Disease. Gummy stem blight. Causes leaf spot, stem canker, black leaf and fruit rot; common name refers to the characteristic gummy exudate. Didymella bryoniae (Auersw.) Rehm [anamorph Phoma cucurbitacearum (Fr.) Sacc.] is the causative agent of gummy stem blight (GSB), a disease affecting. Gummy stem blight of cucurbits produces a variety of symptoms which are referred to as leaf spot, stem canker, vine wilt and black fruit rot. Lesions on leaves.
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DuBose for taking photographs of symptoms on cucurbits. Fungal plant pathogens and diseases Food plant pathogens and diseases Pleosporales.
The disease is caused by the ascomycete Didymella bryoniae Fuckel Rehm [anamorph Phoma cucurbitacearum Fr. Published 24 October Petiole-mediated inoculation method for seedling test for gummy stem blight Didymella bryoniae resistance in melon.
Leaf spots frequently display alternating rings of dark and light brown necrosis, which correspond to diurnal periods of pathogen growth when leaves are wet with dew Fig. Incubate fresh material to allow production of spores within leaf, petiole, and fruit lesions.
Didymella bryoniae – Wikipedia
Hosts All commonly cultivated cucurbits members of the botanical family Cucurbitaceae are susceptible to gummy stem blight, although the degree of susceptibility differs among species and horticultural types. Gummy stem blight can be distinguished from cucurbit anthracnose by the larger leaf spots, larger lesions that encircle petioles, and crown cankers.
In this study, the positive and negative bryoniqe could be successfully distinguished with the naked eye by adding calcein. Thus, a low level of latently infected seedlings could potentially result in a major disease epidemic under favorable environmental conditions Ling et al.
The designed primer sequences for D. Isolation of the causal agent on potato dextrose agar PDA from leaf and stem pieces of watermelon and pumpkin plants in Arusha showed white-to-olivaceous green mycelium.
To distinguish both genotypes of D. The reaction mixtures in the microcentrifuge didymela were visually inspected by the naked eye to determine the color change.
Note that production of pseudothecia is variable among isolates and between laboratories.
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As reported previously, the pathogen has been found to move from infected source seedlings to adjacent seedlings in transplant greenhouses Keinath, Gummy exudates may occur from cracks, especially in bryonoae and pumpkin.
American Phytopathological Society Press, St. Water-soaking may also be visible on the leaf underside on main veins that pass through lesions. Seeds from healthy fruits are free of the disease but D. In addition, the study focused only on detection of D.
The assay showed high specificity in discriminating all D. Stems are infected through wounds or mechanical damage 2.
Muskmelon genomic DNA was extracted from the leaves. LAMP products can easily be visualized by gel electrophoresis or by measuring turbidity caused by a white precipitate of magnesium pyrophosphate Notomi et al.
With age these spots darken to brown and black [1,2]. The fungus was reisolated from infected leaves and stems of both hosts.
Gummy stem blight can be confused with anthracnosewhich is caused by a fungal plant pathogen called Colletotrichum lagenarium . In the United States, D.
Fruiting bodies of the pathogen in the affected tissue can be used to distinguish black rot from blossom end rot on watermelon. Detection of Puccinia kuehnii causing sugarcane orange rust with a loop-mediated isothermal amplification-based assay.
However, use of DNA-binding dyes increases the rates of cross-contamination because of the open cover operation Notomi et al. Actively expanding lesions on leaves, petioles, and pedicels often are water-soaked, as the pathogen produces cell wall-degrading enzymes, in particular polygalacturonase 27 Fig. Actively expanding leaf spots of gummy stem blight on a bottle gourd Lagenaria siceraria leaf with water-soaked margins due to cell wall-degrading enzymes produced by Didymella bryoniae.