Management of the legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) with field applications of the entomopathogenic fungus, Beauveria bassiana and a mixed formulation of the baculovirus MaviMNPV with emulsifiable neem oil

The present study assessed the effectiveness of the entomopathogen fungus Beauveria bassiana in comparison with neem oil combined with the baculovirus MaviMNPV and a synthetic insecticide deltamethrin for the control of Maruca vitrata Fabricius under field conditions. The trial was conducted in six villages at Glazoue and Djakotomey, two districts in Benin. Four treatments consisting of (1) untreated control, (2) neem + MaviMNPV, (3) B. bassiana and (4) deltamethrin were arranged in a complete randomized block design with three replicates. Reproductive organs of cowpea plants were sampled for estimating population of M. vitrata. In spite of the importance between-field variations observed, bio-pesticides significantly reduced the population density of M. vitrata as well as its damage level. Similarly, grain yields were improved in sprayed cowpea compared to the untreated control, regardless of the experimental zone. In Glazoue, yields ranged from 724.06 ± 5.04 kg/ha (deltamethrin) to 933.03 ± 8.7 kg/ha (B. bassiana). In Djakotomey, 649.1±4.7, 611.07±5.1, 583.19±4.04 and 217.11±3.9 kg/ha were recorded for deltamethrin, B. bassiana, neem + baculovirus, and untreated control, respectively. The possibilities of the using bio-pesticides as efficient IPM components in cowpea are discussed. Key words: Cowpea pests, bio-pesticides, Beauveria bassiana, neem, baculovirus MaviMNPV, deltamethrin.