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Author(s):  
yage xing ◽  
Jing Tang ◽  
Xuanlin Li ◽  
Ruihan Huang ◽  
Lin Wu ◽  
...  

This study investigated the ultraviolet (UV) light-induced effect of chitosan-titanium dioxide-silver (CTS-TiO2-Ag) nanocomposite film solution against Penicillium steckii ( ( P. steckii ) , as well as the underlying the physiological mechanism. The results indicated that the longer the UV exposure time, the better the pathogenic inhibition effect. After UV photoinduced treatment for 120 min, the colony diameter of P. steckii was the smallest at 4.85 mm. However, when this process is followed by an 8-h storage period, the conductivity of the P. steckii culture medium reached its highest level at 713 μs/cm. After a 120 h growth period in the same conditions, the lesion diameters and pathogenicity of the mangoes reached 12.61 mm and 41.67%, respectively. Since the cell membrane was severely disrupted, its permeability increased, causing serious intracellular protein and nucleic acid material extravasation. Furthermore, the malondialdehyde (MDA) , catalase (CAT) and superoxide dismutase (SOD) in the   P. steckii reached maximum levels after 8 h of incubation, at 2.1106 μmol/mL, 44.06 U/mL, and 24.67 U/mL respectively. These results indicated significant P. steckii inhibition via the UV light induction of the CTS-TiO 2 -Ag composite film solution.


Author(s):  
Jitendra Sharma ◽  
G.S. Rathore ◽  
S.L. Yadav ◽  
S.K. Goyal ◽  
Suresh Meena

Background: Alternaria cyamopsidis (Rang. and Rao) causes Alternaria blight of clusterbean and it is one of the significant disease of clusterbean. Studies were conducted to compare the Cultural, morphological and pathogenic variability among ten isolates of Alternaria cyamopsidis from clusterbean, in five districts of Rajasthan viz., Bikaner, Barmer, Churu, Hanumangarh and Jaipur. Methods: During 2016-17 exhaustive survey was conducted in clusterbean growing areas of Rajasthan and collected diseased samples of clusterbean caused by Alternaria. All the samples were processed for isolation, purification and their pathogenicity was proved in cagehouse and laboratory and standard methods were adopted for cultural and morphological variability study. Result: All the isolates showed variation in their morphological characters, i.e., colony color and shape; conidial number, size, width, length, shape and septation on PDA. Out of ten isolates two isolate, viz., AlcyJp1 and AlcyJp2 showed maximum colony diameter 89.50 and 86.30 mm, respectively. All the isolates varied in their spore length and width and virulent on the tested variety of clusterbean for virulence. AlcyJp1 was the most virulent and produced maximum (65.50%) disease intensity, followed by AlcyJp2 isolate (61.22%).


2021 ◽  
Vol 29 (3) ◽  
pp. 167-175
Author(s):  
Edwin Aprianda ◽  
Gunawan Djajakirana ◽  
Darmawan Darmawan

Cordycep militaris (L) is known in oil palm plantations as a natural enemy of nettle caterpillars.  This fungus infects the caterpillars that descend down to become pupae around the palm circle, so that the pupae do not develop into imago and the pest's life cycle will be interrupted. This fungus is one of the 3 main entomopathogenic fungi used as bioinsecticides to control pests in oil palm plantations. In this study, the characteristics of C. militaris were observed from 5 oil palm plantations cultured in vitro using two types of media and two incubation methods. The results showed that there were mycelium pigmentation in nutrient-rich media Sabouraud Dextrose Agar plus Yeast extract (SDAY) when incubated with lighting.  Only one of five mycelium cultures using SDAY media showed pigmentation on the no-light incubation method. Pigmentation did not occur in nutrient-poor media such as agar (WA), either incubated with lighting or with no-light. The growth of isolates was generally higher on SDAY media than on WA media. This study showed that C. militaris is a facultative phagotrophic fungus. The highest growth of isolates cultured on SDAY media incubated with lighting was found in isolates A and C, with colony diameter 90 mm, high mycelium density (+++) and hairy texture like cotton at the end of the 3rd week after inoculation.  In the no-light incubation method, the highest growth was found in isolates B and C with colony diameter 90 mm, high mycelium density (+++) and hairy texture like cotton at the end of the 3rd week after inoculation. Isolates A and C showed high virulence potential to be used as bioinsecticides.


