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Effect of application of different bioagents on Alternaria leaf spot disease under greenhouse conditions. A) Trichoderma viride B) T.harzianum c) T.album D) Bacillus subtilis E) B1 F) Positive control Effect of different selected fungicides on cabbage leaf spot disease using protective and curative treatments
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Screening of cabbage Alternaria leaf spot disease, in different localities of El-Sharkia governorate, Egypt, was carried out during 2010-2011 growing season. Alternaria black leaf spot disease appeared to be wide spread in cabbage fields. Isolation procedures yielded several fungal genera with variable frequencies, but Alternaria brassicicola was t...
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Pathogens are known to cause losses to forest yield. Fungicidal application has been found to be effective against many pathogens but biological control holds promise as a strategy for disease management and it is environment friendly too. So, three pathogen having vast host range of forest plants viz., Pestalotiopsis sp., Cerotocystis sp., Armilla...
Citations
... Leaves free from infection Spots covering <5% leaf area Spots covering 5.1-10% leaf area Rings covering 10.1-25% leaf area Blight symptom covering 25.1-50% leaf area Blight symptom covering >50% leaf area exhibit impact on interaction between host and pathogen [18]. Similar results were observed by [19] who found that the out of tested 42 genotypes, only two genotypes were consistently showing some level of resistance against Alternaria Blight. ...
Current study was conducted to evaluate the five varieties of each cauliflower and cabbage against Alternaria Blight, while, plant extracts (neem, garlic, ginger) with three strengths (10%, 20%, 30%) were also applied to assessed their impact in growth as well as yield attributes and against disease. Minimum severity, with respect to days, was observed in CKD-555 and CKD-1104 for cauliflower and cabbage respectively. Regarding varietal response in cauliflower, Shumaila and CKD-1041 exhibited highly susceptible response, Pari showed susceptible, CKD-555 and CKD-961 found moderately susceptible, whereas, no variety exhibited resistant response. In cabbage varietal response, CKD-1104 exhibited resistant response, Snow Drift and CKD-1105 showed moderately resistant response, whereas, Saint-F1 and Snow Dome expressed moderately susceptible response. Regarding plant extracts, neem (30% concentration) minimized the severity and maximized the growth as well as yield (fresh plant weight, head diameter, head weight) in cauliflower and cabbage against Alternaria Blight. Decreasing trend was assessed viz. neem followed by garlic and ginger over control with similar trend of plant extract strength 30% ˃ 20% ˃ 10% in disease control as well as in growth and yield attributes. In crux, neem with 30% strength can be used in reduction of Alternaria Blight and enhancement of yield as a eco-friendly control measures.
... Parameter yang diamati adalah: (1) masa inkubasi, yaitu waktu pertama kali gejala penyakit bercak daun muncul sejak tanaman diinokulasi; dan (2) intensitas penyakit, yang diamati perkembangannya setiap hari. Intensitas penyakit bercak daun dihitung menggunakan skor keparahan penyakit (Disease Severity Index/DSI) menggunakan skala 0-9 (Sabry et al., 2015). Pengamatan terhadap produksi tidak dilakukan karena penelitian lebih difokuskan kepada pengaruh perlakuan terhadap resistensi tanaman. ...
Penyakit bercak daun Curvularia merupakan penyakit baru pada tanaman sawi. Pengendalian penyakit dengan fungisida sintetik sangat berbahaya karena daun sawi dikonsumsi sebagai sayuran mentah atau pengolahan minimal, untuk itu diperlukan alternatif cara pengendalian yang lebih aman bagi kesehatan seperti menginduksi resistensi tanaman menggunakan bahan kimia. Penelitian ini bertujuan untuk mengetahui keefektifan beberapa bahan penginduksi resistensi seperti asam salisilat, kitin, K2HPO4, dan vitamin B1. Sementara, Bion M1/48, bahan penginduksi komersial, digunakan sebagai pembanding. Bahan penginduksi diaplikasikan melalui cara perendaman benih dan disemprotkan. Pada perlakuan perendaman, benih direndam dalam suspensi bahan penginduksi selama 12 jam, sedangkan pada perlakuan penyemprotan, bahan penginduksi disemprotkan satu kali yaitu dua hari sebelum inokulasi dilakukan. Inokulasi patogen yang digunakan memiliki suspensi konidia kerapatan 5 x 105 konidia ml-1. Penelitian ini menggunakan Rancangan Acak Kelompok dengan empat ulangan. Pengamatan dilakukan terhadap masa inkubasi dan intensitas penyakit. Hasil pengujian menunjukkan bahwa perendaman benih asam salisilat, kitin dan K2HPO4, mampu menunda kemunculan gejala sakit lebih lama dibandingkan Bion M 1/48. Terhadap intensitas penyakit, asam salisilat, kitin, dan K2HPO4, juga efektif menginduksi resistensi tanaman sawi terhadap penyakit bercak daun Curvularia. Ketiga senyawa kimia ini potensial untuk digunakan sebagai pengganti fungisida sintetis dalam mengendalikan penyakit bercak daun Curvularia pada tanaman sawi.ABSTRACTCurvularia leaf spot is a new disease on mustard green (Brassica juncea L.). The diseases control with synthetic fungicide is dangerous since mustard green leaves are freshly consumed or with minimum treatments. Therefore, a safer alternative method must be sought such inducing plant resistance using chemical inducers. This research aimed to evaluate effectiveness of salicylic acid, chitin, K2HPO4, vitamin B1, as resistance inducers. Meanwhile, Bion M 1/48, a commercial inducer, was used as the check treatment. These substances were applied as either seed soaking or spraying. In the soaking treatmet, the seeds were soaked for 12 hours duration, whereas in the spraying treatment, chemicals were applied once, at two days before inoculation with conidial suspension of 5 x 105 conidia ml-1. Experimental plants were arranged in a Randomized Block Design with four replicates. Observation was carried out on incubation period and disease intensity. Results showed that soaking the seed in salicylic acid, chitin and K2HPO4 was able to delay the appearance of symptoms, better than of Bion M 1/48. Towards disease intensity, salicylic acid, chitin, and K2HPO4 were also effective in inducing resistance of mustard green leaves against Curvularia leaf spot. The three substances were potential to be applied as an alternative to synthetic fungicide in managing Curvularia leaf spot on the mustard green.
