Abstract Theobroma cacao L. is cultivated in Mexico, primarily in Tabasco, a southern state where the climatic conditions are suitable for producing cacao, the source of chocolate. However, these conditions are also suitable for cacao pathogens such as Phytophthora spp., the causative agents of black pod rot, a disease that is difficult to eradicate once established. In this study, we collected cacao

Abstract Under cool and wet conditions, high levels of botrytis grey mould (BGM) can occur on lentil in western Canada. Identification of local Botrytis isolates from lentil based on conidial morphology (N = 74) and sequence analysis (N = 5) indicated that B. cinerea was the predominant cause of BGM in this region. Eight field experiments at two sites (Saskatoon, SK and Outlook, SK) over two seasons

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 Mycosphaerella blight, caused by Peyronellaea pinodes (Berk. & A. Bloxam) Aveskamp, Gruyter & Verkley (syn. Mycosphaerella pinodes (Berk. et Blox.) Vesterg.), is a destructive foliar pathogen of field pea that is managed, in large part, through application of foliar fungicide at flowering. The fungicides are usually applied into dense crop canopies, so reaching the lower areas of the canopy

Abstract Chickpea (Cicer arietinum L.) is an important food legume worldwide, providing a source of high quality protein. Fifteen chickpea samples showing leaf yellowing and root rot were obtained from southern Alberta, Canada, in 2018. Twenty single-spore Fusarium isolates were obtained from those samples. Based on the morphological characteristics, five species of Fusarium were identified, with F

Abstract Wasabi (Wasabia japonica (Miq.) Matsum) plants are grown over a period of 12-18 months for their valuable rhizomes, and pathogens infecting the rhizome are of economic importance for producers. During 2016 and 2017, symptoms of wilting and internal vascular blackening of rhizomes were observed in two greenhouses in British Columbia, with disease incidence in the range of 5-10%. Isolates recovered

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

Abstract A greenhouse pot study was conducted on four cover crops (annual ryegrass, perennial tetraploid ryegrass, winter wheat cv. ‘Caledonia’ and sorghum-sudangrass) and one rotation crop (sweet corn cv. ‘Sheba’) to compare the efficiency of these crop species as hosts of Paratrichodorus minor (Colbran) Siddiqi, and the ability of the nematodes to acquire tobacco rattle virus (TRV) from roots of

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 2015–2019 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 Cherry trees (Cerasus pseudocerasus (Lindl.) Loudon) in Bai Lu Yuan, Shaanxi Province, China, are susceptible to a serious disease that causes substantial economic losses. The pathogens causing this disease, designated black spot disease, are currently unknown. To identify the relationship between microbial community structure and the status of plant health, we obtained samples from the rhizosphere

Abstract Cercospora canescens Ellis & Martin is an important fungal pathogen that causes leaf spot and defoliation in mungbean (Vigna radiata (Linn.) Wilczek.). Molecular methods for detection of this pathogen have not yet been developed. In this study, we developed a real-time and visual loop-mediated isothermal amplification (LAMP) assay based on the cytochrome b (cytb) gene to detect C. canescens

Abstract Fusarium head blight (FHB) is a major fungal disease that contributes to severe economic losses for wheat and barley production in Canada and other parts of the world. Rapid developments in molecular biology over the past three decades have improved the ability to devise predictive management tools to combat the effects of the disease. Important aspects of Fusarium species in terms of the

Abstract Powdery mildew on cannabis (Cannabis sativa L., marijuana), caused by Golovinomyces cichoracearum, reduces plant growth and overall quality. To investigate disease management options, biological, chemical and physical approaches were assessed. A mildew-susceptible strain, ‘Copenhagen Kush’, was grown indoors with continual exposure to mildew inoculum. Treatments were applied weekly over a

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

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

Abstract Wheat is affected by many fungal diseases that can cause severe yield and quality losses. Disease prediction models generally employ weather data to estimate potential for infection to determine timing for fungicide applications, but these models fail to account for the presence and quantity of pathogen inoculum. This study adapted highly specific qPCR primers to identify and quantify, in

Abstract Rhynchosporium commune, the cause of barley scald, is an important disease of barley in Canada. Multiple studies have indicated that cryptic sexual reproduction may occur between opposite mating types (MAT1-1 and MAT1-2). The occurrence of R. commune mating types in Canada has not been determined previously. Infected leaves from barley cultivars in seven commercial fields and three breeding

Abstract Stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), has potential to cause major yield losses in durum wheat. Development of durum cultivars with improved resistance to stem rust is a sustainable option for effective control of this disease. The present study was conducted to identify genomic regions associated with resistance to Ug99-derived Pgt races using a doubled haploid (DH)

