These may be observed with a hand lens. Infected, stunted shoot tip of tip blight-infected Scots pine. Fungal pycnidia at the base of infected Scots pine needles. Sphaeropsis can also infect buds, twigs, and cones. Frequently, the lowest branches of old, well-established trees are affected and the disease gradually spreads upward.
Excessive resin flows from infected twigs and branches.
Blighted needles may become trapped in this resin glue and remain on the tree. Stunted needles, dead shoot tips, excess resin flow, and needle retention are key diagnostic symptoms for this disease. Pycnidia and microscopic spores are fungal signs that provide confirmation of the tip blight diagnosis. Spores ooze out of pycnidia under wet conditions in spring and early summer. Spores are spread by wind, splashing rain, animals, and pruning equipment.