pinus resinosa/agar

Two morphotypes of Sphaeropsis sapinea, designated A and B, are recognized in the north central United States. Nonwounded seedlings of red (Pinus resinosa) and jack pine (P. banksiana) were inoculated with conidial suspensions of isolates of each morphotype obtained from hosts in Michigan,

Shoot blight was observed on lodgepole pine (Pinus contorta Douglas ex Loud.) seedlings in fall 1994 at the USDA Forest Service Bessey Tree Nursery, Halsey, NE. Shoots were stunted, cankered, and sometimes curled at the tips, and bore brown needles that often had been killed before full elongation.

ABSTRACT The aggressiveness of Sphaeropsis sapinea isolates was compared on water-stressed and nonstressed 3-year-old red pines (Pinus resinosa) in greenhouse and growth chamber experiments. Water was withheld from stressed seedlings to achieve mean predawn needle water potentials (psi(PD)) above