... Percentage infection= ×100 (Sabry, Ali, Abdel-Kader, & Abou-Zaid, 2015). Percentage of infected leaves for each plant was calculated using the following formula according to (Sabry, et al., 2015): ...
... The species and cultivars such as Pruktor F1 which tend to be less sensitive to Alternaria pathogens have relatively more epicuticular wax than others. Older leaves are more susceptible than younger ones to the pathogen; this is probably due to high levels of wax in the young immature leaves which make them resistant against it (Sabry et al., 2015). ...
Dark leaf spot (Alternaria brassicicola) is an important disease of cabbage crop. It is a major constraint in cabbage production in Kenya causing substantial losses if not managed properly. Hybrid varieties are now in the market but there exists little information on their resistance and tolerance to this disease. To undertake breeding for resistance and come up with improved varieties, there is need to identify cabbage genotypes for possible sources of resistant genes to the disease. This study was carried out to assess the response cabbage varieties to Alternaria brassicicola pathogen at the University of Eldoret, School of Agriculture and Biotechnology Plant Pathology Laboratory and in the greenhouse. Isolation and purification of the pathogen was done in appropriate conditions in the laboratory and inoculated on to 10 days old transplanted seedlings. The experiment was laid as completely randomized design (CRD) with each variety replicated four times. Scores were made using a scale of 1-10 on nature of the leaf with leaf spots and percentage disease index per plant was calculated. Data collected was analyzed using Genstat software version 14.1. The study revealed no significant difference in percentage infection among varieties. Using single link method three clusters were formed at 95% similarity coefficient axis. It was concluded that Gloria F1 and Copenhagen were susceptible; Queen F1 was tolerant while Pruktor F1 and Sugarloaf varieties were resistant. Breeding institutions and farmers are recommended to use tolerant varieties for breeding improvements and high yields.
To ensure sustainable agricultural production and protection of crops from various biotic and abiotic stresses, while keeping in view environmental protection, by minimal usage of chemicals, the exploitation of beneficial microorganisms and modern nanotechnologies in the field of agriculture is of paramount importance. This study aimed to investigate the effects of Serendipita indica and guanidine-modified nanomaterial on the growth, and other selected parameters, of cabbage, as well as incidence of black spot disease. S. indica was applied in substrate and by seed inoculation. S. indica had a positive impact on the development of plants, and resulted in reduced black spot severity. The maximum plant height (119 mm) and number of leaves (8.3) were observed in S. indica-treated plants. Pigments were enhanced, i.e., chlorophyll a (0.79 mg/g), chlorophyll b (0.22 mg/g), and carotenoid content (0.79 mg/g), by substrate treatment. The highest antioxidant capacity (9.5 mM/L), chlorophyll a and b (1.8 and 0.6 mg/g), and carotenoid content (1.8 mg/L) were reported in S. indica seed treatment. S. indica treatment resulted in 59% and 41% disease incidence decrease in substrate and seed treatment, respectively. Guanidine-modified nanomaterial was seen to be effective in improving plant growth and reducing disease incidence; however, it did not perform better than S. indica. Application of nanoparticles resulted in enhanced normalized difference vegetation index and fluorescence by increasing chlorophyll a, b, and carotenoid content. Nitrogen content was the highest in plants treated with nanoparticles. However, the effect of the combined application of fungus and nanoparticles was similar to that of S. indica alone in substrate treatment, although negative impacts were reported in the biochemical parameters of cabbage. S. indica has great potential to enhance plant growth and manage Alternaria incidence in cabbage crops.
A mixture of the isolates of Fusarium graminearum, Alternaria brassicicola, Verticillium dahliae, and Pythium ultimum was examined to determine antimicrobial activity of the extracts of water-based and alcohol-based propolis at different concentrations (10, 20, 30, 40, 50, and 60 mg/ml) according to in vitro (disk diffusion and well diffusion methods) and in vivo (seed, foliar, and seed + foliar treatments) assays. In disk diffusion and well diffusion assays, the diameter of inhibition zones at a concentration of 60 mg/ml of propolis extracts exhibited a considerable increase against all of the pathogenic isolates. For both methods, the most effective concentration of the water-based propolis extract against V. dahliae and of the alcohol-based propolis against A. brassicicola was determined to be 60 mg/ml with inhibition zones above 4.2 cm and 4.3 cm, respectively. For in vivo assays, while the seed + foliar treatment of alcohol-based propolis extract at a concentration of 60 mg/ml was determined to have the highest antimicrobial activity with an inhibition rate of 97.9% against A. brassicicola in cabbage plants, the seed + foliar treatment of water-based propolis extract at a concentration of 60 mg/ml was found to exhibit the highest antimicrobial activity with an inhibition rate of 91.6% against V. dahliae in alfalfa plants. The results verified that the propolis extracts had a high capacity, as a promising and an eco-friendly alternative against various plant pathogens, to minimize the use of chemical pesticides.
