Changes to 2,4-D registrations
From October 4th, 2018 the APVMA suspended the labels of all products containing the active
ingredient 2,4-D and replaced them with a permit that includes new rules about how those products must be applied.
This action has been taken in response to wide spread damage to sensitive crops over several years, including grapes, horticultural crops, summer pulses and cotton.
The new permit covers all products that contain 2,4-D and covers all users. Growers and applicators are not required to make individual applications to use 2,4-D products, they simply need to follow the new directions covered in the permit relating to its use.
Summary of the new directions for use stated 2,4-D permits:
- Applicators must now use a VERY COARSE (VC) spray quality
- Downwind buffers now apply (typically less than 50 meters, subject to the rate of product applied)
- Advisory statements have been added for the period between October 1st and April 15th to use an Extremely Coarse (XC) Spray Quality and to take further steps to mitigate the risk of spray drift
- Clearer instructions have been added about identifying temperature Inversions to help avoid spraying when they are present
- Record Keeping requirements remain, as per previous labels.
Nozzles required to achieve VERY COARSE and EXTREMELY COARSE.
For many grain growers the requirement for using a VERY COARSE or EXTREMELY COARSE spray quality will require an additional set of nozzles.
Many low-pressure air induction nozzles such as the Teejet AIXR or Hardi Minidrift are not able to produce VC or XC droplets at useful pressures in the orifice sizes most commonly used, which are 02 (yellow), 025 (lilac) and 03 (blue).
Many spray operators will need to change to high pressure air induction nozzles, such as the Hardi Injet, Teejet TTI or TTI-60, or the Agrotop TD-XL-D. These nozzles should be operated at pressures above 4 bar (ideally 5-6 bar), so their use may require increasing application volumes unless changing the orifice size currently used.
Refer to Figure one below for examples of nozzles that can produce VC (green) and XC (white) spray qualities:
Nozzle Options for Spray Operators using Pulse Width Modulation Systems
Very Coarse spray qualities can be achieved on Pulse Width Modulation systems using Wilger MR-04 or SR-06 nozzles at pressures below 2.4 Bar. Other orifice sizes may be appropriate if using the Wilger DR or UR nozzle types to achieve Extremely Coarse or Ultra Coarse spray qualities.
Adjusting Application Volumes when using Coarser Spray Qualities.
When increasing the droplet size it is important to consider increasing the total application volume to maintain coverage and efficacy. In low stubble environments a minimum of 70L/ha has be shown to provide acceptable efficacy when using XC spray qualities. In heavier stubbles this may need to be increased to 80L/ha or more.
Further information is also available in the GRDC Factsheet “Maintaining efficacy with Larger Droplets”.
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