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Forest & Shade Tree Pathology

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About this site:

This site is provided as an aid to those learning forest and shade tree pathology.  It has been called an online textbook; I hope that it lives up to that billing.

These web pages are dedicated to current and past students of ESF (College of Environmental Science and Forestry, State University of New York). The pages were initiated while the author was Associate Professor at ESF, teaching Forest and Shade Tree Pathology, among other courses. It has since been updated, expanded and refined.

A calendar of upcoming forest pathology meetings and other events is on the home page. If you have an event you would like to see listed there, please contact me.

Please make suggestions! Any comments you have about the design or content of these pages will be gladly received. Should more words be defined in the popup boxes (see below)? Should additional websites be linked? New references listed?   Please email me at email graphic.

This site has popup definitions available for words that are shown in purple without underline. Point your mouse over the word "popup" for an example. Once again I have redone the code so it works in modern browsers. I am greatly indebted to a great website for help with this: http://www.howtocreate.co.uk/. If they don't work (i.e., show up when you mouse over the word, beside the cursor, but not going into window edges), please email me (jworrall at forestpathology dot org), providing browser and operating system details. Some such words also link to more complete explanations in context for further information. A more complete illustrated glossary of plant pathology can be found elsewhere. The definitions here include contributions by Kristin Belanger, former student of ESF. She drew on class lecture notes as well as these sources:

The information and files presented here (except for some of the illustrations) are the intellectual property of the author. Please do not copy any of the content for use in other websites or printed material.

Throughout the site, symbols indicate links to Forest Service publications:


FIDL icon "FIDLs" (Forest Insect and Disease Leaflets)
How-to logo How-to Bulletins


About the author:



photo of Jim


Curriculum Vitae

James J. Worrall

 
Plant Pathologist
USDA Forest Service, Rocky Mountain Region, Forest Health Management
216 N. Colorado St.
Gunnison CO 81230

Education:

Research Interests:

Professional Experience:

Teaching Experience:

Awards and Honors:

Society Memberships:

