2. Surviving wild oats per square metre at 47 days after application at North Star trial 

Figure 2. Surviving wild oats per square metre at 47 days after application at North Star trial

Uptake 0.5% added to all treatments containing Verdict or Status, Supercharge 1% added to all treatments ONLY containing Factor.    DAA = days after application

Summary
  • Similar pattern of results to the Mungindi site
  • Verdict applied alone failed to give effective control
  • Factor applied alone or as a tank-mix with Verdict failed to give effective control
  • The Verdict + Status tank-mix gave the best level of control
  • There was a significant rate response for Status.
  • Addition of Liase significantly improved the performance of Status

    Trial LB1409 Bowenville

     Figure 3. Surviving wild oats per square metre at 38 days after application at Bowenville trial

    Figure 3. Surviving wild oats per square metre at 38 days after application at Bowenville trial

    Uptake 0.5% added to all treatments containing Verdict or Status, Supercharge 1% added to all treatments ONLY containing Factor.    DAA = days after application

    Summary:
    • Verdict gave effective (although not complete) control of wild oats at this site
    • Factor applied alone was not commercially acceptable giving ~ 80% reduction in surviving plant number. Factor gave no improvement when tank-mixed with Verdict compared to Verdict applied alone
    • The Verdict + Status tank-mix gave very good control with complete control achieved by the nix of 75ml/ha of Verdict and 250 ml/ha of Status
    • There was a non-significant rate response for Status.
    • Addition of Liase trended to improve the performance of Status – even though rain water was the carrier

      Trial AM1409 Edgeroi

      Figure 3. Surviving wild oats per square metre at 34 days after application at Edgeroi trial 

      Figure 4. Surviving wild oats per square metre at 34 days after application at Edgeroi trial

      Uptake 0.5% added to all treatments containing Verdict or Status, Supercharge 1% added to all treatments ONLY containing Factor.    DAA = days after application

      Summary:

      • Treatment list changed at this site following earlier results
      • Verdict either alone or in mixture gave excellent control of wild oats at this site
      • Factor applied alone at 180 g/ha only gave an unacceptable 60 % reduction in surviving wild oat number
      • As in the other 3 trials there was a (not statistically significant) rate response for Status and addition of Liase trended to improve the performance of Status

        Conclusions

        Remarkably similar responses considering the different resistance profiles of the wild oat populations.

        • Factor applied alone was not effective at any of the sites.
        • Addition of 250 ml of Status to Verdict improved efficacy where the haloxyfop resistance was in question.
        • Addition of Factor to Verdict did not improve efficacy
        • A rate response for the herbicide Status was indicated in all trials
        • There was a Liase response when added to Status irrespective of the water quality

        Acknowledgements

        The research undertaken as part of this project is made possible by the significant contributions of growers through both trial cooperation and the support of the GRDC, the author would like to thank them for their continued support.

        Contact details

        Lawrence Price
        Northern Grower Alliance
        Ph: 07 4639 5344
        Email: lawrie.price@nga.org.au

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        GRDC Project Code: NGA00003,