Causes of mortality at different stages of Cactoblastis cactorum in the native range

Abstract

Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae) is native to South America and has been used successfully as a biocontrol agent against invasive species of Opuntia (Cactaceae). After its release in the Caribbean, it entered North America, dispersed to southeastern USA, and may reach Mexico threatening native cacti biodiversity and industry based on Opuntia spp. Identifying mortality factors acting on insect populations is central to develop pest management programs. The objective of this study was to estimate mortality causes of C. cactorum in its native range through life table experiments conducted on the exotic O. ficus-indica (L.) Miller and the native species O. quimilo K. Schum. and O. megapotamica Arechav., to detect vulnerable stages and natural enemies. The main mortality factors were generalist predators and native plant defenses. Apanteles opuntiarum Martinez & Berta (Hymenoptera: Braconidae) was found to be the parasitoid with the highest potential as a biocontrol agent.