Oomycete species occupy many different environments and many ecological niches. The genera Phytophthora and Pythium for example, contain many plant pathogens which cause enormous damage to a wide range of plant species. Proper identification to the species level is a critical first step in any investigation of oomycetes, whether it is research driven or compelled by the need for rapid and accurate diagnostics during a pathogen outbreak. The use of DNA for oomycete species identification is well established, but DNA barcoding with cytochrome c oxidase subunit I (COI) is a relatively new approach that has yet to be assessed over a significant sample of oomycete genera. In this study we have sequenced COI, from 1205 isolates representing 23 genera. A comparison to internal transcribed spacer (ITS) sequences from the same isolates showed that COI identification is a practical option; complementary because it uses the mitochondrial genome instead of nuclear DNA. In some cases COI was more discriminative than ITS at the species level. This is in contrast to the large ribosomal subunit, which showed poor species resolution when sequenced from a subset of the isolates used in this study. The results described in this paper indicate that COI sequencing and the dataset generated are a valuable addition to the currently available oomycete taxonomy resources, and that both COI, the default DNA barcode supported by GenBank, and ITS, the de facto barcode accepted by the oomycete and mycology community, are acceptable and complementary DNA barcodes to be used for identification of oomycetes.

he effect of chemicals and biotic inducers i.e., Bion [benzothiadiazole (BTH)], Salicylic acid (SA), Bacillus subtilis and Trichoderma harzianum as seed treatments of snap bean (Phaseolus vulgaris L. cv. Paulista.) compared to the fungicide Topsin M-70, were evaluated in the greenhouse and under field conditions during the two successive growing seasons 2016/2017 and 2017/2018 at Ashmoun, Menoufia Governorate, Egypt to control the white mold disease caused by Sclerotinia sclerotiorum (Lib.) de Bary. All the tested chemicals and biotic inducers treatments significantly reduced the percentages of pre-and post-emergence dampingoff compared with the untreated control under greenhouse conditions. The highest percentage of survived plants was achieved by Topsin M-70 and Bion, followed by B. subtilis, Salicylic acid, and T. harzianum. Activities of defense-related enzymes peroxidase (PO), polyphenoloxidase (PPO) enzymes, and phenol content were determined. Bion treatment showed the highest increase in PO and PPO activity and total phenols followed by B. subtilis, Salicylic acid, and T. harzianum treatments in the presence of S. sclerotiorum. In the two successive growing seasons under field conditions, all the tested chemicals and biotic inducers treatments reduced the percentage of white mold incidence and severity of the treated snap bean plants compared with the untreated control. The highest reduction of disease incidence and severity was recorded by Topsin M-70 followed by Bion, B. subtilis, Salicylic acid, and T. harzianum, respectively. As well as, all treatments significantly increased vegetative characteristics i.e., plant height, No. of branches/plant, plant fresh and dry weight, and yield parameters i.e., average pod weight (g) and yield (ton/fed). Furthermore, chemical composition of green pods showed a significant increase in protein and carbohydrates content (%) beside all minerals Nitrogen (N), Phosphorus (P) and Potassium (K) content as compared with the untreated control in the two growing seasons.

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Cucumber powdery mildew disease caused by Podosphaera xanthii (Castagne) U. Braun & Shishkoff severe disease-causing yield losses worldwide. This research study was conducted to evaluate the efficacy of the tested bio-agents, Trichoderma harzianum, T. viride, Bacillus subtilis, Paenibacillus polymyxa, and Serratia marcescens, as well as the fungicide score (Difenoconazole), on cucumber infected with P. xanthii, in vitro and under greenhouse conditions. Results indicated that culture filtrate of the tested bio-agents and the fungicide (control) significantly reduced P. xanthii conidial germination in vitro; the reduction percentage ranged between 91.17 and 76.06%. Also, score recorded the highest reduction percentage (97.19%). All treatments significantly decreased the disease severity and area under disease progress curve (AUDPC) post spraying the bio-agents on cucumber plants under greenhouse conditions. Score followed by B. subtilis significantly decreased disease severity percentage (67.33 and 65.38%, respectively) and AUDPC (322.84 and 342.06) than the untreated control (988.13 AUDPC). Additionally, treated cucumber plants showed a significant increase in plant growth parameters (plant height, total chlorophyll, fresh, and dry weight) and yield parameters (fruit number/plant and fruit weight/plant) as well the activity of defense-related enzymes, i.e., peroxidase (PO) and polyphenol oxidase (PPO), and total phenols content (TPC) compared to the untreated plants.

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amping-off and root-rot are important diseases attacking chickpea (Cicer arietinum L.) in Egypt. The effect of biofumigation, using mustard (Brassica juncea) and canola (Brassica napus) seed meals were evaluated to control damping-off and root-rot diseases of chickpea in vitro and in vivo (under greenhouse and field conditions trials) conducted in Sers-Ellian

Damping-off and root-rot are some of the most important diseases attack soybean (Glycine max (L.) Merr.) in Egypt. The effect of biocides, i.e. Bio-Cure-F, Plant guard, and Rhizo-N, and essential oils of eucalyptus, thyme, and lemongrass oils, as well as the fungicide Vitavax-200, were evaluated in vitro, greenhouse and under field conditions during the two successive growing seasons, 2018 and 2019 to control damping-off and root-rot diseases of soybean. All the tested biocides and essential oils used significantly inhibited the linear growth of the tested pathogenic fungi, i.e., Fusarium moniliforme, Fusarium solani and Rhizoctonia solani compared with the control. Under greenhouse and field conditions in both growing seasons, obtained results indicated that all the tested biocides and essential oils significantly reduced the percentages of soybean damping-off and root-rot severity furthermore improved photosynthetic pigments content, growth parameters, and seed yield. Vitavax-200 and Plant guard gave the highest values of reduction in this respect, followed by Rhizo-N, lemongrass oil, Bio-Cure-F, thyme oil, and eucalyptus oil respectively. Besides, the quality parameters of soybean seeds showed a favorable elevation in total oil content, on the contrary, there was a general decrease in the seeds protein content. However, the correlations between seeds oil and protein contents were negatively correlated. It could be concluded in biocides and essential oils examined can be recommended for biocontrol of soybean damping-off and root-rot diseases.