Watermelon diplodia rot is more prevalent in warm, humid climates where it does not get killed off by winter frosts, but in some climates it can over winter in garden debris, fallen leaves, stems, or fruit. Gummy stem blight, also known as black rot when affecting fruits, is caused by the fungal pathogen Didymella bryoniae (anamorph = Phoma cucurbitacearum). Didymella bryoniae, the fungus that causes GSB, favors warm and humid weather, leaving the Southeast growing region susceptible to the disease’s devastating effects. Watermelon is eaten fresh and used in many culinary dishes for its nutritional value. Photos provided by Tom Isakeit, Department of Plant Pathology, Texas A&M University, unless otherwise noted. Symptoms include leaves with brown or tan spots of various sizes that may eventually cover the entire leaf. The roots of the peperomia watermelon need to have access to a lot of room and oxygen. Gummy Stem Blight and Black Rot of Cucurbits Kenneth W. Seebold Extension Plant Pathologist University of Kentucky College of Agriculture Plant Pathology Extension PPFS-VG-08 FIgure 1 gummy stem blight and black rot in a commercial field of watermelon. Older leaves yellow and fall. Initial symptom of Phytophthora crown and root rot is partial to complete wilting of infected plants. F. falciforme has not been described to infect watermelon but records showed that it could cause crown rot in muskmelon. Symptoms of watermelons with stem end rot may first appear as discolored or wilted leaves. As the disease progresses, stems are colonized by the fungus leading to breakdown of cortical tissues. At this point, it's important to prune out all the remaining affected roots. This fungus is able to infect stems at the soil level, as well as leaves and fruit above ground. Gummy stem blight (also called black rot) is one of the most serious foliar diseases of muskmelon and watermelon in Indiana. Resistance to Phytophthora fruit rot of watermelon caused by Phytophthora capsici in U.S. Plant Introductions (PI). Remove Damaged Roots. Symptoms Of Root Rot. Requirements Watermelon is a warm-season crop, requiring lots of sun and good drainage to develop optimally and growing best at temperatures between 18 and 28°C (65–82°F). The soil for this plant must drain well because if it doesn’t, it will develop stem rot. PACKAGING. Stem Rot Caused by Fungi and Parasites . Fruit may develop water-soaked rings around the stem end, which gradually grow into large, dark, sunken lesions. Most commercial cultivars have resistance to to race 1, but not race 2. HortScience. Watermelon is grown in both residential and commercial gardens. Races 1 and 2 of this fungus are present in several watermelon-growing areas of Texas. The yellowing and dropping … In 1998, a similar disease of watermelon (Citrullus vulgaris L.) transplants occurred in central Serbia, resulting in losses estimated at 20% of plants grown in the nurse … It can affect most aboveground parts of the watermelon plant. An initial suspicion was a fusarium disease and/or a possible Gummy Stem Blight caused by Didymella bryoniae, though this is very uncommon for the watermelon in California. This fungus also causes a fruit rot called black rot. Infected plants are stunted (Fig. A diagnostic sign of gummy stem blight is the black fruiting bodies (pycnidia), which can be found in the lesions. Could CA Farmers Lose CalEPA & Science-Based Pesticide Regulation? The fungi Rhizoctonia and Fusarium, and the oomycetes Pythium, a parasitic plant pathogen, live in the soil from where they attack the plant, often in the seedling stage.Symptoms include spots on the lower part of the stem, in a wide range of colors: gray, brown, black, or vibrant … Stem Rot on Squashes Watermelons (Citrullus lanatus) take around 90 days from planting the seeds to harvesting the fruit -- a long time in the world of vegetable growing. At 50 F. (10 C.) or below, fungal growth goes dormant. 