Abstract Powdery mildew diseases on crops and ornamental plants are common and cause significant economic losses, by reducing the yield and quality of crops and downgrading the value of ornamentals. In surveys published annually in the Canadian Plant Disease Survey, powdery mildews were reported frequently. In recent years, the taxonomy of powdery mildew fungi has changed tremendously as the result

Abstract Leaf rust caused by Puccinia hordei is a major disease of barley and is best managed by deploying effective resistance genes. The effect of post-inoculation temperature [18 ± 2°C (low), 22 ± 2°C (mid), or 26 ± 2°C (high)] on the expression of a selection of known all stage resistance (ASR) Rph genes and their interaction in combination with the adult plant resistance (APR) gene Rph20 were

Abstract Stripe rust, caused by Puccinia striiformis Westend. f.sp. tritici Erikss. (Pst), is one of the most devastating diseases of wheat (Triticum aestivum L.) globally. Exploring and utilising new sources of resistance is essential for breeding resistant wheat cultivars. Thus, a doubled haploid population (n=291) derived from the cross ‘AAC Innova’/‘AAC Proclaim’ was evaluated to dissect the genetics

Abstract Southern corn rust, caused by Puccinia polysora, is a yield limiting disease on corn (Zea mays). As a biotrophic fungal pathogen, P. polysora requires a living host for its survival. Southern corn rust is favoured by high-temperatures and humid environmental conditions, and therefore is more prevalent in the southern United States. In August 2020, corn plants displaying signs and symptoms

Abstract Beneficial endophytes are key factors in plant productivity and disease control; therefore, research is ongoing to characterize the potential of endophytes as microbial inoculants to promote plant growth and act as biocontrol agents. In this study, we searched for and identified a set of endophytes occurring naturally in a few important crops. Beneficial endophytes were shown to antagonise

Abstract The development of resistant cultivars is a preferred way to manage the wheat rust pathogens. Successful breeding relies on the continuous discovery, characterization and deployment of genetically diverse resistance sources. This investigation covers the identification and characterization of the stripe rust (caused by Puccinia striiformis f. sp. tritici) resistance carried by a pre-Green

Abstract The induction of resistance is an important strategy in integrated plant disease management. This strategy has a great potential to be adopted by farmers, motivated by the worldwide demand for a reduced pesticide use in food production. Studies have shown that resistance inducers are effective against a wide variety of pathogens, including Phakopsora pachyrhizi, the causal agent of Asian soybean

Abstract Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a devastating disease of wheat in Turkey and worldwide. This pathogen can overcome known resistance genes and negatively affect wheat production. The objectives of this study were to determine the virulence patterns of wheat stripe rust isolates collected from the coastal areas (Aegean and Mediterranean regions) of Turkey, and

Abstract Resistance breeding is an effective strategy against wheat stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici (Pst). To identify and map quantitative trait loci (QTL) associated with stripe rust resistance, a durum wheat doubled haploid population (n=87) derived from ‘Strongfield/Blackbird’ was evaluated for disease severity near Toluca, Mexico (2017 - 2019) and Lethbridge

Abstract This study was conducted to identify and map stem rust resistance genes in Canada Western Red Spring (CWRS) wheat variety ‘AAC Prevail’ and elite line ‘BW961ʹ. A population of 227 doubled haploid lines from ‘AAC Prevail’/‘BW961ʹ and parents were evaluated for their response to stem rust (Puccinia graminis) at Njoro, Kenya, from 2016-2019 and genotyped using a targeted genotyping by sequencing

Abstract Organ-specificity of plant defense is an under-represented axis of research in plant biology. However, recent publications point out the importance of this concept in plant-pathogen interactions. Indeed, assuming the resistance status of a whole plant against a given pathogen following studies conducted on a single organ might lead to erroneous conclusions. This study aims at understanding

Abstract Neodothiora populina Crous, G.C. Adams & Winton was determined to be a new pathogen of trembling aspen (Populus tremuloides) growing in Alaska, based on completion of Koch’s Postulates in replicated forest and growth chamber inoculation trials. The pathogen is responsible for severe damage and widespread rapid mortality of sapling to mature aspen (≥ 80 years) in the boreal forests of interior

