Inventory and world geographical distribution of the olive tree (Olea europaea L.) diseases caused by viruses, bacteria and phytoplasma

The objective of this work is to prepare an Inventory about the viral and bacterial diseases of the olive tree (Olea europaea L.) and to study their Geographical distribution in the world. Fifteen viruses were considered as pathogens on the olive tree, these viruses were reported in 22 countries in five continents showing different symptoms on different olive tree varieties. All viruses were reported in Italy, some of these viruses were found only in the Eurepean continent, such as Olive vein yellows associated virus (OVYaV), Olive yellow mottling and decline associated virus (OYMDaV), Olive mild mosaic virus (OMMV) and Olive semilatent virus (OSLV). Two bacteria were reported as pathogen on the olive tree; Pseudomonas savastanoi. pv. savastanoi responsible bacteria of thr olive knot; a serious disease of olive (Olea europaea L.) in the Mediterranean region. This bacteria was detected in 22 countries in five continents, the majority of these countries exist in the Mediterranean Basin. Another bacteria was Xylella fastidiosa responsible of the quick decline syndrome of olive (OQDS), was deteted in Europe in four countries (Italy, Spain, Portugal and Slovenia) and in America in three countries (USA, Argentina and Brazil). Phtoplasmas was reported in 5 countries in three continents (Europe, Asia and Australia)

Effects of a Composite Endomycorrhizal Inoculum on Olive Cuttings under the Greenhouse Conditions

This study was carried out in a nursery to evaluate the impact of mycorrhizal fungi on the cutting's root growth, and root colonization of a Moroccan olive variety ‘Picholine Marocaine' under greenhouse conditions during 2 years of cultivation. The results revealed that the inoculation with a composite inoculum of arbuscular mycorrhizal fungi (AMF) stimulated an early root formation and high development of vegetative shoots in inoculated cuttings respectively, 35 days (50 days in the control plots) and 40 days (60 days in the control plots) after their culture. The progressive establishment of mycorrhizal symbiosis in the roots of the inoculated plants showed that the root and vegetative masses were respectively 24 g and 19.5 g two years after inoculation. The average height and the leave's number of the inoculated plants relative to the control were respectively s 42/ 12 cm and 145/12. The newly formed roots were mycorrhizal and present different structures characteristic of AMF: arbuscules, vesicles, hyphae and spores, whose frequency and intensity reached 90% and 75% two years after cuttings cultivation. The arbuscular and vesicular contents and the number of spores were 67%, 96% and 212 spores/ 100 g of soil respectively. The fourteen species of mycorrhizal fungi isolated from the rhizosphere belong to 4 genera (Glomus, Acaulospora, Gigaspora, and Scutellospora) and three families (Glomaceae, Acaulosporaceae and Gigasporacea).The Glomus genus was the most dominant (65%) followed by the Gigaspora genus (22%). Glomus intraradices, Gigaspora sp.2, Glomus versiformes are the most abundant species, their frequency of occurrence are respectively 30%, 21% and 16%