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Potato plants and their tubers in Egypt are affected by one of the most renowned soil-borne pathogen, Ralstonia solanacearum, that caused brown rot in potato tubers and wilt in plants. There is no efficient therapeutic bactericide so; control of bacterial wilt is very rough. The study investigated three different concentrations of seven essential plant oils under in vitro and in vivo conditions as a result of their effects on Ralstonia solanacearum growth and their possibility use as potato seed pieces dressing for controlling bacterial wilt disease incidence. In vitro, anise oil at the three tested different concentrations (0.04, 0.07, and 0.14% vol/vol) was the most effective one inhibiting the growth of T4 and W9 isolates of Ralstonia solanacearum then pursued by thyme, lemongrass, and clove oils. On the other hand, rocket oil at the tested concentration was the least effective one followed by fennel oil. However, wheat germ oil was not completely effective. In vivo, experiment revealed that anise oil at the three concentrations significantly reduced disease incidence and severity in sponta and hermes potato cultivars and their effect was associated with increase of peroxidase, polyphenoloxidase, phenols and the foliar fresh weight of treated plants as well as the weight of tubers/plant followed by thyme and lemongrass oils compared to the infected untreated control. Morphological differences in bacterial cell structure have been observed using a transmission electron microscope (TEM). Anise oil at higher concentration caused of cell wall rupture and degraded cellular components.

Bacterial wilt is one of the main diseases of Solanum spp., which caused by Ralstonia solanacearum (RS), formerly known as Pseudomonas solanacearum. Different concentrations of chitosan nanoparticles have been evaluated as one of the alternative methods of disease management in vitro and in vivo to reduce the risks of pesticide residues. Results in vitro experiment indicated that RS5 isolate was the most virulence one compared to RS1 and RS3. Increasing concentration of nano-chitosan, lead to increase inhibition zone, and this was observed at higher concentrations (100 and 200 µg/ml). In vivo results showed the highest concentration of spraying chitosan nanoparticles increase percentage reduction of disease incidence and severity, in effected potato and tomato plants. Recorded data of disease incidence and severity in treated potato plants were 78.93 % and 71.85 %, while on tomato plants were 81.64 % and 77.63 %, respectively compared to untreated infected potato plants were recorded 15.38 %, 20.87 %, and tomato plants were 20.98 % and 28.64 %. Results also revealed that 100 µg/ml of chitosan nanoparticles the lowest treatments used as soil amended curative treatments led to incease percentage reduction of disease incidence and severity, respectively on potato and tomato plants, but less than preventive treatment. The results registered that on potato plant were 54.93 % and 52.65 %, whilst recorded on tomato plants were 59.93 % and 56.74 %. Transmission electron microscopy (TEM) micrpgraphs illustrated that morphological of healthy R. solanacearum cells were undesirably stained with uranyl. The electron-dense uranyl acetate dye was limited to the cell surface slightly than the cytoplasm, which designated the integrity of the cell film of healthy cells. While bacterial cells treated with nano-chitosan, showed modification in the external shape, such as lysis of the cell wall and loss of cell flagella. Also, the result of using Random amplified polymorphic DNA (RAPD)-PCR observed that differences in treated Ralstonia solanancearum genotype by nano-chitosan compared to the genotype of the same untreated isolate.

