ROOT ROT OF SLASH PINE AND ITS RELATION TO DEFOLIATION CAUSED BY DENDROLIMUS PUNCTATUS

Root rot disease of slash pine was further confirmed to be mainly caused by Diphlodia pinea (Desm. ) Kickx. It was also found that Sphaeropsis sapinea (Fr. ) Dyko & Sutton was one of the causal agents. The mentioned 5. sapinea was quite different from the usual D. piuea (synonymy: S. saqinea) in morthology, cultural characters and germination and may be a variety of this species. Inoculation tests showed that both D. pinea and S. sapiuea could make 2-year -old seedlinks as well as 16-year-old weakened uees of slash pine dead, and that the infection of the pathogens was closely related to the defoliation of slash pine caused by Dendrolinus punctatus.