scholarly journals In vitro Efficacy of Bio-control Agents against Mycosphaerella musicola causing Sigatoka Leaf Spot of Banana

2020 ◽  
Vol 9 (9) ◽  
pp. 1505-1509
Author(s):  
R. Guru Nandan Kumar ◽  
JP Mishra ◽  
Rajendra Prasad
Keyword(s):  
Leaf Spot ◽  
Mycosphaerella Musicola

scholarly journals In vitro effects of fungicides on conidium germination of Spilocaea oleagina the cause of olive leaf spot

2005 ◽  
Vol 58 ◽  
pp. 278-282
Author(s):  
E.O. Obanor ◽  
M. Walter ◽  
E.E. Jones ◽  
M.V. Jaspers
Keyword(s):  
Leaf Spot ◽  
Copper Hydroxide ◽  
Olive Leaf ◽  
Olive Leaves ◽  
Benzimidazole Fungicides ◽  
Low Concentrations ◽  
Conidium Germination ◽  
In Vitro Effects ◽  
Demethylation Inhibitor

Twenty fungicides were tested in vitro for their effects on the germination of conidia of Spilocaea oleagina the fungus that causes olive leaf spot Conidia used in this evaluation were obtained from naturally infected olive leaves in Canterbury Of the fungicides tested kresoximmethyl and captan were the most effective in preventing conidium germination at low concentrations with EC50 values of 0002 and 0003 g/ml respectively The newer fungicides boscalid and boscalid/pyraclostrobin were also effective (EC500031 and 0006 g/ml respectively) Of the benzimidazole fungicides tested carbendazim was effective (EC500005 g/ml) but thiophanatemethyl was not (EC5026 g/ml) None of the demethylation inhibitor fungicides tested were very effective (EC50 values gt;1 g/ml) except flusilazol (EC500075 g/ml) Two coppercontaining fungicides copper hydroxide and copper sulphate were ineffective for preventing conidium germination (EC5030 and 443 g/ml respectively) This study has identified candidate fungicides for further evaluation as tools for management of olive leaf spot

scholarly journals Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh

2021 ◽  
Author(s):  
Sayma T. Nira ◽  
Md. Farhad Hossain ◽  
Nur Uddin Mahmud ◽  
Oliul Hassan ◽  
Md. Tofazzal Islam ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Maximum Growth ◽  
Pathogenicity Test ◽  
Culture Studies ◽  
Alternaria Leaf Spot ◽  
Cultural Methods ◽  
Molecular Phylogenetic ◽  
Alternaria Sp

  This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of the pathogen was obtained at 30 °C and pH 6.0. Tilt 250 WC showed the highest potential in suppressing the mycelial growth of the A. alternata in vitro at a concentration as low as 50 µg/mL. The results from this study contributed to the positive identification of the pathogen and characterised A. alternata as a destructive pathogen of broccoli which may be successfully controlled by the fungicide Tilt.  

scholarly journals  Leaf spot and dieback of Buxus caused by Cylindrocladium buxicola

2013 ◽  
Vol 49 (No. 4) ◽  
pp. 165-168 ◽  
Author(s):  
I. Šafránková ◽  
L. Holková ◽  
M. Kmoch
Keyword(s):  
Dna Sequencing ◽  
Leaf Spot ◽  
Mycelial Growth ◽  
Leaf Blight ◽  
Visual Symptoms ◽  
Buxus Sempervirens ◽  
Microscopic Features ◽  
South Moravia ◽  
Molecular Characters

Leaf blight symptoms were observed on potted box plants (Buxus sempervirens cv. Suffruticosa and B. microphylla) in a nursery in South Moravia in August 2010. These symptoms were suggestive of box blight on Buxus spp. Characteristics of the visual symptoms, microscopic features, and identification of the isolates using DNA sequencing are described. The causal agent was isolated and identified as Cylindrocladium buxicola Henricot by means of morphological, cultural, and molecular characters. The effect of five commercial fungicides on C. buxicola in vitro was studied. The most effective fungicides (kresoxim-methyl, azoxystrobin, and mancozeb) inhibited conidia germination and mycelial growth (kresoxim-methyl, myclobutanil, and penconazole) of C. buxicola more than 96%.  

