[Effect of some plant extracts and Neemix4.5 insecticide on immature stages of Culex pipiens mosquito under laboratory conditions]

The environmental risks of random abuse of chemical pesticides for the control of agricultural and general health pests have been recently arisen and accordingly, natural pesticides, particularly of plant origin, are now considered to be promising alternatives. This study aims at testing aqueous plant extracts of Piper nigrum, Allium sativum, Syxgium aromaticus, Artemisia abyssinica, Eucalyptus camaldensis at the rates of 30, 40, and 50 ml/lit of water; in addition to neem [Azadirachta indica] oil and a neem insecticide [Neemix4.5] at the rate of 0.5, 1.0 and 1 .5ml/l of water, for their effect immature stages of Culex pipiens mosquito. The results have shown that there was no statistical significance between the plant extracts and the control on the hatchability of eggs. However, neem oil as well as the neem insecticide Neemix when applied at the rate of 1.5 mI/l water reduced significantly the hatchability of eggs [61%and 84%], compared to the control [96%]. Accumulated mortality percentage of larvae, resulted from eggs of C. pipiens, have reached 100% in P. nigrum, A. sativum, S. aromaticus, and E. camaldensis plant extract treatments when used at 50 ml/l water. The same result has been reached when neem oil and Neemix 4.5 insecticide when used at l.5ml/1; and none of the larvae have, reached the pupal stage. This means that these plant extracts as well as neem oil, which are available in the area, could easily be applied in an integrated Pest Management Program for mosquito in Yemen

[ study of some chemical changes in banana fruit during ripening]

This study was conducted in the years 2005 and 2006. The study aims to investigate some chemical changes which occur in banana fruit during ripening in two different ripening 1-The artificial ripening method in a cold storage room with temperature 2 1 +/- 1°C, after dipping the fruits in Ethrel solution [1000ppm] for 5 minutes. 2-The traditional method, in which the fruits are put in plastic boxes and enrolled with journals. Then these bananas are kept in normal room temperature about 36°C and 30°C for the 2005 and 2006 experiments, respectively. In addition, the study also includes investigation of the changes which occur during different ripening periods[3,6 and 9 days]. From the results of this study, we can see that the difference between the two ripening methods in total sugars[TS], reducing sugars[RS], sucrose, and total soluble solids[TSS] were not significant in 2005 and 2006, the six day ripening period showed the highest significant increasing rates for [TS], [RS], sucrose and [TSS] in both years compared to the other ripening period whereas the artificial ripening method showed significant decrease in chlorophyll content in comparison with the normal room ripening method in both years