Nota técnica

abstract chrysoperla externa (hagen) is an important insect predator on several agricultural pests. effect of feeding on several preys on life span of c. externa was studied under laboratory conditions (27 ± 2 oc mean temperature and 60 ± 5 % r.h.). each of the following preys was daily offered ad libitum to predator: sitotroga cerealella (oliver), aphis craccivora (koch), aphis nerii boyer de fonscolombe, thrips tabaci lyndeman and tetranychus cinnabarinus (boisduval). duration of larval stage was significant lower (7.7 and 10.15 days) when fed on s. cerealella or a. craccivora, whilst when fed on a. nerii, t. tabaci and t.cinnabarinus it lasted 20.3, 19.1 and 16.4 days, respectively. predator reached pupal stage just when fed on s. cerealella eggs or a. craccivora nymphs and adults showing time mean of 7.95 and 7.55 days, respectively. conversely, only one individual reached this stage when feeding on a. nerii or t. tabaci, and no predator reached pupal stage when t. cinnabarinus was used as food source. it is concluded that s. cerealella and a. craccivora were the most adequate food sources for predator development, while a. nerii, t. tabaci and t. cinnabarinus resulted less appropriate