Optimum timing and use of fungicides for disease control are improved by an understanding of the characteristics of fungicide physical mode of action. Greenhouse and field experiments were conducted to quantify and model the duration of pre- and postinfection activity of fungicides most commonly used for control of hop downy...
Impact and relevance are valued by both plant pathologists and
the supporters of research and extension. Impact has been characterized
as the “So what?” of research results, and in applied research
in agriculture typically involves some change in human
behavior. This might involve, for instance, avoidance of broad
spectrum pesticides,...
Host resistance, both quantitative and qualitative, is the preferred long-term approach for disease management in many pathosystems, including powdery mildew of hop (Podosphaera macularis). In 2012, an epidemic of powdery mildew occurred in Washington and Idaho on previously resistant cultivars whose resistance was putatively based on the gene designated R6....
The kinetic mechanism of the unidirectional
H2-oxidizing hydrogenase from soybean nodule bacteroids has
been investigated with highly purified enzyme. Measurements
of the K, for H2 vary from 0.97 to 2.6 pM, and the K,,, for
methylene blue varies from 6 to 17 pM. With H2 and
methylene blue as substrates,...
Photosynthetic production of organic matter by microscopic oceanic phytoplankton fuels ocean ecosystems
and contributes roughly half of the Earth's net primary production. For 13 years, the Sea-viewing Wide
Field-of-view Sensor (SeaWiFS) mission provided the first consistent, synoptic observations of global ocean
ecosystems. Changes in the surface chlorophyll concentration, the primary...
A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new species Phytophthora obscura sp. nov. is formally named based on phylogenetic analysis, host range, Kochs...
Fusarium crown rot (FCR), caused by and , reduces wheat ( L.) yields in the Pacific Northwest (PNW) of the US by as much as 35%. Resistance to FCR has not yet been discovered in currently grown PNW wheat cultivars. Several significant quantitative trait loci (QTL) for FCR resistance have...
Morphological and chemical studies of Hypogymnia from the Himalayas revealed one new species, three species new to the region, and a previously unrecognized synonym. Hypogymnia crystallina, distinguished by its rimmed holes in the lobe axils, a pruinose disc, POL+ epihymenium, and distinctive chemistry (zeorin, hypoprotocetraric acid, usnic acid and atranorin)...
RNA sequencing (RNA-seq) and genotyping-by-sequencing (GBS) were used for single nucleotide polymorphism (SNP) identification from two economically important obligate plant pathogens, Pseudoperonospora cubensis and P. humuli. Twenty isolates of P. cubensis and 19 isolates of P. humuli were genotyped using RNA-seq and GBS. Principle components analysis (PCA) of each data...
Pyrenophora tritici-repentis (Ptr), a necrotrophic fungus and the causal agent of tan spot of wheat, produces one or a combination of host-selective toxins (HSTs) necessary for disease development. The two most studied toxins produced by Ptr, Ptr ToxA (ToxA) and Ptr ToxB (ToxB), are proteins that cause necrotic or chlorotic...