First report of Apple bitter rot caused by in Ontario.

Bitter rot is an emerging disease of apple () fruit in Ontario in part due to changing weather conditions. The disease was mostly documented in warm and humid regions such as the southern USA, and Central and South America. Thirteen Ontario orchards in the fall of 2019 and 15 in 2020 were scouted for bitter rot based on their previous history of the disease.

Influence of plant species, mycorrhizal inoculant, and soil phosphorus level on arbuscular mycorrhizal communities in onion and carrot roots.

Arbuscular mycorrhizal fungi (AMF) are ancient and ecologically important symbionts that colonize plant roots. These symbionts assist in the uptake of water and nutrients, particularly phosphorus, from the soil. This important role has led to the development of AMF inoculants for use as biofertilizers in agriculture.

Characterization of a virulence factor in Plasmodiophora brassicae, with molecular markers for identification.

Symptom severity on differential host lines is currently used to characterize and identify pathotypes of Plasmodiophora brassicae, which is an obligate, soil-borne chromist pathogen that causes clubroot disease on canola (Brassica napus) and other brassica crops. This process is slow, variable and resource intensive; development of molecular markers could make identification of important pathotypes faster and more consistent for deployment of cultivars with pathotype-specific resistance. In the current study, a variant of gene 9171 was identified in the whole-genome sequences of only the highly virulent pathotypes of P.

Stemphylium Leaf Blight: A Re-Emerging Threat to Onion Production in Eastern North America.

Stemphylium leaf blight (SLB), caused by , is a foliar disease of onion worldwide, and has recently become an important disease in the northeastern United States and Ontario, Canada. The symptoms begin as small, tan to brown lesions on the leaves that can progress to defoliate plants. Crop loss occurs through reduced photosynthetic area, resulting in smaller, lower-quality bulbs.

Risk assessment of secondary metabolites produced by fungi in the genus .

The fungal genus (phylum Ascomycota, teleomorph ) includes plant pathogenic, endophytic, and saprophytic species with worldwide distributions. spp. produce prodigious numbers of airborne spores, so are a human health concern as allergens.

Entomopathogenic nematodes for control of carrot weevil: efficacy and longevity in muck and mineral soils.

Background: Carrot weevil is an important pest throughout carrot-producing regions in Canada. Pesticides to control carrot weevil adults require application when the majority of adults have emerged and often this occurs after oviposition has already commenced and damage will be realized. One alternative to conventional pesticides are entomopathogenic nematodes.

The Role of Ascospores and Conidia, in Relation to Weather Variables, in the Epidemiology of Stemphylium Leaf Blight of Onion.

Stemphylium leaf blight (SLB), caused by , is an important foliar disease of onion in northeastern North America. The pathogen produces conidia and ascospores, but the relative contributions of these spore types to epidemics in onion is not known. Determining the abundance of ascospores and conidia during the growing season could contribute to a disease forecasting model.

Oviposition, Feeding Preferences and Distribution of Species (Diptera: Anthomyiidae) in Eastern Canadian Onions.

and are three root maggot species commonly considered pests in Eastern Canadian onions. The onion maggot, is considered the primary root maggot pest in onion but it remains unclear whether the other two species are also causing damage. In order to develop updated management strategies for root maggot, we tested adult oviposition and feeding preference by larvae on four growth stages of onion using bioassays and we determined the species composition across the four major onion growing regions in eastern Canada.

Evaluation of the TOM-CAST Forecasting Model in Asparagus for Management of Stemphylium Leaf Spot in Ontario, Canada.

In the last 5 years, asparagus acreage in Canada has increased by over 25%. Stemphylium leaf spot, caused by Stemphylium vesicarium, has emerged as the predominant foliar pathogen of asparagus. Typically, contact fungicides are applied every 14 days; however, regardless of the number of applications, growers are not achieving adequate control of the disease.

The Impact of the Carrot Rust Fly and Carrot Weevil Integrated Pest Management Program on the Ground-Dwelling Beetle Complex in Commercial Carrot Fields at the Holland Marsh, Ontario, Canada.

Carrot rust fly (CRF), Psila rosae (Fabricius, 1794) (Psilidae: Diptera) and carrot weevil (CW), Listronotus oregonensis (Le Conte, 1857) (Curculionidae: Coleoptera) are economic pests of carrot; larval tunneling on roots results in direct damage rendering the carrot unmarketable. The Holland Marsh in Ontario, Canada, is a major carrot production area. The ground-dwelling beetle (Coleoptera) fauna in commercial carrot fields in this region has not been described.

Proteomic Profiles of Adipose and Liver Tissues from an Animal Model of Metabolic Syndrome Fed Purple Vegetables.

Metabolic Syndrome (MetS) is a complex disorder that predisposes an individual to Cardiovascular Diseases and type 2 Diabetes Mellitus. Proteomics and bioinformatics have proven to be an effective tool to study complex diseases and mechanisms of action of nutrients. We previously showed that substitution of the majority of carbohydrate in a high fat diet by purple potatoes (PP) or purple carrots (PC) improved insulin sensitivity and hypertension in an animal model of MetS (obese Zucker rats) compared to a control sucrose-rich diet.

The Effect of Anthocyanin-Rich Purple Vegetable Diets on Metabolic Syndrome in Obese Zucker Rats.

