Olive Knot Disease in Jordan

A field survey conducted in 2002 revealed the occurrence of olive knot disease (Pseudomonas savastanoi pv. savastanoi Smith) in different olive growing areas in Jordan. The disease incidence varies with location and cultivar. However, high disease incidence was reported in Amman, Aljuhfia, Deir yosef, Almazar Alshamali, Wadi Alsir, Alsmik, and low incidences were recorded in other areas. The reaction of cultivars to natural or artificial infection varied; as Nabali Muhasan, Rasei, Atrana and Shami were susceptible and Nabali Baladi was the less susceptible cultivar. Infection has significantly reduced the growth of twig length, fruits number, weight and size. These parameters were found to be correlated with the number of knots/seedling. The pathogen was also isolated from Jasmine, Oleander and Ziziphus. Isolates of these hosts were found pathogenic to olive grown either inside or at the border of olive orchards. Consequently, these hosts could play an important role as a source of olive knot inocula, and in disease epidemiology. Dipping olive twigs in Cuprosan suspension, Trimiltox, Copper Sulfate, Copper hydroxide, resulted in a reduction of disease incidence, knots number, and increased the fruits number in comparing it to the control group