Name

The official name of Pine Pitch Canker Fungus is Fusarium subglutanins f. Sp. Pini.

In 1998 a new name, Fusarium circinatum, was proposed. As of 2001 its usage is increasing.

History

The fungus was common in the southeastern United States previous to 1986. It was first detected in California and in pinus Radiata (Monterey pine) in 1986. In 1992 Carmel began a survey of infected trees, finding only one. By November 1993, 132 infected trees were found which aroused first governmental and public concern. By 1996 the number of infected trees had risen to 586.

Mapping

The fungus is common in the southeastern United States from Virginia to Florida to Louisiana and has been reported in Mexico, Japan, Spain and confirmed in South Africa. The disease is found in 22 coastal and adjacent California counties from San Diego to Mendocino. The only known local scale maps of the fungus in Monterey pine (radiata) forests were created from a survey of the Cambria forests by Greenspace in 1997. 

Affected Species Breadth

The disease is known to affect 39 of the 100 pine species worldwide and Douglas Fir. It affects 22 native U.S. pine species including 10 species of native California pines. In the southeast, the most commonly affected species are Loblolly and Slash pine. Pinus Radiata (Monterey Pine) is among the most susceptible to the disease, Oocarpa is among the least.

Symptoms 

In certain observational plots, up to 85% of the Monterey Pine trees have become symptomatic. That is not to say the other 15 percent won't get it. Trees can have the disease at a cellular level without exhibiting human scale symptoms.

Mortality vs. Symptoms 

There is little data on the percent of symptomatic trees that die from the disease. Some symptomatic Monterey Pine trees have survived eight (8) years, others have died within two (2) years. While it may take up to a decade for the tree to die exclusively from the disease, trees weakened by fusarium are then susceptible to quick death from attack by bark beetles.

Susceptibility v. Resistance

There is some evidence that new growth has a higher rate of infection than mature tissue. Young trees appear to have a higher number of infections than mature trees. Planted trees seem to have a very high rate of infection. Trees in high humidity (near the ocean) seem to have higher rate of infection than trees in lower humidity (farther from ocean or higher in altitude).

• Trees standing alone or those more exposed to human impacts by edge effect appear more affected than trees in deep core areas of a natural Monterey pine forest - away from human impacts. 

Detection

Pitch Canker can only reliably detected in a laboratory. Leading Pitch Canker experts have learned not to be mislead by their field observations.

Spread

The disease spores are transmitted by air, soil, insects, logs and wood waste. It can survive up to a year in dead wood and soil. The disease seems to spread quickly. At Sunset Beach near Santa Cruz in 1988, at most 1 tree was symptomatic. There is now extensive mortality. In Carmel in 1992 only 1 infected tree was found. By November 1993, 132 infected trees were found, and by 1996 the number of infected trees rose to 586. 

Strains (or VCGs)

Eight (8) distinct strains of the fungus have been collected in California. South Africa has identified 27. The southeastern US probably has a wider genetic diversity of the fungus than California or overseas. Some strains can have twice the virulence of others. There is some data suggesting there is little geographic overlap of the strains.

Cures, Individual

None. There is a tiny bit of non-Replicated, preliminary evidence that injections of FUNGISOL, in trees not yet in a poor state of health, may (not "will") reduce the incidence of the disease, reduce progress of new infections and allow a tree to recover from infection.