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Abdel-Monaim M.F.,Egyptian Plant Pathology Research Institute | Abo-Elyousr K.A.M.,Assiut University | Morsy K.M.,Egyptian Plant Pathology Research Institute
Crop Protection | Year: 2011

The aim of this study was to evaluate water and organic solvent of plant extracts for protection of lupine plants against damping-off and wilt diseases caused by Fusarium oxysporum f. sp. lupini, F. oxysporum f. sp. lupini Snyder & Hansen was isolated from diseased lupine roots collected from different locations of Minia, Assiut and New Valley governorates. Water leaf extracts of Calotropis procera, Nerium oleander, Eugenia jambolana, Citrullus colocynthis, Ambrosia maritime, Acacia nilotica and Ocimum basilicum and fruit extracts of C. colocynthis, C. procera and E. jambolana reduced damping-off and wilt diseases caused by F. oxysporum f. sp. lupini. Water extracts of E. jambolana leaves, C. colocynthis fruits and N. oleander leaves were the most effective ones for controlling such diseases. In contrast, A. nilotica and O. basilicum extracts were the least effective ones. Organic solvent extracts of tested plants reduced damping-off and wilt diseases than water extracts. Butanolic and ethereal extracts were highly effective in reduction of diseases than the other tested extracts. Under field conditions, during winter growing seasons 2008/09 and 2009/10, ethereal and butanolic extracts of N. oleander and E. jambolana leaves and C. colocynthis fruits significantly reduced the percentage of wilt severity as well as improved growth parameters (plant height, number of branches, pods and seeds per plant) and increased seed index, total seed yield/hectare compared with control treatment, while protein content in seeds was not effected. In conclusion, our study demonstrated that some plant extracts can be used for biocontrol of lupine damping-off and wilt diseases. © 2010 Elsevier Ltd.


Youssef K.,Egyptian Plant Pathology Research Institute | Roberto S.R.,State University Londrina
Postharvest Biology and Technology | Year: 2014

The efficacy of some potassium and calcium based salts, namely potassium sulphate (PS), potassium sorbate (PSo), potassium carbonate (PC), potassium bicarbonate (PB), calcium sulphate (CS), calcium chelate (CCh), calcium chloride (CC) and calcium silicate (CSi) against gray mold of 'Italia' table grapes, was evaluated. In in vitro experiments, PSo, PC, PB, and CCh completely inhibited mycelial growth of Botrytis cinerea at 0.25%. Under artificial inoculation, salts at 1% (immersed or sprayed) showed a variable effect against the pathogen. For natural infection, salt solutions (1%, w/v) were applied according to three strategies: (a) spray (one week) before harvest, (b) immersion after harvest, and (c) combined treatments spray and immersion. The decay incidence of gray mold was evaluated after 30 days at 2. ±. 1. °C and 90-95% RH, followed by 7 days of shelf-life at 22. ±. 2. °C. All tested salts significantly reduced the decay incidence of gray mold as compared to a water control for the three strategies. The percentages of reduction ranged between 77-100, 91-98, and 61-100% for the preharvest treatment, in combined application, and in the postharvest treatment, respectively. PB and PSo were the most effective salts, completely inhibiting development of gray mold when applied before harvest and as a postharvest treatment. The influence of salts on physical and chemical properties of berry quality including total soluble solids, titratable acidity, pH, color index, weight losses and microbiological profiles was also investigated. New strategies are needed with the critical goal of controlling gray mold of grapes with no fungicide residues. Salts applied just before harvest may be an effective way to minimize gray mold during storage. © 2013 Elsevier B.V.


