Insect pests and mycoflora of oilbean (Pentaclethra macrophyllaBenth.) pods and seeds in southeastern parts of Nigeria

Abstract

Introduction. Pentaclethra macrophylla, Mimosaceae, is the only species of the genus present in West Africa. The plant's diseases are not well known. The numerous uses of the plant's seeds and pods aroused our interest in investigating its pests and mycoflora, which would cons- titute a drawback to the plant's production, value and use. Materials and method. Mature pods of P. macrophylla were collected from different locations in Nigeria and tree-top observations were also made for studying the pests present. Isolation, characterization and identification of the myco- flora were done by plating washings from pods, skin and seeds on different media and incubating for 2 to 3 days at 28 °C. Control plating was done with sterile peptone water. Streptomycin was incorporated in the test and control media to avoid bacteria. Some pods and seeds were also stored before being treated as above. A pathogenicity test was also carried out. Results and discussion. Many insect species and pathogens were found to attack the pods and seeds of the plant. The major insect pests identified were Cossus cadaribae, Sitophilus spp., Spodoptera exempta and silkworms. The major fungal pathogens included Aspergillus niger, Rhizopus stolonifer, Cladosporium her- barum, Penicillium sp., Botryodiplodia theobromae and Fusarium sp. Some of the insect pests skeletonize the green pods, depriving them of photosynthetic surfaces; some bore into the pods, eating up and damaging the seeds' fleshy cotyledons; others lacerate the pods, causing lesions of varying sizes and shapes, thereby creating portals for the penetration of fungal and bacterial patho- gens which invade and rot the predisposed seeds. Conclusion. Our study established many pests and mycoflora which attack P. macrophylla pods and seeds. They might have been the cause of the observed symptoms and damage, and the cause of the reduction in the crops planted, reported by previous authors. Nigeria / Pentaclethra macrophylla / pests / microbial flora / identification Insectes parasites et mycoflore des gousses et graines de Pentaclethra macrophylla Benth. dans le sud-est du Nigeria.