Cunninghamella meinickella (fungus)
Pine trees found to be infected include. Jeffrey, Monterey, and ponderosa pines.
Nutrient abnormalities, crowding, poor sites, basal or root wounding are main contibutating factors.
Found mainly in California.
Symptoms include, needles fade to whitish green, becoming yellow to brown, falling prematurely. Exudation of yellow pitch on roots and root collars. Occurs near old stumps. Infected trees are weak and predisposed to bark beetle infestation.
This fungus is completely soilborne as a common soil saprophyte. Infection generally occurs from germination of small spiny spores which attach to the bark. During spring thaws or rains they germinate and grow into any small wounds, entering and eventually invading the phloem and xylem, blocking the flow of nutrients. The tree responds with a copious flow of pitch at the point of invasion.