Treesearch

The collective U.S. housing market, on a monthly basis, was mixed in April 2018. Encouraging were the year-over-year readings, which were overwhelmingly positive, except for existing house sales. Single-family housing starts, permits, and under construction improved on a monthly basis. Existing house sales were negative on a month-over-month and year-over-year basis. Regionally, data were mixed across all sectors.

Sugar pine (Pinus lambertiana) is a five-needle pine native to the mixed-conifer forests of the Sierra Nevada and Cascade Ranges of western North America. Sugar pine has great aesthetic, ecological, and economic value and is among the largest of all pines. Like other five-needle pines, sugar pine is susceptible to white pine blister rust (WPBR), caused by the nonnative pathogen Cronartium ribicola. Although tree-breeding efforts have been the most successful strategy against WPBR, artificial pruning by removing the lowest branches (where infections are most common) can potentially enhance...

The breakdown of host resistance to plant pathogens is of critical concern in agriculture, forestry, and the management of natural systems. Evolution of the fungal poplar rust pathogen Melampsora larici-populina has been shown to have been dramatically influenced by the deployment of resistance genes in commercial poplar (Populus spp.) plantations, with pathogen populations inundated by virulent genotypes (Xhaard et al. 2011). The deployment and subsequent breakdown of resistance genes in poplar plantations provide an experimental system for understanding the dynamics of pathogen evolution...

White pine blister rust (WPBR; causal agent: Cronartium ribicola) has been a threat to both forest resources and agricultural commodities since its introduction to North America in the early 1900s. Eastern white pine (Pinus strobus) is the most economically important timber species in New Hampshire (USA). From 1917 to 1970 Ribes throughout the State was eradicated to protect the timber industry. After the lifting of the Federal Quarantine Act (USDA Bureau of Entomology and Plant Quarantine Federal Domestic Plant Quarantine number 63 [1938]) restricting Ribes and the more recent availability...

Surveys of two stem rust diseases of Pinus kesiya were implemented in Da Lat, Lam Dong province, in the Central Highlands of Vietnam. Symptoms of the first disease, a gall rust, are very similar to those of Cronartium quercuum in North America. Our surveys found many Quercus cambodiensis trees severely infected by the uredinial and telial states of a Cronartium species, later identified by microscopic characteristics as Cronartium orientale, which is native to eastern Asia. The aecial state of C. orientale occurs on various two-needle pines. We tentatively identified the gall rust on P....

The German Barcode of Life (GBOL) project is a large-scale DNA barcoding initiative to assess the biodiversity of animals, fungi, and plants of Germany. Here we introduce the subproject focusing on rust fungi (Pucciniales, Basidiomycota). This is the only group of fungi represented in the initial 3.5-year phase of the project.

Restoration of forests devastated by nonnative invaders often dominates the attention of forest managers and their actions. However, taking a broader view of the invasion beyond the crisis areas reveals opportunities where proactive management can alter the outcome of the invasion in threatened areas. Proactive management moves past the idea of protecting the hosts from exposure to the established nonnative invader and shifts toward facilitating naturalization by preparing the landscape to sustain critical ecosystem function into the future in the presence of the invader (Schoettle and...

The recent completion of genome sequencing for some rust fungi has contributed to suggest a link between biotrophic specialization and genome size expansion. The measurement of genome sizes for a selection of rust fungi has revealed some of the largest genomes among fungi, with nine rust species with haploid genomes between 300 and 780 Mbp. In particular, Uromyces appendiculatus, Phakopsora pachyrhizi, U. transversalis, and Hemileia vastatrix genomes were measured as 652, 716, 746, and 772 Mbp, respectively. Moreover, flow cytometric analysis of H. vastatrixinfected coffee (Coffea spp.)...

In North America, the nonnative rust fungus Cronartium ribicola kills immature native five-needle pine trees and indirectly predisposes maturing trees to secondary attack by insects and other fungi, which may result in severe mortality. Since the early 1900s when C. ribicola arrived, environmental factors, individual trees, the rust fungus, and insects (for example, mountain pine beetle [Dendroctonus ponderosae]) have all interacted to dramatically change forested ecosystems across North America. To date our white pine blister rust (WPBR) research has generated genomics data from the WPBR...

The health and regeneration of sugar pine (Pinus lambertiana), a major species in the mountain forests of California (USA), has been substantially affected by an exotic pathogen, Cronartium ribicola, which causes white pine blister rust. Seedlings from trees with major gene resistance (MGR) are being used to increase field survival in plantations. Partial resistance (PR) due to multiple genes is considered to be more durable than MGR, providing protection to sugar pines exposed to a virulent form of blister rust.