Mansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Use of Organic Acids for Controlling Damping-off Caused by Rhizoctonia solani on Cotton2052104092910.21608/jppp.2019.40929ENEman A. M.OsmanPlant Pathology Research Institute, Agricultural Research Center, Giza,EgyptShereen E. M.El NahasPlant Pathology Research Institute, Agricultural Research Center, Giza,EgyptMaryan M.YoussefPlant Pathology Department, Faculty of Agriculture, Cairo University, EgyptMaggie E. M.HassanPlant Pathology Research Institute, Agricultural Research Center, Giza,EgyptJournal Article20190715The four organic acids; Gallic acid (GA), Jasmonic acid (JA), Oxalic acid (OA) and Tannic acid (TA); (used in three concentrations for each acids) were evaluated <em>in vitro</em> and <em>in vivo</em> for suppression of <em>Rhizoctonia solani </em>caused damping-off on cotton. <em>In vitro</em> study showed that JA and OA were ineffective in inhibiting linear growth of the fungus, while GA and TA showed antifungal activities. In non-infested soil, none of the tested acids caused phytotoxicity under greenhouse conditions for seedlings of cotton cultivar Giza 95 when they were applied as soil drench. All the organic acids caused significant increases in plant height and dry weight of seedlings. In infested soil, GA was effective in controlling damping-off disease only at the low concentration (25.0 mM). All the applied concentrations of the other acids were effective in controlling the disease. Plant height and dry weight were not affected by any acid. The effects of organic acids on peroxidase, polyphenol oxidase, free phenolic compounds and total phenolic compounds were variable depending upon the applied concentration.Mansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Prolongation of the Shelf-Life of Strawberry Fruits by the Reduction of the Gray Mold; Botrytis cinerea using Gamma Irradiation and/or Chitosan2112154093010.21608/jppp.2019.40930ENAbeer A.AliMycological Research and Plant Diseases Survey Department, Plant Pathology Research Institute, Agricultural Research Center, Giza, Egypt.E. A.SalemFood Irradiation Department, National Center for Radiation Research and Technology, Atomic Energy Authority, Egypt.Journal Article20190715Chitosan plays a central role as an antifungal agent, its impact depends mainly on the concentration. In this respect, chitosan (0.4%) decreased the radial growth of <em>Botrytis cinerea</em> by 77.8 % under <em>in vitro</em> conditions. <em>In vivo,</em> the infection severity significantly reduced after three weeks of storage (13°C). Fruit coating by chitosan (0.4%) significantly increased fruit firmness, whereas reduced the total soluble solids, this effect was obvious with the progress of the storage time. Vitamin C content of the fruit gave fluctuated trend with the progression of storage time. The severity of the infected strawberry fruits was reduced from 100% to 49.9% as a result of gamma irradiation (2.5KGy) whereas, in the healthy strawberry fruits, the severity was reduced from 100% to 29.1% after 3 weeks of storage period. Combination of chitosan and gamma irradiation led to a significant increment of peroxidase activity. Scanning electron microscopy of the pathogen, that was treated by chitosan, showed damages in cell structure and changes in surface morphology, the same effect was observed by gamma irradiation. The same combination was found to alter the pathogen morphology and caused damage to the cell structure. So, it is recommended using such combination for extending the shelf-life of strawberries fruitsMansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Effectiveness of pH and Butylated Hydroxyanisole (BHA) on Fungicidal Activity of Certain Fungicides for Controlling Green and Blue Mold Diseases on Orange Fruits2172234093210.21608/jppp.2019.40932ENW. SameerDepartment of Plant Protection, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo, EgyptI. S.IbrahimDepartment of Plant Protection, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo, EgyptJournal Article20190715Green and blue molds caused by <em>Penicillium digitatum</em> and <em>P. italicum</em>, respectively, are the major postharvest cause of orange fruit decay, resulting in economic losses in the citrus industry. Four fungicides (i.e. boscalid, kresoxim-methyl, boscalid+kresoxim-methyl and cyprodinil+ fludioxonil) and the antioxidant butylated hydroxyanisole (BHA) were evaluated separately and in mixtures against <em>P. digitatum</em> and <em>P. italicum</em> causing green and blue mold diseases of navel orange fruits, respectively. The <em>in vitro</em> studies showed that higher (8-11) and lower (3-5) pH values reduced the growth of <em>P. digitatum</em> and <em>P. italicum</em>. Also, the results showed that the premixed fungicide formulations were more efficient in inhibiting the mycelial growth of fungi than individual forms. Both fungi tolerated high concentrations of BHA. The potency of fungicides and BHA against fungi growth was interestingly increased at pH 3 and 9. Also, the fungitoxic activities of fungicides were increased by adding BHA to fungicide-amended medium. The <em>in vivo</em> studies illustrated that all the separated fungicide treatments, particularly the mixtures of them, effectively controlled the diseases, while the separate BHA treatments slightly reduced the incidence of diseases. Also, the addition of BHA to the fungicides greatly increased their efficiencies against the incidence of diseases. Moreover, the potency of fungicide and BHA was considerably increased at pH values of 3 and 9.Mansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Monitoring of Pesticide Residues in Cucumber Samples Marketed in Egypt2252284093310.21608/jppp.2019.40933ENM. A. IAhmedPlant Protection Dept., Fac. Agric., Assiut Univ., Assiut 71526, EgyptDoaa A.HashemPlant Protection Dept., Fac. Agric., Assiut Univ., Assiut 71526, EgyptS. A.AhmedPlant Protection Dept., Fac. Agric., Assiut Univ., Assiut 71526, EgyptN. S.KhalidCentral Agricultural Pesticides Laboratory, Agricultural