Abstract
Grapefruit diseases, especially Esca disease, are one of the most important factors in reducing the viability of grapevine trees in the vineyard and can result in severe crop losses and mortality of grapevine trees. The cause of these diseases are several species of Phaeoacremonium spp and Phaeomoniella spp and some basidiomycetes such as Fomitiporia and Botryosphaeria species. In order to identify the factors of general deterioration and Esca in the northeast of the country, infested gardens were sampled in Khorasan, Khorasan and Semnan provinces in 1395 and 1396. Samples were transferred to the lab in a paper bag after labeling. The presence of internal signs of deterioration was investigated from the Samples collected by providing the transverse and longitudinal sections in the laboratory. Signs in the wooden part of the trunk were compared with the markings on the leaves of the infected trees. The result showed that in 65% of the sampled trees, external signs of deterioration were observed, which mainly consisted of a general burn from the margin to the main vein. In 32% of the trees, there were symptoms of Esca that were visible as a leprosy skin. Three percent of the specimens were found in the woody side of the Esca special mark, but in the leaves there were no specific signs of Esca and the leaves showed only general burns. In laboratory culture, fungi Phaeomoniella chlamydospora, Phaeoacremonium sp and Fomitiporia mediterranea were isolated and identified from North Khorasan and Khorasan Razavi provinces and the genus Botryosphaeria and two fungi from Semnan province.