none Cotesia marginiventris, is an endoparasitoide of several species of Noctuidae. The aim of this work was to determine the efficacy of this parasitoid in controlling Noctuids and to investigate the possibilities for its use in protected sweet pepper crops. The trials were conducted in commercial greenhouses located in Campo de Cartagena and Almeria (Southeastern Spain), with several levels of caterpillar infestation. Spodoptera exigua was the most abundant species found, S. littoralis y Chrysodeixis chalcites were also detected but were of minor importance. In all sites and at several release rates C. marginiventris controlled the pest, achieving parasitism levels of 100%. Commercial applications of this parasitoid should start immediately after the first captures of adult noctuids in pheromone traps. Cotesia marginiventris is a koinobiont parasitoid that parasitizes the first instars but doesn't kill its host until the third instar. As is demonstrated in the present study, high infestation pressures (detectable in pheromone traps) can still result in unacceptable fruit damage. This damage could be minimized by integrating parasitoid releases and treatments with a selective chemical such as Bacillus thuringiensis. Animals and man; Control; Biological control; Nutrition; Diet; Parasites diseases and disorders; Parasites; Insect parasites; Hosts; Insect hosts; Habitat; Land and freshwater zones; Palaearctic region; Europe Spodoptera (Noctuidae); Control by; Cotesia marginiventris (Hymenoptera); Food plants; Sweet pepper; Hymenopteran parasites; Cotesia marginiventris; Biocontrol potential on food plants; Man made habitat; Spain; Almeria & Cartagena; Hymenopteran parasites biocontrol potential on food plants, greenhouse crops Cotesia marginiventris (Braconidae); Control of; Spodoptera (Lepidoptera); Lepidopteran hosts; Spodoptera; Man made habitat; Spain; Almeria & Cartagena; Biocontrol potential, greenhouse crops