University of maryland, 27664 nanticoke road, salisbury, md 21801. The pathogen is soil and seed borne and can overwinter in infected. Breeding watermelon citrullus lanatus for resistance to. This field was a 100% loss with no fruit harvested. While it is impossible to conduct any testing procedures to give results with 100% certainty with regard to the. Evolutionary history and genetic diversity of didymella bryoniae. This document is pp280, one of a series of the plant pathology department, uf ifas extension. A gummy brown material will ooze from older stems in the later stages of disease. Plants were transplanted on 15may with distinction seedless and sentinel seeded melons at a 3. Evaluation of fungicides for control of anthracnose and gummy stem blight of watermelon, sampson county 20. Visual detection of didymella bryoniae in cucurbit seeds.
Abstracts need to be submitted with the following formatting and specifications. Effect of alternative treatments on seedborne didymella lycopersici in tomato article in journal of applied microbiology 1051. Cluster analysis confirmed that it is not related to mycosphaerella. Evaluation of fungicides for control of anthracnose and gummy. Black rot didymella bryoniae also called gummy stem blight when it occurs on other plant parts, black rot produces a distinctive black decay. Didymella bryoniae anamorph phoma cucurbitacearum is an ascomycete that causes gummy stem blight, a foliar disease that occurs on cucurbits in greenhouses and. Disease concerns for cucurbit growers, especially of pumpkins, run the gamut from early season concern for bacterial wilt, midseason occurrence of powdery mildew and late season occurrence of gummy stem blightblack rot and phytophthora blight. Wick, university of massachusetts d61ucurbits, black rot c lesions caused by the fungus didymella bryoniae on acorn squash fruit.
Factors influencing internal fruit rot of cucumber caused by didymella bryoniae. Is the synthetic substance an inert 176 ingredient which is not on epa list 4, but is exempt from a requirement of a tolerance, per 40 cfr part 177 180. Effective over plant material at rates as low as 0. In this study, morphological characteristics and rdna internal transcribed spacer its sequences were analyzed to identify the causal organism of this disease. The epidemiology of spur blight of raspberry didymella applanata niessl sacc. Cucurbit genetics cooperative agricultural research service. The experiment was conducted in acommercial watermelon field near clinton, nc n3454. Evaluation of fungicides for control of anthracnose and. Iii didymella bryoniae cantaloupe 58,000 71,436 ii and iv nematodes iii powdery mildew grapefruit 60,400 64,790 ii and iv nematodes lemon 54,300 59,001 ii and iv nematodes tangerines 66,400 56,883 ii and iv nematodes apricot 9,700 12,179 ii and iv nematodes peach 94,070 94,836 ii and iv. Pdf an improved realtime pcr system for broadspectrum. Lesions on the crown and stem are brown and usually turn white with age. Santa barbara county agricultural commissioner plant pathology entomology heather scheck brian cabrera.
As both species have been recorded only in the andes area, s. Depending on the cultivar a storage life of 2 to 6 months can be expected at 12. Initially, a brown to pink, watersoaked area develops in which numerous, conspicuous black fruiting bodies are embedded. The following 7 files are in this category, out of 7 total. Evaluation of fungicides for management of foliar diseases on. Didymella bryoniae is a pathogenic fungus that causes gummy stem blight gsb in cucurbitaceae crops e. In a previous study using rapd analysis, little genetic diversity was found among isolates of d. Media in category didymella the following 2 files are in this category, out of 2 total.
Didymella bryoniae, a fungus, is a serious disease which continues to be a serious risk in many areas of watermelon cultivation. Effect of alternative treatments on seedborne didymella. Effects of environmental factors and leaf age on growth and infectivity of didymella bryoniae. Aflp analysis of a worldwide collection of didymella bryoniae. The influence of ventilation temperature and of little ventilation with an electric fan, with an air exchange of four compartment volumes per hour, on the development of didymella bryoniae in glasshousegrown autumn cucumber crops was studied on both inoculated and uninoculated plants. Characteristics in relation to suitability for cucumber 5. University of massachusetts extension vegetable notes. The experiment was conducted in a commercial watermelon field near clinton, nc n3455. The pathogen was identified as didymella bryoniae upon incubation on potato dextrose agar plates. The plant center retreat, university of georgia, oct. Mathews paret, nicholas dufault, gary vallad, shouan zhang fanny iriarte, susannah. Epidemiologia zamierania pedow malin didymella applanata niessl. Current status of research on plant pathogens and biological pesticides 1 suraj baidya, senior scientist s4 plant pathology division.
Phylogenetic analysis of cercospora and mycosphaerella based. Phylogenetic analysis of cercospora and mycosphaerella. Didymella bryoniae anamorph is phoma cucurbitacearum is an ascomycete fungus that can survive on seeds, weeds citron, balsam pear, and other volunteer cucurbits, and plant debris from previously infected cucurbits. Everts university of maryland, 27664 nanticoke road, salisbury, md 21801. Iii didymella bryoniae cantaloupe 58,000 71,436 ii and iv nematodes iii powdery mildew grapefruit 60,400 64,790 ii and iv nematodes lemon 54,300 59,001 ii and iv nematodes tangerines 66,400 56,883 ii and iv nematodes apricot 9,700 12,179 ii and iv nematodes peach 94,070 94,836 ii and iv nematodes. The causal fungus can often be observed to reproduce on the crowns or stem le. On young seedlings, lesions on the cotyledons and true leaves are round or irregular, brown, with faint concentric rings. Cucumis melo, didymella bryoniae, disease resistance, screening. Sclerotinia stem rot sclerotinia sclerotiorum 16 fl oza. In vitro growth and sporulation of didymella bryoniae and a glasshouse method for screening for.
