The present studies includes were conducted to study the effect of planting distances (5, 10 and 15 cm.), intercropping with onion plants and garlic varieties on the population of Thrips tabaci on onion plants during two successive seasons (2017 /2018 and 2018 / 2019) in Assiut Governorate, Egypt, using the two garlic varieties (Egyptian and Chinese). Results indicated that the three mentioned variables have significant effect on the population of the pest. The plant distances were the most significant factor, with the high numbers of thrips closest spacing (5 cm.) between plants. Intercropped garlic with onion showed that the garlic harbored lowest number of the pest whereas; in onion solo the density of pest is high compared with intercropped with garlic. Onion with garlic Egyptian variety is lower infested than the onion with garlic Chinese variety one. It was also noticed that the highest yield of onions was given when the distance between plants was (10 cm.) and loading onions with garlic resulted in a lower yield than onions grown separately during the two seasons.
Keywords: Onion, garlic, planting distances, intercropping with
garlic varieties, Thrips tabaci , population, yield.