Journal of Phytopathology and Pest Management (Al-Azhar University)
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Impact of applying certain bio-agents and plant extracts to control root and pod rot peanut pathogens
Get PDFThe current study was performed to evaluate the efficacy of some bacterial and fungal bio-agents and certain plant extracts i.e. garlic, neem and mint against Fusarium spp., the causal agent of peanut root and pod rot diseases. In vitro tests clarified that Penibacillus polymyxa (BP) and Pseudomonas fluorecensce (PF2) achieved the highest inhibition percentage of the tested pathogenic fungi followed by Bacillus subtilis (BS1) and P. fluorecensce (PF1) while, P. fluorecensce (PF3) and Bacillus megaterium (BM2) came in the last order. Addition of suspensions of Bacillus (B1), P. fluorecensce (P11), inoculum of T. harzianum (T10) and combination of all bio-control agents (Mixture) to infected soil significantly increased yield of peanut plants (Giza 6 cv), such as fresh weight (gm /plant), dry weight (gm /plant), plant height (cm /plant), number of pods /pot and weight of pods /pot. Regarding plant extracts, garlic extract was the most effective plant extract in suppressing the mycelial growth of the pathogenic fungi than any other treatment. Mint extract showed the lowest effect on reduction of linear growth of the tested pathogens. Concerning root rot disease management, addition of bio-agents in vivo resulted in distinct disease reduction obtained by P. fluorecensce (PF2) and Mixture treatments followed by Penibacillus polymyxa (BP) and T. harzianum (T10), respectively. In the concern of pod rot disease, the mixture and T. harzianum (T10) treatments recorded the highest disease reduction as compared to control while, P. fluorecensce (PF2) and Penibacillus polymyxa (BP) came in the last order. Treated seeds of peanut (Giza 6 cv.) with certain plant extracts (garlic, neem and mint) at concentration of 30% significantly reduced the severity of root and pod rot diseases compared to control. Garlic extract gave the highest reduction of root and pod rot severities on peanut plants followed by neem extract then mint extract, respectively
Bacterial blight disease caused by Pseudomonas cichorii on chrysanthemum in Egypt
Get PDFChrysanthemum (Dendranthema grandiflorum) is one of the important cut flowers and pot plants which belong to family Asteraceae. The aim of this study is to isolate and identify causal pathogens of Chrysanthemum bacterial blight disease, samples showing typical symptoms of bacterial blight disease on leaves, buds, stems or flowers obtained from different geographical areas of Egypt were used. The most conspicuous symptoms in infected leaves appear as water-soaked spots then become brown and dry. Ten bacterial isolates were isolated from different parts of Chrysanthemum which collected from different localities. In this respect, the bacterial isolates designated as Wl-1 and Wb-2 which were isolated from leaves and buds respectively of chrysanthemum white variety in Qualubia (Moshtohor). Meanwhile, the isolates coded as Ps-3 and Pf-4 were isolated from stems and flowers of chrysanthemum purple variety respectively in the same governorate (El-kanater El-khairia), the bacterial isolates coded as Ws-5 and Wf-6 were isolated from stems and flowers of chrysanthemum white variety planted in Menoufia governorate (Shebeen El-kom). While, the isolates coded as Yl-7 and Yb-8 were isolated from leaves and buds of chrysanthemum yellow variety respectively in Giza governorate (Kirdasah). The isolate Rs- 9 and Rf-10 were isolated from stems and flowers of chrysanthemum red variety from the same governorate (Elmariotia). Identification of isolated bacteria using the traditional techniques according to their inspected morphological, cultural characteristics, biochemical and physiological characteristics, these traditional tests revealed that these isolates may be belong to three genera i.e., Wl-1, Pf-4 and Rs-9 could be identified as Pseudomonas cichorii, while, the isolate Yb-8 could be identified as Pseudomonas fluorescens while the isolate Wf-6 was identified as Bacillus subtilis. The present study examined the level of genetic diversity and its molecular variation of the bacterial blight disease caused by Pseudomonas cichorii, three isolates from five geographic regions in Egypt. In addition, the isolates were pathogenic to eight plants from different plant families by artificial inoculations. This bacterium has a wide host range and this work is important for cataloging plant pathogenic bacteria that occur throughout special conditions may become epidemic in Egypt
Chemical control of tomato early blight caused by Alternaria solani using certain fungicides and chemical inducers
