EFFECTS OF TANNINS ON SPORE GERMINATION AND GROWTH OF FUSARIUM SOLANI f. PHASEOLI AND VERTICILLIUM ALBO-ATRUM

1967 ◽  
Vol 13 (12) ◽  
pp. 1655-1661 ◽  
Author(s):  
J. A. Lewis ◽  
G. C. Papavizas

Gallotannin, wattle, canaigre, and chestnut tannins in a complete medium affected in vitro spore germination and mycelial growth of Fusarium solani f. phaseoli and Verticillium albo-atrum. The pH values and tannin concentration were important factors determining the effectiveness of tannins as inhibitors. Under acidic conditions (pH 5), gallotannin, canaigre, and chestnut tannins at concentrations varying from 39 p.p.m. to 625 p.p.m. inhibited spore germination of both fungi. At a concentration of 1000 p.p.m. these tannins completely prevented growth at pH 5 of both fungi during a 20-day period. Under near neutral conditions (pH 6–7) there was a minimum inhibition of spore germination and mycelial growth with all tannins tested. Under alkaline conditions (pH 8) there was some degree of inhibition of spore germination, but, in general, growth was similar to that under neutral conditions. Wattle tannin was unusual in that it did not prevent growth of either fungus under acidic conditions although the growth of V. albo-atrum was appreciably reduced compared with the control. Gallotannin, however, prevented growth of both fungi under alkaline as well as acidic conditions.

2021 ◽  
Vol 10 (3) ◽  
pp. e5210312994
Author(s):  
Paula Fernanda de Azevedo ◽  
Ana Carolina de Almeida ◽  
Rodrigo Domiciano Marques ◽  
Christiane Luciana da Costa ◽  
Anderson Roberto Benedetti ◽  
...  

Cassava root rot causes significant production losses. Difficulties of management, along with the lack of chemical fungicides officially registered by the Ministry of Agriculture, Livestock and Supply (MAPA), require alternative control methods. This study investigated the in vitro antagonistic activity of Trichoderma harzianum as well as a biological fertilizer MICROGEO® on Fusarium solani. The phytophatogenic strains of F. solani, called F1 and F2 were isolated from rotted cassava tubers and T. harzianum, strain ESALQ 1306, from a biological fungicide. Continuous liquid composting of bovine ruminal content, water and MICROGEO® produced the biological fertilizer. Dual culture method was used at the bioassay with T. harzianum. Sterilized (St) and unsterilized (USt) biological fertilizer were tested in different concentrations (% v/v) diluted in the culture media. Colony diameters were measured daily in order to establish the mycelial growth velocity index, inhibition percentage, aside from the sporulation rate and spore germination percentage. The mycelial growth of F. solani isolates was interrupted after hyphae encounter with T. harzianum, due to the occurrence of mycoparasitism, but without influence on the sporulation rate. Sterilized biological fertilizer induced no biocontrol, whereas the unsterilized product (concentration 2.5%) inhibited approximately 64% and 85% of the mycelial growth of isolates F1 and F2, respectively. Moreover, spore germination declined with increasing concentration. In conclusion, T. harzianum and the unsterilized biofertilizer showed in vitro antagonistic activity on F. solani.


Author(s):  
Harleen Kaur ◽  
Monique DeSouza ◽  
Raghuwinder "Raj" Singh

Boxwood is one of the most common and widely planted perennial ornamentals in both home gardens and commercial landscapes. Recently reported boxwood dieback, a fungal disease caused by Colletotrichum theobromicola, has been spreading at an alarming rate within the U.S. Boxwood breeders, nursery growers, and landscape professionals have shown great concerns regarding the lack of effective management practices. Therefore, the primary objectives of this study were to devise effective disease management strategies including screening cultivars to determine their susceptibility to boxwood dieback and screening various fungicides to determine their effectiveness in managing the disease. Host range studies were conducted by screening a wide variety of boxwood cultivars under greenhouse conditions. Although, boxwood cultivar ‘Little Missy’ showed much delayed symptom expression as compared to rest of the cultivars but none of the 11 cultivars were found to be resistance to boxwood dieback. In vitro screening of nine fungicides was conducted to determine mycelial growth as well as spore germination inhibition of eight isolates of C. theobromicola collected from eight states in the U.S. Of the nine fungicides, difenoconazole+pydiflumetofen showed maximum mycelial growth and spore germination inhibition at 1 ppm active ingredient followed by fluxapyroxad+pyraclostrobin, and pyraclostrobin+boscalid at 5 ppm active ingredient. Azoxystrobin+benzovindiflupyr significantly inhibited mycelial growth at 1 ppm but reduced spore germination at 10 ppm active ingredient. This study provides the boxwood industry professionals with critical and applied information pertaining to host susceptibility and fungicide efficacy to effectively mitigate boxwood dieback and to reduce its further spread.


