We report here on the diversity and composition of Coreidae and Pentatomidae species, as well as their egg parasitoids collected on cowpea (Vigna unguiculata [L.] Walp) (Fabaceae) plants from a field in Teresina, central-northern Piauí State, Brazil. Weekly sweep net sampling was performed during the phenological cycle of this crop in the rainy and dry seasons. In the pentatomid collections, 14 species were identified from 3 subfamilies (Asopinae, Edessinae, and Pentatominae). Five species of Coreidae also were collected from the subfamily Coreinae. We found that Euschistus heros (F.), Crinocerus sanctus (F.), Chinavia ubica (Rolston), and Piezodorus guildinii (Westwood) (all Hemiptera: Pentatomidae) were the most abundant hemipteran species associated with cowpea. Generally, species richness and diversity of individuals from this order were higher in the rainy season than in the dry season. The parasitoid species identified from field-collected hemipteran egg masses were: Anastatus coreophagus Ashmead (Hymenoptera: Eupelmidae), Neorileya flavipes Ashmead (Hymenoptera: Eurytomidae), Ooencyrtus anasae (Ashmead) (Hymenoptera: Encyrtidae), O. submetallicus (Howard) (Hymenoptera: Encyrtidae), and Trissolcus urichi (Crawford) (Hymenoptera: Platygastridae). We found that about 52% of hemipteran egg masses collected from the cowpea field were naturally parasitized by the above parasitoids, whereas nearly 10% of C. sanctus and C. ubica sentinel egg masses were parasitized.

Nitrogen (N) is the second most accumulated nutrient in rocket. This nutrient greatly affects growth, productivity and quality of the vegetable. Rocket is the second most widely grown leafy vegetable in hydroponic system; however, no studies on how N concentration in nutrient solution affects this crop can be found in literature. We studied four concentrations (79.2; 118.8; 158.4 and 237.6 mg L-1 of N) in a randomized block design with five replicates. Maximum number of leaves, leaf area, dry mass and productivity of rocket cv. ‘Folha larga’ were obtained with the highest N concentration. The rocket quality, evaluated by the nitrate content, was maximum with 210.2 mg L-1 of N and its value in the concentration which maximized productivity is in the acceptable range for vegetables; so, it is recommended to grow rocket with 237.6 mg L-1 of N in the nutrient solution.