Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2001. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2001. / Härtill 4 uppsatser.

Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 84-90). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1927. / Typescript. With this is bound: A relation between chemical constitution and toxicity / By R.H. Baechler." ... advance copy of a report to be presented at the Thirty-Second annual meeting of the American Wood-Preservers' Association ... January 28, 29 and 30, 1936 ... ", 4 p. Includes bibliographical references.

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Thesis (M.S.)--Oregon State University, 2004. / Printout. Includes bibliographical references (leaves 148-159). Also available online.

Studies were conducted to determine the incidence and severity of Heterobasidion annosum (Fr.) Bref. root rot in loblolly pine (Pinus taeda L.) unthinned plantations and subsoiled seed orchards and to demonstrate the potential for direct root colonization by percolated basidiospores. Twenty-two 0.02 ha circular plots were installed in nine unthinned loblolly pine plantations in Virginia. Five plantations were located on sites classified as high hazard for annosum root rot while four plantations were located on low hazard sites. Bulldozer excavation of the root systems permitted extensive analysis of annosum root rot incidence and severity which was substantiated by isolation of the asexual stage of the fungus from symptomatic resinous and stringy-decayed roots. On low hazard sites, 10 of 300 trees (3.3 percent) were colonized by H. annosum with 2 trees (0.7 percent) severely colonized ( > 1 percent of the total root system mass). On high hazard sites, 29 of 348 trees (8.3 percent) were colonized with 5 trees (1.4 percent) severely colonized. On low hazard sites, the predominant colonization symptom was stringy decay which indicated an older established disease situation as opposed to colonized trees on high hazard sites which exhibited resin-soaking characteristic of more recent infection and colonization. No basidiocarps were observed on any trees on low hazard plots while only 2 trees exhibited conks on high hazard sites. Mean radial increment growth differences between H. annosumcolonized and noncolonized trees were analyzed using the Duncan's Multiple Range test and for the 10-year period prior to excavation no significant growth reduction was observed. Due to low incidence and severity of annosum root rot in unthinned loblolly pine plantations and the absence of reduced radial increment growth, the disease is not a primary management consideration, especially on low hazard sites. However, the disease may be of secondary importance in managing first-generation unthinned loblolly pine plantations on high hazard sites due to inoculum production from residual stumps of H. annosum trees removed during thinning. The root systems of 2, 20 and 30 loblolly pines at the Chesapeake Corporation, Virginia Division of Forestry and Union Camp Corporation seed orchards, respectively, were excavated with a backhoe to permit intensive analysis of subsoiled roots for annosum root rot incidence and severity. The absence of wound callus, lack of adventitious root formation and the presence of a resin-soaked band greater than approximately 6 mm wide at the wound surface were three criteria for determining whether a lateral primary root had failed to heal following subsoiling. Soil texture was closely associated with the incidence and severity of general root disease as the wetter soil conditions at the Chesapeake Corporation seed orchard probably afforded a more amenable environment for the healing of subsoiled roots. Sandy, drought-susceptible soils at the Union Camp Corporation and Virginia Division of Forestry seed orchards were associated with the higher incidence and severity of root disease among subsoiled lateral primary roots. The asexual stage of H. annosum was not successfully isolated from resin soaked subsoiled root tissue at any of the three orchards. Duncan's Multiple Range analysis demonstrated that mean radial increment growth was significantly decreased among healthy and declining subsoiled trees at the three orchards. At the Union Camp Corporation orchard, when healthy and declining trees were subsoiled they exhibited significantly less radial increment growth than their respective control counterparts. Loblolly pine root segments were inoculated with a suspension of H. annosum basidiospores and observed using scanning electron microscopy. Appressorial-like structures occurred at distal ends of elongated germ tubes demonstrating probable direct infection of loblolly pine root segments. / Ph. D.

This thesis is based on three inter-related studies: the first part deals with the microbial consortium, the identification of microbes and their volatiles, the second part deals with the study of bio-chemical control methods of two conifer pests; the pine weevil Hylobius abietis (L.) and the root rot fungi Heterobasidion spp., and the third part describes the production of styrene by a fungus using forest waste.The large pine weevil (Hylobius abietis L.) is an economically important pest insect of conifers in reforestation areas of Europe and Asia. The female weevils protect their eggs from feeding conspecifics by adding frass (mixture of weevil feces and chewed bark) along with the eggs. In order to understand the mechanism behind frass deposition at the egg laying site and to find repellents/antifeedants for pine weevils, microbes were isolated from the aseptically collected pine weevil frass. Microbial produced volatile organic compounds (VOCs) were collected by solid phase micro extraction and analyzed by GC-MS after cultivating them on weevil frass broth. The major VOCs were tested against pine weevils using a multi-choice olfactometer. Ewingella sp., Mucor racemosus, Penicillium solitum, P. expansum, Ophiostoma piceae, O. pluriannulatum, Debaryomyces hansenii and Candida sequanensis were identified as abundant microbes. Styrene, 6-protoilludene, 1-octene-3-ol, 3-methylanisole, methyl salicylate, 2-methoxyphenol and 2-methoxy-4-vinylphenol were the VOCs of persistently isolated microbes. In behavioral bioassay, methyl salicylate, 3-methylanisole and styrene significantly reduced the attraction of pine weevils to their host plant volatiles. Heterobasidion spp. are severe pathogenic fungi of conifers that cause root and butt rot in plants. Bacterial isolates were tested for the antagonistic activity against fungi on potato dextrose agar. Bacillus subtilis strains significantly inhibited the growth of H. annosum and H. parviporum. Styrene is an industrial chemical used for making polymeric products, currently produced from fossil fuel. A strain of Penicillium expansum isolated from pine weevil frass was investigated for the production of styrene using forest waste. Grated pine stem bark and mature oak bark supplemented with yeast extract produced greater amounts of styrene compared to potato dextrose broth. / <p>QC 20130507</p>

Diss. (sammanfattning) Alnarp : Sveriges lantbruksuniv., 2007. / Härtill 4 uppsatser.