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Papers by Nathaniel Oigiangbe

African Crop Science Journal, 1997

journal of biopesticides, 2013

The bioactivity of Alstonia boonei De Wild leaf alkaloid was tested under laboratory bioassay aga... more The bioactivity of Alstonia boonei De Wild leaf alkaloid was tested under laboratory bioassay against the legume pod borer, Maruca vitrata Fabricius. The alkaloid was incorporated into standard M. vitrata artificial diet at five doses [0.00 % (Control), 0.02 %, 0.05 %, 0.10 % and 0.20 %], and fed to the newly emerged first instar M. vitrata larvae in plastic wells under laboratory conditions. Significant differences (P < 0.05) were recorded in the larval survival, wet and dry weights of the larvae at ten days after infestation (DAI). Mean larval survival ranged from 34.78 to 65.00 percent in the treatments with the alkaloid compared with 91.67 percent in the control. At 15 DAI, all the survivors in the control had pupated normally compared with the 4.34 to 35.00 percent pupation (with various levels of deformity) in the treatments with the alkaloid. The mean percentage adult emergence was also significantly different in the control (83.33 %) compared with the other treatments (ra...

Journal of Applied Entomology, 2019

Cowpea (Vigna unguiculata (L.) Walp.; Fabaceae) is an important grain legume grown especially in ... more Cowpea (Vigna unguiculata (L.) Walp.; Fabaceae) is an important grain legume grown especially in the dry savannah agro-ecologies of sub-Saharan Africa (SSA). In Africa, cowpea is part of the traditional cropping systems and it is considered as a strategic crop because of its multiple uses as human food, animal feed, source of nitrogen for soil restoration and income for resource-poor farmers

International Journal of Tropical Insect Science, 2007

The insect fauna of rain-fed rice, Oryza sativa, was assessed using the sweep net and direct coun... more The insect fauna of rain-fed rice, Oryza sativa, was assessed using the sweep net and direct count methods. The objective of the study was to provide basic information on the insect pest complex of rice in the area and their natural enemies. One hundred and five insect species belonging to nine orders and 57 families were found. The insect orders in order of abundance were Diptera (45.67%), Coleoptera (12.77%), Lepidoptera (12.23%), Orthoptera (8.44%), Heteroptera (8.23%), Homoptera (7.03%), Hymenoptera (3.25%), Dermaptera (1.95%) and Dictyoptera (0.43%). Diopsis thoracica Westwood (Diopsidae) (69.43%) was the most abundant dipteran followed by the sarcophagids (14.93%) and calliphorids (7.11%). Members of the family Chrysomelidae represented 50% of the coleopterans followed by the coccinellids (17.46%). While 31% of the lepidopterans were noctuids, 60% were pyralids. The pentatomids (50.57%) were the most abundant heteropterans while the acridids (43%) were the most prevalent orthopterans. The homopterans were mainly Cofana unimaculata Signoret (which represented 79%). The insects were clustered into three groups with D. thoracica alone in group 1, C. unimaculata and Sarcophaga species in group 2 and the rest in group 3. We therefore conclude that D. thoracica is the most important pest of rice in Ekpoma while C. unimaculata may also be very important, but Sarcophaga species appears to be the most important natural enemy in the system.

Journal of Applied Entomology

Journal of Zhejiang University. Science. B, 2007

The bioactivity of the aqueous extracts of the leaf and stem bark of the medicinal plant, Alstoni... more The bioactivity of the aqueous extracts of the leaf and stem bark of the medicinal plant, Alstonia boonei De Wild (Apocyanaceae), against the pink stalk borer, Sesamia calamistis Hampson (Lepidoptera: Noctuidae) was studied in a laboratory bioassay. The extracts were incorporated into artificial diet at a rate of 0.0% (control), 1.0%, 2.5%, 5.0%, and 10.0% (w/w). Both extracts significantly (P<0.01) reduced larval survival and weight in a dose dependent manner. The concentrations that killed 50% of the larvae (LC(50)) for the stem bark extract were 2.8% and 2.1% at 10 and 20 DAI (days after introduction), respectively, while those for the leaves extract were 5.6% and 3.5%. The weights of the larvae also varied significantly (P<0.05) between the treatments in a dose dependent manner. We conclude that both leaf and stem bark extracts of A. boonei are toxic, used as growth inhibitors to S. calamistis larvae, and hold good promise for use as alternative crop protectants against S....

JBiopest 5(1): 1-6 © 391 JBiopest 6(2):173-177 Bioactivity of Alstonia boonei De Wild leaf alkalo... more JBiopest 5(1): 1-6 © 391 JBiopest 6(2):173-177 Bioactivity of Alstonia boonei De Wild leaf alkaloid on the growth and development of Maruca vitrata Fab.