47(12):1682-1689. The vines will usually wilt by … This publication describes the cycle and symptoms of gummy stem Blossom end rot is a common problem of watermelons, caused by a severe lack of available... Watermelon Rotting on the Vine. Current Status of CA Groundwater Sustainability Agencies – Deadline Approaching, New Studies Show Soil Health Practices Increase Farm Profitability, UC Davis Releases 5 New Strawberry Varieties, USDA Announces Details of Support Package for Farmers, EPA Registers Long-Term Use of Sulfoxaflor While Ensuring Pollinator Protection, Western Growers’ Jason Resnick Promoted to Senior Vice President. Fungal diseases such as diplodia stem end rot on watermelons can be especially disheartening as the fruits you’ve patiently grown all summer suddenly seem to rot right off the vine. When harvesting, a large portion of the peduncle should remain attached to the fruit. The fungus Didymella bryoniae causes a disease in watermelons called gummy stem blight, also known as black rot. Watermelons are packaged in 55 to 80-lb cartons holding 3-5 melons; 80-lb 2WGA crates; 800 to 1000-lb small bins; 1400 to1800-lb medium bins; or, shipped in bulk truck loads weighing 34,000-45,000 lb. Race 2 causes only a fruit rot and has been reported only in California and Ohio. Gummy stem blight and powdery mildew are the most common diseases in spring crops. Continue reading to learn more about recognizing and treating stem end rot of watermelon plants. EMBED. Gummy Stem Blight Also known as black rot, gummy stem blight is caused by the fungus Didymella bryoniae. D. bryoniae invades the leaves and stems of watermelon, cucumber, and muskmelon (cantaloupe). Cucurbits, such as watermelon, tend to have high calcium demands and become more susceptible to diseases and disorders when this nutrient need is not met. There are no stories that do not relate directly and exclusively to the vegetable industry, and it is the only publication that covers exclusively the western vegetable industry. Black rot of watermelon fruit only occurs if the vines are severely infected. The first sign of disease is a white, cottony growth on infected tissue. An initial suspicion was a fusarium disease and/or a possible Gummy Stem Blight caused by Didymella bryoniae, though this is very uncommon for the watermelon in California. Stem rot disease was found in garlic (Allium sativum L.) cultivated from 2008 to 2010 in the vegetable gardens of some farmers in Geumsan-myon, Jinju City, Gyeongnam province in Korea.The initial symptoms of the disease were typical water-soaked spots, which progressed to rotting, wilting, blighting, and eventually death. Calcium deficiencies contribute to a plant’s vulnerability to diplodia stem end rot. Gummy stem blight is a problem on cucurbits every year in all parts of South Carolina and other Southeastern states. Early planted fields can have a higher chance to be infected as disease is favorably developed under a cooler temperature. This oftentimes occurs as fruit is setting and the result is weak, sickly fruit. Black rot of watermelon fruit only occurs if the vines are severely infected. A diagnostic sign of gummy stem blight is the black fruiting bodies (pycnidia), which can be found in the lesions. The stems split open and exude a gummy, brown residue. In addition, choosing clean seeds or fungicide-treated seeds can reduce disease initiation. Early symptoms are stunted plants and yellowing of the plant’s old crown leaves. Leaf discoloration and dark chocolate lesions signify fusarium crown rot. What Causes Watermelon End Rot? Harvested fruits should be checked regularly for rotting near the stem and discarded if the disease is present. Fruit may develop water-soaked rings around the stem end, which gradually grow into large, dark, sunken lesions. The first lesions on the fruit will be oval to circular and greasy green in color. Temperatures above 90 degrees Fahrenheit can cause internal flesh breakdown and increase decay, causing the melon to become soft. The disease is of minor importance. The stems may split to form open … A four-year rotation of planting non-cucurbit species is usually chosen for the disease control. The rind of watermelons with stem rot is usually thin, dark, and soft. You might have to cut off a significant amount of the root system if the plant is severely affected. – By Zheng Wang, UCCE Vegetable Crops Farm Advisor, Your email address will not be published. Infection can occur very early in the growing season, but above ground symptoms are not usually apparent until much later in the season. As the disease progresses, the plant gradually turns yellow and may die. The disease is most severe on cucumber, but watermelon, pumpkin, and melon can also be affected. Growing your own fruit can be an empowering and delicious success, or it can be a frustrating disaster if things go wrong. To fight root rot, if a plant is in the ground, then allow the soil to completely dry before watering it again. Find more gardening information on Gardening Know How: Keep up to date with all that's happening in and around the garden. Fruit is rarely