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Avoid Getting Burned by Herbicide Residues

Herbicide residues in the tank can cause devastating yield losses:

Even if the sprayer has been "rinsed out" with water the addition of surfactants or liquid fertilizers (eg. AGRAL 90, 28% UAN) to the next tank load may cause inadvertent loosening of previous residues. If possible use a dedicated sprayer for herbicides. In strawberries for example, if you apply Poast Ultra + Merge or Venture L herbicide within two weeks of Sinbar application, the surfactants in the grass herbicides can increase uptake of Sinbar, causing noticeable phyto-toxicity and potential yield loss.

Here are some pointers, along with information specified on the product labels that should be used to minimize the risk of contamination.

General tank clean out steps:

1. Before cleaning the sprayer, dispose of surplus spray solution. The Grower Pesticide Safety Course suggests diluting the remaining spray solution with water at a 1:10 ratio. This diluted solution can be applied to the previously treated area provided that the maximum recommended product rate on the label is not exceeded.
   
2. Fill tank with water and add detergent, ammonia or other tank cleaner products (See table 1) and allow vigorous agitation for 10-20 minutes.
   
3. Flush the boom, hoses and nozzles with solution. Be sure to operate every circuit in the pumping system. Flush each boom section individually with full liquid flow. Important: When flushing the boom, open the boom ends to blow out particles and spray solution from the line. Drain tank.
   
4. Wash out any self-cleaning filters or strainers using your cleaning solution.
   
5. Wash outside of sprayer with soap and water.
   
6. Remove all screens, nozzles and wash separately in a bucket containing cleaning solution. Wash out any measuring containers with the cleaning solution.
   
7. Thoroughly rinse tank, booms, hoses, strainer and pump. These parts are often overlooked and can trap residues. Because of today's highly active, low-use-rate herbicides, it is essential to clean out every trace of herbicide.
   

General Precautions:

• Wash water contains herbicide residues. Never allow wash water to run into any water source (i.e. a well, pond, lake).
  
• Do not leave puddles that may be accessible to children, pets, farm animals or wildlife.
  

Choose the right cleaner:

Each herbicide should have a recommended cleaning agent listed on the product label. The following table summarizes herbicide-specific cleaning agents found after several hours of combing through product labels. This is by no means a comprehensive list and therefore the pesticide label should always be consulted.

What if the label doesn't specify a cleaning agent or a cleanout procedure?

Some product labels simply do not state a cleanout procedure. In that case, the 7 step cleanout procedure above along with one of the three "cleaning solutions" listed would be acceptable. For "group II" products like Pursuit, the preferred cleaning agent is household ammonia, according to the manufacturer.

Cleaning Solutions

• Clean water rinse (i.e. triple rinse)
  
• Ammonia solution at 3%/100L water
  
• Strong detergent solution (i.e. 1.0 kg detergent/150 L water)
  
• Warning: Do not mix ammonia with chlorine bleach. This can produce toxic chlorine gas.

   

  Table 1. Recommended tank-cleaning agent for several herbicides used in Ontario

  Herbicide(s)	Recommended Cleaner
  2,4-D	1% ammonia/100 L water
  Assure II	Clean water
  Basagran Forté	*Not specified on label
  Chateau	3% ammonia/100 L water
  Devrinol	*Not specified on label
  Dual II Magnum	Clean water
  Eptam	*Not specified on label
  Frontier	*Not specified on label
  Gesagard	*Not specified on label
  Glyphosate	*Not specified on label
  Goal 2XL	*Not specified on label
  Gramoxone	Use a wetting agent (AGRAL 90 at 60 mL per 100 L of water, flush and spray out, then thoroughly rinse with clean water.
  Ignite	Strong detergent
  Lontrel	Clean water
  Lorox	*Not specified on label
  MCPA	*Not specified on label
  Nortron SC	*Not specified on label
  Pardner	*Not specified on label
  Pinnacle	Clean water, followed by 3% ammonia/100 L water
  Poast Ultra	Clean water containing detergent
  Princep Nine-T	Clean water
  Prism	Clean water
  Prowl	*Not specified on label
  Pursuit	3% ammonia/100 L water
  Pyramin	Clean water containing detergent
  Sinbar	Clean water
  Venture	Detergent