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Priority: Post-emergent control of broadleaf weeds in wheat

Background

The trial was sown on the 3rd of June in Dumbleyung and the next significant rain event was on the 18th of June where 20mm was recorded. The treatments were applied 27 days after seeding. Wild Radish Raphanus raphanistrum and volunteer Bonito Canola were spread prior to spraying IBS treatments, to mimic a medium-high weed burden of approximately 8 plants/m2. Post emergent (PE) applications were sprayed at the 4-6 leaf growth stage of weeds.  Priority was assessed against ADAMA’s Quadrant, Colt and Legacy herbicides, both standalone and with the inclusions of Priority tank mixed at 25g/ha. Industry standards such as Velocity were compared and contrasted, as well as other commercially used broadleaf weed post-emergent products.

Objectives

  1. compare the efficacy of various post-emergent herbicides in wheat.
  2. compare and contrast of ADAMA’s post-emergent herbicides with and without the addition of Priority spike herbicide.

PRE-SEEDING

Early Knockdown- 23/3/20: Nufarm Weedmast DST 1.5L/ha, Hammer 400EC 15ml/ha, Nufarm striker 60ml/ha.

Roundup ready Canola Knockdown – 14/4/2020: Sharpen 20g/ha, Nufarm Estercide Xtra 680 400ml/ha, Hasten 1%.

Early Knockdown – 2/6/2020: Nufarm Weedmast DST 1.5L/ha, Sharpen 20g/ha, Hasten 1%, Ammonium Sulphate 1%.

Immediately Pre-seeding – 3/6/2020: Syngenta Paraquat 250 1L/ha, Nufarm TriflurX 2L/ha, Conquest Alpha Forte 40ml/ha.

Early Nitrogen Application – 3/6/2020: CSBP Flexi N 80L/ha.

SEEDING

Seeding – 3/6/2020: Wheat Scepter 70kg/ha, Suphate of Potash 50kg/ha, Double Phos 130kg/ha, Evergol Energy seed treatment 130ml/100kg, Impact in furrow fungicide 400ml/ha.

POST-EMERGENT

Nitrogen Top-up – 10/7/2020: CSBP Flexi N 80L/ha.

Treatment Applications – 30/7/2020: As per trial design.

Results

Visual control ratings at 21DAA (blue no stripes) & 48 DAA (blue stripes) expressed as percentage (%) between 1-100, with control=0%.

Percentage Control & Phytotoxicity Rating 21DAA

AOV table, 42DAA percentage control ratings depicting statistical difference between treatments

Phytotoxicity %

Photos

Control Pre-spray vs
21DAA

Velocity Pre-spray vs
21DAA

Frequency + Brom200 + Hasten Pre-spray vs 21DAA

Frequency + MCPA + Hasten Pre-spray vs 21DAA

Howitzer Pre-spray vs
21DAA

Flight Pre-spray vs
21DAA

Condor Pre-spray vs
21DAA

Quadrant Pre-spray vs
21DAA

Colt Pre-spray vs
21DAA

Legacy Pre-spray vs
21DAA

Quadrant + Priority Pre-spray vs 21DAA

Colt + Priority Pre-spray vs 21DAA

Legacy Pre-spray vs 21DAA

Key Findings

  • All treatments applied post-emergent, had a good effect on Wild Radish and volunteer canola
  • Treated weeds with Priority tank mix showed symptoms within 3-7 days effect, with an increased residual activity lasting into the season (21-42DAA).
  • Treatments containing Priority were significantly more effective than those without the tank mix.
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