Author(s):  
Alicia Zárate-Ramos ◽  
Adrián Raymundo Quero-Carrillo ◽  
Leonor Miranda-Jiménez ◽  
Cristian Nava-Díaz ◽  
Leticia Robles-Yerena

Banderita (<em>Bouteloua curtipendula</em>), produces abundant and appetizing forage for cattle under extreme arid conditions. The demand for its seed in Mexico is a direct function of the potential for the establishment of pastures and therefore, the sanitary quality of this is fundamental. Phytopathogenic fungi affect the seed and establishment of prairies. The objective was to evaluate<em> in vitro</em> the effect of six agrochemicals and one biological against fungi associated with Banderita seed, to reduce losses caused by these. Treatments were carried out in PDA culture medium combined with Captan, Thiophanate-methyl, Mancozeb, Benomil, Prochloraz, Thiabendazole and <em>Bacillus subtilis</em> at concentrations according to the case of 0 (control), 0.005, 0.001, 0.05, 0.01, 0.5, 0.1, 1.5, 10, 100, 150, 200, 250 and 300 mg L-1, against <em>Alternaria alternata</em>, <em>Bipolaris cynodontis</em> and <em>Fusarium incarnatum</em>. The bi-directional colony diameter was measured every 48 h. The effective concentration of 50% was estimated by a non-linear regression model; in relation to the percentage of inhibition of mycelial growth. <em>Bacillus subtilis</em> presented higher mycelial inhibition 97% (P &lt;0.05), followed by Thiophanate-methyl (96%), Prochloraz (94%), Captan (93%) and Mancozeb (92%). Benomyl and Thiabendazole showed low inhibition of fungi with 46 and 37%.<em> B. subtilis</em> and Thiophanate-methyl are the products with the greatest possibility of controlling pathogens associated with Banderita grass seeds.


Plant Disease ◽  
2021 ◽  
Author(s):  
Jie Chen ◽  
Shan Han ◽  
Shujiang Li ◽  
Tianmin Qiao ◽  
Yujue Zhou ◽  
...  

