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Publication #FOR236

Pitch Canker Disease of Pines1

Tyler Dreaden and Jason Smith2

Introduction

Pitch canker, a disease of conifers, is caused by the fungus Fusarium circinatum. The disease was first described in North Carolina by Hepting and Roth in 1946. It is named after the large amount of resin that is exuded from the host tree when it is infected with the pathogen. In the beginning, it was thought that the disease affected middle-aged and older pine trees; however, it was later found the disease could infect trees at any point in the life cycle (Barnard and Blakeslee 1980; Dwinell 1999). F. circinatum infects 57 species of pines (Pinus spp.) and Douglas-fir (Pseudotsuga menziesii) (Wingfield et al. 2008).

Symptoms and Signs of Pitch Canker and Disease Biology

F. circinatum can infect a susceptible host at any point in the tree's life cycle: flower, seed, seedling, and mature tree. The fungus can also infect many different parts of hosts, including shoots, branches, cones, seeds, stems, and exposed roots. The symptoms of pitch canker can vary among different hosts and the environments in which they are grown.

In southern pines, pitch canker is often detected in mature trees by "flagging," which occurs most frequently from late fall through spring (Barnard and Blakeslee 1987). Flagging is dieback of lateral or terminal shoots in which, the needles turn reddish-brown and are easily distinguished from the contrasting live, green needles (Figure 1). The infected shoots usually die within a few months due to the fungus girdling the shoot (Barnard and Blakeslee 1987). The wood of the infected shoots becomes impregnated with resin, which can also cover the outside of the infected shoots (Figure 2). The amount of resin both inside the wood and on the surface of the shoot varies among pine species. The large amount of resin on the surfaces of infected shoots will frequently cement the dead needles to the dead shoot, where they can remain for over a year (Figure 3). During this time, the needles turn from bright reddish-brown to brown, and then to grey.

Figure 1. 

Typical flagging on longleaf pine with pitch canker. (Photo by Jason Smith)


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Figure 2. 

Longleaf pine with pitch canker, showing the large amount of resin on the outside of the stem and resin soaked wood. (Photo by Jason Smith)


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Figure 3. 

Slash pine sapling infected with pitch canker, showing the resin on the outside of the stem. (Photo by Tyler Dreaden)


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Fusarium circinatum can produce lesions called "cankers" on the main stem that can become lethal if the cankers encircle the stem. Cankers usually exude resin, retain bark, and cause a depressed canker face (Barnard and Blakeslee 1987). In southern pine nurseries, the symptoms of pitch canker on seedlings include 1) off-color, yellow-green needles; 2) wilting of foliage and succulent leaders; 3) red-brown, discolored foliage and small clumps of soil on the lower stem and roots (these adhere to the resin); and 4) pitch-soaked lesions in stem and root collars (Barnard and Blakeslee 1980). Some seedlings may also have fungal fruiting structures, known as sporodochia (Figure 4). These are small, salmon-pink structures on the bark of affected stems. The fungus can cause both pre- and post-emergence damping off of seedlings. When F. circinatum infects cones of southern pines, the cones are often misshapen and stunted, and some have necrotic tips with internal resin pockets.

Figure 4. 

Sporodochia of Fusarium circinatum, the causal agent of pitch canker. (Photo by George Blakeslee)


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Geographical Distribution

Since its initial discovery in North Carolina, pitch canker has been found in the southeastern United States from Virginia to southern Florida and as far west as eastern Texas, where it affects southern pines (Dwinell et al. 1985). The origin of F. circinatum is not completely known, but it is thought to be native to Mexico and has been established for a long time in the southeastern United States. In 1986, pitch canker was reported in California where it was found on several Pinus species. The disease is now found in the coastal regions in California from Mendocino County in the north to San Diego in the south (Wingfield et al. 2008). In California the pathogen was first isolated to pines planted in landscapes and right-of-ways in the central coast of California but was later found in native stands of Monterey pine, Pinus radiata. On Monterey pine, systemic induced resistance (SIR) has been reported to greatly reduce the effect of the disease when previously infected trees are re-inoculated with the pathogen, which may help restrict the overall impact of the disease on this species (Bonello et al. 2001). Douglas-fir, Pseudotsuga menziesii, the only known non-pine host of pitch canker, has also been found in California (Gordon et al. 2006).

