In 2014, 2000 plants showing root rot symptoms were collected from 200 commercial soybean (Glycine max L.) fields in South Dakota, USA. One thousand one hundred thirty fungal isolates obtained from the samples were identified as Fusarium species by morphology and sequencing of the translation elongation factor 1-alpha gene. Fifty-one percent were F. graminearum, 30.0% were F. acuminatum, 8.0% belonged

Apple replant disease (ARD) occurs frequently in old orchards and is an important disease that limits apple production in China. Fusarium oxysporum is one of the causal agents of ARD and its pathogenic mechanism is still unclear. To explore the potential pathogenesis-related genes of this pathogen, a T-DNA insertion library of F. oxysporum HS2 was constructed via optimized Agrobacterium tumefaciens-mediated

Stem rust, caused by Puccinia graminis, is a catastrophic disease that has and continues to cause yield losses in barley, oat, and wheat crops worldwide. Use of host resistance genes is the most economic, efficient, and environmentally best method to control the disease. Resistance genes have been incorporated into most commercial cultivars and have been effective, for races in the North American populations

Powdery mildew, caused by Podosphaera xanthii (U. Braun & Shishkoff), is a widespread disease on greenhouse cucumber in many countries, including Canada. The efficacy of seven biological or chemical products to manage powdery mildew was evaluated. These included Rhapsody® (Bacillus subtilis Ehrenberg strain QST 713), Microflora PROTM (B. subtilis, Bacillus amyloliquefaciens Priest et al., Bacillus

Fusarium solani and F. tricinctum are important root rot pathogens of soybean in the northern Great Plains of North America. The role of temperature on their growth was investigated in vitro at temperatures between 0 to 35ºC, while disease development in the soybean cultivar ‘Barnes’ was tested at 15°C, 20°C, 25°C and 30°C using several methods over 1 to 4 weeks. All experiments were conducted in a

(2020). Correction. Canadian Journal of Plant Pathology. Ahead of Print.

Setosphaeria turcica causes Northern corn leaf blight (NCLB). In this study, 92 isolates of S. turcica were collected from naturally infected corn fields at 57 sites within China to determine physiological race composition and genetic diversity. Based on the reaction of differential hosts, isolates were divided into 14 physiological races (0, 1, 2, 12, 3, 13, 23, N, 1N, 2N, 3N, 13N, 23N, 123N). Races

Several virus diseases cause damage to Vitis vinifera L., but information on their incidence and impact on hybrid cultivars is scarce, particularly under cool-climate conditions. In Nova Scotia (NS), the wine industry is based predominantly on interspecific hybrid cultivars. To understand the occurrence of major grapevine viruses in NS, surveys were conducted in 2016, 2017 and 2018. A total of 965

A severe branch dieback and canker was observed on black walnut (Juglans nigra L.) in Yili county, Xinjiang, China, during the spring and summer, 2016. A fungus was consistently isolated from infected branches. Pathogenicity tests showed that the fungus could infect branches, and produced the same symptoms under artificial inoculation conditions as those observed in the field. The fungus was identified

The presence of well-defined and depressed circular leaf spots, dark in their core and surrounded by a light brown dim halo, was observed on Dendrobium nobile plants in the municipality of Ixtaczoquitlán, state of Veracruz, Mexico, in 2019. Colletotrichum isolates were consistently obtained from symptomatic plants of D. nobile. The morphological characteristics of these isolates resembled each other

Root rot is a concern in the pea growing areas of Canada and elsewhere in the world, since it can cause significant yield loss. Fusarium spp. are considered major pea root rot pathogens. In this study, the pathogenicity and host range of Fusarium species collected from earlier surveys of commercial pea fields in Alberta were evaluated. Forty-five isolates belonging to six Fusarium species were selected

A shift to larger farms, bigger equipment and reduced crop diversity has been occurring in North American agriculture for many years. This has resulted in an increased reliance on genetic resistance and pesticides because much of the pest reduction from natural biological control (ecosystem services) associated with crop rotation and biological diversity has been lost. This shift has contributed to