Abstract Field surveys indicate blackleg of canola has increased in western Canada since 2010. Earlier studies showed changes in the pathogen (Leptosphaeria maculans (Sowerby) P.Karst.; Lm) population between 2007 and 2010–2011. In this study, Lm isolates were collected from trap plots (591) and/or commercial fields (372) on the prairies between 2012 and 2014, and tested for the profile of avirulence

Abstract Florida or Cuban royal palm (Roystonea regia (Kunth) O.F. Cook) is an important ornamental plant with many uses for humans. Royal palm trees grown in Muscat, Oman, were found exhibiting leaf yellowing, leaf decay starting on the mature leaves, and leaf stunting. Trunk tissue samples were collected and analysed with nested and semi-nested PCR assays for the 16S rRNA, translation elongation

Abstract Soybean plants showing symptoms of root rot were collected from fields in Manitoba, Canada, in 2017, to determine the causal agent of the disease. Of 240 isolated strains, including some known as root rot pathogens, five were identified as Fusarium sporotrichioides Sherb. based on morphological characteristics. All five isolates were pathogenic when inoculated on soybean under controlled conditions

Abstract Surveys of alfalfa (Medicago sativa L.) seed production fields on the Canadian Prairies from 1993 to 2017 demonstrated that epidemics of blossom blight caused by Botrytis cinerea Pers. and Sclerotinia sclerotiorum (Lib.) de Bary developed almost every year at some location(s). Blossom blight symptoms were prominent when epidemics were severe, but more difficult to identify when present at

Abstract Root rot is an important disease of field pea (Pisum sativum L.) on the Canadian Prairies. The composition and alternative crop hosts of fungal and oomycete communities colonizing pea residues from Alberta and Manitoba were studied in field trials over two years. Standing pea residues were sampled from diseased and asymptomatic patches of 17 commercial fields in 2013 and 2014 after harvest

Abstract Horse purslane (Trianthema portulacastrum L.) is a common weed in Mexico, where it competes with different agricultural crops and grows along watercourses, railways and roadsides, abandoned fields, and urban communities. In Sinaloa, this weed grows abundantly during the rainy season (July–September) and competes with summer crops such as corn and sorghum during the fall-winter season, and

Abstract The ascomycete fungi Dothistroma septosporum (Dorogin) M. Morelet and D. pini Hulbary are both responsible for Dothistroma needle blight disease (DNB) on pines. Using a DNA-barcoding approach, we confirmed that the DNB infection of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), jack pine (P. banksiana Lamb.) and their hybrid in four research sites in northern Alberta (Canada)

Abstract Stem rust is a major disease on barley, oat, and wheat crops worldwide. The primary means of control is by host resistance genes that are incorporated into commercial varieties and have been effective against most races of Puccinia graminis Pers., the causal pathogen. Since this pathogen continually mutates, analyzing the population virulence structure is crucial to detect new races with increased

Abstract Blackleg [Leptosphaeria maculans (Desm.) Ces. & de Not.] is the most widespread disease of canola (Brassica napus L.) on the Canadian prairies. It has a noticeably increased incidence in recent years possibly due to shifts in the pathogen population and erosion in cultivar resistance. This study was conducted to assess foliar-applied fungicides for mitigating the risk of blackleg. Field trials

Abstract Clubroot disease caused by Plasmodiophora brassicae Woronin is one of the most devastating diseases of canola (Brassica napus L.). Pathotype 3H has been the most prevalent and virulent pathotype in western Canada. Many resistant cultivars have been developed in Canada in recent years. However, large-scale cultivation of these cultivars resulted in the identification of several new virulent

Loofah [Luffa acutangula (L.) Roxb.] is grown in some regions of Asia, Africa and the Americas. This vegetable is well known for its high nutritional and medicinal value. Loofah plants showing typical symptoms of phytoplasma infection, such as witches’ broom, fruit deformation, flower proliferation and phyllody were observed in a commercial field in Sinaloa, Mexico, in January 2015. Nineteen symptomatic

Plasmodiophora brassicae causes clubroot on Brassica vegetables and canola around the world. A diverse assemblage of new pathotypes have been identified on canola in the Canadian province of Alberta since 2012, but the pathotypes present in the rest of Canada have not been assessed in detail in recent years. Brassica vegetable and canola fields in Ontario were surveyed for clubroot in 2017–2019. The

Symptoms of ringspots and vein-clearing were observed on wasabi (Wasabia japonica (Miq) Matsum) plants in three greenhouses in British Columbia during 2017. Ten indicator plant species, including four Nicotiana species, were inoculated with sap extracts from symptomatic leaves; after 4–11 days, necrotic lesions developed on all plants. Transmission electron microscopy revealed rod-shaped virions, 250–300 nm

