ChemCert Spray Applicator Checklist for 2,4D 2019
Go through the checklist below to help determine important factors which may affect spray drift when using 2,4D Chemicals.
☐ Pre-operational check carried out on a clean sprayer with fresh water and a pre-season calibration performed to ensure correct application rates as well as proper machine function.
☐ Product labels checked especially the “Spray drift Restraints” and Mandated Spray Quality, Weather Conditions and Downwind No-Spray/Buffer Zones. Note the updated spray quality charts below for a selection of spray nozzles reflecting the new ASABE S572.1 standard (Figure 1 GRDC Nozzle Selection Guide). Also note some spray nozzles that originally met the spray quality requirements no longer do, i.e. many low-pressure air induction nozzles in 02/025 sizes.
Figure 1. GRDC Nozzle Selection Guide (New ASABE S572.1 with a 40 dynes/cm adjuvant to better mimic a tank mix).
☐ My spray nozzles can produce the required spray quality requirements at the range of operating pressures produced for the application volumes and spraying speeds I use
Note the APVMA repealed all 2,4D labels last year, put in place permit 87174 and many distributors have now updated labels to reflect these changes, as a guide the permitted changes include:
- The minimum mandatory droplet size increases to VERY COARSE (VC) from the previous mandatory requirement of Coarse Spray quality. An advisory statement has been added that “Farmers are advised to use a larger droplet size (EXTREMELY COARSE or ULTRA COARSE).
- Boom height is restricted to a maximum of 50cm above apparent target surface (either the crop canopy, average weed height or top of stubble).
- Downwind buffer zones have been established from sensitive vegetation (terrestrial) and aquatic areas and these distances range from 10 to 160 metres (ground based) depending on the active concentration, application rate and crop or situation used on ( all specified on the permit or updated product label.
- A requirement not to spray in inversion conditions and additional information on recognising inversion conditions.
- Mandatory Record Keeping requirements.
☐ Boom height set at no higher than 50 cms above the apparent target surface, ie average height weed, top of stubble or crop canopy (to meet spray drift restraints as above)
☐ Travel speed set to a maximum of 18 to 20 km/h to minimise pitching and yawing of boom (Permit advises slower travel speeds as a precautionary measure) See figure 2 below for travel speeds, nozzle size and pressures that yield water rates above 70 L/ha.
Figure 2. Spray nozzle flow chart showing an 025 at 3.5 bar and 18km/h highlighted, delivering an application rate of 71.3 L/ha
☐ Weather forecasts checked – Met-Eye, Nufarm “SprayWise Decisions” and “Syngenta Weather”.
☐ No surface temperature inversions present at start of spraying, daytime windspeeds between 3 and 15 to 20 km/h and blowing away from sensitive areas and susceptible plants and crops (check Cottonmap.com.au for cotton plantings, also note the locations of vineyards, canola, tomato crops etc. downwind as part of awareness zones). At night it is suggested that windspeeds should be above 11-12 km/h to avoid inversion conditions.
☐ Record weather details (windspeed and direction, relative humidity and temperature) at start and finish of spraying and at each tank fill in between, monitoring weather for changes during the application. Keep an eye out for fog, dew, frost, smoke or dust hanging in the air and moving horizontally, and/or the flattening of clouds as the evening approaches as signs of inversion conditions.
☐ Ensure state training and application recording ( including federal) requirements are met for herbicide application (make within 24 to 48 hours of application and keep for at least 2 years). See permit 87174 for full extent of what details to include in 2,4D application record
☐ Flush tank and spray-lines with 2 % household ammonia, agitate well and let stand in sprayer overnight. Flush and rinse with clean water several times thoroughly before further use (See specific product labels for individual decontamination procedures)
NB. For those with Pulse width modulation systems: examples of nozzles that can achieve VC, XC and UC spray quality
Very Coarse (VC): Wilger DR 110-03 up to 50 psi ( 1 bar = 14.5psi or 100 kpa)
Wilger MR 110-04 at 30 psi
Wilger MR 110-05 at 40-50 psi
Wilger MR 110-06 at 60-80 psi
Extremely Coarse (XC): Wilger MR 110-06 up to 50 psi
Wilger DR 110-04 at 40 psi
WIlger DR 110-05 up to 70 psi
Wilger DR 110-06 up to 80 psi
Ultra-Coarse (UC): Wilger UR 110-04 or larger at a range of pressures
Users of sprayers fitted with pulse width modulation systems should consult Wilger literature or the ‘TipWizard’ app to evaluate suitable nozzle types and operating pressures to achieve the required spray quality. Note that adjusting operating pressure will affect the ‘duty cycle’ (lower pressure increases duty cycle). It is important when using larger droplets (coarser spray qualities) that the ‘duty cycle’ be maintained as high as possible to avoid misses, as larger droplets will not redistribute in the same way smaller droplets will.
Note also from Teejet - Both the TTI ( Turbo Teejet Induction) and TTI60 ( TTI Twinjet) are suitable for use on sprayers that utilise Pulse Width Modulation (PWM) technology. To avoid misses when spraying VC droplets, the optimum duty cycle should set around 70-80% and no lower than 40%. (Each brand of PWM system have unique design, performance and operating differences which may have some impact on the nozzle performance. Therefore, it is the user’s ultimate decision to determine whether the TTI and TTI60 is suitable for their particular PWM system.
Courtesy of Jonathan Pearson - ChemCert Course Developer/Head Trainer