Full-Length Publications:Publication gif

  1. Tomalak M, Worrall J, Filipiak A. 2013. Bursaphelenchus masseyi sp. n. (Nematoda: Parasitaphelenchinae) – a nematode associate of the bark beetle, Trypophloeus populi Hopkins (Coleoptera: Curculionidae: Scolytinae), in aspen, Populus tremuloides Michx. affected by sudden aspen decline in Colorado. Nematology 15:907–921. <PDF>
  2. Worrall JJ, Rehfeldt GE, Hamann A, Hogg EH, Michaelian M, Marchetti SB, Gray LK. 2013. Recent declines of Populus tremuloides in North America linked to climate. Forest Ecology and Management 299C: 35-51. <PDF>
  3. Worrall JJ, Marchetti SB, Mask RA. 2012. An Epidemic of Needle Cast on Lodgepole Pine in Colorado. Denver, Colorado: USDA Forest Service, Rocky Mountain Region, Forest Health Protection. Biological Evaluation R2-12-01. p. 16. <PDF>
  4. Martinez DL, Ryszka G, Worrall JJ, Mask RA, Eager T, Egeland L. 2011. Deterioration of Fire-Killed Trees in the Rocky Mountain Region. Denver, Colorado: USDA Forest Service, Rocky Mountain Region, Renewable Resources. Technical Report R2-RR-11-01. p. 36. <PDF>
  5. Marchetti SB, Worrall JJ, Eager T. 2011. Secondary insects and diseases contribute to sudden aspen decline in southwestern Colorado, USA. Canadian Journal of Forest Research 41:2315–2325. <PDF>
  6. Stanosz GR, Trummer LM, Rohrs-Richey JK, Smith DR, Adams GC, Worrall JJ. 2011. Response of Alnus tenuifolia to inoculation with Valsa melanodiscus. Canadian Journal of Plant Pathology 33:202–209. <PDF>
  7. Sturrock RN, Frankel SJ, Brown AV, Hennon PE, Kliejunas JT, Lewis KJ, Worrall JJ, Woods AJ. 2011. Climate change and forest diseases. Plant Pathology 60:133–149..  <PDF>
  8. Worrall JJ, Marchetti SB, Egeland L, Mask RA, Eager T, Howell B. 2010. Effects and etiology of sudden aspen decline in southwestern Colorado, USA. Forest Ecology and Management 260:638–648. <PDF>
  9. Worrall JJ, Adams GC, Tharp SC. 2010. Summer heat and an epidemic of cytospora canker of Alnus. Canadian Journal of Plant Pathology 32:376–386. <PDF>
  10. Worrall JJ, Harrington TC, Blodgett JT, Conklin DA, Fairweather ML. 2010. Heterobasidion annosum and H. parviporum in the southern Rocky Mountains and adjoining states. Plant Disease 94:115–118. <PDF>
  11. Worrall JJ, Fairweather ML. 2009. Decay and Discoloration of Aspen. Forest Insect and Disease Leaflet 149. FS-R6-RO-FIDL#149/005-2009. Portland, Oregon: USDA Forest Service, Pacific Northwest Region. 8 p.   <PDF>
  12. Worrall JJ, Nakasone KK. 2009. Decays of Engelmann Spruce and Subalpine Fir in the Rocky Mountains. Forest Insect and Disease Leaflet 150. FS-R6-RO-FIDL#150/006-2009. Portland, Oregon: USDA Forest Service, Pacific Northwest Region. 12 p.   <PDF>
  13. Worrall JJ. 2009. Dieback and mortality of Alnus in the Southern Rocky Mountains, USA. Plant Disease 93(3): 293-298.  <PDF>
  14. Adams GC, Catal M, Trummer L, Hansen EM, Reeser P, Worrall JJ. 2008. Phytophthora alni subsp. uniformis found in Alaska beneath thinleaf alders. Online. Plant Health Progress doi:10.1094/PHP-2008-1212-02-BR.  <PDF>
  15. Worrall JJ, Egeland L, Eager T, Mask RA, Johnson EW, Kemp PA, Shepperd WD. 2008. Sudden aspen decline in southwest Colorado: site and stand factors and a hypothesis on etiology. pp. 63-66 in McWilliams MG (ed): Proceedings of the 55th Western International Forest Disease Workshop, 2007 October 15-19, Sedona Arizona. Oregon Department of Forestry, Salem, Oregon.  <PDF>
  16. Worrall JJ, Egeland L, Eager T, Mask RA, Johnson EW, Kemp PA, Shepperd WD. 2008. Rapid mortality of Populus tremuloides in southwestern Colorado, USA. Forest Ecology and Management 255(3-4): 686-696.  <PDF>
  17. Worrall JJ, Geils BG. 2006. Dwarf mistletoes. The Plant Health Instructor. American Phytopathological Society.  doi:10.1094/PHI-I-2006-1117-01.  <Online lesson>
  18. Worrall JJ, Lee TD, Harrington TC. 2005. Forest dynamics and agents that initiate and expand canopy gaps in Picea-Abies forests of Crawford Notch, New Hampshire, USA. Journal of Ecology 93: 178-190.  <PDF>
  19. Worrall JJ. 2004. Armillaria root disease. The Plant Health Instructor. American Phytopathological Society.  doi:10.1094/PHI-I-2004-070601.  <Online lesson>
  20. Worrall JJ, Sullivan KF, Harrington TC, Steimel JP. 2004. Incidence, host relations and population structure of Armillaria ostoyae in Colorado campgrounds. Forest Ecology and Management 192: 191-206.  <PDF>