2016 ◽  
Vol 10 (47) ◽  
pp. 1992-1998 ◽  
Author(s):  
D’Addazio Veronica ◽  
Aparecida Ahnert dos Santos Renata ◽  
Salomao Bastos Leitao Arthur ◽  
Barreto da Silva Marcelo ◽  
Alves Fernandes Adriano ◽  
...  

2019 ◽  
Vol 11 (17) ◽  
pp. 167
Author(s):  
Vanessa P. Gonçalves ◽  
Cândida R. J. de Farias ◽  
Victoria Moreira-Nunêz ◽  
Renata Moccellin ◽  
Viviana Gaviria-Hernández ◽  
...  

The objective of this work was to evaluate the fungitoxic effect of the agrochemicals used in the cultivation of soybean and irrigated rice on entomopathogenic fungi such as Beauveria bassiana and Metarhizium anisopliae by means of the mycelial growth, sporulation and spore germination. The isolates were inoculated in potato-dextrose-agar (PDA) medium containing the pesticides and exposed to spraying with the products. It was observed that chlorantraniliprole produced the best results regarding and was compatible with the two methods of contact of the product with the fungi. Flubendiamide it’s very toxic to fungi, producing 100% inhibition when incorporated into the medium, when by spraying, the fungus M. anisopliae got mycelial growth. Etofenprox and thiamethoxam changed their toxity classification according to the method of contact with product, was moderately compatible to B. bassiana and compatible to M. anisopliae and spinosad showed more compatibility with M. anisopliae than B. bassiana and was classified as compatible. Among fungicides the tricyclazole was the only compatible with the fungus by the spray method. The results showed that in vitro agrochemicals such as tricyclazole, thiamethoxam, flubendiamide and etofenprox are harmful to fungi. It was found that environmental interference could minimize the effects on organisms, especially when the chemicals are applied by spraying.


1988 ◽  
Vol 250 (2) ◽  
pp. 589-595 ◽  
Author(s):  
M Ozaki ◽  
T Kawabata ◽  
M Awai

Isolated haemosiderin contained iron and nitrogen in a weight ratio of 6.75, with phosphorus and no detectable haem. Considerably more iron was released from haemosiderin under acidic conditions than under neutral conditions in the presence of ascorbate, nitrilotriacetate or dithionite. Unlike the situation with ascorbate, chelators such as citrate, ADP or succinate induced the release of only some iron, with almost no pH-dependence. Dehydroascorbate (the oxidized form of ascorbate with no reducing capacity) behaved like citrate, ADP, succinate or desferal, rather than like ascorbate itself, in releasing iron. GSH had less effect on the release of iron than these chelators, but in the presence of a small amount of chelator the release of iron increased, especially under acidic conditions. Thus reduction, chelation and pH were all found to be important factors involved in the release of iron from haemosiderin. Investigation by e.p.r. of hydroxyl-radical production by the released iron showed high radical productivity at an acidic pH. However, at a physiological pH, almost no radical formation was detected, except in the presence of nitrilotriacetate. These findings suggested that, under physiological conditions, haemosiderin was not an effective iron donor and was almost not involved in radical production. Under acidic conditions, however, such as in inflammation, hypoxia and in a lysosomal milieu, it could possibly be an iron donor and is thought to be implicated in radical production and tissue damage in iron-overloaded conditions.


1997 ◽  
Vol 41 (6) ◽  
pp. 1260-1268 ◽  
Author(s):  
M Tanaka ◽  
M Hohmura ◽  
T Nishi ◽  
K Sato ◽  
I Hayakawa

The in vitro antibacterial activity of DU-6681a, a parent compound of DZ-2640, against gram-positive and -negative bacteria was compared with those of penems and cephalosporins currently available. MICs at which 90% of the isolates are inhibited (MIC90s) of the compound for clinical isolates of methicillin-susceptible and -resistant Staphylococcus aureus and Staphylococcus epidermidis, including methicillin-susceptible and -resistant strains, were 0.10, 25, and 12.5 microg/ml, respectively. DU-6681a inhibited the growth of all strains of Streptococcus pyogenes and of penicillin-susceptible and -insusceptible Streptococcus pneumoniae at 0.006, 0.025, and 0.20 microg/ml, respectively, and MIC90s of the compound were 6.25 and >100 microg/ml for Enterococcus faecalis and Enterococcus faecium, respectively. MIC90s of DU-6681a were 0.20, 0.10, and 0.025 microg/ml for Haemophilus influenzae, Moraxella catarrhalis, and Neisseria gonorrhoeae, respectively. For Pseudomonas aeruginosa, the MIC50 and MIC90 of DU-6681a were 25 and 50 microg/ml, respectively. DU-6681a activity was not affected by different media, varied inoculum size (10(4) to 10(7) CFU), or the addition of human serum but was decreased under acidic conditions against gram-negative bacteria, under alkaline conditions against gram-positive bacteria, and in human urine, as was the activity of the other antibiotics tested. The frequency of spontaneous resistance to DU-6681a was less than or equal to those of the reference compounds. Time-kill curve studies demonstrated the bactericidal action of DU-6681a against S. aureus, S. pneumoniae, Escherichia coli, and H. influenzae.