Get PDFEight isolates were isolated from tomato plants identified as Alternaria solani were involved in pathogenicity tests which resulted in definite symptoms of early blight disease of tomatoes. Four antioxidant compounds were tested against both aggressive and non-aggressive isolates, salicylic acid showed high efficacy in reducing growth of A. solani even as linear growth in vitro or as disease severity in vivo followed by citric acid and catechol respectively, while, ascorbic acid showed lowest effect. On the other hand, laboratory and greenhouse experiments were carried out to evaluated four fungicides for their inhibitory effect on the growth of A. solani aggressive and non-aggressive isolates. Bellis fungicide recorded the best result in controlling the disease either in vitro or in vivo as compared to other fungicides and control. Amistar-top and luna experience exhibited intermediate effect on the fungus isolate, and the lest order was achieved by folio- gold fungicide. In general, fungicides were more effective in controlling the disease than the tested antioxidants but, environmental pollution and hazardous effect, on human health must be considered
Integration between soil solarization and four biofungicides for controlling garlic white rot disease
Get PDFImpact of soil solarization and different biofungicides and/or Folicur fungicide as dipping treatment on the incidence of white rot and bulb yield of garlic was investigated. Results revealed that solarization treatment reduced percentage of white rot (WR) of garlic plants and increased garlic bulb yield compared to un-solarized infested soil under greenhouse and filed conditions. On the other hand, dipping garlic cloves before planting in four biofungicides i.e. Bio Arc, Bio Zeid, Bio Nagi and Bio-4 and/or Folicur fungicide significantly reduced WR disease incidence compared with untreated cloves. Dipping treatment with Folicur fungicide (tebuconazole) gave the highest reduction of WR % followed by the biofungicides i.e. Bio Nagi and Bio Zeid, respectively under greenhouse and field experiments during the two growing seasons (2015/16 and 2016/17), meanwhile, Bio-4 followed by Bio Arc resulted the least effective ones in this respect. Integration between solarization and dipping treatments increased the efficacy of WR reduction with high significant differences compared to un-solarized infested soil under greenhouse and filed conditions. Soil solarized plus Folicur fungicide followed by Bio Nagi and Bio Zeid, respectively were most superior integrated treatments for suppressive garlic white rot disease under greenhouse and filed conditions. Bio Nagi achieved closer results to Folicur fungicide for controlling WR incidence at the two successive seasons. However, the most superior integration treatment for increasing garlic yield was solarization treatment combined with each of Bio Nagi, Bio Zeid and Bio Arc, respectively. Population densities of total fungi, bacteria and actinomycetes in artificially infested soil were greatly reduced directly after solarization than before solarization. Solarization treatment alone or in combined with different dipping treatments were greatly decreased the total fungi, bacteria and actinomycetes population counts as compared with un-solarized infested soil one during the three timing intervals (30, 60 and 90 days after planting). The suppressive effect of solarization and dipping treatments was more effective in reducing soil microbial counts during the first 30 days of planting, then was decreased gradually from 60 to 90 days after planting. However, the total counts of bacteria and actinomycetes were slightly increased in solarized soil after 60 days then it rapidly increased at the 90 days interval
In vivo evaluation of garlic (Allium sativum) extract in the control of potato late blight disease caused by phytophthora infestans
Get PDFÂ In vivo study was conducted to evaluate the efficacy of foliar application of garlic extract and two chemical fungicides (ridomil and z-force) in the reduction of late blight caused by Phytophthora infestans, increase of potato biomass and total tuber yield in natural field condition. The field experiment was conducted in Machambe village, Bokkos Local Government Area of Plateau State. Certified seeds were obtained from the National Root Crop Research Institute, Kuru, Plateau State, Nigeria. Potato seeds were grown in four row plots, 30-meter-long with spacing of 70cm between rows and 30cm within rows. Experiment was laid out in a Complete Randomized Block Design (CRBD) with four replications. Foliar sprays of 0.4 g/l Ridomil, Z-force and garlic extract respectively, at a 3day interval soon after first visible symptoms appeared to reduced disease incidence and resulted in higher biological and tuber