Best Practice Field Training

SSISC offers a hands-on Best Practice Field Training course for Invasive Plant Control (focusing on Knotweed) upon request. The course is aimed at licensed herbicide applicators, or individuals interested in obtaining a pesticide applicator licence through the Province of BC. The course is designed to supplement the pesticide applicator’s license training and certification.

The SSISC Best Practice Field Training course is a 4-hour field session offered at a knotweed treatment site in Squamish, and covers topics such as Integrated Pest Management, legislation & regulations, legal requirements and safety when working with herbicides, equipment, mixing and application techniques. Participants are given the opportunity to practice spray and stem injection control techniques (using water) under the guidance of experienced SSISC staff.

To request a Best Practice Field Training Course for Invasive Plant Control, please contact us.

Treating knotweed is challenging for a number of reasons, one reason being that the plants are usually quite tall, and normal spray techniques used in rangeland environments need to be adapted to ensure that applicators are not spraying over their heads. Amongst other concepts, this course introduces participants to the technique we use to treat tall knotweed called “Knock and Spray”. See below for a video and memo describing the technique and observations of results so far.

Knock & Spray: An Approach for Treating Tall Knotweed


  • Knotweed can grow 3-4m tall in a single season.
  • Many sites on the coast are steep and not always easily accessible.
  • Worksafe BC regulations prohibit pesticide applicators from spraying over their heads.

Existing Treatment Options for dealing with tall knotweed:

We have found that other recommendations for treating tall knotweed are not ideal for a number of reasons.

Use a long spray wand:

  • We found that even with the extended spray wand, you are still spraying over your head.
  • Extended spray wands are a bit of a ‘franken-wand’ with multiple parts not designed to be used together – they can leak easily.
  • It takes some practice to become precise with the longer wand.

Cut down the knotweed, dispose of vegetation, and return later in the season to treat the knotweed when it is approx. 1.5m tall:

  • This is an expensive option, as you have to visit the site twice.
  • You also have to deal with disposal of the cut stems (mileage, dumping fees).
  • Risk of spread through plant fragments, on site, and on the way to the disposal location.
  • You are delivering a smaller ‘dose’ of herbicide as there are fewer leaves to spray.

Stand on the tailgate of the truck and spray:

  • it is not possible to back up a truck to many of our steep sites, they are only accessible on foot with a backpack or hand-held sprayer.

Use a ladder:

  • Unsafe
  • Not possible due to rocky, steep coastal terrain

Possible Solution? ‘Knock & Spray’

In 2013, the Sea to Sky Invasive Species council began to trial a new method of safely applying herbicide to tall knotweed, called ‘Knock & Spray’, at a number of large sites in Squamish and Britannia Beach. This method allows the treatment of knotweed in one visit in a given season, whilst abiding by all regulations and herbicide label requirements.

How to do knock & Spray:

Person 1

  • Clear any old or dead canes from the coppices.
  • Using a machete, a strong stick, or your hand, use a ‘karate chop’ motion to bend the knotweed stems over (one by one), making sure not to break/cut the stem.

Person 2

  • Applicator with a back pack sprayer follows person 1, spraying the leaves of the bent over stems, at waist height.


  • You avoid spraying over head height, which is in line with Worksafe BC requirements.
  • It’s easy for the Herbicide Applicator to navigate through a patch. They can see where they’re going, and what they’ve already sprayed.
  • Due to the stems being bent over, the underside of the leaves are exposed and easy to spray, meaning that you are maximizing the herbicide contact with the stomata (most of which are on the underside of the leaves in knotweed).

Preliminary Results:

The video below shows before and after photos at IAPP site 309488 which is on the Britannia Forest Service Road. We observed an average of 90% efficacy at this site after 1 treatment.

To learn more about Knotweeds, please visit our Knotweed Information page.