Wheat leaves infected with Puccinia triticina, the causal agent of wheat leaf rust, were collected from across Canada in 2014. From these leaves, 102 single-pustule isolates were recovered and tested for virulence on 16 standard differential wheat lines, with 28 unique virulence phenotypes found. The most common were TBDG (16.7%), TBBG (13.7%), MLPS and TNBG (both at 7.8%). Most isolates (95) originated

Blackleg, caused by Leptosphaeria maculans, is a serious disease on canola or rapeseed in Canada, Australia and Europe. Disease levels have increased in western Canada recently and additional tools are needed to improve blackleg management. Seed treatment can be a cost-effective approach against blackleg, but there is currently no registered seed-treatment product targeting aboveground blackleg infection

Wild soybean (Glycine soja) is the ancestor of cultivated soybean (Glycine max). Soybean mosaic virus (SMV) is an important pathogen affecting soybean production worldwide. The effect of exogenous salicylic acid (SA) application on the disease resistance of wild soybean plants infected with SMV is still unclear. In this study, we determined the SA content; reactive oxygen species (ROS) content; lipid

Hosta virus X (HVX) is the most economically significant virus infecting hosta (Hosta spp.) plants worldwide, and has been reported from North America, Europe, Asia and Oceania. In May 2019, various viral-like disease symptoms were observed on hosta plants in a park in Harbin City in Northeast China, and infection by HVX was confirmed by small RNA sequencing, RT-PCR and electron microscopy. The infectivity

Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici (Bgt), is an important disease in China. In this study, airborne spore concentrations were monitored using spore samplers and real-time PCR during 2013– 2015 at three locations in Gangu, Gansu province of China. The effects of meteorological variables on spore concentration were analyzed and models were developed for forecasting dynamics

Soybean (Glycine max) is an annual leguminous plant that has been cultivated in China for over 4500 years. During a survey conducted in 2018, collar rot was observed in soybean crops in Zhangzhou, Fujian Province, China. The disease first appeared as water-soaked lesions on the surface of the stems, followed by the development of large decayed areas with abundant white mycelium. A fungus was isolated

Clubroot is an important root disease of canola/oilseed rape (Brassica napus L.) caused by Plasmodiophora brassicae. To cope with the emergence of new virulent pathotypes of P. brassicae that threaten canola production in western Canada, there is a need to identify novel sources of resistance for breeding programmes. In the present study, a series of nine B. napus genotypes, from different geographic

(2020). Outstanding Young Scientist Award. Canadian Journal of Plant Pathology: Vol. 42, No. 1, pp. 144-145.

The abaca (Musa textilis Nee) is an important fibre crop in the Philippines. Its fibre yield and quality is severely impacted by two potyviruses, namely, banana bract mosaic virus (BBrMV) and sugarcane mosaic virus (SCMV). A multiplex RT-PCR assay was developed for the simultaneous detection of these two RNA viruses in abaca. Primer sets were designed to amplify fragments of BBrMV coat protein (743 bp)

Fusarium head blight (FHB) and the associated mycotoxin deoxynivalenol (DON) negatively impact the wheat industry worldwide. In North America, FHB is mainly caused by Fusarium graminearum sensu stricto. The purpose of this study was to evaluate, under storage conditions, the expression of the DON biosynthetic gene trichodiene synthase (Tri5) of F. graminearum in grain of hard red winter wheat cultivars

In recent years, there has been an increase in the frequency of Cercospora beticola (Sacc.), the cause of Cercospora leaf spot (CLS) in sugarbeet (Beta vulgaris L.), isolates with demethylase inhibitor (DMI) and quinone outside inhibitor (QoI) fungicide resistance collected from commercial fields in Michigan, USA and Ontario, Canada. This study evaluated sensitivity distributions of C. beticola populations

(2020). Outstanding Research AwardThe Canadian Phytopathological SocietyPrix Excellence en rechercheLa Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 42, No. 1, pp. 146-148.