  21. Ginns J, Worrall JJ. 2003. Josiah Lincoln Lowe, 1905-1997. Mycologia 95: 374-378.  <PDF>
  22. Worrall JJ, Sullivan KF. 2002. Discoloration of ponderosa pine on the San Juan National Forest, 1999-2001. Biological Evaluation R2-02-06. Lakewood, Colorado: USDA Forest Service, Rocky Mountain Region, Renewable Resources. 20 p.  <PDF>
  23. Burrill EA, Worrall JJ, Wargo PM, Stehman SV. 1999. Effects of defoliation and cutting in eastern oak forests on Armillaria spp. and a competitor, Megacollybia platyphylla. Canadian Journal of Forest Research 29: 347-355.  <PDF>
  24. Ginns J, Worrall JJ. 1999. Athelia sibirica new to North America and a key to the species of Athelia in Alaska and the Yukon Territory. Kew Bulletin 54(3): 771-776.  <PDF>
  25. Worrall JJ. 1997. Somatic incompatibility in basidiomycetes. Mycologia 89(1): 24-36.  <PDF>
  26. Worrall JJ, Anagnost SE, Zabel RA. 1997. Comparison of wood decay among diverse lignicolous fungi. Mycologia 89(2): 199-219.  <PDF>
  27. Jones HL, Worrall JJ. 1995. Fungal biomass in decayed wood. Mycologia 87(4): 459–466.  <PDF>
  28. Anagnost SE, Worrall JJ, Wang CJK. 1994. Diffuse cavity formation in soft rot of pine. Wood Science and Technology 28: 199–208.  <PDF>
  29. Worrall JJ. 1994. Population structure of Armillaria species in several forest types. Mycologia 86(3): 401-407.  <PDF>
  30. Worrall JJ, Anderson KM. 1993. Sample preparation for analysis of wood sugars by anion chromatography. Journal of Wood Chemistry and Technology 13(3): 429–437. doi: 10.1080/02773819308020526  <PDF>
  31. Blodgett JT, Worrall JJ. 1992. Distributions and hosts of Armillaria species in New York. Plant Disease 76(2): 166-169.  <PDF>
  32. Blodgett JT, Worrall JJ. 1992. Site relationships of Armillaria species in New York. Plant Disease 76(2): 170-174.  <PDF>
  33. Worrall JJ, Yang CS. 1992. Shiitake and oyster mushroom production on apple pomace and sawdust. Hortscience 27: 1131-1133.  <PDF>
  34. Worrall JJ. 1991. Media for selective isolation of hymenomycetes. Mycologia 83(3): 296-302.  <PDF>
  35. Worrall JJ, Wang CJK. 1991. Importance and mobilization of nutrients in soft rot of wood. Canadian Journal of Microbiology 37(11): 864-868.  <PDF>
  36. Worrall JJ, Anagnost SE, Wang CJK. 1991. Conditions for soft rot of wood. Canadian Journal of Microbiology 37(11): 869-874.  <PDF>
  37. Harrington TC, Worrall JJ, Rizzo DM. 1989. Compatibility among host-specialized isolates of Heterobasidion annosum from western North America. Phytopathology 79: 290-296.  <PDF>
  38. Worrall JJ, Hudler GW, Taber DW. 1989. Watch for Armillaria root rot in Christmas tree plantations. Contours of Conservation March-April 1989: 3. 
  39. Worrall JJ, Harrington TC. 1988. Etiology of canopy gaps in spruce-fir forests at Crawford Notch, New Hampshire. Canadian Journal of Forest Research 18:1463-1469.  <PDF>
  40. Worrall JJ, Harrington TC. 1988. Respirometric testing of decay resistance of discolored root wood. Phytopathology 78: 676-682.  <PDF>
  41. Jahnke K-D, Bahnweg G, Worrall JJ. 1987. Species delimitation in the Armillaria mellea complex by analysis of nuclear and mitochondrial DNAs. Transactions of the British Mycological Society 88(4): 572-575. <PDF>
  42. Worrall JJ, Chet I, Hüttermann A. 1986. Association of rhizomorph formation with laccase activity in Armillaria spp. Journal of General Microbiology 132: 2527-2533.  <PDF>
  43. Worrall JJ, Correll JC, McCain AH. 1986. Pathogenicity and teleomorph-anamorph connection of Botryosphaeria dothidea on Sequoiadendron giganteum and Sequoia sempervirens. Plant Disease 70: 757-759.  <PDF>
  44. Worrall JJ. 1983. Cytospora canker of poplars and willows. California Plant Pathology 64: 4-5. 
  45. Worrall JJ, Parmeter JR. 1983. Inhibition of wood decay fungi by wetwood of white fir. Phytopathology 73: 1140-1145.  <PDF>
  46. Worrall JJ, Parmeter JR, Cobb FW. 1983. Host specialization of Heterobasidion annosum. Phytopathology 73: 304-307.  <PDF>
  47. Worrall JJ, Parmeter JR. 1982. Wetwood formation as a host response in white fir. European Journal of Forest Pathology 12(6): 432-441.  <PDF>
  48. Worrall JJ, Parmeter JR. 1982. Formation and properties of wetwood in white fir. Phytopathology 72: 1209-1212.  <PDF>

