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Herbicide Adjuvant Guide

COHORT Surfactant


Product Overview

SACOA COHORT Spray Adjuvant is an acidifying and penetrating surfactant that reduces alkaline hydrolysis of glyphosate.

COHORT's APVMA approved formula delivers the following benefits:

  • Prevents chemical degradation due to alkaline water
  • Increases spray coverage
  • Provides more uniform spray droplets, thereby increasing coverage
  • Improves pesticide uptake by increasing osmosis through the least surface cells
  • Increases rain fastness
  • Increases pesticide efficacy

The Issue

Alkaline Water Reduces Chemical Effectiveness

Alkaline hydrolysis is a chemical process describing the break down or degradation of pesticides in spray solutions that can occur if the water used in a spray mix is alkaline or caused by mixing different pesticides eg. Glyphosate. This is a significant and widespread issue given that most water used for spraying in Australia has varying degrees of alkalinity. The impact of alkaline hydrolysis on pesticide effectiveness is affected by:

  • The susceptibility of the product itself (refer to the table below for examples of particularly susceptible products)
  • Types of different products being mixed
  • The pH of the water
  • Water and environmental temperature

Examples of herbicide subject to alkaline hydrolysis

Active brand names
2,4-D Amicide, Surpass
Dicamba Kamba 200, Kamba 500
Glyphosate Glyphosate 360, Roundup, Roundup CT, Roundup Max, Weedmaster

The Solution

There are two situations where acidifying spray solutions with COHORT can benefit particular agricultural chemicals.

1. Acidifier

  • Minimise chemical degradation
  • Provides favourable pH environment for maximum chemical uptake

2. Assist in managing chemical losses caused by alkaline hydrolysis

  • Reduces chemical imcompatibility between non-selective herbicides

Traditional Adjuvant Benefits

COHORT also offers the traditional spray adjuvant benefits of:

Aid for droplet survival

  • Reduces evaporation rate compared to traditional non-ionic surfactants

Improves spreading/wetting

  • Reduces surface tension to aid wetting and spreading on difficult to wet weeds.

COHORT is ideal for use:

  • With glyphosate and 2,4-D
  • In summer spraying mixtures
  • Against hard to control weeds such as Couch grass, Button Grass

User Guide

Rate of application

Use/Situation Rate per 100ml
Addition to herbicides to improve penetration and spreading 250-500 ml
Reduction of pH to reduce alkaline hydrolysis 100ml
Improve uptake of foliar fertilizers 300-500 ml
Droplet size management to reduce fine droplets and drift potential for most nozzle types by air and ground 300-500 ml

More Information, Tables

Use/Situation Rate per 100ml Adjuvant
Melons only 5-30cm (Afghan & Paddy ) Garlon @ 80-100mL ANTIEVAP Spray Adjuvant 1%
Garlon @ 100-120mL ANTIEVAP Spray Adjuvant 1%
2,4-D Ester800 @ 400-500mL (LV Ester 600 @ 530-670mL) ANTIEVAP Spray Adjuvant 1% OR Amine 625 @ 650mL + ANTIEVAP Spray Adjuvant1%
2,4-D Ester 800 @ 350-500mL (LV Ester 600 @ 470-670mL) + Garlon @ 80-100mL ANTIEVAP Spray Adjuvant 1%.
Melons only > 30cm (Afghan & Paddy ) 2,4-D Ester 800 @ 500mL (LV Ester 600 @ 670mL) + Garlon @ 100-120mL ANTIEVAP Spray Adjuvant 1%.
Garlon @ 120-140mL ANTIEVAP Spray Adjuvant 1%
Garlon @ 140-160mL ANTIEVAP Spray Adjuvant 1%
Melons plus Wireweed Above for melons + Metsulfuron @ 5g + WA 0.2% ANTIEVAP Spray Adjuvant 1%.
Wireweed (50 cm) 1.125 L Glyphosate 480 + 5 g Ally COHORT @ 0.3%
Melon Mix (1 m) + Wireweed (50 cm) 100 mL Garlon + 400 mL Esteron LV + 1.125 L Glyphosate 480 + 3 g Ally COHORT @ 0.3% + 1% SoA
Couch grass 2.8 L Glyphosate 480 COHORT @ 0.5%

1. It is important to identify which melons you have in your paddock. Paddy melons require higher rates of Garlon, while Afghan melons require a higher rate of a 2,4-D ester in the mix for successful control.

2. The ratio of glyphosate to ester should be 2:1 or greater to avoid antagonism.