(2020). Outstanding Research AwardThe Canadian Phytopathological Society Prix Excellence en rechercheLa Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 42, No. 1, pp. 142-143.

(2020). FellowThe Canadian Phytopathological SocietyMembre associéLa Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 42, No. 1, pp. 140-141.

Passiflora edulis plants with typical symptoms of begomovirus infection, including leaf curling and dark green, swollen veins, were discovered in Yunnan province, China. The full-length viral components and satellite molecules of the infected P. edulis plants were obtained by enrichment of circular DNA by rolling circle amplification, restriction enzyme digestion, cloning and DNA sequencing. The viral

Anthracnose was observed on postharvest avocados (Persea americana) in a commercial market in Jinju, South Korea, in 2019. Symptoms included soft rot and sunken lesions leaking necrotic fluid. Orange conidial masses were observed on the outer surfaces of these unappealing avocados. Colletotrichum fungi producing grey to olive colonies with orange conidial masses were consistently recovered from the

Aphanomyces euteiches is an important root pathogen of several legume and forage crops worldwide. Disease management is challenging due to resilient oospores that can persist in the soil for long periods of time. Several research groups are working towards incorporating disease resistance into crop cultivars involving large-scale disease resistance screening and, for some crops, the use of molecular

Several Fusarium species cause Fusarium head blight (FHB), a devastating disease that affects wheat and other small grain cereals. Besides causing significant yield losses, FHB pathogens reduce the quality of the grain and may produce mycotoxins that are harmful to both humans and animals. The development of effective management strategies for this disease requires an understanding of the composition

Yield losses in wheat and barley cultivars varying in stripe rust reactions were determined under natural infection conditions in fungicide treated and untreated plots at Lacombe and Olds, central Alberta, from 2012 to 2014. Stripe rust caused by Puccinia striiformis was the major disease observed during the 3-year test. Moderate stripe rust severity caused significant yield losses of over 20% in a

Cercospora leaf spot (CLS), caused by Cercospora beticola Sacc., is the dominant foliar disease affecting the profitability of table beet production in New York, USA. The disease is controlled primarily with fungicides, but sustainability is critically threatened by strobilurin resistance within the C. beticola population and a limited suite of alternatives. This study evaluated the temporal dynamics

Armillaria root disease causes growth reduction and mortality in forest trees and agricultural plants. Root colonization is poorly documented but important for predicting interactions with environmental factors and disease spread. Nine planted and one older naturally regenerated Douglas fir (Pseudotsuga menziesii) sites were identified for sampling. Tree roots were pulled out of the soil, cleaned,

Outbreaks of blossom blight in coriander (Coriandrum sativum) and caraway (Carum carvi) are common in western Canada, particularly when cool, wet conditions prevail during flowering, which can lead to total crop loss. Earlier attempts to identify the causal organisms were inconclusive, which has hampered blossom blight management and been a barrier for effective resistance breeding in these two crops

Lily leaf spot is an emerging disease of the globally rare Lilium grayi S. Wats., a species endemic to the southern Appalachian Blue Ridge, USA. The species is considered Threatened or Endangered in the three states where it naturally occurs (North Carolina, Tennessee, Virginia). Disease leads to premature senescence of aboveground tissues and curtailment of sexual reproduction. Spore morphology, completion

The peach (Prunus persica) is a fruit that is susceptible to many fungal infections following harvest, leading to significant losses. This study was aimed at evaluating the efficacy of a novel formulation prepared from mint and thyme essential oils and used to protect peaches from postharvest decay. The formulation was prepared by mixing the oils with Arabic gum as a coating material and Tween 20 as

Fusarium head blight (FHB) caused by Fusarium graminearum Schwabe is a major disease of wheat (Triticum aestivum L.). FHB preferentially infects immature spikes and mycotoxins accumulate in developing grains, reducing yield and nutritional quality. The mycotoxins are type B trichothecene group of compounds including deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON)

(2019). Thorvaldur Johnson. The Dominion Rust Research Laboratory, 1925-1957. Canadian Journal of Plant Pathology. Ahead of Print.

