Final answer:
Registered technicians can apply pesticides under supervision but are normally not authorized to handle all pesticide-related activities. They play a role in the application of plant protection products, like herbicides, to combat pests.
Step-by-step explanation:
The activities that may be performed by a registered technician vary depending on regulatory jurisdictions, but typically they are allowed to handle pesticides and may also apply them under the supervision of a certified applicator. They are generally not authorized to perform all pesticide-related activities independently without supervision. Therefore, option (a) All pesticide-related activities would not be accurate. The best answer, given the usual regulations, might be (b) Apply pesticides, but not handle them, as applying pesticides is a task that can be delegated to a technician under supervision, while handling, which can involve mixing, loading, or transferring pesticides, may not necessarily be within their scope of practice without direct oversight.
The most common use of pesticides, such as herbicides, is to serve as plant protection products, which are primarily applied to protect plants from various pests, including weeds, fungi, or insects. Examples include the use of the fungus Alternaria solani to combat the aquatic weed Salvinia.