Cooking oils and “Triplex” in the control of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) in farm-stored maize

The uses of some cooking oils viz., noug oil, soybean oil, sunflower oil, corn oil and olive oil, and the reputedly non-toxic botanical “Triplex”, were evaluated against maize weevil, Sitophilus zeamais, in stored maize grain under local Ethiopian storage conditions in 2003. For comparison, an untreated sample and the synthetic insecticides, malathion 5% dust and Actellic 2% dust, at the recommended rates of 0.05% (w/w) were included. All the cooking oils tested had a significant toxic effect on the weevils in stored grains. The oil treatments showed significantly higher mortality of adult weevils at each sampling period compared with the untreated grains. The cooking oil treatments also significantly reduced weight loss and grain damage as compared with the untreated control. The Triplex treatment was of comparable effectiveness to the synthetic insecticides, causing high mortality of adult weevils, low-percentage grain damage and low-percentage weight losses. These promising oils and Triplex could be recommended for use as part of an integrated pest management program in stored maize, particularly at low levels of pest infestation and, in the case of cooking oils, for grain intended for home consumption.     

Testing the environmental Kuznets curve hypothesis: an empirical study for East African countries

ABSTRACT

The green economy aims to achieve economic growth and development without an adverse effect on the environment. The environmental Kuznets curve (EKC) hypothesis explains the relationship between economic activity and environmental degradation. Using the EKC hypothesis as a theoretical framework, this study tested the EKC hypothesis for 12 East African countries using the Pooled Mean Group (PMG) approach for the period from 1990 to 2013. The result shows that the relationship between per capita income and CO₂ emissions (a proxy for environmental degradation) is bell shaped and thus is an extended version of the original inverted U-shaped curve relationship between economic activities and environmental degradation. Hence, one can conclude that the economic activities in East African countries do not lead to CO₂ emissions. Therefore, environmental conservation policies, technological advancement and modern industrial policies are required to make the economic growth of East African countries effective in reducing CO₂ emissions.