Plant-parasitic nematodes (PPN) can negatively affect corn production. In this study, incidence and abundance of PPN were assessed in 300 corn fields across 20 counties in North Dakota during 2015 and 2016. Seventy-two percent of the fields were positive for PPN. The major genera identified were Helicotylenchus (incidence: 52%; mean density: 1513 nematodes kg−1 of soil; greatest density: 16 910 nematodes

A study was conducted in five American states and Ontario, Canada, in 2015 and 2016 to determine the effects of fluopyram seed treatment and cultivar on the root rot and foliar phases of sudden death syndrome (SDS) of soybean. Three seed treatments were evaluated: (1) base treatment (control) containing prothioconazole + penflufen + metalaxyl (0.019 mg a.i./seed) + metalaxyl (0.02 mg a.i./seed) + clothianidin

Late season Rhizoctonia root rot in sugar beet is a serious yield limiting disease problem caused by an interaction between Rhizoctonia solani and Leuconostoc spp. in Idaho. To better understand this interaction, the two most common Leuconostoc haplotypes were co-inoculated with 17 R. solani strains representing the range of genetic diversity established previously. The study was conducted twice by

Multiple pathogens are frequently recovered together from diseased soybean seedlings, suggesting a seedling disease complex. Pythium sylvaticum and P. irregulare are prevalent oomycetes and Fusarium oxysporum and F. graminearum are prevalent fungi associated with seedling disease of soybean. We hypothesized that infection with multiple seedling disease pathogens would cause disease symptoms to be more

Wheat stem rust, caused by the fungal pathogen Puccinia graminis f. sp. tritici (Pgt), has re-emerged as an important disease of wheat. This pathogen continues to spread and evolve new virulent races. The international letter-code system of nomenclature has been used to pathotype these new emerging races, and gene SrMcN from ‘McNair 701' winter wheat, which is one of the differential lines, was examined

Strawberry black spot caused by Alternaria is an important foliar disease. In 2016, strawberry leaves with severe black spot lesions were collected from eight districts of Beijing municipality in China. Molecular and morphological criteria were matched to identify the Alternaria species inciting strawberry black spot in Beijing. A total of 102 Alternaria isolates from diseased strawberry leaves were

Fusarium head blight is a globally devastating disease of wheat, for which sources and mechanisms of resistance are urgently needed. The goal of this research was to elucidate the chemical nature of changes incurred in the rachis of a susceptible wheat (‘Chinese Spring’, CS), and a related addition line (CS-7EL) with resistance conferred by a fragment of the 7E chromosome from a wild wheat relative

A single step Direct real-time quantitative reverse transcription quantitative polymerase chain reaction (DRT-qPCR) was applied and optimized for the detection of Grapevine rupestris stem-pitting associated virus (GRSPaV) in grapevine. A probe and primer set were designed from conserved genomic regions from eight GRSPaV accessions from GenBank and used with the Direct Plant Extraction Buffer (DiPEB)

The incidence of tobacco bacterial wilt, caused by Ralstonia solanacearum, is significantly affected by temperature. However, the effect of temperature on the metabolism of carbon and amino acid substrates used in phenotypic characterization of R. solanacearum is still unknown. In order to evaluate the effect of temperature on metabolic phenotypes, the phenotypes of the pathogen were characterized

In the spring of 2018, necrotic and canker symptoms were observed on stems of young apple trees that were bench-grafted by growers on four rootstocks (EMLA 9, Supporter 4, M9-T337 and Pajam 2) in Annapolis Valley, Nova Scotia. The objective of this study was to isolate and identify the causal organism of the disease on apple rootstocks. The diseased tissue obtained from eight infected plants of the

