1. Feasibility of Brown Sugar and Yeast Solution as a Potential Organic Mosquito Trap (OMT)

    Belinda Abdon-Liwanag, Myra L. Tansengco


    Mosquitoes, as well as its larvae, are important food for aquatic animals such as birds, bats, and other arthropods. However, mosquitoes transmit pathogens that cause some of the worst diseases known, including malaria, yellow fever, encephalitis and most of all, dengue fever. Sugars are the smallest carbohydrates containing five to six carbon atoms, hydrogen, and oxygen. Saccharomyces cerevisiae, commonly called yeast, is a single-celled organism that feeds on glucose, and through fermentation converts carbohydrates to alcohols while releasing carbon dioxide (CO2). Carbon dioxide is attractive to mosquitoes. Therefore, solution containing sugar and yeast can be used as baits.

    This study aimed to examine the feasibility of using brown sugar and yeast solutions as baits for mosquitoes. Two types of sugar were used -brown sugar and dark brown sugar (muscovado). Four mixtures were prepared consisting of the same amount of water (200 ml) and yeast (1 g) but with different types and amounts of sugar: 1) 50 g brown sugar, 2) 100 g brown sugar, 3) 50 g dark brown sugar, and 4) 100 g dark brown sugar. Another four mixtures were prepared with the same quantities of water and sugar but without added yeast, which served as the negative controls. The mosquito traps are made of soda 1.5 plastic, covered with newspaper make the inside of the trap dark. The mosquito traps were placed in different corners of the classrooms. The OMT was left in the classrooms for 3days.  Three trials were made with two sets of the OMT.

    Trapped mosquitoes averaged to 14 and 8.6 for solutions with yeast-100 g dark brown sugar and yeast-50 g dark brown sugar, respectively. For solutions with yeast-100 g brown sugar, and yeast-50 g brown sugar, the average trapped mosquitoes were 12 and 6, respectively. For the control solutions (without yeast), the average trapped mosquitoes were 11 for solutions with100 g dark brown sugar solution, 8 for those with 50 g dark brown sugar, 6 for those with 100 g brown sugar, and 3 for those with 50 g brown sugar. Comparison of results in mosquito traps with and without yeast (control) showed that the best mosquito traps are the solutions with yeast containing brown sugar.  Solutions with 100 g or 50 g brown sugar with yeast showed 50% increase in trapped mosquitoes compared to those of the control. Based from the result, the OMT is a good enough as a preliminary study for eliminating pathogenic mosquitoes and a better and cheaper alternative as well.

    Keywords: Brown Sugar, Yeast, Organic Mosquito Trap (OMT).

    Pages: 357 – 361 | Full PDF Paper
  2. Effect of Some Over-Wintering Regimes on Survival and Growth Performance of Nile Tilapia, Oreochromis Niloticus

    Soltan, M. A., Abdella, M. M., El-Sayaad, G. A. and Abu-El Wafa, M. H.


    The present study aimed to study the effectiveness of some over-wintering regimes (covering the tanks with polyethylene sheets, supplementation the fish diets with L-carnitine and using the bio-floc technology) on survival rate, growth performance and proximate composition of Nile tilapia (Oreochromis niloticus). The experiment was carried out during winter season (1st February to 1st April 2013) and the most important results can be summarize as follows:

    At the experiment end (after 90 days), the three regimes, plastic sheet, L-carnitine and bio-floc technology, BFT significantly improved survival rate of O. niloticus and the most effective over-wintering regime (based on survival rate) was recorded by BFT followed by supplementation the diets with L-carnitine and by covering ponds with plastic sheets.

    Fish in the BFT regime showed the highest body weight (BW), the longest body length (BL), the best weight gain (WG) and specific growth rate (SGR) and consumed the highest amount of feed and showed the best feed conversion ratio (FCR) and protein efficiency ratio (PER) compared to the other over-wintering regimes and control, and the differences between the other feeding regimes (L-carnitine, covering with plastic sheets and control groups) for feed intake, FCR and PER are not significant

    Fish group of the bio-floc (BFT) gained the highest significant crude protein and ash and the lowest fat and dry matter content compared with control group.

    Keywords: Over-wintering, survival rate, growth, Nile tilapia.

    Pages: 362 – 374 | Full PDF Paper