Diverse mortality factors for Cactoblastis cactorum and the insects? response in its native Argentine range

LOGARZO, GUILLERMO A.; VARONE, LAURA; BRIANO, JUAN A.; HIGHT, STEPHEN M.; CARPENTER, JAMES E.

San Diego, California

Congreso; 58th Annual Meeting of the Entomological Society of America; 2010

Entomological Society of America

Cactoblastis cactorum Berg (the cactus moth) has become a serious threat to the diversity of Opuntia species both native and cultivates in Mexico and the United States. The functional value of these Cactaceae is not only related to its commercial cultivation, but also by its role in the maintenance of natural ecosystems. In August of 2007, the SABCL started studies in Argentina to control this new pest in North America. The C. cactorum mortality factors were studied building life tables in 2 cultivations (managed and unmanaged) of prickly pear cactus (Opuntia ficus-indica) in Córdoba and Santiago del Estero provinces. In each cultivation, more than 300 egg sticks of C. cactorum were marked in each of the 3 annual generations. The samples were taken every 7-14 days on the different stages. Main mortality factors on egg stage were rain and wind ((29-33%) and predation (12-18%, mostly produced by ants). In larva stage, fail of first instar to penetrate the cladode (12-18%), and parasitoidism (12- 22%) were the main mortality causes. Last instars (get out from the cladode to pupate in the soil) and pupae showed high mortality by predation and dehydration (40-50%). Sex ratio was female biased (1: 1.3). Population trend index was positive (I=1.7) going from 16.6 eggs per plant in the first generation to 29.0 in the second one.