240 Jacobs: Potential of Mulch to Transmit Pathogens grown in partially composted, versus fresh, mulch due to factors including more rapid decomposition and release of nutrients (Hoitink et al. 2001; Hoitink and Changa 2004). The practice of heating mulches prior to their use, whether with partial composting or steam pasteurization, appears to offer the dual benefits of eliminating pathogens along with improving tree growth. CONCLUSIONS This is the first report, to my knowledge, that quantifies field transmission of Sphaeropsis sapinea from needles and shoot tips used as mulch to healthy Austrian pine saplings. Evidence is provided that indicates transmission can be reduced by pre-treating the mulch with high temperature. Heating mulch materials to 60°C (140°C) prior to their application around plants was associated with a twofold reduction in Sphaeropsis tip blight, as well as a significant boost in growth of redbud and oak saplings. Naturally occurring inoculum of S. sapinea was tolerant of 6 weeks exposure to temperatures as high as 55°C (131°F), suggest- ing that heat treatments of mulch, including partial composting, that are intended to rid mulches of pathogens need to meet or exceed this threshold. Of the three diseases studied, the threat of disease transmission in the field via infected mulch was substantiated only for Sphaeropsis tip blight. Botryosphaeria canker and Armillaria root rot diseases appear unlikely to be transmitted in this manner. LITERATURE CITED Ash, C.L. 1999. Personal communication. USDA Forest Service, Durham, NH. Bollen, G.J. 1993. Factors involved in inactivation of plant pathogens during composting of crop residues, pp. 301–318. In Hoitink, H.A., and K.M. Keener (Eds). Science and Engineering of Composting: Design, Environmental Microbiological and Utilization Aspects. Renaissance Publishing, Worthington, OH. Dirr, M.A. 1998. Manual of Woody Landscape Plants: Their Identification, Ornamental Characteristics, Culture, Propagation and Uses. Stipes Publishing, Champaign, IL. 1,187 pp. Faber, B., J. Menge, J. Downer, and H. Ohr. 1995. Mulch effects on avocado root rot, pp. 412–416. In Proceedings, World Avocado Congress III, Tel Aviv, Israel. Foreman, G.L., D.I. Rouse, and B.D. Hudelson. 2002. Wood chip mulch as a source of Verticillium dahliae (Abstract). Phytopathol. 92:S26. ———. 2003. Infectivity of Verticillium dahliae in wood chip mulch (Abstract). Phytopathol. 93:S27-27. Also summarized on-line: www.ipm.msu.edu/CAT03_land/ L09-26-03.htm (accessed 7/26/05). ©2005 International Society of Arboriculture Green, T.L., and G.W. Watson. 1989. Effects of turfgrass and mulch on the establishment and growth of bare- root sugar maples. J. Arboric. 15:268–273. Greenly, K.M., and D.A. Rakow. 1995. The effect of wood mulch type and depth on weed and tree growth and certain soil parameters. J. Arboric. 21:225–232. Hansen, E.M., and K. J. Lewis.1997. Compendium of Conifer Diseases. APS Press, St. Paul, MN. 99 pp. Herms, D., M. Gleason, J. Iles, D. Lewis, H.A. Hoitink, and J. Hartman. 2001. Using Mulches in Managed Landscapes. Iowa State University Extension SUL-12, Bulletin 894. Iowa State Univversity Extension, Ames, IA. 12 pp. Also available on-line: www.forestry.iastate.edu/ext/urban.html (accessed 7/26/05). Hoitink, H.A., and C.M. Changa. 2004. Managing soilborne pathogens. Acta Hortic. 635:87–92. Hoitink, H.A., D.A. Herms, and P. Bonello. 2001. Preventing Problems While Capitalizing on Beneficial Impacts of Mulching. Ornamental Plants Annual Reports and Research Reviews. Special Circular 186-02, Ohio State University Extension. 44 pp. Also available on-line: http://ohioline.osu.edu/sc186 (accessed 7/26/05). Jacobs, K.A. 1995. U.S. National Arboretum is working toward sustainable production of pathogen-free compost and mulch. Am.. Assoc. Nursery. Today 6:7–9. ———. 2001. Redbuds, pp. 329–333. In Jones, R.K., and D.M. Benson (Eds.). Diseases of Woody Ornamental and Trees in Nurseries. APS Press, St. Paul, MN. Koski, R., and W.R. Jacobi. 2004. Tree pathogen survival in chipped wood mulch. J. Arboric. 30:165–171. Lloyd, J.E., D.A. Herms, B.R. Stinner, and H.A. Hoitink. 2001. Mulch Effects on Soil Microbial Activity, Nutrient Cycling and Plant Growth in Ornamental Landscapes. Ornamental Plants Annual Reports and Research Reviews. Special Circular 186-02. Ohio State University Extension. 8 pp. Also available on-line: http://ohioline. osu.edu/sc186 (accessed 7/26/05). Panesar, T.S., F.G. Peet, J.R. Sutherland, and T.S. Sahota. 1994. Effects of temperature, relative humidity and time of survival of pinewood nematodes in wood chips. Eur. J. For. Path. 24:287–299. Perez Sierra, A. 2004. Investigating the Risk of Introducing Honey Fungus in Infected Mulch Material. www.rhs.org.uk/research/projects/Armillaria.asp (accessed 7/26/05). Richard, T. 1992. Municipal Yardwaste Composting. Fact Sheet 6: Building Windrows. Department of Agricultural and Biological Engineering, Cornell University, Ithaca, NY. 6 pp. Also available on-line: http://compost.css.cornell.edu/Factsheets/ FactsheetTOC.html (accessed 7/26/05).
September 2005
| Title Name |
Pages |
Delete |
Url |
| Empty |
Ai generated response may be inaccurate.
Search Text Block
Page #page_num
#doc_title
Hi $receivername|$receiveremail,
$sendername|$senderemail wrote these comments for you:
$message
$sendername|$senderemail would like for you to view the following digital edition.
Please click on the page below to be directed to the digital edition:
$thumbnail$pagenum
$link$pagenum
Your form submission was a success.
Downloading PDF
Generating your PDF, please wait...
This process might take longer please wait
