Stone fruit phytoplasma disease management in Lebanon

The stone fruit production in Lebanon is threatened by the spread of almond witches’ broom. After a decade, the disease spread all over the cultivated regions, affecting also peaches and nectarines, representing a risk for the stone fruit production not only in Lebanon but also in the Middle East and Mediterranean regions. A national survey has been conducted in 495 Lebanese villages, monitoring about 900 orchards. On the basis of symptom observation, 368 plant samples have been collected and analyzed. Ninety-five percent of symptomatic almonds and 100% of symptomatic peach/nectarine samples tested positive to the analysis, whereas 99.1% of asymptomatic almond and 100% of asymptomatic peach/nectarine samples tested negative to the analyses. The disease was detected in 16 out of 26 Lebanese districts, at different rate of infection, on almond peach and nectarine samples. Moreover, a large insect collection, carried out over two years, allowed achieving a deeper knowledge on the fauna biodiversity in the Lebanese stone fruit orchards, finding some putative phytoplasma vectors that will be investigated in further researches.