Similarity between fungi identified as Diplodia pinea f. sp. cupressi in Israel and Botryosphaeria stevensii or Diplodia mutila on Juniperus in the United States

Abstract

SummaryA fungus identified as Botryosphaeria stevensii (anamorph Diplodia mutila) causes a canker disease that results in dieback of Juniperus species in the United States. A fungus identified as Diplodia pinea f. sp. cupressi causes a similar disease of Cupressus species in Israel and elsewhere. Cultural characteristics, pycnidia, and conidia of isolates of these two pathogens were compared. The ability of each fungus to produce cankers on Cupressus sempervirens was tested. Random amplified polymorphic DNA (RAPD) marker patterns also were analysed, using Sphaeropsis sapinea (syn. Diplodia pinea) isolates as an outgroup. Results indicate the fungus identified as D. pinea f. sp. cupressi from cypress in Israel is the same as, or at least highly similar to, the fungus identified as B. stevensii (or D. mutila) from juniper in the United States. Analysis of RAPD markers indicates relatively low similarity between these isolates and those of S. sapinea. Because these results are consistent with a previously published report describing substantial morphological and isozyme differences between isolates identified as D. pinea f. sp. cupressi and those of S. sapinea, use of the name D. pinea f. sp. cupressi should be abandoned. Inconsistencies between these isolates from juniper and cypress and published descriptions of B. stevensii and D. mutila, however, indicate the need for additional investigation into the relationship of these fungi.