In argentinian Northwestern five species or biotypes of the genus Cactoblastis Ragonot are recognized on cacti: C. cactorum (Berg), C. Bucyrus Dyar, C. mundelli Heinrich, C. doddi Heinrich and C. ronnai (Brèthes). Cactoblastis doddi feeds on Opuntia sulphurea, a native cactus. The objectives of this study were to morphologically characterize immature stages of C. doddi and to know bioecological aspects (duration of the development, distribution, larval parasitoids) to understand the insect-plant interaction. Sampling were conducted at seven sites located at different altitudes (2 100-3 100 meters) in Jujuy’s prepuna, Argentina. Each sample consisted of five infested cladodes of O. sulphurea in each site. In the laboratory, lepidopteran breeding was performed under the following conditions: temperature 23 ± 3°C, relative humidity 69 ± 11 % and photoperiod of 12 hours light-12 hours dark. Under previous conditions, Cactoblastis doddi had two generations: a long one in winter (> 258 days) and a short one in summer (147 days), both with seven larval instars. Each immature stage and instars were morphologically characterized. Two larval parasitoids were detected Apanteles opuntiarum Martínez y Berta, and Habrobracon sp. (Hymenoptera: Braconidae). It confirms and extends the Argentinian distribution of C. doddi to Coraya, Jujuy (3 069 m).

Keywords: Cactoblastis doddi, life cycle, distribution, Opuntia sulphurea, Argentina.