Crop and Pest Management Guidelines

A Cornell Cooperative Extension Publication
34228

7.12 Decontaminating and Storing Crop Sprayers

34229

7.12.1 Sprayer Decontamination and Maintenance

Sprayers must be decontaminated thoroughly, inside and outside, after use. Regular maintenance of spraying equipment will prolong its life and ensure accurate trouble-free operation, enabling spraying to be done with the minimum loss of time and taking full advantage of favorable weather conditions.

REMEMBER: Clean up so washings DO NOT enter public sewers, water courses, fields that have underdrainage, and certainly not catchment areas for boreholes or wells. If bowser filling or premixing has been done in a field other than the one that was sprayed, ensure that any livestock withdrawal periods and harvesting intervals are met.

Try to keep the volume of tank washings produced to a minimum. Special low-volume washing systems are now available and should be used. Tank washings may be usable as a diluent when mixing a further batch of spray. In addition, the need for cleaning can be reduced by good planning. For example, if a fungicide and an herbicide are to be used on the same day, select a sequence that avoids the need to clean the sprayer between them.

NOTE: Read the sprayer manufacturer's instructions before beginning to wash out a sprayer. Wear protective clothing appropriate to the pesticide that has been used. This may include an apron.

To clean a rotary atomizer sprayer, rinse out the tank, drain all the unused spray from the system and run the atomizers empty for a short time. Wash out the sprayer with detergent and water or recommended cleansing fluid, making sure that all atomizers are thoroughly clean, and using a brush if necessary. Carefully clean off the outside of the sprayer, drying any electrical connections to prevent the penetration of damp. Oil where necessary.

With all types of sprayers, if frost is likely, thoroughly drain the spray system, paying particular attention to the pump casing and valve galleries, and ensure that all low points where liquid may be trapped are adequately drained. Filter caps and bodies may be stored in the filter basket, along with any drain plugs that have been removed.

Obviously the sprayer is the most important item to clean after use, but the same care must go into cleaning the protective equipment you wear, associated equipment such as bowsers and mixers, the site where filling and mixing is done, the tractor and of course yourself and any other person involved. Wash down protective clothing and remove and store it where it can dry off. Wash and change into normal clothes. See insert in this publication for tips on cleaning pesticide-contaminated clothing.

There are two levels of decontamination:

34230

7.12.2 Cleaning when Similar Products are to be Used

Always wear the protective clothing recommended on the label or at least rubber gloves, coveralls, boots and a face shield.

  1. The last load in the spray tank should be just large enough for the area left to be sprayed. Before cleaning, correctly dispose of any leftover spray liquid. Spray liquid can be left to stand overnight provided cleaning is done early the next day, but note instructions for products containing solvents that may damage hoses, diaphragms etc. if left in the sprayer.
  2. Remove tank drain plugs or open drain cock.
  3. Hose down the tank, inside and out, including the underside of the tank top. Scrub where necessary or use a special low volume washing system.
  4. Replace drain plug.
  5. Remove suction, main and in-line filter elements; wash them thoroughly in clean water with a soft brush and replace.
  6. Remove nozzles, nozzle filters and nozzle bar end-caps if they are fitted. Soak them all in a bucket of water with the appropriate cleaning agent recommended by the manufacturer of the product that has been used.
  7. Partially fill the tank and pump out to flush all parts. Do this more than once if necessary.
  8. Refit nozzles, filters, and other parts.
  9. Hose down the outside of the sprayer and tractor, scrubbing if necessary.
  10. Wash down waterproof clothing, apron, boots and face shield. See inside back cover for tips on cleaning pesticide-contaminated clothing.
  11. Return unused product to the storage.
  12. Wash inside and outside of gloves with soap and water; rinse and dry them.
  13. Finally, thoroughly wash hands, face, and neck with soap and water and complete record sheets.

34231

7.12.3 Cleaning when Product Type is Changed

This procedure also should be followed at the end of a season or before machine maintenance. Always wear the protective clothing recommended on the label or at least rubber gloves, coveralls, boots and a face shield.

  1. Correctly dispose of any spray liquid or contamination left in the tank.
  2. Remove tank drain plugs or open drain cock.
  3. Hose down the tank, inside and out, including the underside of the tank top. Scrub where necessary or use a special low-volume washing system.
  4. Replace drain plug.
  5. Remove suction, main and in-line filter elements; wash them thoroughly in clean water with a soft brush and replace.
  6. Remove nozzles, nozzle filters and nozzle bar end-caps if they are fitted. Soak them all in a bucket of water with appropriate cleaning agent recommended by the manufacturer of the product that has been used.
  7. Partially fill the tank and pump it out to flush all parts. Do this more than once if necessary.
  8. Refill the tank with clean water and pump it through the pipes and spray bars. Leave for as long as practicable, overnight if possible.
  9. Discharge at least one quarter of the contents of the tank through the system and spray bars. Drain off the rest.
  10. Check that no deposits remain in the tank or filters. Any that remain should be hosed down and scrubbed off.
  11. Repeat steps 8 to 10 using clean water with the appropriate cleaning agent recommended by the manufacturer of the product that has been used.
  12. If stubborn deposits still remain, possibly resulting from mixture incompatibility, repeat the washing using 2 lbs. washing soda plus 1.5 fl. oz. Agral per 25 gallons of water. Better results are obtained with warm or hot water.
  13. If changing from one type of product to another, refit nozzles, filters, etc.
  14. After seasonal cleanups, safely store nozzles and filters, and leave valves open and the tank lid loosely closed. If leaving the sprayer unattached, ensure that it is parked safely and securely in a stable position.
  15. Hose down the outside of the tractor and sprayer, scrubbing if necessary.
  16. Wash down waterproof protective clothing, apron, boots and face shield. See inside back cover for tips on cleaning pesticide-contaminated clothing.
  17. Wash inside and outside of gloves with soap and water; rinse and dry them.
  18. Finally, thoroughly wash hands, face and neck with soap and water.

34232

7.12.4 Disposal of Pesticide Waste

The safe disposal of pesticide waste is a serious responsibility for growers and spraying contractors. It is important, therefore, that everything should be done to keep to a minimum the amount of waste generated.

Pesticide waste is of four types:

34233

7.12.5 Storage of Sprayers

Store sprayers carefully after use. Follow the manufacturer's specific instructions; in their absence, use the following general guidelines:

CAUTION

All mounted sprayers tend to be unstable when removed from their tractors. Make sure sprayers are safely chocked before leaving them.

"Need Certification Credits? Get them at the PMEP Distance learning Center".

© 2019 Cornell University All rights reserved.