Distribution of apple stem grooving virus and apple chlorotic leaf spot virus in infected in vitro pear shoots

2010 ◽  
Vol 29 (12) ◽  
pp. 1447-1451 ◽  
Author(s):  
L.P. Wang ◽  
N. Hong ◽  
G.P. Wang ◽  
W.X. Xu ◽  
R. Michelutti ◽  
...  
Keyword(s):  
Leaf Spot ◽  
Spot Virus ◽  
Apple Stem Grooving Virus ◽  
Apple Stem ◽  
Chlorotic Leaf

LEAF SPOT OF BANANAS CAUSED BY MYCOSPHAERELLA MUSICOLA: ASSOCIATED ASCOMYCETOUS FUNGI

1963 ◽  
Vol 41 (10) ◽  
pp. 1481-1485 ◽  
Author(s):  
R. H. Stover
Keyword(s):  
Leaf Spot ◽  
Leaf Tissue ◽  
Leaf Spots ◽  
Mycosphaerella Musicola ◽  
Banana Leaf

In addition to perithecia, spermagonia, and sporodochia of Mycosphaerella nmsicola Leach (Cercospora musac Zimm.), perithecia of M. minima Stahel, Leptosphaeria sp., Micronectridla sp. and Didymella sp. are present in banana leaf spots in Honduras. All of these fungi discharge ascospores from both surfaces of wet leaf spots. Discharges of M. musicola and Didymella are most abundant from June through December whereas ascospores of Micronectriella are abundant from January to June. Ascospores of M. minima and especially Leptosphaeria are abundant at all times. The two-celled ascospores of M. musicola, M. minima, and Didymella are readily identified by size, shape, and type of germination. M. musicola perithecia can be readily distinguished in non-sectioned lactophenol-cleared leaf tissue by the dark thick walls of the ostiole and periderm. M. minima and Micronectriella can produce ascospores in siugle-ascospore cultures. The latter also produces Fusarium macroconidia. Micronectriella sp. is present in young healthy leaves and is considered a banana leaf inhabitant. Perithecia of all species are more abundant in areas of mass leaf spot infection than in single, scattered spots.

Leaf spot of bananas caused by Mycosphaerella musicola: action of oil on the life cycle of the pathogen

1968 ◽  
Vol 46 (12) ◽  
pp. 1495-1505 ◽  
Author(s):  
R. H. Stover ◽  
J. D. Dickson
Keyword(s):  
Incubation Period ◽  
Leaf Spot ◽  
Germ Tube ◽  
Tube Growth ◽  
Disease Development ◽  
Resistant Varieties ◽  
Mycosphaerella Musicola ◽  
Appressoria Formation ◽  
Ascospore Production ◽  
Germ Tube Growth

Oil spray reduced germination, germ tube growth, and appressoria formation by spores of Mycosphaerella musicola under field conditions for periods varying from 2 days to 2 weeks. Inhibition occurred only when spores were on the same leaf surface to which oil was applied. Appressoria formation and germ tube growth were reduced up to 33% and 25%, respectively. Conidia and ascospore production and dissemination were not adversely affected by oil spray. However, there were fewer sporodochia and perithecia in spots that were slow to develop as a result of oil spray. Oil application up to 2 weeks before or after infection increased the incubation period and the generation time, and reduced the number of spots. Oil is effective in retarding spot development when applied either before streaks appear or at the yellow streak stage of disease development. Oil, when applied during the incubation period or to yellow streaks, causes a variable amount of reduction in spotting and in only a minority of cases is disease development stopped completely. Therefore, leaf spot can build up on oil-sprayed plants when inoculum is abundant and weather favorable. The behavior of the pathogen on oil-sprayed susceptible banana plants is similar to that on partially resistant varieties.

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