The Cinnamomum japonicum Sieb is widely cultivated in urban in China. It’s used to make essential, lubricant, soap, and waterproof timber. In September 2019, This new leaf spot was discovered in Chengdu city (30°05′to 31°26′N, 102°54′to 104°53′E), with approximately 61.20% disease incidence. The symptoms started to occur from May to June, the worst from August to September. Firstly, the typical symptom showed round or oval, brown, and slightly sunken necrotic lesions. Gradually, the necrotic lesions increased in number, and expanded; under humid conditions the central part of the spots became black and ruptured, with orange conidial masses emerged at the margin of lesions. Finally, the leaves turn yellow and fall off. Infected tissues from ten samples were cut into small pieces 2 × 2 mm, surface sterilized for 30 s in 3% sodium hypochlorite, 60 s in 75% ethanol, rinsed three times in sterile water, placed onto potato dextrose agar (PDA) amended with streptomycin sulfate (50 μg/mL), and incubated at 25°C in a dark. Finally, 8 typical isolates exhibited the morphology described as C. fioriniae (Amelie Grammen et al. 2019). After 5 days, the colony diameter reached 28.6 to 41.2 mm and had white to light grey aerial mycelium, but was pink at the base. Orange conidia masses formed after 6-7 days, conidia were oval, slender and fusiform with acute ends (Figure 1e, f), measuring 8.3 to 19.6 × 2.9 to 7.1 μm (average: 13.9 × 4.8 μm) (Tashiro et al. 2018; Chechi et al. 2019). For molecular identification, DNA was extracted from 8 fungal colonies using a plant genomic DNA extraction kit (Solarbio, Beijing). The 5.8S nuclear ribosomal genes with the two flanking internal transcribed spacer (ITS), the glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and partial sequences of the actin (ACT), chitin synthase 1 (CHS-1), beta-tubulin (TUB2), histone3 (HIS3), calmodulin (CAL) and glutamine synthetase (GS) genes were amplified and sequenced using the primer pairs ITS1/ITS4 (White et al. 1990), GDF/GDR (Templeton et al. 1992), ACT-512F/ACT-783R, CAL 228F/CAL 737R (Carbone et al. 1999), CHS-354R/CHS-79F (Weir et al. 2012), TUB1F/Bt2bR, CYLH3F/CYLH3R (Crous et al. 2004), and GSF1/GSR1 (Liu et al. 2015), respectively. Sequences were deposited in GenBank (ITS: MT466533, GAPDH: MT460415, ACT: MT460414, CAL: MT954332, CHS-1: MT954330, TUB2: MT460416, HIS3: MT954331, and GS: MT460417). BLAST analysis showed >99.4% identity with several reference sequences of Colletotrichum fioriniae strain CBS 128517 and strain EHS58 (teleomorph of Glomerella fioriniae) previously deposited in GenBank. The conidial suspension (1 × 107 conidia/mL) collected from PDA cultures with 0.05% Tween 80 buffer was used for inoculation by spraying leaves of 5-year-old C. japonicum plants for pathogenicity test. Ten leaves of each plant (10 pots in total) were inoculated with spore suspensions (Approximately 500 μL per leaf). An equal number of control leaves were sprayed with 0.05% Tween 80 buffer to serve as a control. Twenty days later, the inoculated plants showed the similar symptoms as the original diseased plants but the controls remained asymptomatic. The C. fioriniae was re-isolated from the infected leaves and identified by morphological characteristics and DNA sequence analysis. The pathogenicity test was repeated three times with similar results, confirming Koch’s postulates. To our knowledge, this is the first report of C. japonicum anthracnose caused by C. fioriniae in China.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yang Luo ◽  
Pei Tian

In the present study, two Epichloë sinensis endophyte strains isolated from different Festuca sinensis ecotypes were inoculated on potato dextrose agar (PDA) and potato dextrose broth (PDB) media with or without (control) exogenous additives. After 4weeks of growth, the growth (colony diameter, hyphal diameter, and mycelial biomass) and other characteristics (pH and antioxidant capacity of culture filtrate, mycelial ion contents, and hormone contents) were measured. The results showed that the culture conditions had significant effects (p&lt;0.05) on the hyphal diameter, mycelial biomass, and hormone content of the two strains. The mycelial biomass of the two strains in PDB was significantly higher (p&lt;0.05) than that on PDA. Except for strain 1 with indole-3-acetic acid (IAA) treatment and strain 84F with control and VB1 treatments, the hyphal diameter of the two strains in PDB under the other treatments was significantly higher (p&lt;0.05) than that on PDA. In most cases, the IAA, cytokinins (CTK), abscisic acid (ABA), and gibberlic acid (GA) contents in the mycelia on PDA of the two strains were significantly higher (p&lt;0.05) than those in PDB. The two E. sinensis strains exhibited significantly different performances (p&lt;0.05) under the five treatments. The indices, including colony diameter, mycelial biomass, scavenging ability of superoxide anion radicals and hydroxyl radicals, pH of culture filtrate, ion contents, hyphal diameter, and IAA, CTK, GA, and ABA contents were significantly different (p&lt;0.05) between the two strains, although the performance was inconsistent. Exogenous additives had significant effects (p&lt;0.05) on the performance of the two E. sinensis strains. Indole-3-acetic acid and VB1 treatments significantly promoted (p&lt;0.05) the growth of the two strains on both PDA and PDB. Indole-3-acetic acid treatment also significantly increased the hyphal diameters of the two strains in PDB (p&lt;0.05). Indole-3-acetic acid and VB1 treatments significantly reduced (p&lt;0.05) the antioxidant ability of these two strains in PDB. NaCl and ZnCl2 treatments had significant inhibitory effects (p&lt;0.05) on fungal growth and promotion effects on the antioxidant ability of the two strains. The treatments also had significant effects (p&lt;0.05) on hyphal diameters and ion and hormone contents, although the effects varied with different indices.


