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Spot spraying herbicides with a knapsack sprayer


This video will show you how to spot spray herbicides, using water. Click the play button to view the video now or click on the script tab to view the storyboard. To view the video off-line, click the link from the 'download' tab.


This video will show you how to practice spot spraying a herbicide using water. The equipment you will need is:

  • your pesticide label
  • a knapsack sprayer
  • clean water
  • a reflex nozzle
  • measuring cylinders or jugs


and personal protective equipment as directed by your pesticide label.





In this case, to control these weeds with this herbicide, the label advises us to apply






200 mls of herbicide in 9.8 litres of water to make 10 litres of spray solution.






We have elected to use a reflex nozzle and the label states that the spray should cover the weeds evenly but should not cause ‘run-off’.





Before you mix the product, it’s a good idea to practice spraying with clean water. Wear your PPE so that you get used to wearing it and can adjust it so that you are comfortable.





Some pesticide labels will permit the use of long sleeved shirt and trousers as dedicated PPE; a better option is to wear a coverall. Always wash PPE separately.





This knapsack has already been cleaned, checked, and calibrated. If you are not familiar with how to do this, please have a look at our separate videos.




With clean water in a clean, checked and calibrated sprayer,





fitted with a reflex nozzle, make sure the sprayer is comfortable on your back. Pump until the pressure is enough to produce the spray pattern you need. In this case we are using a Reflex nozzle as we want larger drops . It is good practice to use bigger drops when spot spraying as larger drops do not drift so easily in the wind and so your spray is less likely to drift around and damage other plants nearby.





When you are ready to practice, pump the lever to raise the liquid pressure





just enough to form a spray swath of water.





Raising and lowering the nozzle height will change the width of the swath. Raise and lower the nozzle height until you have a swath width that just covers the weeds you will be spraying.





Direct the nozzle over the weed and apply a short burst of spray. Check the spray covers the weed and there is little on the surrounding ground.





Practice and get it right using just water