Abstract Tan spot is a destructive disease of wheat caused by the fungus Pyrenophora tritici-repentis (Ptr), with most fungal isolates in Canada known to produce the necrotrophic effector (NE) ToxA. In this study, 144 Ptr isolates collected from durum, winter bread wheat, and grasses in western Canada were evaluated for race classification on a host differential set. The susceptibility of 114 durum

Abstract Wheat leaf rust, caused by Puccinia triticina Eriks., is a common and destructive disease of wheat worldwide. The durable leaf rust resistance gene Lr34 is typically described as an adult plant resistance gene, which is not expressed at the seedling stage at normal greenhouse temperatures. However, Lr34 is expressed at the seedling stage when plants with Lr34 are grown at low temperatures

Abstract Plants, unlike animals, lack specialized mobile immune cells, so they do not have an adaptive immune system. Instead, plants can launch specific, self-tolerant immune responses and establish immune memory. Plants possess defence mechanisms that efficiently detect and ward off potentially dangerous microorganisms. These defence mechanisms start with multiple signalling processes responsible

Abstract Plants of the cannabis (Cannabis sativa, marijuana) strain ‘Chronic Ryder’ grown outdoors in the Fraser Valley of British Columbia (BC) displayed symptoms of powdery mildew in late July 2019. The disease progressed rapidly under cool, wet conditions to infect leaves, stems, shoot tips and inflorescences by early September. To identify the pathogen, DNA was extracted from healthy and diseased

Abstract Puccinia striiformis f. sp. tritici (Pst) causes wheat stripe rust (also called yellow rust, Yr), one of the most important diseases worldwide. Characterization of virulence in Pst populations is essential for developing wheat cultivars with effective and durable resistance to control the disease. A total of 138 Pst races, including 120 races that were not previously reported, were identified

Abstract Colletotrichum lentis is an important pathogen of lentils in Canada causing the disease anthracnose. Fungicide applications are an important tool for the control of this disease and, historically, QoI fungicides have been used intensively. Reduced field efficacy of QoI fungicides on C. lentis has been reported recently and could be linked to the presence of QoI resistant isolates. In this

Abstract Cannabis (Cannabis sativa L., marijuana) plants with symptoms of crown rot, root decay, wilting and plant death were sampled during 2018 and 2019 from seven production greenhouses. Affected tissues from 140 diseased plants were surface-sterilized and plated onto potato dextrose agar. Ninety-five isolates morphologically resembling Pythium species were subcultured and subjected to PCR of the

Abstract Late blight caused by Phytophthora infestans is a serious threat to potato production. Currently, solutions to manage late blight in organic systems are scare. This study was undertaken to evaluate the effect of selenium (Se) on plant emergence from seed pre-treated with Se and the seed decay pathogens Pectobacterium carotovorum ssp. carotovorum and Fusarium sambucinum, and on foliar potato

Abstract In August 2018, rust was observed on onions (Allium cepa) grown in Dalseong, South Korea. In the field where the rust occurred, the disease incidence exceeded 60%. The urediniospores produced on diseased leaves were globose to ellipsoid and 20‒30 × 20‒28 μm in size. They had a thick outer wall (1‒2 μm) and many spines were apparent on the surface under light microscopy. When the uredinium

Abstract Plasmodiophora brassicae Woronin, the cause of clubroot of crucifers, is now established across most of Alberta, Canada, and has become a major constraint in canola (Brassica napus L.) production. Disease control is achieved mainly by planting clubroot resistant (CR) canola varieties. The first CR canola in Canada was released in 2009. In 2013, severe clubroot was detected on CR canola in

Abstract The oil palm (Elaeis guineensis) is a very important source of vegetable oil worldwide. While oil palm cultivation is not currently economically significant in Brazil, there is immense growth potential for this crop in the Amazon region, with no need for deforestation. Fatal yellowing (FY) is a major phytosanitary barrier to the development of oil palm cultivation in the region. Many plantations

