Study on the effect of shot-hole borer in transmission of Cytosporiose disease on apple and cherry trees

In recent years, there have been considerable damages of shot-hole borer, Scolytus rugulosus Muller, and cytosporiose disease by Cytospora species on twigs, branches and trunks of apple and sweet cherry trees in orchards of Tehran province, Iran. The fungi causes necrotic blotches around internal or external holes of the bark beetle. In the year 2002, samples of infected branches of apple and cherry trees were collected from different parts of Tehran province. The samples were cultured in PDA and MA media, an ten isolates of Cytospora were isolated in which 9 isolates belonged to C. leucostoma. One of the most aggressive isolate was selected to conduct the test of transmission by the beetle. This experiment was carried out based on the following treatments: with three replicates, 1 - releasing two mated females on each young trees, 2 - Spraying Cytospora leucostoma suspension on young trees, 3 - Releasing two mated females covered with the Cytospora leucostoma suspension, 4 - Control. This study confirmed that cytosporiosis of apple and cherry trees is transmitted by the shot-hole borer in the region.