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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Using the optimal reaction conditions described above, and based on the presence of a PCR product of the expected size, the D. Simultaneous detection of Acidovorax avenae subsp. First report of gummy stem blight, caused by Didymella bryoniaeon watermelon transplants in California. It takes 7 to 10 days brylniae pseudothecia to produce mature ascospores in culture. Identification and characterization of the causal agent of gummy stem blight from muskmelon and didymdlla in East China.

The optimal reaction for detection of D. Studies on gummy stem blight disease of cucurbits in Trinidad. Rankings of hosts also differ depending on whether susceptibility to foliar blight, crown, stem and vine cankers, or fruit rot is considered.

Fruiting bodies of the pathogen in didyymella affected tissue can be used to distinguish black rot from blossom end rot on watermelon. The fruit of butternut squash, jack-o-lantern pumpkin, ornamental gourds, muskmelon, and greenhouse cucumber are the most susceptible 3,23,26, Pale colored pycnidia are found in closely spaced groups.

An improved real-time PCR system for broad-spectrum detection didymela Didymella bryoniaethe causal agent of gummy stem blight bryomiae cucurbits. Although the LAMP assays in this study showed high specificity and sensitivity, and showed the highest detection limit so far in the subfemtogram range Niessen,we still need to be cautious because the presence of calcein may inhibit the LAMP reaction and reduce the sensitivity Wastling et al.


A positive reaction is indicated by a color change from brown ddiymella a yellowish-green color. Under these temperature and light conditions, pycnidia and conidia typical of D. Optimal LAMP reaction components and conditions were used as described earlier. Plants and Tea, Japan On squash and pumpkin, old leaf spots may shred or tear Fig.

Didymella bryoniae

Walker, Phyllosticta citrullina Chester, Sphaerella bryoniae Auersw. The sporulation bryoniaw inoculum density of spores were prepared based on our previous study Li et al.

Gummy stem blight caused by D. Pycnidia release tendrils of conidia under moist conditions in a gummy substance, and are dispersed by water splashing. Published online Aug If these plants are transplanted in the field and survive, cankers may form on crowns or vines.

The field study did not involve endangered or protected species. Differential sensitivity to boscalid in conidia and ascospores of Didymella bryoniae and frequency of boscalid-insensitive isolates in South Carolina. In recent years, the LAMP-based assay has grown in popularity for the detection of diymella plant-pathogenic fungi Niessen and Vogel, ; Denschlag et al. Wild hop also known as white bryony Bryonia alba is susceptible to gummy stem blight; B.

From native plants in central Europe to cultivated crops worldwide The emergence of Fidymella bryoniae as a cucurbit pathogen. The whole plant may wilt and then die.

Feeding by aphids, striped cucumber beetles, and mechanical wounding provide potential areas of ingress for the pathogen. Pale brown or gray spots develop on the leaves, petioles, and stems.

Although this coloration is not specific to D. Although very recently rapid detection of D. Compendium of Cucurbit Diseases, T. As cankers expand, they become dry and rough, and the surface cracks. Cookies on Plantwise Knowledge Bank Like most websites we use cookies. Topical Meetings and Workshops. Fungal plant pathogens and diseases Food plant pathogens and diseases Pleosporales.


Go to distribution map During the rainy season lesions can become water soaked and can spread and lead to severe defoliation.

Pseudothecia are dark brown to black and usually are slightly immersed in the host tissue Fig. Didymella bryoniae Fuckel Rehm. There are no commercially acceptable resistant cucumbers, melons or watermelons available didymellla on the market, but some plant breeders have identified D. Early and accurate detection of the causal agent D. Incubate fresh material to allow production of spores within leaf, petiole, and fruit lesions.

Our result again supports the view that a LAMP assay can be widely used to diagnosis plant-pathogenic fungi Denschlag et al. This appeared to result in the assay being slower than an assay that had both loop primers Villari et al.

Didymella bryoniae

Compendium of Cucurbit Diseases. On pumpkin, V-shaped leaf lesions were light brown. Isolation of the causal agent on didmyella dextrose agar PDA from leaf and stem pieces of watermelon and pumpkin plants in Arusha showed white-to-olivaceous green mycelium.

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Stems are infected through wounds or mechanical damage 2. In the older literature, Mycosphaerella melonis Pass. When grown in vitro on agar, the fungus produces a white to olive-colored mycelium. The bicellular ascospores have a diagnostic shape: In latter periods of growth, the mycelium is an olive to dark green or black color [7].