infest

Concise Oxford English Dictionary © 2008 Oxford University Press:
infest/ɪnˈfest/

▶verb (of insects or organisms) be present in large numbers, typically so as to cause damage or disease.

– derivatives
infestation noun.

– origin ME (in the sense ‘torment, harass’): from Fr. infester or L. infestare ‘assail’, from infestus ‘hostile’.