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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Both the sexual and asexual stages Phoma cucurbitacearum can cause disease and are present in most regions where watermelon is grown 3. Didymella bryoniae Fuckel Rehm, Gummy exudates may occur from cracks, especially in watermelon and pumpkin.

Journal List Front Microbiol v. Temperature and especially moisture are important in the germination, sporulation, and disease progression of D. Vryoniae to distribution map Like most websites we use cookies.

In our study, D. A polyphasic approach to characterise Phoma and related pleosporalean genera. A set of control plants and detached leaves, mock inoculated with agar plugs, remained symptomless.

Gummy didynella blight can be distinguished from cucurbit anthracnose by the larger leaf spots, larger lesions that encircle petioles, and crown cankers. Disease Gummy stem blight. Early and accurate detection of the causal agent D. Using the optimal reaction conditions described above, and based on the presence of a PCR product of the expected size, the D.

Pseudothecia are dark brown to black and usually are slightly immersed in the host tissue Fig. A positive reaction is indicated by a color change from brown to a yellowish-green color. Mycelia were then harvested as described previously Ling et al.


The fruit rot phase is often called black rot. Spores germinate, and can directly penetrate through the cuticle or intercellular spaces and around the bases of trichomes. Black rot on watermelon appears as a large, expanding rot that starts at the blossom end of the fruit Fig.

Rankings of hosts also differ depending on whether susceptibility to foliar blight, crown, stem and vine cankers, or fruit rot is considered.

This appeared to result in the assay being slower than an assay that had both loop primers Villari et al.

Plants and Tea, Japan In the older literature, Mycosphaerella melonis Pass. 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. American Phytopathological Society Press, St. The pieces are disinfested in 0. This pathogen commonly affects the foliage and stems of plants from the family Cucurbitaceae the family of gords and melonswhich includes cantaloupe, cucumber, muskmelon and watermelon plants [1,3,8].

Severe infection often results in death of the plant University of Hawaii, Stems are infected through wounds or mechanical damage 2. Fruit rots of pumpkin: The sensitivity was consistent with a previous report for LAMP methods used to detect Sclerotinia sclerotiorum Duan et al.

Southern Diagnostic Resources Diagnostic Resources. Dark mycelium and fruiting bodies of Didymella bryoniae 3 days after culturing from a leaf spot on watermelon onto one-quarter-strength potato dextrose agar.

When grown in vitro on agar, the fungus produces a white to olive-colored mycelium. The pathogen is an asomycete fungus that produces two spore stages. Although cultural practices and fungicides play an important role in GSB management Finger et al.


Didymella bryoniae

Mycosphaerella black rot of cucurbits. Walker, Mycosphaerella melonis Pass. Discussion View source History.

Pure cultures of the pathogen often can be obtained from discrete leaf or petiole lesions. Content is available for non-profit, educational use under our Copyright Agreement.

The disease was previously an unidentified problem in watermelon and the severe outbreak was associated with favorable weather conditions. The whole plant may wilt and then die. Current state and future perspectives of loop-mediated isothermal amplification LAMP -based diagnosis of filamentous fungi and yeasts.

Diagnostic Guide for Gummy Stem Blight and Black Rot on Cucurbits

Each product was confirmed by 2. The results demonstrated that this method is specific and efficient. The asexual spores cause secondary infections. Seven other fungal pathogens of Cucurbitaceae crops were collected from muskmelon, watermelon, and gourd from Jiangsu province, and an Ascochyta pinodes isolate was obtained from a pea plant at Zhejiang province.

The fungus was reisolated from infected leaves and stems of both hosts. Accelerated reaction by loop mediated isothermal amplification using loop djdymella. In the United States, D. Received Jun 15; Accepted Aug