affected, but loss of foliage may affect yield and fruit quality. The root cortex will often slough off. The rind of watermelons with stem rot is usually thin, dark, and soft. The best tip for growing watermelon peperomia plants is never to allow the roots to sit in waterlogged soil. Gummy stem blight shows a variety of symptoms which are referred to as leafspot, stem canker, vine wilt, and black rot or fruit. Eventually, the entire plant wilts and dies. Heat may also affect the quality of the fruit. Fusarium crown and foot rot is caused by F. solani f. sp. Infection on watermelon and cantaloupe is commonly seen in Florida, and the disease can cause significant production losses when conditions are ideal for the spread of this fungal … Based on detailed surveys of 46 commercial watermelon fields in spring 2015 and 2016, 45% of the fields had gummy stem blight on more than 50% of the diseased leaves in the field. are found in most, if not all soils, of the world. Gummy stem blight, a disease caused by a fungal pathogen, results in the formation of brown, soft, circular lesions on watermelon. Gummy stem blight shows a variety of symptoms which are referred to as leafspot, stem canker, vine wilt, and black rot or fruit. Applying calcium nitrate regularly through the growing season is recommended for healthy watermelon plants. Sign up for our newsletter. Gummy Stem Blight can affect a host at any stage of growth in its development and affects all parts of the host including leaves, stems and fruits. Infected fruits should be removed from the plant as soon as they are spotted to redirect energy to healthy fruit and reduce the spread of diplodia stem end rot. I sent leaf, runner, and stem samples to the UC Davis Fungal Pathogen Lab and the results came back with the Fusarium Crown Rot caused by F. solani f. sp. Watermelon Fruit Age and Development of Phytophthora fruit rot on resistant and susceptible lines - … The best fungicides are Luna Experience, Miravis Prime, Switch, or … 4. Symptoms: Stems, leaves and fruit could all be affected, with leaves displaying brown to black spots. Required fields are marked *, Western Growers’ veteran Jason Resnick has been promoted to Senior Vice President and Gene…. The fungi Rhizoctonia and Fusarium, and the oomycetes Pythium, a parasitic plant pathogen, live in the soil from where they attack the plant, often in the seedling stage.Symptoms include spots on the lower part of the stem, in a wide range of colors: gray, brown, black, or vibrant red. Growth of infected plants slows as compared to healthy plants. The disease requires fungicide applications for control. The fungus Didymella bryoniaeis the causal organism for this disease. Initial symptoms may be yellowing leaves, but as the infection progresses, the watermelons may develop rotted areas similar to belly rot -- sunken, dark spots that appear waterlogged. Gummy stem blight . Common Watermelon Peperomia Pests and diseases. D. bryoniae invades the leaves and stems of watermelon, cucumber, and muskmelon (cantaloupe). Above ground portions of the plant can also be highly infected as shown in this case … The most common diseases of watermelon are anthracnose, fusarium wilt, , downy mildew, gummy stem blight, root-knot nematode and virus diseases. The disease can also cause root rot, damping off the transplants, crown rot, and aerial decay. 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Based on detailed surveys of 46 commercial watermelon fields in spring 2015 and 2016, 45% of the fields had gummy stem blight on more than 50% of the diseased leaves in the field. Gummy stem blight (Didymella bryoniae) colonies were not recovered from the samples, which did not surprise me because this disease is mostly prevalent in the southeast and north area, such as Georgia, South/North Carolina, and Delaware. Gummy stem blight and black rot can look like other plant diseases that affect cucurbits; however, this pathogen can be distinguished by stem and vine lesions near nodes, black fruiting bodies on dead tissue along with the characteristic brown gummy exudate from wounds near lesions. Upon closer inspection, browning and/or drying of the stem ends is apparent. Management of Gummy Stem Blight (Black Rot) on Cucurbits in Florida 4 Figure 11. Gummy stem blight refers to the foliar and stem-infecting phase of the disease, black rot to the fruit rot phase (see fact sheet, page 732.10, Fruit Rots of Squash and Pumpkins). That is why vegetable growers and PCAs turn first, and some exclusively, to Vegetables