IPA: //ʌnˈpærəsaɪtaɪzd//
KK: /ʌnˈpærəsaɪtaɪzd/
Not affected by parasites; free from parasitic organisms.
The researchers studied the effects of the treatment on unparasitized plants.
Unparasitized → It is formed from "un-" (meaning not) and "parasitized" (from "parasite" which comes from Greek "parasitos" meaning one who eats at another's table). The word "unparasitized" means not affected by or infested with parasites.
Think of 'not' ('un-') being added to 'infested with parasites' ('parasitized') — that's why unparasitized means free from parasites.