Advances in the integrated pest management in protected-eggplant crops by seasonal inoculative releases of Orius laevigatus

The implementation of IPM on protected eggplant is difficult due to several arthropod pests that can attack this crop. In a two-year survey, two thrips species were found: Frankliniella occidentalis (Perg.) - the most harmful one - and Thrips tabaci Lind. During a three-year period, the possibility to control thrips by means of the pirate bug Orius laevigatus (Fieber) releases was tested in eggplant plastic tunnels. This native predator was able to control effectively the exotic F. occidentalis despite chemical insecticides sprayed against Aphis gossypii Glov. The pirate bug releases, conducted as soon as thrips were detected, allowed to establish an early interaction between prey and predator at a low level of density. When insecticides were used the mass-reared predators were released more than once. The chemical control alone, carried out in check eggplant tunnels against F. occidentalis, showed a low degree of efficacy. Wide-spectrum insecticide treatments disrupted the enhancement of natural control and the releases of mass-reared beneficial arthropods.