Mirid bugs are important biological control agents mainly in protected but also in field vegetable crops. Several species are zoophytophagous meaning they can feed on both animal and vegetable food sources. In Portugal growers have been releasing Nesidiocoris tenuis (Nt) into tomato greenhouses, to control whiteflies and leaf miners, and recently Tuta absoluta. Nt is an exotic species, with pantropical distribution and cryptogenic, that sometimes shows severe phytophagous behaviour damaging tomato crops with economic impact on production. Another mirid bug, Dicyphus umbertae (Du), which is native to Portugal and was actually described in 2006, often colonizes greenhouse tomato crops in the Oeste region. This species, less phytophagous, is being replaced by Nt for reasons not yet fully understood. It is important to understand the mechanisms behind this replacement looking into getting more and new information that will allow the design of conservation strategies for Du, leading to lower pesticide application and improvement on production quality. This species is not available commercially. In this project, and in order to deepen the knowledge regarding specific (and population) diversity of the Dicyphus genus, specimens will be collected from several locations throughout the country. These insects will be kept under controlled laboratory conditions in rearing units in ISA’s insectary following a rearing methodology used for similar marketed mirid species and adapted it afterwards (Task 1a). During this task, the morphology of the different Du populations will be characterized in order to document possible differences (Task 1b) and development time will be assessed (Task1c). The phylogeny and phylogeography of the Dicyphus genus in the Iberian Peninsula will also be addressed by FCID with use of specimens collected in several regions (Task 2). The olfactory response of Du to volatile organic compounds (VOCs) will also be evaluated, in ISA, with the use of a multi-choice dynamic olfactometer (Task 3); VOCs released by pests that are prey to Du (Task 3a), by host plants without prey (Task 3b), and released by host plants attacked by prey (Task 3c). Based on the results from Task 3 VOCs that originate interesting responses will be identified, in FCID, with GC-MS techniques (Task 4). The final objective will be the design of a flow diagram that simplifies making decisions that help biological control through the conservation of Du and thus reducing pesticide use by e.g. ecological infrastructures and/or push and pull strategies (Task 5). It will be the first time that such bioecological studies are performed on this autochthonous species which has the potential to positively impact on a relevant economic activity like vegetable protected crops. These results will provide the technicians with more tools to help them to accomplish to EU Directive 2009/128 and to the Law 26/2013 (Sustainable Use of Pesticides).