Effect of Solarization on Verticillium Wilt in Olive

Verticillium dahliae Kleb. ( ) 15% 1.33 32.9 62.4 72 65.5 17.5% 12345 2.17 3.00 3.17 1.83 0.33 . 58.5- 65 41.5 -48.28 .The study was conducted on olive wilt disease caused by Verticillium dahliae Kleb , which was recently distributed in Iraq . and considered as one of the most important and devastating disease on olive in Iraq .Soil solarization was used for the first time in this study in Iraq, results for one season or two subsequent seasons to control the disease indicated that solarization for two seasons was highly effective in reducing the percentage of infected branches to 32.9,62.4 ,72.0 , 65.5 , and 17.5% for infectin grades 1,2,3,4 and 5 respectively, and reducing the degree of infection to 2.17 , 3.00 , 3.17 , 1.83 and 0.33 respectively for the same degree. The solarization raised temperature up to 58.5-65oC in comparison with 41.5-48.28oC in untreated soils that led to suppression of the fungus and infection reduction especially when the solarization was used for two successive seasons.