Treesearch

In 1998, Australia, Chile, and New Zealand agreed to work together in a program designed to test their elite breeding lines and to test for the genetics of resistance to pitch canker (causative organism Fusarium circinatum). Pitch canker was first discovered in the United States in 1946 and in California in 1986. The first discoveries in California were in ornamental plantings, and the disease was first found in native stands of Monterey pine (Pinus radiata D. Don) in 1992. By 1997, pitch canker was found in 22 counties in California, and the Board of Forestry established a "Zone of...

Swiss needle cast (SNC) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), caused by the ascomycete fungus Phaeocryptopus gaeumannii, is associated with significant volume growth losses (20 to 50 percent) along the Oregon Coast. Although the pathogen is endemic, disease symptoms have intensified in coastal forests of Oregon and Washington since the early 1990s, reaching a peak of 177,691 symptomatic hectares detected in the 2011 aerial survey of western Oregon (fig. 1). This symptom expression is the highest in 16 years of survey, despite the conversion of tens of thousands of pure...

Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murray) Parl.) (POC) is an economically and ecologically valuable tree in the forests of southwest Oregon and northern California and in the horticultural trade worldwide. Phytophthora lateralis, the aggressive, invasive cause of POC root disease, was introduced to the native range of POC about 1950, and has since killed trees along roads and streams throughout the forest area where the tree grows. The federal forest management agencies responded with an integrated disease management program designed to slow further spread of the pathogen in...

A major limiting factor for the culture of true firs as Christmas trees is their susceptibility to Oomycete species belonging to the genus Phytophthora. In North Carolina alone, the Fraser fir (Abies fraseri [Pursh] Poir.) Christmas tree industry loses 6 to 7 million dollars annually to root rot primarily caused by Phytophthora cinnamomi. Because no resistance has been found in Fraser fir, in 2003, the North Carolina State University (NCSU) Christmas Tree Genetics (CTG) Program conducted an extensive resistance screening of 32 Abies species (50 unique taxa) from around the world.

The balsam woolly adelgid, Adelges piceae (Hemiptera: Adelgidae) (BWA), first reported on Fraser fir, Abies fraseri (Pursh) Poiret, on Mount Mitchell in 1955 (Amman 1966, Boyce 1955), is a major pest in Christmas tree plantations and in native stands. Nearly all Fraser fir Christmas trees produced in North Carolina need to be treated one or more times during their 5- to 10-year rotation to prevent or lessen damage caused by this adelgid. These chemical treatments cost the industry over 1.5 million dollars per year (Potter et al. 2005) and may compromise the effectiveness of integrated pest...

American chestnut (Castanea dentata (Marsh.) Borkh.) once was a primary hardwood species in forests of the eastern United States. Sometime during the late 18th century, it is speculated that Phytophthora cinnamomi, which causes Phytophthora root rot (PRR) on many woody plant species, was introduced to the southeast region of the United States, and this pathogen spread as people moved inland from the coast (Zentmyer 1980). In the 1800s, PRR (also known as ink disease) caused extensive mortality to American chestnut trees in the southern portion of its range (Freinkel 2007, Zentmyer 1980)....

Laurel wilt is a highly destructive disease of redbay (Persea borbonia (L.) Spreng.) and other Lauraceous natives in the southeastern United States. The disease and associated vector, the redbay ambrosia beetle (Xyleborus glabratus), has spread through the United States coastal plain. The presence of surviving and asymptomatic individuals in severely-affected stands illustrates the possibility of natural resistance by surviving redbays. In 2008, a field survey was initiated to locate and identify healthy, asymptomatic redbays in areas of severe mortality. Six heavily-affected sites were...

Eucalyptus plantations cover about 1.5 percent of the agricultural area in Brazil, and contribute to 4 percent of GDP and 3 percent in exports of forest products. Technological and research advances in silviculture and genetic improvement have increased productivity up to 80 m³ of wood/ha/year, with an average of 35 to 45 m³/ha/year. The greatest challenge to the introduction and commercial use of exotic species is the adaptation of species to climatic conditions. Even when maladapted species are able to survive, they are subjected to continuous stress that limits the expression of their...

In a greenhouse trial to examine genetic resistance among seedling families (half-sib, full-sib, and selfed) of Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murr.) Parl.) to the root pathogen Phytophthora lateralis, the root tips of seedlings were inoculated, and the subsequent mortality was followed over a 3 year period. Mortality among families at the end of the trial varied from 0 to 100 percent, with continuing mortality for some families occurring throughout the trial period. A preliminary examination of mortality curves for the families indicated that some families were highly...

The Oregon State University (OSU) hazelnut breeding program, initiated in 1969, continues to develop new cultivars for the hazelnut industry that combine suitability to the blanched kernel market with resistance to eastern filbert blight (EFB) caused by Anisogramma anomala. Oregon's hazelnut growers support the program through the Oregon Hazelnut Commission. The need for improved disease-resistant cultivars and pollinizers is the program's driving force. About 5000 seedlings have been planted each year during the past 2 decades, and 10 cultivars and 10 pollinizers have been released....