Youssef K.,Egyptian Plant Pathology Research Institute | Roberto S.R.,State University Londrina
Postharvest Biology and Technology | Year: 2014

Gray mold is the most common postharvest disease of table grapes in most regions of the world. The effect of eight salts, namely sodium silicate (SSi), sodium sulphate (SS), sodium carbonate (SC), sodium bicarbonate (SB), iron chelate (Fech), iron sulphate (FeS), ammonium bicarbonate (AB), and ammonium oxalate (AO) was determined in vitro on mycelial growth and spore suspension of Botrytis cinerea. In particular, SSi, SC, SB, FeS, and AB completely inhibited pathogen growth at 0.25% concentration. Six salt solutions at 1%, immersion or spray, were tested to verify their effect on grapes artificially inoculated with B. cinerea. All salts significantly reduced the percentage of gray mold as compared to control except for Fech after one week at 22±1°C. Three salt solutions were applied, in vivo, according to different strategies: (i) spraying before harvest, (ii) immersion after harvest, and (iii) the combination of pre- and postharvest treatments. Water was involved as a negative control while Rovral (a.i. iprodione) and SO2 served for comparisons. After one month of cold storage at 2±1°C followed by one week of shelf-life at 22±2°C, the natural incidence of postharvest mold was mostly caused by B. cinerea. The efficacy of preharvest applications was noticeably high and statistically was not enhanced by further treatments after harvest. Salts applied only after harvest were not effective in suppressing Botrytis mold, with the exception of FeS. The influence of salts on physicochemical properties for berry quality was also monitored. The field application of salts can be considered as an appropriate regime to enhance their activity since no negative impact of their application on quality profile was observed. The incidence of gray mold can be significantly reduced using some salts which are safe for consumers and the environment. © 2014 Elsevier B.V.


Abdel-Monaim M.F.,Egyptian Plant Pathology Research Institute | Abo-Elyousr K.A.M.,Assiut University
Crop Protection | Year: 2012

Rhizoctonia solani and Fusarium solani were isolated from diseased lentil roots showing damping-off and root rot collected from different locations of New Valley governorate. R. solani isolate R-1 and F. solani isolate FS-9 were the highest virulent isolates. The influence of some agricultural factors on severity of damping-off and root rot disease was studied under greenhouse and field conditions. Intercropping cumin, anise, onion and garlic significantly decreased damping-off and root rot disease and increased seed yield. Anise has the greater effect than other crops, while intercropping onion showed the lowest effect. All tested preceding crops planted before lentil decreased disease severity and population of the tested fungi except in case of soybean and groundnut which increased percentage of disease severity as well as populations of the tested fungi in soil. Cowpea and gaur cultivated before lentil gave the highest decrease in disease severity. On the other hand, lentil cultivated after cowpea produced the highest seed yield followed by gaur and millet. Lowest seed yield production was recorded when plants were cultivated after soybean followed by sesame and groundnut. The lowest population of R. solani was recorded when cowpea cultivated before lentil, while, cultivating sorghum before lentil resulted in the lowest population of F. solani. Root exudates of intercropping and preceding crops reduced mycelial dry weight of the tested fungi invitro except groundnut and soybean. © 2011.


Youssef K.,University of Bari | Youssef K.,Egyptian Plant Pathology Research Institute | Ligorio A.,University of Bari | Nigro F.,University of Bari | Ippolito A.,University of Bari
Postharvest Biology and Technology | Year: 2012

The role of some salts applied in combination with wax on the development of postharvest rots was examined on 'Tarocco' and 'Valencia late' oranges and 'Comune' Clementines. Sodium carbonate and bicarbonate, potassium carbonate and bicarbonate, ammonium bicarbonate, and potassium sorbate, at 6% concentration (w/v), in combination with a commercial wax, were evaluated for their activity against naturally occurring postharvest decay. Fruit were stored for one month at 4°C ('Tarocco' and 'Valencia late' oranges) or 6°C ('Comune' Clementine), followed by one week of shelf life at 20. ± 2°C and high RH.Most decay was from green and blue moulds, caused by Penicillium digitatum and P. italicum, respectively, with an average incidence of 11% for 'Comune' Clementines and 5% for both 'Tarocco' and 'Valencia late' oranges. Decay caused by Botrytis cinerea and Alternaria spp. was also observed. The incidence of postharvest rots on fruit treated with wax alone (11%) was higher than on those treated with water (7%), whereas in fruit treated with wax combined with different salts, decay incidence was significantly lower than with wax and water controls. In particular, potassium sorbate incorporated in wax significantly reduced the incidence of postharvest decay in all tested cultivars. The incidence of decay on fruit treated with imazalil was low, not exceeding 1%. Salts, except ammonium bicarbonate, interfered with the action of the wax to retard weight loss. The results indicate that the addition of the salts to wax may be an easy and effective mode of their application, since no additional equipment is needed. © 2011 Elsevier B.V.