West, Grower & PCA for their vegetable industry news and information. Pythium fruit rot (also called Pythium cottony leak) of cucurbits is caused by several fungus-like organism of the genus Pythium. Tiny black pimple-like fruiting bodies of the fungus (pycnidia) develop within the infected tissue. Watermelon is a common crop in many home gardens and is fairly low-maintenance, but some problems can occur, including conditions that may cause the fruit to turn black and rot. Two races have been described. The dark area at the base of the stem is a result of infection by the fungus Thielaviopsis basicola , causal agent of black root rot of watermelon. Four foliar diseases reduce watermelon yields in South Carolina. Proper sanitary practices can reduce the spread of fungal diseases. cucurbitae and possibility of F. falciforme. Belly rot occurs on the bottoms of ripening watermelon. Watermelon: Gummy stem blight (GSB; Black Rot) Host: Citrullus lanatus var. In the field, 50% of the plants showed leaf and vine wilt and about 20% died (see the field image). The fruits can reach an immense size, with many varieties weighing in at 18 to 25 pounds. Advanced embedding details, examples, and help! The field was planted by a 45-ct and mini-watermelon cultivars. This disease is currently confirmed in multiple locations in Northwest and Northeast of Florida. Main stem lesions enlarge and slowly girdle the main stem resulting in a brown canker that produces a characteristic red or brown gummy fluid. Watermelon should be … Infected watermelon vines stay behind and remain green for a short period, then turn yellow and progressively desiccate until wilted plant is completely brown. The stems split open and exude a gummy, brown residue. General. Symptoms and Signs A wide range of foliar symptoms occurs on cucurbits, which can make diagnosis difficult. Watermelon diseases : Stem end rot (Diplodia) Item Preview remove-circle Share or Embed This Item. Various types of information demonstrate that the pathogen (F. solani f. sp. Gummy stem blight is a stem and leaf disease of cucumber, cantaloupe, pumpkin and watermelon caused by the fungus Didymella bryoniae. Watermelon, an enormous vine, makes an excellent living mulch, snaking, as it does, amongst our tomatoes and okra. Watermelon vine decline is generally a problem in sites with clay or silt soil. Soil moisture does affect the development of the disease. In severely affected plants, pinkish-orange masses of macroconidia and microconidia and/or a cottony-like mycelial growth may be observed on the outside of the stem. The symptoms of monosporascus root and vine rot of watermelon often go unnoticed until a few weeks before harvest. The appearance of spots on the leaves, petioles and stems are a typical sign of infection which usually … The lesions usually form first on the bottom of the fruit, close to where the fruit comes into contact with the soil. Stem cankers can girdle the stems and cause wilting a few weeks after infection. Gummy stem blight (caused by D. bryoniae/P. (Credit: Tom Kucharek and Norm Schenck) moisture level of 85% RH caused by consistent leaf wetness for 1–10 hours. As the stem ends rot, dark black patches may form … Symptoms: Gummy stem blight refers to the stem phase of this disease, which is more common on cantaloupes. Watermelon is a living mulch. Vine-declined and wilted watermelon plants from the disease infection. FIgure 1 Gummy stem blight is a problem on cucurbits every year in all parts of South Carolina and other Southeastern states. The fungus Didymella bryoniae causes a disease in watermelons called gummy stem blight, also known as black rot. Watermelon will yield best if grown in a light, well-draining soil, rich in organic matter and with a pH between 6.0 and 7.0. Blossom End Rot on Watermelon. During high temperatures, plants can lose calcium from transpiration. Gummy stem blight is a highly destructive, foliar fungal disease of watermelon that can cause yield losses of more than 50%. Ideally, you need your peperomia soil to dry out reasonably fast between waterings. Pythium usually causes a brown rot of root tips and cortex that may progress up the stem. Phytophthora crown and root rot/ fruit rot. Newly infected watermelons will start to show symptoms within 7-12 days. Gummy stem blight (GSB) is a major disease of many cucurbits, including watermelon, cantaloupe, cucumber, pumpkin, squash, muskmelon, and other melons. It occurs worldwide and is responsible for the disease in New York. Extremely wet soil