Insecticide Effect of Plant Extracts on Aphids of Watermelon

The watermelon is an important crop in Morocco, an annual plant, originating in the tropical Africa. The consumed part is the mature fruit whose nutritional value is high; it is rich in vitamin and mineral salts. The fruit is used for medicinal purposes (kidneys and cleaning of the urinary tract). In Morocco, the watermelon is cultivated in large quantities in Souss Massa, in Marrakech, in the Loukkos and in Doukkala. A common problem in the production of watermelon is the infestation at the beginning of the season by aphids. They transmit viruses of the tile to the plants. They are more likely to be a problem in the costs time. The presents study is the effects of essential oils (Thyme and Oregano) and vegetable oil (Neem) on aphids of watermelon. The tests have been performed in the months of June to July 2010/2011 on the aphids in the fields of watermelon. It determines the percentage deaths of aphids in function of the dose 0.5 %, 1% and 5% of these products and the time 1, 3, 5, 7 and 11 hours after treatment. These results highlight an activity insecticide on these insects. Keywords: watermelon, insecticide, aphid, neem, oregano, thym