Restrictions about the use of chemicals have limited the availability of control measures against plant-parasitic nematodes. The search for more sustainable approaches has focused the attention on biological control agents, such as Trichoderma species. In recent years, there has been a growing interest in the use of biopolymers for a wide range of applications. These polysaccharide-based compounds

Gray blight, caused by Pestalotiopsis-like species, is one of the most serious diseases in tea [Camellia sinensis (L.) O. Kuntze] production. In this study, eight Pestalotiopsis isolates obtained from diseased tea leaves collected in Chongqing, China were identified as P. chamaeropis Maharachch, K.D. Hyde & Crous. Pestalotiopsis chamaeropis as a causal agent of tea gray blight disease was clearly distinguished

(2020). Alberta Regional Meeting, 2019 / Réunion régionale de l’Alberta, 2019. Canadian Journal of Plant Pathology: Vol. 42, No. 3, pp. 445-452.

(2020). Atlantic regional meeting, 2019/Réunion régionale de l'Atlantique, 2019. Canadian Journal of Plant Pathology: Vol. 42, No. 3, pp. 453-457.

(2020). Southwestern Ontario regional meeting, 2019/Réunion régionale sud-ouest de l’Ontario, 2019. Canadian Journal of Plant Pathology: Vol. 42, No. 3, pp. 465-467.

Stemphylium leaf blight (SLB), caused by Stemphylium vesicarium (Wallr.) E.G. Simmons, has become an important disease of onion (Allium cepa L.) in Ontario, Canada, and the northeastern USA in recent years. The disease presents as elongated lesions on the leaves and severe leaf dieback. The effect on yield is unclear, but the extensive leaf dieback limits uptake of sprout inhibitors that are applied

Ornamental production systems are complicated to manage due to the many species and genera that may be grown and handled together on a single production site. Ornamentals are threatened by various phytopathogenic fungi in greenhouse and field production. Among these, Botrytis cinerea is one of the most notorious pathogens of ornamentals, specifically cut flowers. B. cinerea is responsible for causing

Smutted Bermudagrass (Cynodon dactylon L.) plants with diseased spikelets and completely deformed inflorescences covered with black teliospores were collected from five locations at the borders of plantations in Kafr El-Sheikh province, Egypt, in April 2018. The fungus was isolated from infected plants and identified as Ustilago cynodontis (Passerini) Henn. based on its cultural and morphological characteristics

Clubroot, a soil-borne disease caused by the obligate parasite Plasmodiophora brassicae Woronin, is a threat to canola (Brassica napus L.) production in western Canada. Genetic resistance represents the most effective tool to manage this disease. However, given the rapid spread of clubroot and the emergence of new virulent pathotypes of P. brassicae, it is important to accelerate the resistance breeding

Symptoms of partially bleached and completely white heads were observed in a triticale (× Triticosecale) cultivar ‘BARI Triticale 1ʹ in the research plots at the Regional Agricultural Research Station, Jashore, Bangladesh, during April 2019. Foliar symptoms with elliptical or eye-shaped lesions were also found on plant leaves. The main intention of this study was to isolate and identify the causal

Abstract Cannabis (Cannabis sativa L., marijuana) plants grown under greenhouse or controlled environments with symptoms of leaf yellowing, leaf necrosis and defoliation were observed during 2018–2019. Additional symptoms included crown rot and internal browning or blackening of the pith tissues. Stock (mother) plants as well as plants in the vegetative and flowering stages of 15 cannabis strains (genotypes)

The structure and diversity of wild grass spike-inhabiting Fusarium communities are not well understood. Fifteen common, non-cultivated grasses were surveyed across two years, regions, and land uses for spike-dwelling Fusarium spp. Eleven fungal species were identified from 857 isolates, including two, F. camptoceras and F. lactis, not recorded previously in New York state or on grass hosts. Species

Abstract Fusarium oxysporum causes root browning and crown infection on marijuana (Cannabis sativa L.) plants, resulting in stunted growth, yellowing of leaves, and plant death. Pathogen presence and diversity were assessed in samples of diseased crowns, stems, pith tissues and roots from five commercial production facilities in British Columbia and Ontario. PCR of the elongation factor (EF-1 α) region

Phytoplasmas are a major liming factor to the growth and production of many plant species worldwide. Most studies have used the conserved 16S rRNA gene for phytoplasma identification and classification. The efficiency of the tuf and secA genes length in the characterization of phytoplasmas was evaluated by designing universal primers to amplify the long and short tuf (740 bp and 414 bp) and secA (1232