2021 ◽  
Vol 9 (2) ◽  
pp. 83-90
Author(s):  
Samuel Musime Malaka ◽  
Getrude Okutoyi Alwora ◽  
Shem Nchore Bonuke

Coffee Berry Disease(CBD) caused by Colletotrichum kahawae is a destructive fungal disease of coffee in Kenya, leading to a loss of about 75%. This study aimed to assess the In Vitro efficacy of two fungicides:- CRI 1 (Pyraclostrobin 150 g/L + Fluxapyroxad 75 g/L) and CRI 2 (Pyraclostrobin 128 g/Kg + Boscalid 252 g/Kg) against C. kahawae using poisoned food technique on Potato Dextrose Agar. A total of 170 coffee berries with C. kahawae symptoms were purposively collected from both sprayed and unsprayed plots. Ten rates of each of the two fungicides were assessed ranging from 0.01% to 0.1% at an interval of 0.01%. Two commercial standard fungicides Pyraclostrobin 250 g/L at 0.04% and Tebuconazole 200 g/L + Trifloxystrobin 100 g/L at 0.1% were used as positive controls. Fungal inoculum in PDA media devoid of the fungicide acted as the negative control. Data on colony diameter was collected after every 24 hours for 13 days. Analysis of Variance (ANOVA) of the data on colony diameter was done using CoStat software version 6.400. The results revealed that all the rates of CRI 1 and CRI 2 fungicides controlled the colony diameter of C. kahawae compared to the control treatment. CRI 1 fungicide suppressed the growth of C. kahawae even at the lowest concentration of 0.01% with a percentage control of 64.74 %. The highest concentration of 0.1% had a percentage control of 66.15% . CRI 1 is more effective in controlling C. kahawae since it controls the fungus at a rate even lower than Pyraclostrobin 250 g/L which had a percentage control of 66.10 at a recommended rate of 0.04% and Tebuconazole 200 g/L + Trifloxystrobin 100 g/L fungicides which had a percentage control of 65.76 at a recommended rate of 0.1%. CRI 1 also hade a better percentage control as compared to CRI 2. CRI 2 had a percentage control of 54.63% at the highest rate of 0.1% and a percentage control of 35.60% at the lowest rate of 0.01% . Further studies on CRI 1 and CRI 2 fungicides should be carried out for yield assessment in the field.


Author(s):  
Karuna Chandrakant Kurhade ◽  
Hanumant Dnyandeo Gangawane ◽  
C.D. Deokar ◽  
K.S. Raghuwanshi

Marigold (Tagets erecta) is one of the most important major floriculture crop in India. The leaf blight of marigold is caused by Alternaria tagetica is becoming a common disease on marigold Alternaria blight appeared in mild to severe form in many regions of Maharashtra and sometimes resulting in complete failure of the crop especially during rainy season. The fungal pathogen are greatly influenced by environmental factor therefore the present work undertaken to study the effect of temperature and pH on growth of Alternaria tagetica. The effect of temperature and pH were determined by colony diameter method by using different media like potato dextrose agar and oat meal agar medium. It is clearly evident from the result that all the temperature pH tested showed variation in the diameter of colony. The temperature 25oC encouraged better growth of Alternaria tagetica as compared to 15oC and 35oC. The result also revealed that pH 6 and 7 encouraged better growth of Alternaria tagetica it is concluded from the result that temperature 25oC and pH 6 is optimum temperature and pH for the growth Alternaria tagetica.