Abstract Virus and virus-like diseases are major production constraints in vegetatively propagated crops; once a plant is infected, it remains so throughout its life. This work was undertaken to accelerate the process of eliminating apple chlorotic leaf spot virus (ACLSV) from ex-plants obtained from an infected plum tree, by in vitro heat therapy combined with meristem tip culture. After a minimum

Abstract Clubroot, caused by Plasmodiophora brassicae, is an important soilborne disease of canola (Brassica napus) in Alberta, Canada. As clubroot prefers acidic soils, the application of lime to increase soil pH may reduce disease. Replicated field plot experiments were conducted to evaluate the efficacy of hydrated lime for clubroot management. In 2017, moderate (11.4 t ha−1) to high rates (12.7

Abstract Macrophomina phaseolina is a polyphagous phytopathogenic fungus that causes serious yield losses of economically important crop plants. The most appropriate control measure for this fungus is the utilization of resistance sources. To achieve this, a fast and reliable screening method, in addition to a characterized pathogen population, is a prerequisite to accelerate breeding programmes. The

Abstract Bud rot pathogens cause diseases on Cannabis sativa L. (cannabis, hemp) worldwide through pre-and post-harvest infection of the inflorescence. Seven indoor or outdoor cannabis production sites and three hemp fields were sampled for bud rot and stem canker presence during 2019-2020. Among 178 isolates recovered from diseased tissues, sequences of the ITS1-5.8S-ITS2 region of rDNA, the glyc

Abstract Pseudopyrenochaeta lycopersici is a soilborne fungus causing corky root of tomato. The slow growth and poor sporulation of the pathogen make its isolation difficult. Isolates of the fungus are classified into types 1 and 2, with many different physiological and molecular characteristics between both types. In general, mating type genes enable mating ability and sexual development. The type

Abstract Root rot is an important disease of the medicinal plant Atractylodes macrocephaly (bai zhu) in China. This study evaluated an antagonistic fungal agent, Trichoderma brevicompactum, as an alternative to chemical pesticides for control of root rot caused by Fusarium oxysporum. The inhibitory effect of T. brevicompactum on F. oxysporum was examined in dual-culture experiments, with mycelial growth

Abstract Histological investigations elucidate infection structure development and the subsequent colonization process of rust pathogens in their cereal hosts. No comprehensive information exists for the infection process of the wheat stem rust fungus, Puccinia graminis f. sp. tritici (Pgt), on triticale, an amphiploid species carrying both the wheat and rye genomes. The adult plant stem rust response

Abstract The ability of an insect to vector a plant virus has been traditionally determined through controlled greenhouse transmission experiments that are notoriously resource and time-consuming and of unreliable outcome. Therefore, before committing to these protracted experiments, it is important that researchers identify biologically viable candidate vectors. This research presents an approach

(2021). Outstanding Young Scientist Award The Canadian Phytopathological Society-----------Prix du jeune scientifique exceptionnel La Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 43, No. 2, pp. 323-325.

(2021). Achievements in Plant Disease Management The Canadian Phytopathological Society-----------Réalisations en gestion des maladies végétales La Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 43, No. 2, pp. 326-328.

(2021). Outstanding Research Award The Canadian Phytopathological Society-----------Prix d’excellence scientifique La Société canadienne de phytopathologie. Canadian Journal of Plant Pathology: Vol. 43, No. 2, pp. 329-331.

(2021). British Columbia regional meeting, 2020/Réunion régionale de la Colombie-Britannique, 2020. Canadian Journal of Plant Pathology: Vol. 43, No. 2, pp. 332-338.

(2021). Southwestern Ontario regional meeting, 2020 / Réunion régionale du sud-ouest de l’Ontario, 2020. Canadian Journal of Plant Pathology: Vol. 43, No. 2, pp. 339-343.

