Effect of Post-Planting Soil Solarization and Solar Chamber on Verticillium Wilt of Olive

The objective of this experiment was to determine the effectiveness of single post-planting soil solarization and solar chamber for control of Verticillium wilt of olive. Soil solarization was applied for 3 months starting from mid July in olive orchards under desert plain and up-land environmental conditions in Jordan. A completely closed solar chamber was applied for 12 and 24 hours light to cover individual V. dahliae-infected trees in an upland olive orchard in mid-August. Disease incidence and severity were significantly reduced in solarized trees compared to the non-solarized controls. Percentage of fungal isolations was significantly reduced among solarized trees as compared with non-solarized ones and was diminished to less than 10 % at the two sites. Both recovery and symptoms remission due to soil solarization exceeded natural recovery, which occurred in lower ratios among control trees than among solarized trees. Treatment of Verticillium-infected trees with solar chamber in August for either 12 hours or 24 hours exposure was efficient in reducing the disease development to a significant level. Twenty-four hours solar chamber treatment significantly reduced disease severity and percentage of V. dahliae-infected olive branches as compared to the control from mid-October to mid-January. Effect of solar chamber treatment for 24 hours did not differ significantly from that of 12 hours