ETUDE DE LEFFICACITE DES BIOPESTICIDES A BASE DE GRAINESDE NEEM ET DELENTOMOPATHOGENEBEAUVERIABASSIANA(BALS.) VUILL.POUR LA GESTION DES PRINCIPAUX INSECTES RAVAGEURS DE LA CULTURE DU NIEBE DANS LA REGION DE MARADI AU SAHEL

The insect pests of cowpea, Vignaunguiculata L. Walper, is one of the constraints which affect the cultivation this crop in Africa. The pod sucking bug Clavigrallatomentosicollis(Stål), the flower thripsMegallurothripssjöstedti(Trybom) and the pod borer Marucavitrata(Fabricius) are the main insect pests whose damage causes considerable yield losses on cowpea crop. In this study, neem Azadirachtaindica based biopesticides and the entomopathogenBeauveriabassiana(Bals.) Vuill were tested todeterminetheir efficiency in the management of cowpea insect pests. The trials were established in a farming environment with producers in 15 villages of the Maradiregion during three consecutive cropping seasons 2020, 2021 and 2022. The experimental design is the Fisher block with 4 treatments (Neem grain, B. bassiana, Chemical pesticide and the control without treatment) and two repetitions per site. The results for this studybiopesticide treatments (Neem grains and entomopathicfungus B. bassiana) reduced the insect pest damageof 73.21% and a yields increase of 104.12% compared to the control treatment. . Neem was effective as the synthetic chemical pesticide in the management of insect pests as it reduced the populations of M. sjöstedti, M. vitrata and C. tomentosicollis by 67.29, 70.57 and 71.26%respectively. This Neem biopesticide resulted a yield increase of 140.33% on cowpea for the three years of the study. Thus, for low-income producers, neem is an available resource that can constitute an effective and ecological alternative for managing cowpea insect pests in the Sahel.