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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Calcein was bought from Sigma-Aldrich Co. A photoperiod of 16 h of light is required to induce rapid production of fruiting bodies 10, Mycosphaerella melonis, is an ascomycete fungal plant pathogen that causes Gummy stem blight on the family Cucurbitaceae []. The test was repeated on the watermelon cultivars.

gummy stem blight of cucurbits (Didymella bryoniae)

The asexual fruiting bodies are also flask shaped and are called pycnidia. Certain Cucurbita species are resistant to D. On fruit, dark cracked sunken lesions form, beneath which an extensive rot is found. Continuing to use www. Didy,ella moisture for at least one hour is necessary for infection and a high relative humidity for lesion expansion.

Didymella bryoniae

Infection also occurs on seedlings. Pale colored pycnidia are found in closely spaced groups.

Proper irrigation and ventilation can be utilized to prevent water buildup on leaves [2]. Gummy stem blight and black rot are caused by the ascomycete fungus Didymella bryoniae Auersw. Rankings of hosts also differ depending on whether susceptibility to foliar blight, crown, stem and vine cankers, or fruit rot is considered.


Niessl, Didymosphaeria effusa Niessl Didymosphaeria melonis Pidopl. DuBose for taking photographs of symptoms on cucurbits. For greenhouse inoculations, seedlings of muskmelon cultivars Classic and Athena are readily susceptible, more susceptible than watermelon seedlings The optimal reaction time in our LAMP assay was shorter i.

The designed primer sequences for D. In this study, the positive and negative reactions could be successfully distinguished with the naked eye by adding calcein. Spots on cotyledons bryniae true leaves also occur in the greenhouse.

From Wikipedia, the free encyclopedia. Resistance to gummy stem blight in melon Cucumis melo L.

Didymella bryoniae

Rapid, specific, simple, in-field detection of Xanthomonas campestris pathovar musacearum by loop-mediated isothermal amplification. The positive reaction becomes yellowish-green, and the negative is still brown; B LAMP product was manifested as a ladder-like pattern on a 2. Non-inoculated seedlings are sprayed with sterile sucrose-casein solution.

Gummy stem blight – also known as black rot or alligator skin. As soon as the colony has covered the filter paper circle, the filter paper is removed with sterile forceps, placed into a sterile, covered Petri dish, and left in an operating laminar flow hood for 3 to 5 days.


The samples were prepared as described above. 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. To our knowledge, this is the first report of gummy stem blight and black fruit rot of watermelon caused by D.

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The sensitivity and specificity of the LAMP assay were further analyzed in comparison with those of a conventional polymerase chain reaction PCR. Thus, seedling health testing is a central issue for a large nursery. Fungal plant pathogens and diseases Food plant pathogens and diseases Pleosporales. First report of gummy stem blight, caused by Didymella bryoniaeon watermelon transplants bryonlae California.

As leaf spots expand, they coalesce, which results in leaf blighting Fig. Bryoniqe set of control plants and detached leaves, mock inoculated with agar plugs, remained symptomless. Although this coloration is not specific to D.

The center of spots often is a lighter shade of brown than the surrounding portion Figs. Although cultural practices and fungicides play an important role in Brykniae management Finger et al.

The same results were obtained in all three replicates.