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Highlights • Traditional and modern methods of diagnosing bacterial wilt disease of potato. • Evaluate the susceptibility of some Egyptian potato cultivars against to R. solanacearum. • Differentiate potato cultivars using molecular genetics methods such as SDS-PAGE profile by protein content., Bacterial wilt caused by Ralstonia solanacearum (Smith), is one of the chief severe diseases of potato in warm temperate regions, tropics and subtropics of the world. The study was conducted to isolate and identify bacterial pathogens and select the most resistant cultivars and avoid the decrease in the total value of Egyptian potato exports to the European Union (EU) due to the quarantine restrictions imposed by the EU on potato tubers exported from Egypt affected by bacterial wilt. The results of traditional identification through morphological and serological studies showed that the five isolates were isolated and identified as Ralstonia solanacearum. Furthermore, the results illustrated that RS5 isolate showed the lowest percentage of disease incidence reduction on the three tested potatoes cultivar Bellini, Spunta and Mondial recorded 9.64%, 15.41% and 34.12%, respectively. While, RS8 isolate exhibited the highest effective one the percentage of disease reduction on all tested potato cultivars. This isolate reduced disease incidence 60.60%, 63.21% and 71.66%, compering to the healthy control treatment. The result of molecular identification represent that the probe used in Taq-man (PCR) was of the type (B2) capable to detect only biovar 2 of R. solanacearum bacterial wilt. Furthermore, primer and probe are specific for detection of the race 3 biovar 2 strain. Positive results were obtained in all assays used including IFAS, protein content and SDS-PAGE with all five isolates. So the isolate (RS5) was the most virulence one, followed by RS1, RS3, RS2 and RS8, registered that the tested isolates were R. solanacearum race 3, biovar 2. Also, studies focused on the form of genetic distances and similarities based on pathogenic and plant growth parameters. The results illustrate that the highest genetic similarity (0.998) was found between Bellini and Spunta cultivars as the closest but the lowest value (0.946) was found between Mondial and Bellini as most distant. These results were similarity with genetic distances and SDS-PAGE profile of the three tested potato cultivars.

Date palm (Phoenix dactylifera L.) fruits is considered among the most storage products playing an important role in economic, nutrition and special life in the Arab countries. Fungi are the main source of fruit rots and spoilage, thus reduces their economic value. Seven fungal species were isolated and identified from date fruits cv. Sewee collected at harvesting of Siwa oasis, Egypt, using dilution plate method. The most frequency identified fungi were Botrytis cinerea, Penicillium sp., Aspegillus niger, Alternaria alternata and Fusarium oxysporium, while, Trichoderma sp. and Rhizopus sp. were the lowest detected ones. Washing of date fruits with sterile water decreased the numbers of associated fungi compared with unwashed the control treatment after harvesting (zero time). While pasteurization treatments at 80oC of Sewee date fruits completely reduced the number of fruits associated fungi followed by pasteurization at 70oC compared with zero time. Botrytis cinerea Fr. Res was the most frequently isolated fungus causing the highest spoilage incidence on date palm cv. Sewee. Botrytis cinereal, inoculated date fruitsstored under cooled temperature for six months, increased infection and severity percentage. The lowest date fruits infection was recorded after one month, while the highest infection was calculated after the 6th month of cold storage. In vitro experiment revealed that ginger, cinnamon, clove, olive and thyme oils at 5% were the most effective essential plant oils completely inhibiting mycelial growth of B. cinerea, while, anise, sesame and fennel oils were the lowest effective ones. In vivo evaluation of antifungal activities of essential plant oils were recorded on healthy and B. cinerea infected date fruits as a coated treatment. Treatment date fruits with oil highly reduced spoilage caused by B. cinerea for 6 months cold storage period. Ginger, lemon, castor, clove, cinnamon, and olive oils were the most effective onesat 6 months of cold storage period. Generally, date fruits of infection were markedly increased with increasing storage period in oil treated and untreated fruits, as well as in inoculated or un-inoculated fruits. Botrytis cinerea fungal count on inoculated date palm fruits increased significantly with the prolonged storage period for all treatments. Oils coated fruits significantly recorded the lowest fungal count compared to un-treated inoculated ones. Coated date fruits with essential plant oils recorded the highest fruit firmness (FF), reduced the incensement in juice TSS, increased total sugars, markedly decreased tannin contents, and total phenols percentage as increasingcold storage period.

Zucchini yellow mosaic virus (ZYMV) is one of the most important viruses and is responsible for significant losses in cucurbit crops worldwide. In Egypt, it causes serious economic losses in squash especially in the spring season. During 2014-2015, samples were collected from squash fields in different Provinces, Fayoum governorate. Inspection in Fayoum, ZYMV-naturally infected squash plants exhibited severe mosaic and blisters, leaves deformation, blisters on the fruits and discoloration hardening of flesh, as well as external fruit cracks. Percentages of infection in squash cv. Eskandrani, ranged between 20-35% and 70-78% in mid-March and May, respectively. Meanwhile, it ranged between 15-25% in September and 62% in the end of November. The virus was isolated from naturally-infected squash plants, detected serologically depending on enzyme-linked immunosorbant assay (ELISA), and biologically by mechanical inoculation to different species belonging four families i.e., Amarnthaceae, Chenopodiaceae, Cucurbitaceae, Solanacea. In virus vector relationship, transmission rates recorded 84.6, 86.6, 93.3, 90, and 91.6%, respectively for squash cvs. Alia, Asma, Eskandrani, Mabrouka and Safa. In this context, one insect vector (Myzus persicae) proved its ability and efficacy to transmit ZYMV. Electron microscopy (EM) of partially purified preparation method revealed flexuous particles approximately 750X15 nm. Serologically, TBIA proved to be effective in detecting ZYMV in the infected samples and reliable technique for the virus detection in squash leaf midrib and petioles. Electrophoresis analysis of the reverse transcription polymerase chain reaction (RT-PCR) amplification revealed that the primers amplified a product size of 458bp for the RNA extracted from ZYMV-infected tissues.

Food safety is one of the major issues to fresh fruits and vegetables. The preservation of freshness quality of cherry tomato (Lycopersicon esculentum Mill.) is relevant due to their economical impact. Under modified atmosphere (MA) (12% CO2 + 6% O2) cool storage conditions (7o C ± 1 and RH 90 ± 3%), some essential oils (black seed, fenugreek, cinnamon, spearmint, basil, and thyme) were used to treat, healthy and inoculated fruits with spoilage pathogens Alternaria alternata and Botrytis cinerea. The results indicated that fruits decay decreased in coated fruits treated with essential oils. However, as the storage period progressed, a general declining trend in all fruits quality parameters were observed for all treatments except for tomatoes treated with the essential oils, which, showing a lowest weight loss, firmness, Total Soluble Solids (TSS), pH, sugar fractions and antioxidant components (vitamin C., lycopene and phenolic fractions). The highest color changes were found in control group, inoculated fruits and untreated group. The obtained results suggested that essential plant oils may improve control decay of fruits, enhancement fruit shelf life and quality-related attributes on top of the well- documented antimicrobial protection during cold storage.