In Kansas, the fungal disease brown spot is primarily a problem on Scots pine planted in Christmas tree plantations, although ornamental and windbreak trees of this species also may be attacked. Ponderosa pine is susceptible to brown spot, but Austrian pine is resistant. Symptoms of brown spot first appear in late August or early September.
Affected needles develop yellow to tan, often resin-soaked, spots.
Occasionally the spots enlarge and result in a banding effect on the diseased needle. By mid-fall, diseased needles turn brown and begin to fall from the tree. Heaviest infection and defoliation occurs in the lower portion of the tree crown. The symptoms of brown spot may be confused with those of Dothistroma needle blight. Both diseases occur on Ponderosa pine, and laboratory identification may be required to distinguish between the two diseases.