Douglas-fir (DF, Pseudotsuga menziesii) is the most important forest tree in Oregon and is the second most valuable conifer in New Zealand. Phytophthora pluvialis was described (Reeser et al. 2013) from mixed evergreen forests in southwest Oregon. It was subsequently identified as the cause of red needle cast of radiata...
Gynura aurantiaca is a member of the Senecionaea tribe of the Asteraceae, indigenous to Java. Commonly known as purple velvet plant, this tropical species is well adapted to landscapes in South Florida, but is mostly seen as a potted plant for use in the interiorscape. During February 2013, a local...
Dead and dying Ceanothus sanguineus, C. velutinus, and C. integerrimus plants grown in a native plant nursery in Oregon for landscape restoration were reported in 2011. Plants were wilted with stem lesions above necrotic roots. Using selective media (Hansen et al. 2012), twelve similar Phytophthora isolates were obtained. DNA sequences...
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...
Results of 28 field trials conducted over a 12-year period investigating management of hop powdery mildew caused by Podosphaera macularis were quantitatively summarized by meta-analysis to compare product efficacy and use patterns by mode of action as defined by Fungicide Resistance Action Committee (FRAC) groups. Availability of original observations enabled...
Phytophthora infestans causes potato late blight, an important and costly disease of potato and tomato crops. Seven clonal lineages of P. infestans identified recently in the United States were tested for baseline sensitivity to six oomycete-targeted fungicides. A subset of the dominant lineages (n = 45) collected between 2004 and...
In Australia, pyrethrum (Tanacetum cinerariifolium) is affected by a foliar disease complex that can substantially reduce green leaf area and yield. Historically, the most important foliar disease of pyrethrum in Australia has been ray blight, caused by Stagonosporopsis tanaceti, and other fungi generally of minor importance. Temporal fluctuations in the...
Pseudoperonospora cubensis is an obligate pathogen and
causative agent of cucurbit downy mildew. To help advance
our understanding of the pathogenicity of P. cubensis, we
used RNA-Seq to improve the quality of its reference
genome sequence. We also characterized the RNA-Seq
dataset to inventory transcript isoforms and infer alternative
splicing...
Groundnut ringspot virus (GRSV) and Tomato chlorotic spot virus
(TCSV) are two emerging tospoviruses in Florida. In a survey of the
southeastern United States, GRSV and TCSV were frequently detected in
solanaceous crops and weeds with tospovirus-like symptoms in south
Florida, and occurred sympatrically with Tomato spotted wilt virus (TSWV)...
Root rot of raspberry (Rubus idaeus), thought to be primarily caused
by Phytophthora rubi, is an economically important disease in the
western United States. The objectives of this study were to determine
which Phytophthora species are involved in root rot, examine the efficacy
of different isolation methods (cane, root, and...