Abstract Stem and bulb nematodes (Ditylenchus dipsaci) are plant parasites that can cause severe damage to garlic crops in Ontario, Canada, and other garlic growing regions. Accurate soil sampling is important to determine the risk of nematode damage before planting garlic in a field. However, it is not clear where the nematode is most concentrated in the soil profile or how the nematode is best extracted

Abstract Blossom blight of alfalfa, caused by Botrytis cinerea and Sclerotinia sclerotiorum, can be an important constraint to alfalfa seed production on the Canadian Prairies. Botrytis cinerea is the predominant pathogen in rain-fed production areas across the northern Prairie region. This study assessed the optimum conditions for infection of alfalfa florets by B. cinerea, and susceptibility in alfalfa

Abstract Stem rot (Nakataea oryzae) limits rice (Oryza sativa) production in Uruguay when there are high inoculum levels in the soil. This disease is particularly damaging in potassium (K) deficient soils that receive excessive nitrogen (N) fertilization. Nevertheless, no data exist for the response to stem rot in modern rice cultivars with respect to the interaction between balanced N and K fertilization

Abstract Colletotrichum higginsianum is an economically important anthracnose pathogen of crucifers that causes losses worldwide. For comprehensive control of anthracnose disease, it is essential to understand the mechanisms of pathogenicity in C. higginsianum. A Ser/Thr kinase Sch9 belonging to the AGC (protein kinase A, G, and C) kinase family, commonly found in eukaryotes, plays a vital role in

Abstract The genus Exobasidium includes a number of species that are pathogenic on members of the Ericales, including blueberries (Vaccinium spp.), and Exobasidium leaf spot is an emerging concern for commercial blueberry production. Atypical Exobasidium leaf spot-like symptoms were observed on wild V. angustifolium (lowbush blueberry) in eastern Newfoundland and Labrador, Canada, beginning in 2016

Abstract White pine blister rust, caused by the fungus Cronartium ribicola J. C. Fisch., is a virulent mortality agent of five-needle pines like western white pine (Pinus monticola D. Don.). For decades, low branch pruning has been recommended as a control by removing cankers that can migrate from infected branches to the tree stem and kill the host. These recommendations are mainly based on studies

Abstract Sweet cherries (Prunus avium) are an economically important crop in British Columbia, Canada. Cherries are harvested and distributed locally and overseas, where seemingly healthy fruit can succumb to postharvest diseases if disease conditions are met. Disease mitigation includes pre-harvest controls such as disease prediction models, disease monitoring, and fungicide application. Developing

Abstract Powdery mildew caused by Blumeria graminis f. sp. tritici (Bgt) is a major disease of wheat (Triticum aestivum) in Ontario, which can cause 20% yield loss. The development of resistant commercial wheat cultivars is the most economical means of controlling this disease, but only if the resistance genes used are incompatible with the virulence phenotypes present in the pathogen population. The

Abstract The interaction between the stem and bulb nematode, Ditylenchus dipsaci, and the causal agent of basal rot of garlic, Fusarium oxysporum f. sp. cepae (Foc), was studied in controlled environment trials. Inoculations with the individual pathogens, simultaneous inoculation and sequential inoculations (one pathogen applied 7 d before the second pathogen) were investigated for effects on disease

Abstract Stripe (yellow) rust, caused by the biotrophic fungal pathogen Puccinia striiformis f. sp. tritici (Pst), is emerging as a serious threat to wheat (Triticum aestivum L.) production in many regions of North America. Genetic resistance to stripe rust is typically conditioned by the products of resistance genes that detect pathogen-associated molecular patterns and initiate a cascade of signaling

Fungi Canadenses No. 350: EPICHLOË GLYCERIAE. Canadian Journal of Plant Pathology. Accepted 16 March 2021.

Abstract Fusarium head blight (FHB) has a negative impact on cereal food safety, quality and yield. The majority of FHB resistance genes in wheat (Triticum spp.) have been identified based on reaction to Fusarium graminearum, which, in Canada, has two prevalent trichothecene chemotypes, 3-acetyl-deoxyinvalenol (ADON) and 15-ADON. Three hexaploid (Triticum aestivum L.) and four tetraploid (Triticum

Abstract Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a major disease of wheat. In Kenya, Pgt has caused sporadic but serious losses to farmers since large-scale wheat production began in the early 20th Century. Breeding for stem rust resistance in Kenya has been conducted since 1910. Mutants of Pgt are common in Kenya as large pathogen populations survive on wheat crops planted

