infestant
/ɪnˈfɛstənt/
noun
- An organism (such as an insect, rodent, or parasite) that infests a place or host.
- The exterminator identified the main infestant as termites.
- Certain plants can repel common garden infestants like aphids.
- The lab studied the life cycle of the infestant to find a better pesticide.