yield compared to control (unsprayed plots). Ridomil and garlic extract were most effective in minimizing the disease incidence and producing better biological yields (33.95g and 31.02g) and tuber yields (15.93t/ha and 14.99t/ha) respectively. Control plot produced the least biological and tuber yield of 23.92g and 11.95t/ha respectively. There was no significant difference at P<0.05 between the tested treatments. There was significant difference in disease incidence reduction at (P<0.05) by the extract and chemical fungicides. Late blight incidence reduction effect of garlic extract was slightly higher than that of Z-force fungicide. Therefore, the evaluated plant material (garlic extract) could serve as an alternative to chemical fungicide in the control of late blight disease in potato.Â
Biology of rice kernel smut disease causal organism Tilletia barclayana and its molecular identification
Get PDFIn Egypt, Rice kernel smut disease is a new production biotic constrains, the kernel smut of rice is caused by Tilletia barclayana, which started in appearance in different rice growing governorates, especially in Belkas, Dakahlia governorate whereas the cultivation of cultivar Giza 178 was concentrated in this area. The study aimed to investigate the life cycle of the causal organism of rice kernel smut disease "Tilletia barclayana" and determine all growth stages of this fungus and its relationship with the host '' Oryzae sativa, L'', in addition, molecular identification of this fungus. The life cycle of this disease was investigated; teliospore was germinated as emerging germ-tube and bear a promycelium. This promycelium bear from 20-100 filliform basidiospores at the tip of the promycelium. The non-conjugated basidiospores were germinated and produced mycelium. Both filliform and allantoid sporidia (Crescent-shaped conidia) generally develop from that mycelium on short sterigmata. The allantoid sporidia discharged from strigmata, then was germinated and produced binucleate mycelium which able to infect the different floral tissues, ovary and produced smut balls of teliospores. Concerning the proper time for artificial inoculation, Inoculation at flowering stage induced the highest infection with all cultivars. Inoculation at milking stage recorded the second rank of infection with the cultivar Giza 171. The lowest infection was recorded from inoculation at seedling and maximum tillering. In addition, both the highest infection at flowering stage proofed that the infection was local not systemic. For the proper spore type to artificial inoculation, Allantoid spores induced the highest infection % because it germinate and directly gave the binucleate mycelium which able to invasive the ovary and all tissues of opening spikelets, followed by the filliform sporidia which recorded the second rank of infection %, while teliospores induced the lowest infection %. For the survival of teliospores, the teliospores can survive for more than 2 years and provided the initial inoculum source from season to season. For host resistance, there are a significant source of resistance in the breeding program such as Sakha 101, Giza 179, Sakha 105, Sakha 106, some GZ lines; GZ 10101, GZ10144, GZ 10154 and GZ10305. So, detection of new resistance resources allow to further progress in establishing a successful breeding program of kernel smut For molecular identification based on ITS region, the Egyptian isolates reflected high level of identity with kernel smut from USA, China and India ranged from 80-100%.   Â
Relationship between the population density of the white mango scale insect, Aulacaspis tubercularis (Newstead) (Hemiptera: Diaspididae) and the yield loss of mango trees in Luxor Governorate, Egypt
Get PDFThe main objective of this work is to estimate the relationship between the pest population, Aulacaspis tubercularis (Newstead), infestation through pest activity peaks in September, November, April and June on the yield loss of Goleck mango trees at the district of Esna, Luxor Governorate through two seasons (2016/2017 and 2017/2018). The results revealed that the increment of population density and incidence infestation by the pest gradually decreased the yield of mango, consequently increased the percentage of the yield loss when the data of the yield were colligated with the pest population peaks and its infestation incidence in September, November, April and June months through 2016/2017 and 2017/2018 seasons.Increasing one individual of pest per leaf caused a reduction of the mango yield by 2.14, 1.56, 2.05 and 4.28 kg/tree and 2.08, 1.42, 2.46 and 1.31 kg/tree through the peaks of the two seasons, respectively. Subsequently, increased the yield loss percentages by 1.52, 1.12, 1.47 and 3.06% and 1.44, 0.98, 1.70 and 