Gummy Stem Blight. of Gummy Stem Blight on Grafted Watermelon Seedlings with Fungicides Anthony P. Keinath, Clemson University, Coastal Research and Education Center, Charleston, SC 29414-5329 Abstract Keinath, A. P. 2013. The most significant contributor to establishing the infection is how long plant surfaces remain wet. For example, a fungicide containing chlorothalonil for treating gummy stem and Alternaria leaf blights is diluted at a rate 2 3/4 teaspoons of per 1 gallon of water for squashes. Do not save seed from fields where gummy stem blight has been observed. “It would be important to detect the pathogen very early, before it can spread.” RECENT ISSUES. Daconil ® fungicides from GardenTech ® brand offer highly effective three-way protection to prevent, stop, and control gummy stem blight and more than 65 other diseases, including powdery mildew. Gummy stem blight, caused by the fungus Didymella bryoniae as the sexual stage (perithecia giving rise to ascospores) and Phoma cucurbitacearum as the asexual stage (pycnidia producing conidia), is a common disease of all major cucurbits and is present wherever they are grown. Gummy Stem Blight and Black Rot. The disease can be very difficult to control if infected transplants are planted and wet weather comes our way. Abstract. Gummy Stem Blight is a warm weather southern disease. How to Control Gummy Stem Blight: Early intervention and preventive treatments help reduce the risk of serious crop loss to gummy stem blight. Watermelon gummy stem blight is a serious disease that afflicts all major cucurbits.It has been found in these crops since the early 1900s. Others - Fungicide. See also Watermelon gummy stem blight ... Sterilise the soil and/or spray the next lot of seedlings with a fungicide. “Rhyme fungicide is a powerful tool to combat gummy stem blight and powdery mildew, two of the most damaging diseases in watermelons,” says Darin Sloan, insecticide/fungicide segment manager for FMC. Keep reading to find out what causes gummy stem blight and symptoms of the disease. Gummy stem blight (GSB) is a major disease of many cucurbits, including watermelon, cantaloupe, cucumber, pumpkin, squash, muskmelon, and other melons. It is caused by seed borned fungus Didymella bryoniae. It is just possible to see the black dots that contain the spores in the centre of the spot. Didymella bryoniae, the fungus that causes GSB, favors warm and humid weather, leaving the Southeast growing region susceptible to the disease’s devastating effects. Cucumber gummy stem blight, gummy stem blight of cucurbits. ), damping-off and root diseases caused by Pythium, Phytophthora, Rhizoctonia and Fusarium spp. Evaluation of biological and chemical treatments for control of gummy stem blight on cucumber plants grown hydroponically in greenhouses . “It would be important to detect the pathogen very early, before it can spread.” Intermittent rainfall and/or heavy dews aid LSU!AgCenter! Since gummy stem blight can be seed-transmitted, it is not clear at this time what the best sampling method would be in greenhouses where the seed can potentially be the source of the pathogen,” said McGregor, a cucurbit breeder with the UGA College of Agricultural and Environmental Sciences. 6 Citations. It affects the leaves, stems, and fruits of all cucurbits. The experiment was conducted in a commercial watermelon field near Clinton, NC (N34°55.765’; W078°15.585’). Photo 4. Gummy stem blight (GSB) is a devastating disease of cucurbits that has been effectively managed with fungicide applications. The comments above are applicable to the common foliar diseases mentioned above (Alternaria leaf blight, anthracnose and gummy stem blight). Louisiana!!!! Specifically, Langston says the best conditions for an outbreak are temperatures in the mid-80s and above with relative humidity greater than 95%. No irrigation was used. Gummy stem blight develops in humid conditions and in free moisture on leaf surfaces. Infection of seedlings in the nursery is a major threat to watermelon production as it means the fungus is taken to the field and early infection and spread is guaranteed. Diseases Controlled: Early Blight, Alternaria, Gray spots, Leaf blotch, Bean rust, Anthracnose, Cercospora, Gummy stem, Downy mildew.. Rate of application: 3 - 6 tbsp per gal (1.5 kg per acre in 50 gal water.) However, a trial to determine the best time to apply systemic fungicides has been funded by the Illiana Watermelon Association this year at the Southwest Purdue Ag Center. Fungicide Antracol (contact). Since gummy stem blight can be seed-transmitted, it is not clear at this time what the best sampling method would be in greenhouses where the seed can potentially be the source of the pathogen,” said McGregor, a cucurbit breeder with the UGA College of Agricultural and Environmental Sciences. Evaluation of fungicides for control of anthracnose and gummy stem blight of watermelon, Sampson County 2013. In a fungicide experiment, Pristine was the best material for control of gummy stem blight and powdery mildew. Gummy stem blight symptoms first appear on leaves as circular, tan to dark brown spots, with or without water-soaking. If not managed well, it can cause significant yield loss for growers. Utkhede 1 & C.A. When transplants are infected with gummy stem blight it is always best to discard the infected flat and flats around it that would have become infected due to water splashing when watering with overhead irrigation. Gummy stem blight survives on crop residue and in infected seed. Disclaimer While the Agriculture and Horticulture Development Board seeks to ensure that the information contained within this document is accurate at the time of printing, no warranty is given in respect thereof and, to the maximum extent permitted by law the Agriculture and Horticulture … Stem lesions are circular in shape, and tan to dark brown in color. on all edible crops and all non-edible crops (protected) and outdoor strawberry. 