Youssef K.,Egyptian Plant Pathology Research Institute | Youssef K.,University of Bari | Sanzani S.M.,University of Bari | Ligorio A.,University of Bari | And 2 more authors.
Postharvest Biology and Technology | Year: 2014

The aim of this study was to investigate the ability of two salts, sodium carbonate and bicarbonate, to activate defence mechanisms in citrus fruit against postharvest green mould caused by Penicillium digitatum. In particular, once there was confirmed salt antifungal activity in the absence of direct contact with the pathogen, changes in enzyme activity and expression levels of chitinase, β-1,3-glucanase, peroxidase and phenylalanine ammonia lyase (PAL), and phytoalexin (scoparone, scopoletin, umbelliferone) and sugar (glucose, fructose, sucrose) contents in treated oranges were analyzed. Overall, sodium carbonate and bicarbonate increases the activity of β-1,3-glucanase, peroxidase, and PAL enzymes in orange tissues. Gene expression analyses confirmed PAL up-regulation particularly 12. h after treatment application. HPLC analyses of peel extracts showed increased amounts of the sugars and phytoalexins, compared to control tissues, with sucrose and scoparone being the most represented. The results suggest that, although salts exert a direct antifungal effect on P. digitatum, they are also able to induce citrus fruit defence mechanisms to postharvest decay. The defence response seems correlated with the up-regulation of the phenylpropanoid pathway, which has a role in the adaptation to various stresses. This response could result in natural reaction to wounding and pathogen attack in citrus, enhancing its protective effect. As a consequence, the fruit might have a better chance of successful defence against the decay. © 2013 Elsevier B.V.


Ismail A.M.,Egyptian Plant Pathology Research Institute | Cirvilleri G.,University of Catania | Polizzi G.,University of Catania
European Journal of Plant Pathology | Year: 2013

During 2009 and 2010, twenty-one isolates of Pestalotiopsis spp. Associated with grey patches on the leaves, twigs, and panicles of mango were collected in six orchards located in Sicily (Italy). Morphological characteristics of colony (colour and mycelium appearance), and conidia (size, shape, septation, length and the number of apical and the basal appendages) as well as phylogenetic analysis of the Internal Transcribed Spacer (ITS) region (ITS1, 5. 8S gene, and ITS2) of six representative isolates revealed the occurrence of P. uvicola and P. clavispora. The representative isolates of both species were pathogenic to the artificially inoculated detached mango leaves cv. Kensington Pride and showed significant variation in lesion size. This is the first report worldwide of P. uvicola and P. clavispora causing grey leaf spot of mango. © 2012 KNPV.


Abd El-Hai K.M.,Egyptian Plant Pathology Research Institute
Asian Journal of Plant Pathology | Year: 2015

Experiments have been designed to determine the effect of growth substances, which included Indole Butyric Acid (IBA), Gibbrellic acid (GA3), Ethrel and Paclobutrazol (PBZ) at 50, 100 and 150 ppm in minimizing the damage of Alternaria alternata in faba bean compared to Tridex-80% fungicide. In vitro, results revealed that all concentration of PBZ and high Ethrel concentrate (150 ppm) completely inhibited the linear growth of Alternaria alternata. In vivo, all growth substances at any concentration reduced significantly severity and incidence of Alternaria leaf spot disease. The maximum reduction was recorded with PBZ followed by Ethrel. All photosynthetic pigments significantly increased by IBA, Ethrel and PBZ treatments. PBZ was more effective followed by Ethrel. Whilest, GA3 and Tridex-80% decreased chlorophylls a and b. Total phenols and total soluble carbohydrates are reached to the maximum values when using Ethrel followed by PBZ. Plant height was increased significantly with growth promoter (IBA and GA3), GA3 was the most effective. On the other side, using of growth retardants (Ethrel and PBZ) increased significantly number of branches/plant, paclobutrazol (PBZ) came first. Yield components (pods number/plant and weight of 100 seed) increased significantly with any level of growth substances. The maximum values occurred under Ethrel followed by PBZ. This research clearly showed that there is no significant difference between the efficacy of growth substances (Ethrel and PBZ "at 150 ppm") and fungicide tridex-80% in reducing Alternaria leaf spot disease of faba bean plant. © 2015 Academic Journals Inc.