Dissertation:

  1. Worrall JJ. 1982. Interaction of wetwood and Fomes annosus in white fir [Dissertation]. Berkeley, California: University of California, Berkeley. 119 p.
cover

Books:

  1. Allen KK, Blodgett JT, Burns KS, Cain RJ, Costello SL, Eager TJ, Harris JL, Howell BE, Mask RA, Schaupp WC, Jr., Witcosky JJ, Worrall JJ. 2010. Field Guide to Diseases and Insects of the Rocky Mountain Region. General Technical Report RMRS-GTR-241. Fort Collins, Colorado: USDA Forest Service, Rocky Mountain Region Forest Health Protection and Rocky Mountain Research Station. p. 336. <http://www.fs.fed.us/rm/pubs/rmrs_gtr241.html>
  2. Worrall, JJ, ed. 1999. Structure and Dynamics of Fungal Populations. Kluwer Academic Press, Dordrecht, The Netherlands, 348 pp.

Book Chapters:

  1. Worrall JJ. 2012. Climate, canker, and alder mortality in the southern Rockies. In: Potter KM, Conkling BL, editors. Forest Health Monitoring: 2009 National Technical Report. General Technical Report SRS-167. Asheville, North Carolina: USDA Forest Service, Southern Research Station. p. 183–189. <PDF>
  2. Worrall JJ. 1999. Brief introduction to fungi. In: Worrall JJ, editor. Structure and dynamics of fungal populations. Dordrecht, The Netherlands: Kluwer Academic Press. p 1-18. 
  3. Worrall JJ. 1999. Fungal demography—Mushrooming populations. In: Worrall JJ, editor. Structure and dynamics of fungal populations. Dordrecht, The Netherlands: Kluwer Academic Press. p 175-194. 
  4. Worrall JJ. 1994. Relationships of acid deposition and sulfur dioxide with forest diseases. In: Hüttermann A, editor. Effects of Acid Rain on Forest Processes. Wiley-Liss, Inc. p 163-182. 
  5. Harrington TC, Worrall JJ, Baker FA. 1992. Armillaria. In: Singleton LL, Mihail JD, Rush CM, editors. Methods for research on soilborne phytopathogenic fungi. St. Paul, Minnesota: APS Press. p 81-85. 
  6. Worrall JJ, Harrington TC. 1992. Heterobasidion. In: Singleton LL, Mihail JD, Rush CM, editors. Methods for research in soilborne phytopathogenic fungi. St. Paul, Minnesota: APS Press. p 86-90. 
  7. Harrington TC, Worrall JJ, Rizzo DM. 1989. Root and butt rots and other disturbance agents in montane spruce-fir forests of New Hampshire, USA. Proceedings of the 7th IUFRO Root and Butt Rot Conference (IUFRO Working Party S2.06.01). p 257-266. 
  8. Worrall JJ, Rizzo DM, Harrington TC. 1989. Measurement of the host response and root-rot resistance in Picea rubens and Abies balsamea. Proceedings of the 7th IUFRO Root and Butt Rot Conference (IUFRO Working Party S2.06.01). p 162-170. 
  9. Worrall JJ, Hüttermann A. 1984. The role of soil and soil acidity in rhizomorph production by Armillaria spp. Göttingen, Federal Republic of Germany: pp. 153-158 in Berichte des Forschungszentrums Waldökosysteme der Universität Göttingen, Reihe A, Bd. 3