2009 ◽  
Vol 89 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Mélanie R. Mecteau ◽  
Joseph Arul ◽  
Russell J. Tweddell

The objectives of this study were (1) to evaluate the effect of different salts on the in vitro development of Fusarium solani var. coeruleum, and (2) to evaluate the efficacy of the salts for reducing dry rot severity caused by the pathogen in potato tubers. The study showed that several salts significantly inhibited the mycelial growth of F. solani var. coeruleum. Aluminium acetate, aluminium chloride, sodium benzoate, sodium metabisulfite, potassium sorbate and trisodium phosphate completely inhibited mycelial growth. Exposure of F. solani var. coeruleum conidia to aluminium acetate, potassium sorbate, sodium benzoate, sodium metabisulfite or trisodium phosphate at 0.2 M resulted in 100% mortality of the conidia after 1 h while aluminium chloride and aluminium lactate caused 100% mortality after an exposure of 24 h. In order to evaluate the effect of salts on potato dry rot development, F. solani var. coeruleum-inoculated tubers were treated with the different salts and disease severity was evaluated following an incubation period of 7 d. Among the test salts, only aluminium chloride caused a significant reduction in potato dry rot compared with the control. The study points out the possibility of using aluminium chloride to control potato dry rot.


Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 348
Author(s):  
Qian Xiu ◽  
Lianyu Bi ◽  
Haorong Xu ◽  
Tao Li ◽  
Zehua Zhou ◽  
...  

Fusarium graminearum, causal agent of Fusarium head blight (FHB), causes a huge economic loss. No information is available on the activity of quinofumelin, a novel quinoline fungicide, against F. graminearum or other phytopathogens. In this study, we used mycelial growth and spore germination inhibition methods to determine the inhibitory effect of quinofumelin against F. graminearum in vitro. The results indicated that quinofumelin excellently inhibited mycelial growth and spore germination of F. graminearum, with the average EC50 values of 0.019±0.007 μg/mL and 0.087 ± 0.024 μg/mL, respectively. In addition, we found that quinofumelin could significantly decrease deoxynivalenol (DON) production and inhibit the expression of DON-related gene TRI5 in F. graminearum. Furthermore, we found that quinofumelin could disrupt the formation of Fusarium toxinsome, a structure for producing DON. Western blot analysis demonstrated that the translation level of TRI1, a marker gene for Fusarium toxinsome, was suppressed by quinofumelin. The protective and curative assays indicated that quinofumelin had an excellent control efficiency against F. graminearum on wheat coleoptiles. Taken together, quinofumelin exhibits not only an excellent antifungal activity on mycelial growth and spore germination, but also could inhibit DON biosynthesis in F. graminearum. The findings provide a novel candidate for controlling FHB caused by F. graminearum.


2017 ◽  
Vol 70 ◽  
pp. 112-119 ◽  
Author(s):  
P.N. Wood ◽  
B.M. Fisher

Phlyctema vagabunda (syn: Neofabraea alba) is a plant pathogenic fungus that causes bull’s eye rot on apples and pears. Phlyctema vagabunda fruit infections occur in orchards predominantly pre-harvest, and eventually express as a fruit rot after 4—5 months of cool storage. Twelve fungicides (captan, carbendazim, copper hydroxide, cyprodinil, difenoconazole, dithianon, dodine, isopyrazam, metiram, lime sulphur, sulphur and trifloxystrobin) were tested in vitro for their effects on spore germination and mycelial growth of P. vagabunda. Spore germination was inhibited by metiram, captan, dodine, dithianon, lime sulphur, carbendazim and isopyrazam, in order of effectiveness. Carbendazim, isopyrazam, difenoconazole and cyprodinil, in order of effectiveness, inhibited mycelial growth when used at label rates. Wettable sulphur was ineffective in both assays. On detached apple fruit, carbendazim, cyprodinil, trifloxystrobin and isopyrazam (in order of effectiveness) inhibited lesion development.


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