When supplemental food becomes essential: biological control of Nezara viridula by Podisus maculiventris

Abstract: Nezara viridula (Hemiptera: Pentatomidae) is an invasive pest that causes significant damage to greenhouse pepper production in Europe. Although the predator Podisus maculiventris (Hemiptera: Pentatomidae) preys on N. viridula, it establishes poorly under greenhouse conditions. This study investigated whether supplemental food provisioning could overcome these limitations and enable effective pest suppression. Nezara viridula alone proved nutritionally insufficient to sustain P. maculiventris, as no individuals completed development when fed exclusively on this prey. In contrast, supplemental provisioning of Tenebrio molitor (Coleoptera: Tenebrionidae) larvae enabled predator establishment and effective pest suppression in both cage and semi-field trials. However, discontinuing supplemental food provisioning after pest arrival reduced P. maculiventris oviposition by 78 % compared with continuously supplemented populations, indicating an interaction consistent with apparent amensalism. Despite successful establishment and pest suppression under semi-field conditions, commercial greenhouse deployments failed to establish predator populations, revealing spatial constraints related to the distribution of feeding stations and behavioral constraints associated with reduced cooperative prey subjugation at low predator densities.