especially with drip tape breakage creates a favorable microclimate, which definitely accelerates the reproduction of spores and spread of the disease to other rows. Phytophthora fruit rot of watermelon causes large, soft areas to develop on mature watermelon fruit. If not managed well, it can cause significant yield loss for growers. Gummy stem blight (GSB), also known as black rot, is a common issue for watermelon producers in the Southeast. Gummy stem blight is large, round spots on the edges of leaves and dry cankers on the main stem (figure 1). Black rot symptoms on watermelon, honeydew melon, and butternut squash. cucurbitacearum) is one of the most important diseases of watermelons in Florida. It is named Watermelon Peperomia because its leaves resemble the rind of a watermelon. cucurbitae) is seedborne and survives only for two to three years in soil. Watermelon Root & Vascular Diseases For a larger view and narrative of each disease please click on the photo. Pythium spp. It is a fungus that can kill the roots and infect the soil. Watermelon Peperomia is a tropical evergreen herbaceous shrub that is erect and bushy, grows up to 8" tall and can be used as a houseplant in temperate climates. Anthracnose; Bacterial Fruit Blotch; Bacterial Rind Necrosis; Belly Rot; Blossom End Rot; Bottle Neck; Cross Stitch; Fruit Cracking/Scarring; Lasiodiplodia Fruit Rot / Diplodia Stem-End Rot; Pimples; Splitting; Sunburn; Watermelon Insects; Watermelon Root & Vascular Diseases. The lesions subsequently merge and become brownish-black in color—hence the disease is also known as black rot … On watermelon, the disease is mainly confined to the foliage (leaves and petioles), although seedling blight and fruit rot occasionally occur. Watermelon Fruit Diseases. Watermelon fruit will rot if the vines are severely infected. After a thorough soaking, an ideal soil mix should become … In late June, I was contacted by a watermelon grower and visited his field near the border of Stanislaus and Merced County. Remove any roots that are black, brown or feel soft. Host Crops and Plants Gummy stem blight affects all cucurbit crops such as cucumber, watermelon, melon, cantaloupe, squash, and pumpkin. The ideal temperature for storing watermelons is 50 to 60 degrees Fahrenheit. Infected fruits may just fall off the plant, leaving the stem still hanging on the plant and a dark rotted hole in the fruit. There are no upcoming events at this time. Cause: Fungus – Didymella bryoniae. Nighttime temperature and moisture conditions prevalent in Florida are ideal for Store watermelons in a dry place; high humidity can encourage stem-end rot. Also known as black rot, gummy stem blight is caused by the fungus Didymella bryoniae. As the disease progresses, the rot on the crown develops from a light-colored, water-soaked area to be darker. State of the California Tomato Industry with Bruce Rominger, Farmer Member on CA Water Resources Control Board Urges Farmers. Those same lesions will become brown to black and look sunken. As the stem ends rot, dark black patches may form in the decayed lesions. The vegetable variety is listed first followed by the resistant diseases. More information about the Fusarium crown rot on cucurbits can be found at UC IPM: http://ipm.ucanr.edu/PMG/r116100911.html. Gummy stem blight is a stem and leaf disease of cucumber, cantaloupe, pumpkin and watermelon caused by the fungus Didymella bryoniae. Bright but indirect sunlight and over-watering will cause root rot … The disease causes the plant to form large dark brown spots on its leaves that may have a ringed appearance. In 1989, a wilt and stem rot of muskmelon (Cucumis melo L.) was reported on seedlings grown under plastic in northern Serbia (1). Initial symptoms may be yellowing leaves, but as the infection progresses, the watermelons may develop rotted areas similar to belly rot -- sunken, dark spots that appear waterlogged. The first sign of disease is a white, cottony growth on infected tissue. Root rot occurs when plant roots have been in stagnant water for too long. Lasiodiplodia Fruit Rot / Diplodia Stem-End Rot Causal Agent: (fungus – Lasiodiplodia theobromae): Watersoaking is seen at the stem end and the tissue is soft. Below is a list of common vegetables and seed varieties that are resistant to disease and other conditions. Stem infections consist of brown, oblong, water-soaked lesions. Damp, soggy soil causes root rot and, eventually, plant death. Roots appear dark brown or black and few or no white roots or root tips