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Oral squamous cell carcinoma (OSCC) has the characteristics of early regional lymph node metastasis. OSCC patients often have poor prognoses and low survival rates due to cervical lymph metastases. Therefore, it is necessary to rely on a reasonable screening method to quickly judge the cervical lymph metastastic condition of OSCC patients and develop appropriate treatment plans. In this study, the widely used pathological sections with hematoxylin-eosin (H&E) staining are taken as the target, and combined with the advantages of hyperspectral imaging technology, a novel diagnostic method for identifying OSCC lymph node metastases is proposed. The method consists of a learning stage and a decision-making stage, focusing on cancer and non-cancer nuclei, gradually completing the lesions' segmentation from coarse to fine, and achieving high accuracy. In the learning stage, the proposed feature distillation-Net (FD-Net) network is developed to segment the cancerous and non-cancerous nuclei. In the decision-making stage, the segmentation results are post-processed, and the lesions are effectively distinguished based on the prior. Experimental results demonstrate that the proposed FD-Net is very competitive in the OSCC hyperspectral medical image segmentation task. The proposed FD-Net method performs best on the seven segmentation evaluation indicators: MIoU, OA, AA, SE, CSI, GDR, and DICE. Among these seven evaluation indicators, the proposed FD-Net method is 1.75%, 1.27%, 0.35%, 1.9%, 0.88%, 4.45%, and 1.98% higher than the DeepLab V3 method, which ranks second in performance, respectively. In addition, the proposed diagnosis method of OSCC lymph node metastasis can effectively assist pathologists in disease screening and reduce the workload of pathologists.

Aphanomyces root rot (ARR) of field pea (Pisum sativum), caused by Aphanomyces euteiches, can cause severe root damage, wilting, and large yield losses under wet soil conditions. To identify ways to manage this disease, the effect of A. euteichesinoculum density on field pea was studied under greenhouse and field conditions in 2015 and 2016. Increases in inoculum density reduced seedling emergence, root nodulation, and plant vigor, and resulted in increased root rot severity in both field and greenhouse tests. Seed treatments with the fungicides Apron Advance (thiabendazole + fludioxonil + metalaxyl) + Vibrance (difenoconazole + metalaxyl-M + sedaxane), INTEGO Solo (ethaboxam), BAS 516F (boscalid + pyraclostrobin), BAS 720F (metalaxyl + pyraclostrobin + fluxapyroxad), and BAS 516F + BAS 720F (3:1) were evaluated for their efficacy against ARR. All seed treatments except Apron Advance + Vibrance reduced root rot severity under controlled conditions. BAS 516F, BAS 720F and INTEGO Solo improved plant vigor and all treatments reduced seedling blight to varying degrees under greenhouse conditions, but not in the field. A collection of 22 pea genotypes was evaluated for resistance to root rot in field plot experiments. Line 00–2067 showed the least severe root rot symptoms, whereas ‘Spring D’ showed the lowest reduction in yield. The results suggest that there may be an opportunity to combine partial host resistance and fungicidal seed treatments to adequately manage ARR of field pea.

Field pea (Pisum sativumvar. arvenseL.) is an important legume crop around the world. It produces grains with high protein content and can improve the amount of available nitrogen in the soil. Aphanomycesroot rot (ARR), caused by the soil-borne oomycete Aphanomyces euteichesDrechs. (A. euteiches), is a major threat to pea production in many pea-growing regions including Canada; it can cause severe root damage, wilting, and considerable yield losses under wet soil conditions. Traditional disease management strategies, such as crop rotations and seed treatments, cannot fully prevent ARR under conditions conducive for the disease, due to the longevity of the pathogen oospores, which can infect field pea plants at any growth stage. The development of pea cultivars with partial resistance or tolerance to ARR may be a promising approach to analyze the variability and physiologic specialization of A. euteichesin field pea and to improve the management of this disease. As such, the detection of quantitative trait loci (QTL) for resistance is essential to field pea-breeding programs. In this paper, the pathogenic characteristics of A. euteichesare reviewed along with various ARR management strategies and the QTL associated with partial resistance to ARR.