Rhizomania is one of the most damaging and widespread diseases in the major sugar beet (Beta vulgaris L. subsp. vulgaris) growing regions worldwide. The causal agent, Beet necrotic yellow vein virus, is transmitted by a plasmodiophorid vector, Polymyxa betae Keskin. In this study, the inhibition of BNYVV multiplication was evaluated, under field conditions, in six sugar beet transgenic events generated

Fusarium species cause various diseases of tomato, the most common being vascular wilt and cortical rots. A study was carried out to characterize Fusarium spp. found in the stems of wilted tomato plants from farms in Mwea West Sub-county, Kirinyaga County, Kenya. Isolates were collected from tomato stems showing vascular discolouration. One hundred and one isolates of Fusarium spp. were obtained and

Root-knot nematodes are responsible for substantial losses in rice production. These parasites are difficult to control, particularly in flooded fields, which require carefully designed strategies to avoid contamination of water bodies. This study investigated whether biotic and abiotic elicitors can induce resistance to the root-knot nematode Meloidogyne graminicola in rice plants. An initial screening

Black rot, caused by Xanthomonas campestris pv. campestris (Pammel) Dowson (Xcc), is a devastating disease of cruciferous crops worldwide and a threat to the economic production of Brassica oleracea L. in China. Strategies to control this disease are limited. In addition, knowledge of the molecular mechanisms of pathogenicity and host resistance are still only poorly understood. In this study, we performed

Hybrid wheat shows promise to increase yield potential, but many questions remain about the hybrid system. One of the most important is how hybrids will perform in terms of diseases such as Fusarium head blight (FHB). It is unknown if a hybrid produced from a resistant by susceptible cross will express acceptable resistance levels. This experiment tested hybrids produced from four resistant parents

Abstract In two glasshouse experiments, colonization of potato (Solanum tuberosum L.) plants by the bacterial pathogens Dickeya solani and Pectobacterium parmentieri was studied after leaf infection. Leaves, whether or not artificially wounded, were spray-inoculated with various densities of green-fluorescent protein tagged strains of the pathogens, avoiding contamination of soil during inoculation

Powdery mildew on wasabi (Wasabia japonica (Miq.) Matsumura)plants reduces photosynthesis and severe infections can result in chlorosis and defoliation, resulting in reduced yields. Erysiphe cruciferarum Opiz ex L. Junell was confirmed as the causal agent using sequence analysis of the ITS1-5.8 S-ITS2 region, along with conidial and conidiophore morphology. To evaluate reduced-risk management options

Common bean (Phaseolus vulgaris L.) can be affected by several viral diseases, including golden mosaic caused by the Bean golden mosaic virus (BGMV). When infected by BGMV, bean plants undergo major physiological changes, leading to a reduction or complete loss of productivity. This study aimed to evaluate and compare seven bean cultivars and lineages, as well as the legume calopo (Calopogonium mucunoides

Clubroot of canola (Brassica napus L.), caused by Plasmodiophora brassicae Woronin, has spread to more than 3000 fields in Alberta, Canada, since it was first identified in 2003, but the disease had not been reported in the Peace Country Region in the northwest of the province. In 2017, 21 cases of clubroot were found in Big Lakes County, the southeastern-most district in this region. In 2018, an additional

This study aimed to evaluate the antifungal activity of oregano and clove essential oils and their main components (thymol, carvacrol and eugenol) against Penicillium digitatum, as well as against isolates of Penicillium italicum and Geotrichum candidum resistant to imazalil or guazatine, respectively. In vitro tests were conducted by a direct contact method on potato dextrose agar medium. The results

Abstract The objective of this study was to assess harvested dried inflorescences (buds) of cannabis (Cannabis sativa L., marijuana) for fungal presence and diversity. Samples from drying rooms of three licenced facilities in British Columbia were tested repeatedly during 2017–2019. A swab method was used, wherein sterile cotton swabs were gently swabbed over bud surfaces and directly streaked onto

(2020). British Columbia regional meeting, 2019 / Réunion régionale de la Colombie-Britannique, 2019. Canadian Journal of Plant Pathology: Vol. 42, No. 3, pp. 458-464.

Brown spot, caused by Septoria glycines Hemmi, is a highly prevalent foliar disease of soybean (Glycine max (L.) Merr.). Despite its wide distribution, the development of Septoria brown spot and its relationship with yield reduction remain poorly characterized. In this study, we conducted replicated multi-location inoculated field trials to characterize the disease development and evaluated the relationship

Downy mildew caused by Plasmopara viticola is a devastating disease of grapes. Four formae speciales have been identified in the pathogen, with P. viticola f. sp. aestivalis and P. viticola f. sp. riparia responsible for epidemics in eastern Canada. The objective of this study was to evaluate the effect of temperature on