PHAEOTHECA DIMORPHOSPORA AS A POTENTIAL BIOCONTROL AGENT FOR SHOOT BLIGHT CAUSED BY GREMMENIELLA-ABIETINA

An isolate of Phaeotheca dimorphospora from an elm (Ulmus americana) b ranch was tested for its capacity to suppress shoot blight caused by G remmeniella abietina on red pine (Pinus resblosa) seedlings. In vitro germination of G. abietina conidia was strongly inhibited by P. dimorp hospora microconidia. In a greenhouse bioassay, P. dimorphospora estab lished itself on the foliage of red pine seedlings without causing any ill effects. A summer application of P. dimorphospora microconidia to the foliage of G. abietina-inoculated seedlings significantly reduced the disease severity in the following year, compared with the nontrea ted control. These results suggest that P. dimorphospora has potential in biocontrol of this shoot blight on red pine.