The Sustainable Use Directive (SUD) requires that all pesticide application equipment (PAE) is tested on a regular basis.*
The Plant Protection Products (Sustainable Use) Regulations 2012 states that all types of PAE must be tested to certain timescales depending on the age of the machine and further information can be found here on the frequency of testing required. The legislation relates to all sectors, agriculture, horticulture, amenity and fruit but for anyone applying a professional pesticide, the equipment must be tested. Application equipment that does not require an NSTS test are knapsacks, handheld and pedestrian equipment. These need to be inspected by a competent person, repairs made as required and a record kept. For knapsack sprayers a checklist is available here to use and record the results.
* The legal requirements are contained in the Plant Protection Products (Sustainable Use) Regulations 2012