Mahmoud M.A.,Egyptian Plant Pathology Research Institute
Foodborne Pathogens and Disease | Year: 2015

Aspergillus flavus is the main species from section Flavi responsible for aflatoxin accumulation in stored peanuts. Rapid methods to detect A. flavus could help to prevent aflatoxins from entering the food chain. A real-time polymerase chain reaction (RTi-PCR) assay was standardized for rapid, specific, and sensitive detection of A. flavus in stored peanuts. A. flavus was detected in 53.6% and 50% of peanut samples by RTi-PCR and A. flavus and Aspergillus parasiticus agar culture, respectively, with 95% agreement between them. Twenty-two A. flavus isolates were screened using high-performance liquid chromatography for their capacity to produce aflatoxin AFB1 (B1). B1 was produced by >72% of the isolates. Sixteen isolates produced B1 at concentrations ranging from 1.64 to 109.18μg/mL. Four aflatoxin biosynthetic pathway genes (aflD, aflM, aflP, and aflQ) were evaluated using PCR and reverse-transcription PCR in 22 A. flavus isolates from peanut kernels with the aim of rapidly and accurately differentiating toxigenic and atoxigenic isolates. The PCR amplification of genes did not correlate with aflatoxin production capability. The expression of aflD and aflQ was a good marker for differentiating toxigenic from atoxigenic isolates. © Copyright 2015, Mary Ann Liebert, Inc.


Abdel-Monaim M.F.,Egyptian Plant Pathology Research Institute
Mycobiology | Year: 2013

Rhizoctonia solani, Fusarium solani, F. oxysporum, and Macrophomina phaseolina were found to be associated with root rott and wilt symptoms of faba bean plants collected from different fieldes in New Valley governorate, Egypt. All the obtained isolates were ableto attack faba bean plants (cv. Giza 40) causing damping-off and root rot/wilt diseases. R. solani isolates 2 and 5, F. solani isolate 8, F. oxysporum isolate 12 and M. phaseolina isolate 14 were the more virulent ones in the pathogenicity tests. Biocontrol agents (Trichoderma viride and Bacillus megaterium) and chemical inducers (salicylic acid [SA] andhydrogen peroxide) individually or in combination were examined for biological control ofdamping-off and root rot/wilt and growth promoting of faba bean plants in vitro and in vivo. Both antagonistic biocontrol agents and chemical inducers either individually or in combination inhibited growth of the tested pathogenic fungi. Biocontrol agents combined with chemical inducers recorded the highest inhibited growth especially in case SA + T. viride and SA + B. megaterium. Under green house and field conditions, all treatments significantly reduced damping-off and root rot/wilt severity and increased of survival plants. Also, these treatments increased fresh and weights of the survival plants in pots compared with control. The combination between biocontrol agents and chemical inducers were more effective than used of them individually and SA + T. viride was the best treatment in this respect. Also, under field conditions, all these treatments significantly increased growth parameters (plant height and number of branches per plant) and yield components (number of pods per plant and number of seeds per plant, weight of 100 seeds and total yield per feddan) and protein content in both seasons (2010~2011 and 2011~2012). Faba bean seedssoaked in SA + T. viride and SA + B. megaterium were recorded the highest growth parameters and yield components. Generally, the combination between biocontrol agents and chemical inducers recorded the best results for controlling damping-off and root rot/wilt diseases in greenhouse and field with addition improved plant growth and increased yield components in field. © The Korean Society of Mycology.

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