Effect of Pinus radiata needle monoterpenes on spore germination and mycelial growth of Dothistroma pini in vitro in relation to mature tree resistance

1982 ◽  
Vol 21 (1) ◽  
pp. 55-63 ◽  
Author(s):  
R.A. Franich ◽  
R.E. Gaskin ◽  
L.G. Wells ◽  
J.A. Zabkiewicz
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.


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.


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.


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.


1998 ◽  
Vol 123 (5) ◽  
pp. 875-881 ◽  
Author(s):  
Elazar Fallik ◽  
Douglas D. Archbold ◽  
Thomas R. Hamilton-Kemp ◽  
Ann M. Clements ◽  
Randy W. Collins ◽  
...  

Some plant-derived natural volatile compounds exhibit antifungal properties and may offer an opportunity to control the causes of postharvest spoilage without affecting quality of, or leaving a residue on, fresh produce. The natural wound volatile (E)-2-hexenal has exhibited significant antifungal activity in earlier studies, but effects on spore germination and mycelial growth have not been separated, nor has the inhibitory mode of action been determined. To determine the efficacy of (E)-2-hexenal for control of Botrytis cinerea Pers. ex Fr. spore germination and mycelial growth, and to examine the mode of action, in vitro and in vivo studies were performed. Under in vitro bioassay conditions, spore germination was more sensitive to the compound than was mycelial growth. Vapor from 10.3 μmol of (E)-2-hexenal in a 120-mL petri dish completely inhibited spore germination. However, 85.6 μmol of (E)-2-hexenal was required to completely inhibit mycelial growth. Lower concentrations of the compound (5.4 and 10.3 μmol) significantly stimulated mycelial growth, especially when the volatile was added 2 days following inoculation. Mycelial growth did not occur as long as the vapor-phase concentration was 0.48 μmol·L-1 or greater. Light microscopy analysis indicated that a high concentration of volatile compound dehydrated fungal hyphae and disrupted their cell walls and membranes. Exposure of B. cinerea-inoculated and non-inoculated strawberry (Fragaria ×ananassa Duch.) fruit in 1.1-L low-density polyethylene film-wrapped containers to vapor of (E)-2-hexenal at 85.6 or 856 μmol (10 or 100 mL, respectively) per container for durations of 1, 4, or 7 days during 7 days of storage at 2 °C promoted the incidence of B. cinerea during subsequent shelf storage at 20 to 22 °C. Loss of fruit fresh mass and fruit firmness during storage at 22 °C was increased by (E)-2-hexenal treatment, but fruit total soluble solids, pH, titratable acidity, and color (L, C, and H values) were not affected. Thus, maintenance of a high vapor-phasel level of (E)-hexenal, perhaps >0.48 μmol·L-1, may be necessary to inhibit mycelial growth and avoid enhancing postharvest mold problems, while significantly higher levels may be necessary to completely eliminate the pathogen.


2020 ◽  
Vol 8 (4) ◽  
pp. 82
Author(s):  
Cleverson Rodrigues ◽  
João Aguilar Massaroto ◽  
Grace Queiroz David ◽  
Dilânia Lopes de Matos ◽  
Walmor Moya Peres ◽  
...  

Products derived from renewable sources have been studied for their use in agriculture enabling increments in the production of agricultural culture, such as in the case of the pyroligneous extract. The research aimed at evaluating the fungitoxic potential of the pyroligneous extract of teak (Tectona grandis L.) on mycelial growth, sporulation and spore germination of Colletotrichum gloeosporioides. The experiment was conducted in completely randomized design with five treatments and four replications. Five doses of pyroligneous extract were tested (0, 25, 50, 100, 150 mL L-1) following the pour-plate methodology in 10 mL of potato dextrose agar media and kept in the incubating room maintained at 25 ± 2 °C in a 12 hour-photoperiod for eight days. Mycelial growth variables (cm), mycelial index growth speed, growth inhibition (%), sporulation inhibition (%) and spore germination (%) were evaluated. There was a reduction for the mycelial growth as well as for the rate of mycelial growth, sporulation inhibition and spore germination as the doses were increased. The percentage inhibition of mycelial growth was 56 % for the highest dose (150 mL L-1). Pyroligneous extract of teak has a direct fungitoxic action on growth, sporulation and germination in vitro of the fungus C. gloeosporioides.


2007 ◽  
Vol 60 ◽  
pp. 99-103 ◽  
Author(s):  
K.R. Everett ◽  
O.E. Timudo-Torrevilla

Avocado fruit rots are most commonly caused by five fungi Colletotrichum acutatum C gloeosporioides Botryosphaeria parva B dothidea and Phomopsis sp These rots are controlled by applying copper fungicides in the field on eight occasions during the season Alternatives to standard copper fungicides were screened in the laboratory against these five pathogens for inhibition of spore germination and mycelial growth In total seven fungicides were tested (boscalid boscalid/pyraclostrobin three formulations of copper hydroxide copper hydroxosulphate and dithianon) The effective concentration at which 50 of spore germination or mycelial growth was inhibited (EC50) was calculated for each fungicide The EC50 values for spore germination were lowest for boscalid/pyraclostrobin and dithianon and were le;185 g/ml against all five test fungi For boscalid/pyraclostrobin all EC50 values were le;7 g/ml Copper formulations effectively inhibited spore germination by 50 at concentrations ranging from 01 g/ml to 141 g/ml but were less effective against mycelial growth


2021 ◽  
Vol 42 (6) ◽  
pp. 1461-1469
Author(s):  
K. Priya ◽  
◽  
G. Thiribhuvanamala ◽  
C. Sangeetha ◽  
A. Kamalakannan ◽  
...  

Aim: The objective was formulated to screen the extracts of medicinal plants for tapping the antimicrobial activity against Collectotrichum capsici. Further, the work was planned to characterize and identify the nature of antimicrobial compounds and their functional groups. Methodology: Extracts of eleven medicinal plants were tested against the mycelial growth and spore germination of C. capsici under in-vitro conditions. Based on these results, the potential plant extracts of A. vasica and A. paniculata found effective against C. capsici were assayed for the presence of antimicrobial metabolites through TLC, GC-MS and FTIR analysis. Results: Among the medicinal plants screened, the crude extracts from Adathoda vasica and Andrographis paniculata inhibited mycelial growth and spore germination of C. capsici by 53.33% and 38.14%, respectively, under in-vitro conditions. GC-MS analysis of ethyl acetate extracts of A. vasica indicated antimicrobial compound, 1H-Pyrrolo[2,1-b]quinazolin-9-one,3-hydroxy-2,3-dihydro- and A. paniculata showed the presence of two compounds, docosahexaenoic acid and oleic acid. Similarly, FTIR analysis revealed esters, alcohols, and halide groups, which are known antimicrobials. Interpretation: The medicinal plants, A. paniculata and A. vasica possessed antimicrobial metabolites, which was responsible for inhibiting the mycelial growth and spore germination of C. capsici.


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