04367. Researchers in key melon regions adjusted management recommendations for this disease during 2017 that growers can use to prepare for 2018.. Gummy stem blight infection,Didymella bryoniae, on a seedling. Working in watermelon fields that are wet from rain or dew may spread gummy stem blight. Ten fungicides were evaluated in 2 experiments with rockmelons for control of gummy stem blight caused by Didymella bryoniae. However, the Stagonosporopsis spp. Gummy stem blight occurs in hot, wet weather. & Nakai] in most production areas of the United States. It often appears once the crop canopy has closed and air movement is restricted. On fruit the disease is known as black rot. Gummy stem blight (GSB), caused by the fungus Didymella bryoniae, is the most destructive disease of watermelon and is managed primarily with fungicides. Gummy stem blight of watermelons and other cucurbits refers to the foliar and stem infecting phase of the disease and black rot refers to the fruit rotting phase. Cucurbit powdery mildew in some areas has … “Rainfall really gets it going,” he adds. that cause GSB have rapidly evolved resistance to multiple classes of fungicides. If resistance to Quadris occurs in the area, you must use a fungicide from different fungicide group. While there are some products labeled for organic operations, no efficacy data has been published. ), grey mould (Botrytis sp. Nonetheless, a fungicide trial conducted in North Carolina last year revealed some products that are effective in controlling gummy stem blight on conventional operations. One hour of free water on leaves is sufficient for initial infection; however, continuous leaf wetness is required for subsequent expansion of lesions. Didymella bryoniae), Stagonosporopsis citrulli, and Stagonosporopsis caricae], is a major disease of watermelon [Citrullus lanatus (Thunb.) Lesions often develop first at leaf margins, but eventually entire leaves become covered with lesions. Koch 1 BioControl volume 49, pages 109 – 117 (2004)Cite this article. It prefers moderate temperatures (20- 25°C, 68- 77°F), high humidity and extended periods of leaf wetness. However, do not make more than three applications of Group 3 fungicides per season to reduce the risk of resistance. The fungus is known to infect cucurbits, including cucumber, pumpkin, squash, watermelon, cantaloupe and many others. Gummy Stem Blight Best ... Fungicides effective against gummy stem blight do not control anthracnose. Department!of!Plant!Pathology!&!Crop!Physiology! Stem cankers develop on cortical tissues and often produce brown, gummy exudates. The fungicides (g a.i./ha) tebuconazole (100 and 160), fentin hydroxide (226), prochloraz Mn (231 and 370), benomyl (400), benomyl (400, 500) plus white oil (2 L/ha), propiconazole (100), mancozeb (1600), mancozeb plus phosphonic acid (1600 + 1000), myclobutanil … Melanie!L.!Lewis!Ivey! gummy stem blight and powdery mildew in bio-aerosols during cucurbit production Annual 2016. Sterilise the soil by heating it for one hour, either (i) in a half 44-gallon drum over a fire, or (ii) in an earth oven over hot stones, and covered by leaves or damp sacks. The fungus Didymella bryoniae is the causal organism for this disease. Gummy stem blight control is known to cause yield loss of 30-40% if not properly managed. R.S. 209 Accesses. Either Bravo or Dithane could be alternated with Pristine and there was no difference between these two rotational partner fungicides. Gummy stem blight (GSB), also known as black rot, is a common issue for watermelon producers in the Southeast. PHILADELPHIA, May 31, 2018 – FMC Agricultural Solutions announces it is marketing Rhyme® fungicide for use in watermelon crops, excluding California. Powdery mildew appears during dry spells in June as yellow or white powdery spots on the top or bottom of leaves. Matsum. Plants were transplanted on 23 May with ‘Distinction’ seedless and ‘Sentinel’ seeded melons at a 3:1 ratio (14 plants/plot). In a media release issued by Clemson announcing their release of the 2017 guide, researchers pointed out a major change to recommendations which now … Harvest Fungicide applications are not necessary within two to three weeks of the final harvest. Often, leaves may yellow from powdery mildew growing on the bottom side of the leaf. The disease has become increasingly severe as fungicide usage and genetic resistance have resulted in the effective control of other cucurbit diseases. Prestop is a biofungicide for moderate control of gummy stem blight (Didymella sp. For a complete report of results from our gummy stem blight trial please refer to our Metrics details. Gummy stem blight was first reported in 1891 in France, Italy, and the United States. to manage gummy stem blight. Gummy Stem Blight of Greenhouse Cucumber March, 2018 Gummy stem blight (GSB) is caused by the fungus Didymella bryoniae, previously known as Mycosphaerella melonis. Gummy stem blight (GSB), caused by three related species of Stagonosporopsis [Stagonosporopsis cucurbitacearum (syn. 2015!Fungicide!Spray!Guide!for!VegetablesProduced!in!