A study was carried out on the insecticidal effects of the powdered stem bark extract of Uvaria chamae and its ethanolic extract on three most devastating stored products pests (Coleopterous) in Nigeria, namely: Callosobruchus maculatus F. (Bruchidae), Rhizopertha dominica F. (Bostrichidae) and Sitophilus zeamais Motschulsky (Curculionidae). Graded concentrations of each formulation of the powdered bark and ethanolic extracts were in exposure chambers of each insect in laboratory bioassays under ambient conditions (25±2°C). S. zeamais, R. dominica and C. maculatus were exposed to the following concentrations 0.00, 0.10, 0.20, 0.40, 0.80, and 1.60 mg/L grains in three replicates per treatment and control. The mortality of the insects was used to compute mean lethal concentration (LC 50) values by probit analysis. All the concentrations tested showed appreciable toxicity against each test insect species. The computed LC 50 values for powder formulation gave significantly (P≤0.05) higher toxicity against C. maculatus (1.281 g/kg) than either S. zeamais (2.145 g/kg) or R. dominica (5.189 g/kg). However, the ethanolic extract was more toxic on C. maculatus (0.134 mL/L), S. zeamais (0.173 mL/L) or R. dominica (0.359 mL/L). It was found that the higher the concentration of the ethanolic extract, the higher the mortality. The result implies that, U. chamae powdered and ethanolic stem bark extracts have potentials for use during storage of grains, ensuring food security, profit maximization and availability of seeds for the next planting season without being damaged by these test insect species. The presence of high concentration of steroids and terpenes may be responsible for the observed high insecticidal activity of the test extracts.

The study was carried out to evaluate the heavy metals accumulation in the stems, leaves and roots of Lactuca sativa (Lettuce) and Spinacia oleracea (Spinach). Pot experiment was conducted to examine the phytoextraction ability of these plants for some heavy metals (Cd, Cu, Fe, Pb and Zn) in contaminated soils obtained from an area where indiscriminate burning of waste materials is being carried out beside FCE Katsina. Atomic Absorption Spectrophotometer (AAS) was used for the determination of heavy metals concentrations. The mean levels of metals accumulation evaluated in Lactuca sativa show a higher amount of Fe (47.97 mg/kg) with the lowest amount of Pb (0.44 mg/kg) which follows the order Fe>Zn>Cu>Cd>Pb. Similarly, Spinacia oleracea followed the trend where higher amount of Fe (24.13 mg/kg) with lower Cd (0.25 mg/kg) content was detected, which follows Fe>Zn>Cu>Pb>Cd. The bioaccumulation factor (BAF) was

Rhyzopertha dominica (Bostrichidae: Coleoptera) is one of the most serious devastating insect pests attacking stored wheat grains in Nigeria. The most common strategy adopted in controlling this insect pest is the application of synthetic pesticides which is costly, toxic to non-target organisms and is non eco-friendly. Botanical pesticides are recently used as alternatives to synthetic pesticides due to their non-hazardous effect on the environment and non-target organisms, cost effectiveness and direct impacts on the target organisms. This study was carried out to determine the toxicity of leaf powders obtained from three species of plants: Ageratum conyzoides, Momordica charantia and Tephrosia vogelii in the control of R. dominica infestation on stored wheat grains. Five doses (0.50, 1.00, 2.00, 4.00 and 8.00 g) per 20.00 g were measured from the powdered leaves of the tested plants with ethanol treatment as the control (0.00 g 20.00 g-1). The powdered doses were applied onto wheat grains before the insects were introduced. The experiment was laid down in completely randomized design (CRD) with three replications. The data obtained was analyzed using analysis of variance at 5% probability level with Least Significant Difference used to separate the means. The results showed significant (p ≤ 0.05) differences in the magnitude of toxicity imparted by various doses of the powders on R. dominica. The treatments influence high rate of mortality, reduced number of laid eggs and emerged adults when compared with the control. The toxicity of the powders increased with increase in dosage. It was concluded that 8.00 g 20.00 g-1 of the powders were more toxic to R. dominica, inducing 28.00-77.30% insects’ mortality thereby protecting grain damage to as low as 1.04% at 6th month of storage. T. vogelii leaf powders were recommended for use against R. dominica in stored wheat grains. Key words: botanicals, dose, lesser grain borer, wheat

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