Book Review:

  1. Worrall JJ. 1989. Fungal decomposition of wood: Its biology and ecology [Book review]. The Quarterly Review of Biology 64: 350-351. <PDF>

photo of Jim

Invited Symposia:

  1. Worrall, JJ.  1992.  Establishment and fate of Armillaria clones.  Joint Meeting of American Phytopathological Society and Mycological Society of America, 10 Aug., Portland OR.
  2. Worrall, JJ.  1990.  Recent advances in the taxonomy and bio­geography of basidiomycetous pathogens of woody plants.  Fourth International Mycological Congress, 30 Aug., Regensburg (Abstracts, p. 313)

Published Abstracts:

  1. Tomalak M, Filipiak A, Malewski T, Worrall JJ. 2012. Morphological variation among new species of Bursaphelenchus in the 'xylophilus' group. Proceedings of the 31st International Symposium of the European Society of Nematologists, Adana, Turkey, September 23-27, 2012.
  2. Worrall JJ, Mask RA, Eager T, Egeland L, Shepperd WD. 2008. Sudden aspen decline in southwest Colorado. Phytopathology. 98(6): S173.  <PDF>
  3. Worrall JJ, Mask RA, Eager T, Egeland L, Shepperd WD. 2008. Sudden aspen decline in southwest Colorado.  Poster presented at the 2008 USFS Forest Health Monitoring Workgroup Meeting, Feb. 11-14, San Antonio, Texas [Abstract].
  4. Adams GC, Catal M, Trummer L, Worrall JJ. 2008. First finding of Phytophthora alni subspecies uniformis in North America.  Poster presented at 2008 USFS Forest Health Monitoring Workgroup Meeting, Feb. 11-14, San Antonio, Texas. [Abstract].
  5. Worrall JJ, Adams GC, Johnston BC. 2006. Dieback and mortality of Alnus in the southern Rockies.  Poster presented at the 2006 USFS Forest Health Monitoring Workgroup Meeting [Abstract].
  6. Worrall JJ, Adams GC. 2006. Cytospora canker of Alnus in the Southern Rocky Mountains [Abstract]. Inoculum 57(4): 40.
  7. Worrall JJ, Johnston BC, Adams GC. 2005. Dieback and mortality of Alnus in the southern Rocky Mountains [Abstract]. Hyphal Bridges over the Pacific: Advancing mycology.  Joint meeting of Mycological Society of America and Mycological Society of Japan, Hilo, Hawai'i, 30 July through 5 August, 2005.: 220.
  8. Worrall JJ, Johnston BC, Adams GC. 2005. Dieback and mortality of Alnus in the southern Rocky Mountains [Abstract]. Presented at the Fifty-Third Western International Forest Disease Work Conference, Snow King Resort, Jackson, Wyoming, August 26-29, 2005: [abstract was omitted from the proceedings].
  9. Worrall JJ, Johnston BC, Adams GC. 2005. Dieback and mortality of Alnus in the southern Rocky Mountains [Abstract]. Inoculum 56(4): 65.
  10. Worrall JJ, Sullivan KF, Harrington TC, Steimel JP. 2004. Armillaria root disease in campgrounds of southern Colorado [Abstract]. Proceedings of the 51st Annual Western International Forest Disease Work Conference, Grants Pass, Oregon, Aug. 18-23, 2003: 51.
  11. Worrall JJ, Sullivan KF. 2002. Widespread damage caused by Davisomycella ponderosae on ponderosa pine on the San Juan National Forest [Abstract]. Inoculum (Supplement to Mycologia) 53(3): 60.
  12. Worrall JJ, Sullivan KF, Harrington TC. 2001. Armillaria root disease in campgrounds of southern Colorado.  Presented at joint meeting of Mycological Society of America, American Phytopathological Society, and Society of Nematology, Salt Lake City. [Abstract]. Phytopathology 91: S127.