Seedling screens of melon cucumis melo for high resistance to gummy stem blight, caused by the fungus didymella bryoniae auersw. Black rot, caused by didymella bryoniae, anthracnose caused by colletotrichum orbiculare, and phytophthora fruit rot are common in areas with high rainfall and humidity during production and harvest an extensive list of stemend, blossomend, rind decay or surface lesions may occur, including the bacterium erwinia and the fungal pathogens. Didymella bryoniae powdery mildew sphaerotheca fuliginea, erysiphe cichoracearum 1216 fl oza 16 fl oza 67 fl oza 1 12 begin applications prior to disease development and continue on a 5 to 14day interval. Use higher rate and shorter interval when disease pressure is high. Santa barbara county agricultural commissioner enforcement of federal, foreign and domestic plant pest quarantines california state exterior and interior quarantines. The fungus produces two spore stages, a sexually produced spore perithecia giving rise to ascospores. Cucumber green mottle mosaic virus cucumber green mottle mosaic virus cgmmv is a serious disease which continues to be a serious risk in many areas of watermelon production. A watermelon field in the fall completely devastated by gummy stem blight didymella bryoniae following a significant rain event. Draft watermelon producers guide to preparing for and. Expressed in warm wet weather the optimal temperature is 74 degrees f, symptoms include round, black, wrinkled spots on leaves and sunken dark areas on stems. Calcein was used as an indicator for the endpoint visual detection of dna amplification. Reaction of melon genotypes to didymella bryoniae fuckel rehm. Technical evaluation report polyoxin d zinc salt crops december 12, 2017 page 5 of 16 175 concern i. The symptoms on leaves will first appear in an area of plants surrounding an infected seedling.
Schroth faces of the future symposium, annual meeting of the american phytopathological society, aug. Poster digital files will be made available for viewing online. Watermelon seed may carry the pathogens which cause bfb and gsb. Watermelon citrullus lanatus millionaire anthracnose. Jun 28, 2016 a method was developed using a loopmediated isothermal amplification assay lamp for detecting didymella bryoniae in cucurbit seeds. A method was developed using a loopmediated isothermal amplification assay lamp for detecting didymella bryoniae in cucurbit seeds. Symptom development following splashing of spores onto nearby foliage. Aug 30, 2016 didymella bryoniae is a pathogenic fungus that causes gummy stem blight gsb in cucurbitaceae crops e. The influence of ventilation temperature and of little ventilation with an electric fan, with an air exchange of four compartment volumes per hour, on the development of didymella bryoniae in glasshousegrown autumn cucumber crops was studied on. Rapid and sensitive detection of didymella bryoniae by visual. Characterization of the black rot fungus and an update on bacterial wilt. Pdf factors promoting pycnidia production of didymella bryoniae. Gummy stem blight gsb caused by a fungus, didymella bryoniae is a serious disease which continues to be a significant risk in many areas of watermelon cultivation. Current status of research on plant pathogens and biological.
Pdf visual detection of didymella bryoniae in cucurbit seeds. An accredited seed pathology laboratory using the most current and accepted methods available has. Gsb produces lesions on the stems and leaves, and can also be spread by seeds. Gummy stem blight gsb didymella bryoniae is one of the most important diseases of texas watermelons. The actin region of isolates of stagonosporopsis and allied species of boeremia, didymella. The lamp primers were designed based on the dnadependent rna polymerase ii rpb140 gene rpb2 from d. Didymella bryoniae epicoccum nigrum fusarium moniliforme fusarium oxysporum fusarium solani fusarium solani geotrichum cutaneum malassezia pachydermatis. Rapid and sensitive detection of didymella bryoniae by. Citrullus lanatus colletotrichum orbiculare 1 gummy stem. Pdf a method was developed using a loopmediated isothermal amplification assay lamp for detecting didymella bryoniae in cucurbit. A watermelon field completely defoliated due to disease. Sections of dead, dried watermelon vines naturally infected with didymella bryoniae were placed in nylon mesh bags, covered with soil, and placed in a field at 0, 12.
Transmission of seedborne infection of muskmelon by didymella bryoniae and effect of. Pdf gummy stem blight in cucurbitacea caused by the pathogen didymella bryoniae under high humid conditions was previously recorded. Reaction of melon genotypes to didymella bryoniae fuckel. Kantzes, university of maryland d60ucurbits, black rot c lesions caused by the fungus didymella bryoniae on winter squash fruit. Marin talbot brewer curriculum vitae caes wordpress. United states department of agriculture agricultural. Watermelons were sunburned prior to ripening resulting in 100% loss. Ministry of agriculture, project 9702qa directions for general surface disinfection use 8ml kleengrow per litre of water. An accredited seed pathology laboratory using the most current and accepted methods available has done all testing. Gummy stem blight of balsam pear caused by didymella bryoniae and its anamorph phoma cucurbitacearum. Management of gummy stem blight black rot on cucurbits in. Management of gummy stem blight black rot on cucurbits. Characterization of the black rot fungus and an update on.
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