INNSA Standard 1 - Spraying Requirements for Japanese Knotweed

Spraying of chemical herbicide is a commonly used and cost-effective means of Japanese knotweed control.

  • All operatives carrying out spraying works will hold (or be directly supervised by someone holding) a valid NPTC PA1 certificate, as well as the relevant Award relating to the equipment being used (e.g. NPTC PA6)
  • INNSA Approved Companies offering invasive weed treatment should provide additional continued training to all site operatives. This training should provide specific information and techniques regarding all non-native invasive species which the site operatives will be required to treat.
  • Where chemical application works are carried out in or near to water, a relevant Award (e.g. PA6W) must be held by a supervising member of the site team.
  • Operations being carried out near water should apply for and comply with Environment Agency or SEPA Water Quality Management regulations.
  • Chemical application works should always be carried out using appropriate PPE. -
  • Chemical application works should be carried out with a relevant policy in place to minimise the risks of cross-contamination.
  • Companies should be forthcoming with customers about the risks of chemical treatments.
  • Companies should always provide a written method statement, risk-assessment and COSHH assessment for all chemical application works that are undertaken
  • Companies should implement measures to avoid applying chemical to non-target species, taking account of e.g. spray drift and the variety of application methods available.
  • Companies should, where possible, and where appropriate, obtain written permission from neighbouring landowners, where treatment may pose a risk to non-target species on their land.
  • When offering chemical eradication of Japanese knotweed, companies should recommend treatment plans as standard, which include a minimum number of sprays, over a minimum period of time.
  • Single applications of chemical may be offered, but should not be recommended as a long-term solutions


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