2021 ◽  
Vol 17 (1) ◽  
pp. 36-42
Author(s):  
Handry R D Amanupunyo ◽  
Nace E Tahitu ◽  
Gratiana N C Tuhumury

Various problems have caused the decline in peanut production, among others the low resistance of peanut plants to various diseases. One of the obstacles in peanut production is the attack of plant diseases, such as the fungus Sclerotium rolfsii Sacc. The use of plant-based insecticides can be an alternative to disease control in peanuts. This study aimed to obtain the appropriate and effective dose of clove leaves and flower stalks in suppressing the in vitro growth of the fungus S. rolfsii Sacc causing damping off in peanuts, and to test the effectiveness of clove leaves and flower stalks on the formation of sklerotia of the fungus. This study used ‘tuni’ clove powder from Waai Village, Salahutu District. This experimental study employed a completely randomized design (CRD) with 8 treatments and 3 replications. The results showed that the growth of the fungus S. rolfsii Sacc. was inhibited by clove flower stalk powder at a dose of 1.5 g per100 mL of PDA, which was indicated by the number of sklerotia formed of 13.67% and propagule weight of 0.12 g, followed by a dose of clove leaf powder of 1.5 g per100 mL PDA, with amount of sklerotia formed of 27.33% and propagule weight of 0.17 g. These results were statistically shown on the parameters: colony diameter, Sklerotia formation time, number of Sklerotia, and weight of propagules. Keywords: Clove powder, dosage, in vitro, Sclerotium rolfsii Sacc.   ABSTRAK Berbagai masalah telah menyebabkan turunnya produksi kacang tanah, diantaranya masih rendahnya ketahanan tanaman kacang tanah terhadap berbagai penyakit. Salah satu kendala dalam produksi kacang tanah adalah serangan penyakit tanaman, seperti jamur Sclerotium rolfsii Sacc. Penggunaan insektisida nabati dapat menjadi alternatif pengendalian penyakit pada kacang tanah. Penelitian ini bertujuan untuk memperoleh dosis daun dan tangkai bunga cengkih yang tepat dan efektif dalam menekan pertumbuhan jamur S. rolfsii Sacc penyebab damping off pada kacang tanah secara in vitro, serta menguji efektifitas daun dan tangkai bunga cengkih terhadap pembentukan sklerotia jamur. Penelitian ini menggunakan bubuk cengkih tuni, dari Desa Waai, Kecamatan Salahutu. Penelitian eksperimental ini menggunakan Rancangan Acak Lengkap (RAL) dengan 8 perlakuan dan 3 ulangan. Hasil penelitian menunjukkan bahwa pertumbuhan jamur S. rolfsii Sacc. terhambat oleh bubuk tangkai bunga cengkih pada dosis 1,5 g per 100 mL PDA yang ditunjukan oleh jumlah sklerotia terbentuk 13,67% dan berat propagul 0,12 g dan diikuti oleh dosis bubuk daun cengkih 1,5 g per 100 mL PDA, dengan jumlah sklerotia 27,33% dan berat propagul 0,17 g. Hasil ini secara statistik ditunjukkan pada parameter: diameter koloni, waktu terbentuk sklerotia, jumlah sklerotia, dan berat propagul. Kata kunci: bubuk cengkih, dosis, in vitro, Sclerotium rolfsii Sacc.


Author(s):  
Karuna Chandrakant Kurhade ◽  
Hanumant Dnyandeo Gangawane ◽  
C.D. Deokar ◽  
K.S. Raghuwanshi

Marigold (Tagets erecta) is one of the most important major floriculture crop in India. The leaf blight of marigold is caused by Alternaria tagetica is becoming a common disease on marigold Alternaria blight appeared in mild to severe form in many regions of Maharashtra and sometimes resulting in complete failure of the crop especially during rainy season. The fungal pathogen are greatly influenced by environmental factor therefore the present work undertaken to study the effect of temperature and pH on growth of Alternaria tagetica. The effect of temperature and pH were determined by colony diameter method by using different media like potato dextrose agar and oat meal agar medium. It is clearly evident from the result that all the temperature pH tested showed variation in the diameter of colony. The temperature 25oC encouraged better growth of Alternaria tagetica as compared to 15oC and 35oC. The result also revealed that pH 6 and 7 encouraged better growth of Alternaria tagetica it is concluded from the result that temperature 25oC and pH 6 is optimum temperature and pH for the growth Alternaria tagetica.


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