Field pea crops in central Alberta were surveyed for ascochyta blight from 2011 to 2012 and fungal isolates were recovered from foliar lesions on selected plants. Cultural and microscopic characterization of the 275 isolates obtained revealed that 272 were of Mycosphaerella pinodesand three were of Phoma medicaginisvar. pinodella. Ascochyta pisior Phoma koolungawere not identified. Isolates of M. pinodeswere divided into two groups, GI and GII, based on visual assessment of culture characteristics. GI isolates (light to dark, mostly gray colony color; pycnidial distribution radial and concentric; conidia 10.5–14.5×4.2–6.2μm most with one septum, occasionally two, constricted at the septum; spore mass light buff to flesh color) were predominant (83%), while GII isolates (dark to gray colony color; pycnidia abundant; conidia 8–16×3.5–6.2μm most with 1 septum, constricted at the septum; spore mass light buff to flesh color) were less common (17%). The cultures of GII isolates were similar to recent descriptions of A. pisi, but they differed in spore color. In a host differential study, 13 pathotypes of M. pinodeswere identified from 110 single-spore isolates. Pathotype I was predominant (88 isolates) and virulent on all nine differential genotypes. The other pathotypes (pathotypes II–XIII) were rare (1–6 isolates of each). Comparison of the present results with earlier studies suggests that pathotype I has been prevalent for many years, and that its aggressiveness on the host differentials has increased over time. Emphasis should be placed on breeding for resistance to M. pinodesin field pea cultivars intended for deployment in central Alberta.

Ascochyta blight, caused by Didymella rabiei, is one of the most important factors limiting chickpea production worldwide. In western Canada repeated applications of the strobilurin fungicide pyraclostrobin is relied upon for the control of ascochyta blight. Pyraclostrobin sensitivity of baseline population of D. rabieiobtained from Saskatchewan during 1997–2000 was determined. Based on colony growth the mean EC50value of the baseline isolates was 1.0 μg ml−1. Only one isolate out of 122 isolates collected in Alberta in 2007 was sensitive at the baseline EC50of pyraclostrobin. The mean EC50value of nine Alberta isolates collected in 2007 was determined to be 90.0 μg ml−1. Based on this EC50, among the 91 isolates of 2007 60% of the isolates were insensitive and 40% of the isolates were sensitive, while among the 2013 isolates 81.5% were insensitive and 18.5% were sensitive. Based on the spore germination method the mean EC50value of seven isolates collected in 2007 was 1.9 μg ml−1. Data revealed a 90x increase in the mean EC50value of the 2007 isolates compared to baseline isolates, suggesting a shift in the population structure towards higher insensitivity to pyraclostrobin in western Canada.

Mycosphaerella blight (Mycosphaerella pinodes) occurs throughout western Canada and can severely reduce seed yield and quality of field pea (Pisum sativum). Field experiments were conducted to assess the impact of seeding date and timing of epidemic initiation on the severity of mycosphaerella blight on field pea. Early seeding or early initiation of the epidemic (early July) resulted in the highest severity and area under disease progress curve of mycosphaerella blight at the end of the growing season. Plants seeded later in the growing season showed less severe symptoms of mycosphaerella blight compared to those seeded earlier, and the blight severity was declined by delaying 1–2 weeks of disease initiation. However, late seeding reduces yield potential offsetting the benefit of disease reduction. A greenhouse study on the effect of both plant and tissue age on susceptibility to mycosphaerella blight revealed that both whole plants and leaf tissues became more susceptible as they aged. We conclude that delay of epidemic initiation in late June to early July through the use of foliar fungicides is effective in reducing mycosphaerella blight severity on the Canadian prairies.

