Research
Morphomeric Variability among Samples of Callosobruchus Subinnotatus (Pic.) (Coleoptera:Chrysomelidae) in Northwestern Nigeria
Morphometric studies aimed at identifying some existing variations among different samples of Callosobruchus subinnotatus (Pic) collected from three locations each of five Northwestern States (Kaduna, Zamfara, Kebbi, Kano and Katsina) in Nigeria was evaluated. Thirteen diagnostic features were used in which measurements were carried out on ten characters using handheld digitalized Miscope microscope (40-140x magnification) while three ratios were used as explanatory variables. Data obtained were analyzed using the parametric statistical tools of mean, standard deviation and standard error. The distribution and relationships among samples studied were expressed using two step cluster analysis, results of which were drawn into cluster distributions, centroids of means of morphoclusters and the simultaneous confidence intervals (95%) used to determining the level of significance among measured variables of the samples. The result gave two morphoclusters revealing the existence of two possible races of C. subinnotatus in Northwestern Nigeria. Race 2 constituted the highest percentage distribution across the States with 53.3% against race 1 with 46.7%. Race 2 were relatively bigger in size than race 1.
Bioassay of Mundulea Sericea Ethanol Leaf Extract and Leaf Powder against Callosobruchus Maculatus (F.) on Stored Cowpea
Bioassay of ethanolic crude extract of Mundulea sericea (Willd.) A. Chev. (syn. M. suberosa Benth.) was compared with the leaf powder for their insecticidal potential against Callosobruchus maculatus on stored cowpea using actellic (25 EC) and actellic (2 %) as standard checks with an untreated control. Five pairs of day old adult C. maculatus were sexed and used to infest 100 g IAR-48 (SAMPEA 7) cowpea seeds stored for three months containing 1, 2 and 3 ml or g of the treatments with each replicated three times. All treated jars were shaken thoroughly to ensure effective coating of seeds with treatments and left on laboratory benches in the Storage Entomology Laboratory of Crop Protection Department, Institute for Agricultural Research(IAR)/Faculty of Agriculture, Ahmadu Bello University, Zaria under open conditions of 28± 2OC and 70± 10 % relative humidity. Insect mortality, oviposition, progeny emergence as well as percentage seed damage and viability were assessed. The results revealed that, the plant materials like their synthetic counterparts (Actellic 25 EC and 2 % dust) significantly (P< 0.05 %) caused higher insect mortality, reduced oviposition and inhibited progeny emergence with not much damage to seed integrity and viability. Though both plant materials were found to be effective in protecting cowpea seeds against C. maculatus attack however, the Mundulea ethanolic extract was significantly better than the dust which was in turn better than the untreated control but was not as good as the synthetic pesticides.
First Report of A New Bruchid Species aoMegacerus Cubiculus (Coleoptera;Chrysomelidae)a Found on Cowpea in Nigeria and A Brief Description of The Species
Introduction - The large-horned bruchid (Megacerus Fahraeus) is a distinct genus of Bruchinae that merits being the sole member of the tribe Megacerini in the subfamily Bruchinae, with more than 50 species distributed from U.S.A. and Canada to Chile and Argentina (Tera´n and Kingsolver 1977; McNamara 2004). These bruchids have been reported to feed only on the seeds of the morning glory family (Convolvulaceae), with an occasional unconfirmed exception (Center and Johnson 1974; Maes and Kingsolver 2003). Recently the larvae of Megacerus flabelliger were found feeding on seeds of Merremia macrocalyx a convuolvulaceous weed in Venezuela (Johnson and Raimundez-Urrutia, 2008). The weed (M. macrocalyx ) produces fruits with one to four seeds and the bruchid was found to oviposit more frequently on fruits with multiple seeds but only one seed was attacked while in some cases fruits with multiple seeds had eggs. Oviposition occurred most frequently on seeds still on the plant and only eggs of M. flabelliger that were found on seeds of M. macrocalyx (Johnson and Raimundez-Urrutia, 2008).
