Influence of conventional and non-converntional insecticides as well as the macro-and micro elements on population density of the onion Thrips, Thrips tabaci Lins

The experiments were carried out at Experimental Research Station, Faculty of Agriculture, Mansoura University during two successive seasons 2008 and 2009 to evaluate the efficacy of some conventional and non- conventional insecticides as well as the macro and micro elements against the onion thrips Thrips tabaci Lind. The conventional insecticide Sumithion and non-conventional insecticides, Sulfer and Biofly exhibited a high efficiency against the onion thrips population with the highest percentage of reduction in the two successive seasons of the study. On the other hand, Radiant and Citrax oil exhibited intermediate efficiency against T. tabaci nymphs. Moreover, soybean oil or cotton seed oil caused the lowest percentage of reduction after three, five or eight days after treatments. Statistical analysis recorded a highly significant differences (P0.01) between the different conventional and nonconventional insecticides after three, five or eight days from treatments during the two seasons. The micro-element Born was the highest effeciancy (the highest percentage of reduction) with (72.8 and 76.5%), (76.6 and 75.7%) (28.1 and 26.7%), (37.5 and 46.6%), and (57.4 and 60.3%) followed by Manganese (71.0 and 71.3%), (76.4 and 74.2%), (25.5 and 29.4%), (36.2 and 45.7%), and (54.7 and 55.1%) after one day, four days, one week, two weeks and three weeks from treatments in the two successive seasons (2008 and 2009), respectively. On the other hand, micro element Zinc gave the intermediate percentage of reduction of T. tabaci nymphs during the two seasons of study. Moreover, the macro element Potassium exhibited the lowest percentage of reduction or the lowest effeciancy. Highly significant differences (P0.01) were recorded between the different macro and micro elements during the two successive seasons.