stylistic:style_transfer
Sirococcus blight (Deuteromycotina, Coelomtcetes)

The closely related species Sirococcus conigenus and Sirococcus piceicola cause shoot blight and seedling mortality of conifers in North America, Europe, and North Africa. Twig blight damage to seedlings of white and red spruces in a nursery near Asheville, North Carolina, was reported by Graves (1914). Hosts include white, black, Engelmann, Norway, and red spruces, although they are not the plants most commonly damaged. Sirococcus blight of spruces in nurseries show up randomly in seedlings to which the fungus was transmitted in infested seed. First-year seedlings are often killed, and larger plants may become too deformed for planting. Outbreaks involving < 30% of spruce seedlings in seedbeds have been traced to seed lots in which only 0.1% to 3% of seeds were infested. Seed infestation has in turn been traced to the colonization of spruce cones by S. conigenus in forests of the western interior. Infection develops readily if conidia are deposited on succulent plant parts that remain wet for at least 24 hours at 10 °C to 25 °C. Longer periods of wetness favour increasingly severe disease. Twig tips killed during growth the previous year show a characteristic crook.