Consumption of highly colored fruits and vegetables rich in anthocyanins has been associated with numerous health benefits. Purple carrots (PC) and purple potatoes (PP) have higher anthocyanin concentrations and higher biological activities compared with less pigmented cultivars. We hypothesized that substitution of the majority of carbohydrate in a high fat diet with PP or PC, for 8 weeks, would improve insulin resistance and hypertension, major components of metabolic syndrome, compared with orange carrots (OC), white potatoes (WP) or a control, high fat, sucrose-rich diet (HFD) in obese Zucker rats.

Propidium Monoazide Improves Quantification of Resting Spores of Plasmodiophora brassicae with qPCR.

Plasmodiophora brassicae, which causes clubroot of Brassica crops, persists in soil as long-lived resting spores. Quantitative polymerase chain reaction (qPCR) analysis is often used to quantify resting spores but does not distinguish between DNA of viable and nonviable spores. The impact of pretreating spores with propidium monoazide (PMA), which inhibits amplification of DNA from nonviable microorganisms, was assessed in several experiments.

Identification of Genome-Wide Variants and Discovery of Variants Associated with Brassica rapa Clubroot Resistance Gene Rcr1 through Bulked Segregant RNA Sequencing.

Clubroot, caused by Plasmodiophora brassicae, is an important disease on Brassica species worldwide. A clubroot resistance gene, Rcr1, with efficacy against pathotype 3 of P. brassicae, was previously mapped to chromosome A03 of B.

A Multiplex qPCR Assay for Detection and Quantification of Plasmodiophora brassicae in Soil.

Various physical and chemical factors in soil can inhibit the detection and quantification of soilborne plant pathogens using quantitative polymerase chain reaction (qPCR) assays. A multiplexed TaqMan qPCR assay, including a competitive internal positive control (CIPC), was developed to identify and (where necessary) compensate for inhibition in the quantification of resting spores of Plasmodiophora brassicae from soil. The CIPC amplicon was developed by modifying a sequence coding for green fluorescent protein so that it could be amplified with P.

The Role of Primary and Secondary Infection in Host Response to Plasmodiophora brassicae.

The disease cycle of Plasmodiophora brassicae consists of a primary phase in root hairs followed by a secondary phase in the root cortex and adjacent tissues. However, the role of root hair infection in subsequent cortical infection and development of P. brassicae is not well understood.

Reaction of Lines of the Rapid Cycling Brassica Collection and Arabidopsis thaliana to Four Pathotypes of Plasmodiophora brassicae.

The clubroot reaction of five Rapid Cycling Brassica Collection (RCBC) lines (Brassica carinata, B. juncea, B. napus, B.

Effect of temperature on cortical infection by Plasmodiophora brassicae and clubroot severity.

A study was conducted to assess the effect of temperature on infection and development of Plasmodiophora brassicae in the root cortex of Shanghai pak choy (Brassica rapa subsp. chinensis) and on subsequent clubroot severity. Ten-day-old seedlings were grown individually, inoculated with resting spores, and maintained in growth cabinets at 10, 15, 20, 25, and 30?C.

Management of Botrytis Leaf Blight of Onion: The Québec Experience of 20 Years of Continual Improvement.

Botrytis leaf blight (BLB) of onion (Allium cepa) is caused by Botrytis squamosa. The disease has been reported on onion crops in several of the onion production areas of the world including North and South America, Europe, Asia, and Australia, although it is not a problem in arid production regions such as the western United States. In eastern Canada, the disease is generally present every year and is especially severe on cultivars of yellow globe onion.

Effect of Foliar Trimming and Fungicides on Apothecial Number of Sclerotinia sclerotiorum, Leaf Blight Severity, Yield, and Canopy Microclimate in Carrot.

Foliar trimming of the carrot canopy has potential for reducing the severity of Sclerotinia (Sclerotinia sclerotiorum) rot of carrot (Daucus carota subsp. sativus). The effect of trimming the carrot foliage once or twice, with and without fungicide application, was examined on carrot plants grown on organic soil for 3 years at the University of Guelph-Muck Crops Research Station in Ontario, Canada.

S-alk(en)yl-L-cysteine sulfoxides and relative pungency measurements of photosynthetic and nonphotosynthetic tissues of Allium porrum.

Three standard assays for pyruvate gave equivalent measurements of relative pungency for two leek cultivars ( 'Tadorna' and 'Ramona'). Background pyruvate levels varied depending on the assay used, ranging from 0.4 (lactate dehydrogenase) to 1.

Lateral Clipping of Canopy Influences the Microclimate and Development of Apothecia of Sclerotinia sclerotiorum in Carrots.

Four canopy management treatments were evaluated in carrot (Daucus carota) production in Bradford Marsh, Ontario, in 2001 and 2002: (i) unclipped control; (ii) unclipped canopy with manual removal of collapsed senescing leaves at 2-week intervals following the first appearance on the soil; (iii) lateral clipping of the canopy at the initial emergence of apothecia, leaving the debris in the furrow, and (iv) lateral clipping of the canopy with manual removal of the debris from the furrow. Clipping reduced the canopy width by ca. 20% on both sides of the carrot bed by cutting off overlapping leaves above the furrow and senescing foliage on the soil surface.