The pathogen has also been reported in Chile, Haiti, Amanioochima and Okinawa islands in Japan, Korea, Mexico, South Africa, and Spain (Wingfield et al. 2008, Thoungchaleun et al. 2008).

Management of Pitch Canker

As with many diseases, proactive prevention is the best way to prevent losses due to pitch canker. Barnard and Blakeslee (1987), recommend using the Pinus species and provenance that is best suited for a specific site. For sites with historically high levels of pitch canker, a more resistant Pinus species or genetically resistant genotype can be planted. Sanitation is also important. Check seedlings to ensure they are free of infection before planting, burn infected trees, and remove logging slash and pruned infected branches to reduce the numbers of spores in the area. The excessive use of fertilizer should be avoided, which is especially important in urban areas as excess nutrients can increase disease incidence and severity (Lopez-Zamora et. al. 2007). More information on management considerations for pitch canker in southern pines can be found in Blakeslee et. al 1980 and Barnard and Blakeslee 1987.

Literature Cited

Barnard, E.L., and G.M. Blakeslee. 1980. Pitch canker of slash pine seedlings: A new disease in forest tree nurseries. Plant Disease. 64. 695–696.

Blakeslee, G.M., L.D. Dwinell, and R.L. Anderson. 1980. Pitch canker of southern pines: Identification and management considerations. USDA Forest Service. Southeastern Area State and Private Forestry, Atlanta, GA. http://www.forestpests.org/pitchpine/. Accessed on 4/14/2009.

Barnard, E.L., and G.M. Blakeslee. 1987 revised 2006. Pitch canker of southern pines. Florida Department of Agriculture and Consumer Services, Division of Plant Industry, Gainesville. Plant Pathology Circular No. 302.

Bonello, P., T.R. Gordon, and A.J. Storer. 2001. Systemic induced resistance in Monterey pine. Forest Pathology. 31. 99–106.

Dwinell, L.D., J. Barrows-Broaddus, and E.G. Kuhlman. 1985. Pitch canker: A disease complex of southern pines. Plant Disease. 69. 270–276.

Dwinell, L.D. 1999. Association of the pitch canker fungus with cones and seeds of pines. Pages 35–39 in: Devey, M.E., A.C. Matheson, and T.R. Gordon (eds) Current and potential impacts of pitch canker in Radiata pine. Proc. IMPACT Monterey Workshop, Monterey, CA, USA, 30 Nov. to 3 Dec. 1998. CSIRO. Australia.

Gordon, T.R., S.C. Kirkpatrick, B.J. Aegerter, D.L. Wood, and A.J. Storer. 2006. Susceptibility of Douglas fir (Pseudotsuga menziesii) to pitch canker, caused by Gibberella circinata (anamorph=Fusarium circinatum). Plant Pathology. 55. 231–237. doi: 10.1111/j.1365-3059.2006.01351.x

Hepting, G.H., and E.R. Roth. 1946. Pitch canker, a new disease of some southern pines. Journal of Forestry. 44. 724–744.

Lopez-Zamora, I., C. Bliss, E.J. Jokela, N.B. Comerford, S. Grunwald, E.L. Barnard, and G.M. Vasquez. 2007. Spatial relationships between nitrogen status and pitch canker disease in slash pine planted adjacent to a poultry operation. Environmental Pollution. 147. 101–111.

Thoungchaleun, V., K.W. Kim, D.K. Lee, C.S. Kim, and E.W. Park. 2008. Pre-infection behavior of the pitch canker fungus Fusarium circinatum on pine stems. Plant Pathology Journal. 24. 112–117.

Wingfield, M.J., A. Hammerbacher, R.J. Ganley, E.T. Steenkamp, T.R. Gordon, B.D. Wingfield, and T.A. Coutinho. 2008. Pitch canker caused by Fusarium circinatum – a growing threat to pine plantations and forests worldwide. Australasian Plant Pathology. 37. 319–334.

Footnotes

1.

This document is FOR236, one of a series of the School of Forest Resources and Conservation Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date March 2010. Reviewed June 2013. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

Tyler Dreaden, PhD student, School of Forest Resources and Conservation; and Jason Smith, assistant professor, School of Forest Resources and Conservation, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.