Fusarium root rot

Fusarium root rot is one of the most common diseases of conifer seedlings in the world and is widespread in North American. 

The foliar symptoms of fusarium root rot are variable: newly infected seedlings typically have scattered chlorotic or curled needles followed by tip dieback, wilt symptoms, and stunting as the disease progresses.

The seedling foliage often turn a reddish brown just before the seedling dies.  Diseased root systems show lack of fine root development and extensive cortical decay so that the epidermis is easily stripped away from the core tissues.

One of the most diagnostic signs of this disease is the production of fruiting structures (sporodochia) on the seedling stem, where yellow-orange spore masses are exuded. These spores are typically multicellular and sickle-shaped and can be used to positively identify the fungus