0.90% when the yield data were correlated with the population density of the pest in September, November, April and June peaks during the two connective seasons (2016/2017 and 2017/2018), respectively. These results confirmed that the pest population and the percentages of infestation incidence of A. tubercularis during the peak of April caused the least expected values in the yield of mango and the greatest loss in mango yield. On contrary, the peak during November was less effective, causing the highest expected values in mango yield and the lowest reduction in the yield of mango during the seasons of 2016/2017 and 2017/2018. Generally, the reduction in the yield of mango was a summation of different factors (time, level and variety ability to infestation)
Toxicity of some medicinal plant extracts to Pieris brassicae and combined effects with Proteus® against Brevicoryne brassicae
Get PDFBrevicoryne brassicae (Homoptera: Aphididae) is a considerable pest of cabbage. Pieris brassicae (Lepidoptera: Pieridae) exist in most countries where cabbages are cultivated. In this research, we were examined the synergistic interaction between Satureja hortensis L., Trachyspermum ammi I. Sprague, Ziziphora tenuior L., Cuminum cyminum L. and Foeniculum vulgare Mill. methanolic extracts with Proteus® against B. brassicae adults and toxicity of mentioned extracts to eggs and second instar larvae of P. brassicae under laboratory conditions. Probit analysis of extracts showed that the most effective extracts were ziziphora and savory which both exhibited LC50 values on adults of B. brassicae equivalent to 26.66 ppm. Methanolic extracts (except fennel) synergized the performance of Proteus®. Treated eggs of P. brassicae by methanolic extract of ziziphora elicited the lowest percentage of hatching rate. Studying of toxicity of extracts to 2nd instar larvae of P. brassicae demonstrated that ammi, cumin and savory 5% methanolic extracts exhibited the highest efficacy to the pest
In vitro antimicrobial activity of some medicinal plant and propolis extracts against mulberry silkworm, Bombyx mori L. pathogens
Get PDFThis study has been conducted to determine the antimicrobial activity of some medical plant extracts against mulberry silkworm, Bombyx mori L. pathogens. A total of 22 bacterial and 9 fungal isolates were successfully isolated from the external and internal silkworm larvae. Four bacterial species isolated from the infected larvae in this study were identified as follows: Staphylococcus aureus M., Escherichia coli M., Bacillus licheniformis C. and Bacillus thuringiensis B., while 6 fungal species were isolated as follows: Aspergillus niger V., Aspergillus flavus L., Aspergillus terreus T., Aspergillus fumigatus F., Pencillium citrinum F. and Fusarium oxysporum F. The highest activity among medicinal plant extracts against all pathogenic bacterial and fungal isolates was Cinnamomum zeylanicum J. while, Curcuma longa L. and Foeniculum vulgare M., showed no activity against tested pathogenic microorganisms. It is our hope that the data generated will be an addition to the existing pool of biocontrol silkworm pathogens in Egypt
Efficiency of some organic acids as safe control mean against root and stem rot disease of Coleus forskohlii
Get PDFColeus (Coleus forskohlii) is an important medicinal crop containing forskolin in their roots. Root rot is considered the most important disease in coleus, causing serious losses affecting growth and yield. Infected coleus plants showing root and stem rots were collected from Giza gardens and nurseries. The pathogenicity tests of the isolated fungi (Fusarium oxysporum, F. roseum, F. semitectum, F. solani, Macrophomina phaseolina, Pythium splendens and Rhizoctonia solani) revealed the ability of these fungi to cause infection. Application of three organic acids (Ascorbic, oxalic and salicylic acid) each at 250 and 500 ppm, against R. solani, F. semitectum, F. oxysporum and F. solani was performed in the greenhouse. All the tested organic acids reduced significantly disease incidence when used as dipping unrooted cuttings and/or spray plants 30 days after planting or soil drenching under greenhouse conditions particularly at 500 ppm compared with untreated plants. In general, oxalic acid at 500 ppm was more efficient in reducing infection with root and stem rot diseases. As for plant growth parameters, soil drenching with oxalic acid was the best treatment in increasing plant height and branch number compared with the other treatments. However, ascorbic acid was the least effective treatment compared with the other treatments. On the other hand, dual combination of three organic acids was superior on the other treatments and also recorded superiority in peroxidase and polyphenol oxidase enzyme activities