Silver nanoparticles (AgNPs) are a potentially effective tool for preventing viral plant diseases. This study was carried out to evaluate the effectiveness of AgNPs for managing bean yellow mosaic virus (BYMV) disease in faba bean plants from the plant-virus-vector interaction side. AgNPs were evaluated as foliar protective and curative agents. In addition, the effect of AgNPs on virus acquisition and transmission by its vector aphid was investigated. The results indicated that AgNPs exhibited curative viricidal activity and were able to inactivate BYMV when applied 48 hours after virus inoculation. The occurrence of disease was prevented using an AgNP concentration as low as 100 mg L-1, whereas virus infection was completely inhibited when plants were preventatively treated with AgNPs at a concentration of to 200 mg L-1 24 h before virus inoculation. AgNPs proved to be highly bio-reactive, binding to viral particles and suppressing their replication and accumulation within plant tissues. Moreover, AgNPs, at all concentrations tested, were found to upregulate the pathogenesis-related gene PR-1 and induce the production of defense-related oxidizing enzymes in treated plants. Exposure of aphids to AgNPs-treated plants before virus acquisition reduced BYMV acquisition and transmission efficiency by 40.65 to 100% at 24 h post-application, depending on the AgNP dosage. At 10 days after treatment, virus acquisition was reduced by 36.82% and 79.64% upon exposure to AgNPs at a concentration of 250 and 300 mg L-1, respectively. These results suggest that AgNPs have curative viricidal activity due to targeting the virus coat protein and affecting virus-vector interactions. Accordingly, AgNPs may contribute to alleviating the natural disease and virus transmission under field conditions. This is the first report on the activity of nanomaterials against plant virus acquisition and transmission by insects.

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.

The present work was conducted to study the efficacy of compost powder and compost extract (tea) in the management of root rot and root-knot nematode disease complex infecting pepper plants under in vitro and in vivo. The inhibitory effect of compost extract concentrations (25%, 50%, 75 and 100%) on Fusarium solani (Mart.) Sacc and Rhizoctonia solani Kuhn were evaluated, the latter was higher sensitive than F. solani by 88.33% and 82.83%, respectively at 100% concentration. The results also, showed that nematicidal effect of unsterilized compost tea (65.98% and 52.3%) was significantly more than sterilized compost tea (54.02% and 45.9%) on the rate of Meloidogyne incognita egg hatching and juvenile mortality, respectively in all tested concentrations. In vivo, the obtained results cleared a decrease in the root rot incidence percentage in disease complex of both compost powder and compost tea extract to 22.1% and 20.1% compared with control treatment. Application of compost powder with the recommended dose, as well as the compost tea extract, led to a significant decrease in gall number (64 and 59 galls/root) compared to the comparative treatment (108 galls/root). This result has led to a significant reduction in egg-masses formation. Furthermore, the obtained results indicated that plant growth parameters significantly increased (plant length, fresh and dry weights) by the application of compost and compost tea extract. In general, application of compost and compost tea extract might be a safe and eco-friendly tool in the sustainable management of disease complex.

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.

Silver nanoparticles (AgNPs) are a potentially effective tool for deterring viral plant pathogens. This study was carried out to evaluate the efficacy of AgNPs to defeat Bean yellow mosaic virus (BYMV) on faba bean plants from the host, virus and vector aphid tripartite interactions side. The antiviral capabilities were evaluated during a foliar protective and curative scheme. Furthermore, the efficiency of AgNPs on virus acquisition and transmission by its vector aphid was investigated. Results indicated that the AgNPs had greatly exhibited curative viricidal activities for inactivation BYMV when applied 48 h post-virus inoculation. The disease occurrence was entirely inhibited with AgNPs rate as low as 100 mg.l− 1, while the infectivity was completely arrested when plants were preventively exposed to 200 mg.l− 1 24 h pre-virus inoculation. AgNPs proved high bio-reactivity by binding to viral particles, suppressing their replication and accumulation within the plant tissues. Moreover, it was noticeably showed to upregulate the pathogenesis-related gene (PR-1) and promote the defense-related enzymes and protein profiles in treated plants irrespective of concentration. Exposure of aphids to AgNPs-treated plants before virus acquisition excitingly reduced the BYMV acquisition and transmission efficiency by 40.65% up to 100 % 24 h post-application and the virus acquisition was affected for 10 days by 6.89 Up to 79.64 % depending on the AgNPs rate. These results concluded that the AgNPs have a high curing viricidal activity by targeting the virus envelop, and more excitingly it can affect the virus-vector combination, suggesting that it may contribute to alleviating the natural disease occurrence and virus transmission under field conditions. Therefore, according to the available literature, this study provides the first report on the deterring activity of nanomaterials against plant virus acquisition and transmission by its vector insects.

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.