Survey of Species of the Genus Orius in the Tunisian Sahel Region

Species of the genus Orius belong to the Anthocoridae family. They are polyphagous predators of small sized insects and they are of great importance in biological control. During an inventory of Orius species on Chrysanthemum coronarium flowers undertaken in 2010 and 2011 in different locations in the Tunisian Sahel region, three species were encountered namely O. laevigatus, O. albidipennis and O. majusculus. These species are predators of mites and small insects such as thrips, aphids, and white. The first species was the most abundant one in all localities (a total of 4358), followed by O. albidipennis and O. majusculus with 51 individuals. Temporal evolution of Orius species showed that activity of the predaceous bugs depends essentially on the flowering period of C. coronairum. Orius species occurred during spring period with various densities, depending on species, and increased considerably in June. O. leavigatus was detected in February and remained active until June. Regarding O. albedipenis and O. majusculus, their activity has begun in April-May but with different densities. Monitoring revealed the abundance of females as compared to males within Orius species which indicated that females occupy a significant importance within population.