Development of Metarhizium anisopliae and Beauveria bassiana formulations for control of malaria mosquito larvae

<p>Abstract</p> <p>Background</p> <p>The entomopathogenic fungi <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana </it>have demonstrated effectiveness against anopheline larvae in the laboratory. However, utilising these fungi for the control of anopheline larvae under field conditions, relies on development of effective means of application as well as reducing their sensitivity to UV radiation, high temperatures and the inevitable contact with water. This study was conducted to develop formulations that facilitate the application of <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana </it>spores for the control of anopheline larvae, and also improve their persistence under field conditions.</p> <p>Methods</p> <p>Laboratory bioassays were conducted to test the ability of aqueous (0.1% Tween 80), dry (organic and inorganic) and oil (mineral and synthetic) formulations to facilitate the spread of fungal spores over the water surface and improve the efficacy of formulated spores against anopheline larvae as well as improve spore survival after application. Field bioassays were then carried out to test the efficacy of the most promising formulation under field conditions in western Kenya.</p> <p>Results</p> <p>When formulated in a synthetic oil (ShellSol T), fungal spores of both <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana </it>were easy to mix and apply to the water surface. This formulation was more effective against anopheline larvae than 0.1% Tween 80, dry powders or mineral oil formulations. ShellSol T also improved the persistence of fungal spores after application to the water. Under field conditions in Kenya, the percentage pupation of <it>An. gambiae </it>was significantly reduced by 39 - 50% by the ShellSol T-formulated <it>Metarhizium anisopliae </it>and <it>Beauveria bassiana </it>spores as compared to the effects of the application of unformulated spores.</p> <p>Conclusions</p> <p>ShellSol T is an effective carrier for fungal spores when targeting anopheline larvae under both laboratory and field conditions. Entomopathogenic fungi formulated with a suitable carrier are a promising tool for control of larval populations of malaria mosquitoes. Additional studies are required to identify the best delivery method (where, when and how) to make use of the entomopathogenic potential of these fungi against anopheline larvae.</p

Bacterial quality of a smoked meat product (“Suya”)

The bacteriological quality of “suya” sold within Makurdi metropolis was determined. Suya samples from four selected locations were examined bacteriologically for both Total Plate and Coliform Counts. Mean Total Plate and Coliform Counts varied from 3.7x105cfu/g to 2.4x106cfu/g and 1.9x102cfu/g to 1.0x103cfu/g of samples respectively. Faecal coliform bacteria were isolated from all suya samples with the same pattern of distribution. There was significant difference (p>0.05) of bacterial contamination among samples from the different locations using Tukey\'s LSD multiple comparison test. The Total Plate Count and Coliform Counts of most samples were within recommended safe limit for meat except the coliform count of the Wurukum (WK) sample that was above the limit of 4x102cfu/g for Escherichia coli. Isolation of faecal coliforms from all samples in this investigation should be a serious concern to consumers. This calls for urgent improvement on the hygienic handling of the product by suya processors. Keywords: suya, faecal coliforms, contamination, bacteriological quality, hygienic conditionsNigerian Food Journal Vol. 23 2005: 239-24

Changes in Total Protein and Transaminase Activities in Clarias Gariepinus Exposed to Diazinon

The aim of the study was to assess the effects induced by diazinon on total protein and transaminase activities in Clarias gariepinus, a common Niger Delta wetland fish. Fish were exposed to varying sub-lethal concentrations of diazinon (1.0, 2.5, 5.0, and 10.0 mg/I). Values decreased as the concentration of the toxicant increased. Plasma total protein and total protein in all organs tested were significantly lower (p&lt;0.05). Plasma alanine amino transferase (ALT) increased at some treatment levels contrary to aspartate amino transferase (AST) in plasma. Activities of ALT and AST decreased as the concentration of diazinon increased in all the organs tested; hence, the effects were dose dependent. It is obvious from this study that diazinon negatively affects total protein and transaminase activities in Clarias gariepinus