Abstract Fusarium basal rot is a major disease of onion production in Mexico. Recently, Fusarium falciforme and F. brachygibbosum were reported as two new causal agents of basal rot of onion in Mexico. However, little is known about the pathogenicity and virulence of these pathogens on this crop globally. The virulence (severity of disease) of F. falciforme and F. brachygibbosum isolates recovered

Abstract Alternaria panax (sect. Panax) is reported to be the main causal agent of alternaria blight on ginseng (Panax ginseng) in Asia. However, the species distribution causing ginseng alternaria blight in China has not been examined since 1964. Two hundred fifty-seven Alternaria isolates were obtained from 2015 to 2019 from 13 ginseng-producing areas in Jilin province, China. Based on morphological

Abstract Tomato spotted wilt virus (TSWV) infecting chrysanthemum (Dendranthema grandiflora L.) has been identified as a major constraint for chrysanthemum cut-flower industries in Southern India. The disease symptoms include veinal necrosis, necrotic spots on leaves, deformed flowers, and stem necrosis. The presence of TSWV in chrysanthemum plants collected from farms at Kotagiri, Nedugula, and Yercaud

Abstract Clubroot, caused by Plasmodiophora brassicae Woronin, is an important soilborne disease of canola (oilseed rape; Brassica napus L.). In Canada, clubroot management relies heavily on the planting of resistant cultivars, but since 2013, resistance has been broken in an increasing number of fields. Prior to the introduction of resistance, P. brassicae pathotype 3H, as defined on the Canadian

Abstract Mango malformation disease caused by Fusarium spp. is one of the main limiting factors for mango production in Mexico. Fungal isolates obtained from symptomatic tissue from mango trees in Sinaloa, Mexico, were subjected to phylogenetic analysis of the TEF-1α gene, and evaluated for mating type, morphological markers and pathogenicity. Fifteen monosporic Fusarium isolates were identified as

Abstract Wheat leaves infected with Puccinia triticina, the causal agent of wheat leaf rust, were collected annually throughout Canada from 2015 to 2019. There were 47, 75, 44, 38 and 54 different virulence phenotypes, respectively, found annually, representing 154 unique virulence phenotypes. From Alberta, there were three virulence phenotypes, MBDS, TDBJ, and TDBS, found in 2015 and eight in 2019

Abstract Wheat leaves infected with Puccinia triticina, the causal agent of wheat leaf rust, were collected annually throughout Canada from 2015 to 2019. There were 47, 75, 44, 38 and 54 different virulence phenotypes, respectively, found annually, representing 154 unique virulence phenotypes. From Alberta, there were three virulence phenotypes, MBDS, TDBJ, and TDBS, found in 2015 and eight in 2019

Achievements in Plant Disease Management - The Canadian Phytopathological Society / Réalisations en gestion des maladies végétales - La Société canadienne de phytopathologie. Canadian Journal of Plant Pathology. Accepted .

Abstract Pythium spp. are the most common pathogens associated with soybean damping-off in the United States. The diversity of Pythium spp. recovered is extensive and the relative pathogenicity or aggressiveness of species common across states has varied among studies. We compared the aggressiveness and fungicide sensitivity of 118 isolates of four Pythium spp. (P. lutarium, P. oopapillum, P. sylvaticum

Abstract Botrytis blight is an economically important disease of lowbush blueberry that causes significant yield loss annually. In this study, the biofungicides, Diplomat 5SCⓇ (polyoxin D), Timorex GoldⓇ (tea tree oil), FractureⓇ (BLAD) and Serenade MAXⓇ (Bacillus subtilis) were evaluated for their disease suppression potential against B. cinerea individually and in rotation with Switch® (cyprodinil

Abstract Greenhouse-grown cannabis (Cannabis sativa L., marijuana) plants with yellowing, crown rot and root-browning symptoms were sampled from six production facilities during 2019–2020. Among 34 fungal isolates recovered, 28 were identified as Fusarium solani and six isolates were provisionally identified as Cylindrocarpon sp. based on morphology. These latter isolates produced slow-growing colonies