Mycosphaerella blight, caused mainly by Mycosphaerella pinodes(Berk. and Blox.) Vestergren, is the most important foliar disease on field pea (Pisum sativumL.) in western Canada. A quantitative trait analysis of resistance to M. pinodeswas undertaken on five crosses with reciprocals of P. sativumto examine broad‐sense (H2) and narrow‐sense (h2) heritability, minimum number of genes involved (MNG), midparent heterosis (MPH), cytoplasmic inheritance, and epistasis. Mean H2was 0.75 (range 0.67–0.80) and mean h2was 0.59 (range 0.41–0.70), indicating that additive variance is important and that improvement in resistance can be achieved through breeding. Mean MNG was 2.16 genes (range 0.06–6.22), indicating that genes for resistance differed among parent lines. Mean MPH was 50% (range 47–57%), indicating that heterosis did not influence the expression of resistance to M. pinodesThere was no difference between the mean of any F1population and its reciprocal, indicating lack of maternal inheritance. The mean of the epistatic points was −0.01 (range −0.1 to 0.12), indicating that epistasis was not important in these crosses. These results will further the understanding of the natural genetic diversity for disease resistance to M. pinodesin P. sativum

Comprehensive assessments of germplasm collections of field pea (Pisum sativumL.) have failed to identify any accessions that are highly resistant to Mycosphaerella blight, caused by Mycosphaerella pinodesIn the present study, the broad‐sense heritability of resistance to M. pinodeswas studied on 558 pea genotypes in a detached‐leaf assay and in field trials over 2 yr. In addition, analysis of covariance in disease reaction between the two assessment methods was examined. Only a few genotypes displayed relatively high levels of resistance, and as expected, no complete resistance was observed. The pattern of differences in reaction to M. pinodesamong the genotypes demonstrates that resistance is quantitative and moderately heritable. Broad‐sense heritability was higher in the detached‐leaf assays than in the field trials, likely because of more environmental variance in the field. Covariance between repetitions of the detached leaf assays was not significant but was significant between the field tests. This indicates that detached‐leaf assessments are more reliable for assessment of large numbers of accessions.

Foliar pathogens attack alfalfa wherever the crop is grown, but their impact, especially on seed production, is poorly understood. In greenhouse trials, leaf spot injury caused by inoculation with various pathogens reduced the crude protein content of infected alfalfa leaves by 22% compared with a healthy control. There was a negative relationship between disease injury and the photosynthetic efficiency of alfalfa plants, as determined by measuring chlorophyll fluorescence in leaves from inoculated vs. non-inoculated seedlings. In field trials at two sites in Alberta from 2001 to 2003, inoculation with Phoma medicaginisincreased disease incidence in four of six trials, Phoma sclerotioidesincreased incidence in four of five trials, and Leptosphaerulinatrifoliiand Stemphyliumbotryosumincreased incidence in two of six trials. There was a trend for inoculation treatments to reduce seed yield, despite high levels of background infection by indigenous pathogens. The fungicides benomyl and propiconazole inhibited radial growth of Phomaspp. in vitroand reduced disease incidence in inoculated greenhouse experiments. In field trials, applications of benomyl and propiconazole reduced disease incidence, but did not always increase seed yield.Foliar pathogens attack alfalfa wherever the crop is grown, but their impact, especially on seed production, is poorly understood. In greenhouse trials, leaf spot injury caused by inoculation with various pathogens reduced the crude protein content of infected alfalfa leaves by 22% compared with a healthy control. There was a negative relationship between disease injury and the photosynthetic efficiency of alfalfa plants, as determined by measuring chlorophyll fluorescence in leaves from inoculated vs. non-inoculated seedlings. In field trials at two sites in Alberta from 2001 to 2003, inoculation with Phoma medicaginisincreased disease incidence in four of six trials, Phoma sclerotioidesincreased incidence in four of five trials, and Leptosphaerulinatrifoliiand Stemphyliumbotryosumincreased incidence in two of six trials. There was a trend for inoculation treatments to reduce seed yield, despite high levels of background infection by indigenous pathogens. The fungicides benomyl and propiconazole inhibited radial growth of Phomaspp. in vitroand reduced disease incidence in inoculated greenhouse experiments. In field trials, applications of benomyl and propiconazole reduced disease incidence, but did not always increase seed yield.