Epimedium brevicornum Maxim (EbM) is a perennial herb grown in China for traditional Chinese medicines. Grey mould symptoms were observed on EbM leaves in several fields in Hubei Province, China, from April to June in 2015, 2016 and 2017. V-shaped blights or concentric rings appeared initially on the basal leaves, followed by necrosis gradually spreading from the tips and margins to the entire leaf

Wheat leaves infected with leaf rust collected across Canada in 2013 were used to isolate 265 Puccinia triticina Eriks. single uredinial isolates. When these were analysed for virulence on 16 standard differential wheat lines 38 virulence phenotypes were found, with MBDS (11.7%), TBBG (11.3%), TNBG (10.2%) and MBTN (8.3%) the most common. In Manitoba and Saskatchewan, 29 virulence phenotypes were found

Pileolaria pistaciae is a species originally found attacking Pistacia chinensis Bunge in Japan and a few other Asian countries. In this study, we report the presence of P. pistaciae in Pakistan. Infected leaves of P. chinensis were collected from two different sampling sites in the Abbottabad and Shangla districts of Khyber Pakhtunkhwa province of Pakistan in September-October, 2014. The causal fungus

(2019). Fungi Canadenses No. 349 Claviceps zizaniae. Canadian Journal of Plant Pathology. Ahead of Print.

Recent advances in genomics have led to a greater understanding of blackleg disease of canola, caused by the fungus Leptosphaeria maculans. Genome sequences are available for several L. maculans isolates and different Brassica species, and several resistance and avirulence genes, which have a ‘gene for gene’ relationship, have been characterised. Although several pairs of complementary resistance and

The pathogenic Fusarium oxysporum species complex (FOSC) causes significant yield losses in the family Solanaceae including on tomato, eggplant and pepper in the Aegean and Mediterranean regions of Turkey. Fusarium wilt of pepper, caused by Fusarium oxysporum f. sp. capsici (Foc), has emerged recently in Turkey, where its significance has not been investigated thoroughly. In the present study, disease

Powdery mildew (Erysiphe pulchra) is a devastating disease in nursery production of flowering dogwood (Cornus florida L.). Disease management relies heavily on season-long use of chemical fungicides and there is a demand for alternative strategies. An endophytic bacterium IMC8 was isolated from disease-free C. florida stem tissue, and was shown to be an effective biological control agent against E

Cronartium ribicola causes white pine blister rust (WPBR) on five-needle pines worldwide. After accidental introduction into North America about 100 years ago, this invasive fungus has caused heavy mortality in western white pine (Pinus monticola) and other related five-needle pines across North America. Breeding by selection of rare resistant trees is time-consuming; therefore, genomics-based tools

Species of Phytophthora pose one of the most serious biosecurity threats to forest ecosystems worldwide. Despite management efforts and increased awareness of forest pathogens, there is continued introduction and spread of Phytophthora species. Uncertainty about the center of origin for many of the invasive species hampers disease control efforts. Additionally, the management efforts are often made

Hydrangea macrophylla, also known as big leaf hydrangea, is an economically valuable ornamental garden plant. From 2016 to 2018, a high incidence of leaf spot disease of hydrangea occurred in Hunan Province of China. Symptoms consisted of irregular to circular lesions, dark brown in color with gray-white centers and delimited by dark brown borders. The lesions further coalesced to form irregularly

Citrus sinensis is an important fruit crop valued for its juicy fruit pulp and aromatic rind. Grafted twigs with rot progressing from both ends were observed on C. sinensis trees in 12 orchards in Zigui, China, in June 2017, with only 5% of grafted twigs surviving in some orchards. Severe infection resulted in a rot of the entire twig, with the twig becoming covered by a white mycelium. A fungus frequently

Squash leaf curl (SLC) disease causes serious damage in a great diversity of horticultural crops worldwide and is due to infection by different ssDNA bipartite begomoviruses (Family Geminiviridae). Symptoms of leaf yellowing, stunting and curling have been observed in squash crops in the southern region of the Baja California (BC) Peninsula in the northwestern region of Mexico for at least a decade