can be found when the root ball is washed free of soil. Unlike fusarium wilt caused by F. oxysporum f. sp. This disease will still grow and spread in post-harvest storage. niveum, the vascular system of crown rot infected plants typically does not show discoloration far above soil line, instead, necrotic rot of crown and taproot can be seen. A watermelon field with 100% loss in yield due to Phytophthora fruit rot is to the left. *Note that although some plants naturally have brown dark … Ovoid-shaped sporangia on infected tissue releases zoospores, the asexual reproductive structure, which can easily move in water spreading the disease. Race 1 causes a root, stem, and fruit rot. In melons, calcium helps build thick, firm rinds while also regulating salt and activating available potassium. This fungus also causes a fruit rot called black rot. Symptoms may be difficult to distinguish from other foliar diseases and include brown to black leaf spots, stem cankers, or fruit spots. Watermelon Fruit Diseases. Apply fungicide to the soil before its first watering. Sign up to get all the latest gardening tips! Vascular discoloration of the stem at the base of the plant is a characteristic symptom of Fusarium wilt. Symptoms generally consist of circular dark tan lesions that blight the leaf, water soaked leaves, stem … Tools and storage equipment should also be washed with bleach and water. Stem Rot Caused by Fungi and Parasites . Symptoms appear from mid to late summer and can run rampant in humid semi-tropic to tropical locations, when temperatures steadily linger between 77 and 86 F. (25-30 C.). Irrigating watermelons. Fruit rot in watermelon is only a problem if the vines are severely infected with gummy stem blight. Anthracnose; Bacterial Fruit Blotch; Bacterial Rind Necrosis; Belly Rot; Blossom End Rot; Bottle Neck; Cross Stitch; Fruit Cracking/Scarring; Lasiodiplodia Fruit Rot / Diplodia Stem-End Rot; Pimples; Splitting; Sunburn; Watermelon Insects; Watermelon Root & Vascular Diseases. The grower told me that the field was just harvested once but symptoms were already present beforehand. cucurbitae. Diplodia Stem End Rot On Watermelons – Behandelen van watermeloenen met Stem End Rot Schimmelziekten zoals diplodia stengelrot op watermeloenen kunnen bijzonder ontmoedigend zijn omdat de vruchten die je de hele zomer geduldig hebt gekweekt plotseling lijken … Storage and marketing diseases are black rot, phytophthora rot, rhizopus rot, and stem-end rot. All cucurbits are susceptible to sclerotina stem rot. Watermelons are available in both seeded and seedless varieties and range in size based upon the variety grown. Lesions on fruits of cucumber, muskmelon, and watermelon are first oval to circular and greasy green in color. These lesions may expand and spread to cause a root and stem rot. Symptoms include leaves with brown or tan spots of various sizes that may eventually cover the entire leaf. Gummy Stem Blight is a cucurbit-rot disease caused by the fungal plant pathogen Didymella bryoniae (anamorph Phoma cucurbitacearum). Growers using surface drip irrigation should specifically pay more attention to the tape damage and fix the problem timely. Watermelon diplodia is a fungal disorder, spread by Lasiodiplodia theobromine fungi, that generally results in post-harvest crop loss of watermelon, cantaloupe, and honeydew. Another common problem to watch for is blossom end rot, which causes dark, rotting areas on one end of the watermelon. Evidence indicated that fusarium crown rot is more common on summer squash and pumpkin, however, all cucurbits can be infected. Adding fertilizer to the peperomia soil shouldn’t … I’ve laid down a layer of straw as mulch, but the watermelon adds a little more to the shade and water retention effort. As the disease progresses, the plant gradually turns yellow and may die. First published in 1996, from cole crops to cucurbits, from legumes to nurseries, from bulbs to rooting vegetables, and from small growers to large, Vegetables West covers them all. Upon closer inspection, browning and/or drying of the stem ends is apparent. Monosporascus cannonballus infects the roots of plants, primarily the secondary and tertiary roots. 4), and lower leaves may turn yellow, curl, and fall off.Under severe conditions, entire plants are killed. Watermelon is a delicious summer treat, but to protect your health, it's important to know if a watermelon is bad. The disease causes the plant to form large dark brown spots on its leaves that may have a ringed appearance.