Ghent University. Faculty of Bioscience Engineering
Abstract
Biological control of arthropod pests is gaining the interest of growers all over the world. Species of the genus Orius are important natural enemies of thrips and other harmful arthropods in a variety of agricultural and horticultural crops and have been widely used in biological control programmes in Europe, the Americas and Asia. In South Africa, thrips are key pests in major crops, with the sugarcane thrips, Fulmekiola serrata Kobus, as a model example. As thrips are notably difficult to control with pesticides, an effective indigenous natural enemy could provide local growers with an alternative management strategy against this pest. During surveys performed in and around South African sugarcane fields, the two little studied anthocorid predators, Orius thripoborus (Hesse) and Orius naivashae (Poppius), were selected as candidate biocontrol agents. In this dissertation, the autecology of these flower bugs was studied and their potential as biocontrol agents of thrips and other arthropod pests in South Africa was assessed based on field observations and laboratory tests.
Based on our study, O. thripoborus appeared to be, in many aspects, a more suitable biocontrol agent than O. naivashae for use against arthropod pests in South Africa. Due to its better nutritional plasticity, O. thripoborus is a more easy and cheaper to rear natural enemy with an overall better predator performance compared with O. naivashae. Based on these findings, a South African company has recently started up the mass production of O. thripoborus for commercial biological control purposes in South Africa. Further research is needed to optimise the augmentative application and conservation of O. thripoborus as a biocontrol agent of thrips in sugarcane and other major crops in South Africa
