Diagnosis and incidence of diseases associated with a decline of sweet cherry trees in California orchards

In recent years, a heavy loss of sweet cherry (Prunus avium L.) trees has occurred in California. During 1985 and 1986, several orchards were examined and the findings revealed that several biotic agents and abiotic disorders, all capable of causing tree decline or nonproductiveness, were represented in affected orchards. Confirmation of disease identification for a representative number of symptomatic trees was accomplished by a variety of test procedures including DNA hybridisation assay for the X-disease MLO.