  13. Hughes M, Wargo PM, Worrall JJ, Weir A, Rogers S. 2000. Root disease and fungal communities in a forest ecosystem [Abstract]. Inoculum (Suppl. to Mycologia) 51(3): 37.
  14. Burrill EA, Worrall JJ, Wargo PM. 1994. Effects of thinning and defoliation on Armillaria and a potential antagonist [Abstract]. Phytopathology 84: 1106.
  15. Worrall JJ. 1994. Distribution and ecology of Armillaria species in New York [Abstract]. Program and Abstracts, New York Natural History Conference III, New York State Museum: 71.
  16. Jones HL, Worrall JJ. 1993. Errors in wood decay studies attributable to fungal biomass [Abstract]. Phytopathology 83: 1364.
  17. Worrall JJ. 1992. Clonal development of Armillaria species in several forest types [Abstract]. Phytopathology 82: 1152.
  18. Worrall JJ. 1992. Establishment and fate of Armillaria clones.  Invited symposium presentation [Abstract]. Joint Meeting of American Phytopathological Society and Mycological Society of America, 10 Aug., Portland OR.
  19. Worrall JJ. 1991. Competitive relationships between Armillaria calvescens and Tricholomopsis platyphylla [Abstract]. Phytopathology 81: 1141.
  20. Worrall JJ. 1990. Recent advances in the taxonomy and biogeography of basidiomycetous pathogens of woody plants.  Invited symposium presentation [Abstract]. Fourth International Mycological Congress, 30 Aug., Regensburg (Abstracts): 313.
  21. Worrall JJ. 1989. Distribution and host relations of Armillaria spp. in New York [Abstract]. Mycological Society of America Newsletter 40(1): 54.
  22. Worrall JJ, Harrington TC. 1988. Causes of mortality of canopy trees in spruce-fir forests of the White Mountains, New Hampshire [Abstract]. Proceedings SAF Symposium on Acidic Deposition and Forest Decline.
  23. Harrington TC, Worrall JJ, Rizzo DM. 1987. Interfertility of host-specialized isolates of Fomes annosus from California with 'S' and 'P' testers from Europe [Abstract]. Mycological Society of America Newsletter 38: 28-29.
  24. Worrall JJ, Harrington TC. 1987. Respirometric wood decay testing [Abstract]. Mycological Society of America Newsletter 38: 56.
  25. Worrall JJ, Harrington TC. 1986. Etiology of canopy gaps in coniferous forests of the White Mountains, N.H. [Abstract]. IV Intl.  Congress of Ecology, Syracuse.
  26. Worrall JJ, Chet I, Hüttermann A. 1985. Some features of rhizomorph morphogenesis in Armillaria spp. [Abstract]. Phytopathology 75: 1297.
  27. Worrall JJ, Parmeter JR. 1982. Wetwood formation as a host response in white fir [Abstract]. Phytopathology 72: 966.
  28. Worrall JJ, Parmeter JR. 1982. Wetwood properties inhibitory to decay fungi [Abstract]. Phytopathology 72: 929.
  29. Worrall JJ, Parmeter JR, Cobb FW. 1982. Host preference in Fomes annosus [Abstract]. Proc. Thirtieth Ann. Western Intl. Forest Disease Work Conf.: 108.
  30. Worrall JJ, Schneider RW, Parmeter JR. 1981. Characteristics of wetwood in white fir [Abstract]. Phytopathology 71: 266.
  31. Worrall JJ, Parmeter JR. 1981. Survey methods for and incidence of Fomes annosus in white fir [Abstract]. Phytopathology 71: 913.


Last modified 19 Dec, 2013


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