Research Center, Dokki, Giza 12618, EgyptJournal Article20190715Pesticide residues in vegetables are considered a potential risk to consumers and a human health concern. Herein, we performed determination and quantification of pesticides, metabolites, and isomers residues by LC-MS/MS and GC-MS in cucumber samples collected from six markets in two governorates in Egypt, i.e. Giza (Dokki) and Assiut (El-Zahraa, El-Gomhoria, El-Welidia, El-Fath, and Abnoub). As a result, a total of 12 pesticide residues were found. One of them slightly exceeded the maximum residue levels (MRLs) (Thiophanate-methyl= 0.12 mg/kg). Iprodione and propamocarb were the most frequently found pesticides. Furthermore, there were no health risk index recorded among the pesticide residues. A regular pesticide residues analysis program should be applied to monitoring and determine the pesticide residues in vegetables to keep the food safe in Egypt.Mansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Comparative Study on Effects of Chemical Fungicides and a Biocide on Cotton Seedling Damping-Off Caused by Rhizoctonia solani2292364093410.21608/jppp.2019.40934ENShereen E. M.El NahasPlant Pathology Res. Institute Agricultural Research Center, Giza,EgyptEman A. M.OsmanPlant Pathology Res. Institute Agricultural Research Center, Giza,EgyptMaggie E. M.HassanPlant Pathology Res. Institute Agricultural Research Center, Giza,EgyptJournal Article20190715The present study evaluated the efficacy of the fungicides Moncut and Rizolex-T and the biocide Bio-Control T34 (Trichoderma asperellum) on suppressing incidence of cotton seedling damping-off caused by Rhizoctonia solani on cotton cultivar Giza 86. The dual treatments of the two fungicides and the biocide also evaluated in vitro and in vivo. In vitro studies showed that Moncut completely inhibited R. solani linear growth when it was applied at a rate of 250ppm, while Rizolex-T completely inhibited R. solani growth when it was applied at a rate of 125ppm. The biocide inhibited the linear growth of R. solani by 59.17%. The biocide growth was not affected by all the applied concentrations of Moncut, while it was partially inhibited by the high concentrations of Rizolex-T. Under greenhouse conditions, the two chemical fungicides suppressed incidence of damping–off, while the biocide was unable to suppress the disease. The use of Moncut before or after the biocide succeeded in reducing the disease incidence. On the other hand, Rizolex-T caused significant reduction in disease incidence only when it was applied before the biocide. The application half or fourth the initial dose of the chemical fungicides before or after the biocide caused significant reduction in the disease incidence. The application of Moncut by the initial dose followed by the biocide caused increases in the activity of polyphenol oxidase (PPO) and phenols and sugars contents of the seedlings. Application half the initial dose of Moncut before or after the biocide caused increases in the previously mentioned variables. The use fourth the initial dose of Moncut caused increases in the same variables when it was followed by the biocide, while the use of this dose after the biocide caused decreases in the same variables.Mansoura University, Faculty of AgricultureJournal of Plant Protection and Pathology2090-367710420190401Improved the Shelf Life of Guava Fruits by Salicylic Acid against Postharvest Black Spot Disease2372434093610.21608/jppp.2019.40936ENK. H.ArafatPlant Pathology Department-Faculty of Agriculture-New Valley University, EgyptJournal Article20190715Guava fruit (<em>Psidium</em> <em>guajava</em> L.) is one of the most important popular fruits in the tropical and subtropical zones. It is a perishable and has a short postharvest shelf life at environment temperature due to climacteric ripening with changes in physicochemical properties; However, the most serious microorganisms attacked guava fruits are the fungi. Guava black spot (GBS) is a latent infection disease caused by the ascomycete fungal <em>Phyllosticta capitalensis</em>, that infect immature guava in the field. This postharvest decay can lead to significant economic losses. Since the commercial application of fungicides to control postharvest diseases found harmful to human and the ecosystems. Therefore, the search of finding alternative fungicides, safety and environmentally friendly strategy is a major aim of the researchers worldwide. Salicylic acid (SA) is one of the safe, natural compounds applied in the postharvest treatment of fruit. The present investigation aimed to evaluate the effect of different concentrations of SA on fungal growth in vitro and postharvest treatment of infected fruit to improve the shelf life of guava fruits. Guava fruit collected from local supermarket and measurement of disease incidence and severity (DI & DS%) carried out in the three seasons (2015-2017). SA at different concentrations assessed on mycelial linear growth inhibition (MLGI%) of <em>P.</em> <em>capitalensis</em> <em>in</em> <em>vitro</em>. Exogenous postharvest treatment of guava fruit with SA tested at five concentrations, three times of immersion and kept for three periods time of shelf life. DS% evaluated after three period time. Total soluble solids (TSS) and weight loss (WL) evaluated after three period time. SA concentrations at 6 mmol/L significant on MLGI of <em>P.</em> <em>capitalensis</em> in vitro. Postharvest treatment with SA at 3 mmol/L significantly reduced DS% on guava fruit, at three immersion time and after three periods of shelf life, compared to control. SA with a concentration at 4 mmol/L decreased TSS and WL after three periods of shelf life. Postharvest treatment with SA solutions had an overall positive effect on fruit quality of guava during shelf life. A decay incidence decreased, TSS and weight loss noticed in treated guava fruit compared to control. The present study demonstrated the efficacy and potential of SA solutions in preserving the shelf life of a highly perishable like guava fruits.