Watermelon is susceptible to Fusarium wilt in successively mono-cropped soil. Larvae injure plants by feeding on roots and tunneling through stems. Photos provided by Tom Isakeit, Department of Plant Pathology, Texas A&M University. This disease affects only susceptible watermelon cultivars. They may start as yellow areas, but soon turn brown with purple spores on the undersides of infected leaves. Bacterial wilt of cucurbits also exhibits wilting that begins in only a few leaves. From there it made its way around the Mediterranean and to India and Europe. Affected leaves display marginal chlorosis and necrosis. NC State University and NC Cooperative Extension prohibits discrimination and harassment regardless of age, color, disability, family and marital status, gender identity, national origin, political beliefs, race, religion, sex (including pregnancy), sexual orientation and veteran status. Regularly examine for cucumber beetles. Downy Mildew – Downy mildew is notable for the angular leaf spots it creates as it works its way through watermelon leaves. THE DISEASE AND PATHOGEN Fusarium wilt is one of the most economically important diseases of watermelon. Symptoms begin with wilting, which may be confined to individual runners or may involve the entire plant. Example products for Fusarium wilt control in watermelon: Organic growers have no chemical control options that are effective and need to completely rely on host resistance and cultural strategies for disease control. Fusarium wilt of watermelon causes plants to wilt, and it may begin in one or more vines. The fungus can create survival spores that will live in the soil for many years (5-10). A sticky sap will ooze from … Typically, one side of the plant will exhibit more severe symptoms than the other (Figure 1), which is known as unilateral wilting (Figure 4). They also help spread squash mosaic virus. 89(suppl. Keeping Cucumber Beetles under control can help reduce problems with this disease. The management of bacterial wilt starts with the control of cucumber beetles. Strands do not always form, so repeat several times until seen. Watermelon Foliar Diseases For a larger view and narrative of each disease please click on the photo. Downy mildew is well-known for the leaf spots it forms as it goes its direction into watermelon leaves. Once inside the plant the bacteria multiply and inhibit the transportation of water and nutrients. The disease is present worldwide, and it can result in yield losses nearing 100% when severe. (2) R. X. Latin. Phytopathology (Abstr.) Leaves eventually yellow and brown at the margins, completely wither and die. These two diseases both present unilateral wilting, and cannot be distinguished in the field. It is carried by spotted and striped cucumber beetles. Figure 4. Watermelon Farming. 1 The pathogen that causes this disease is the … Cucumbers are also susceptible to bacterial wilt. It has been more severe where crops are initiated with transplants compared to direct seeding. Bacterial Wilt MWVD also is confused with bacterial wilt, which is caused by Erwinia tracheiphila, a pathogenic bacterium spread by striped and spotted cucumber beetles. Fusarium wilt of watermelon is a specific disease that can’t be transmitted to other plants, including cantaloupe, cucumbers, or others in the same plant family. This factsheet was prepared by the NCSU Vegetable Pathology Lab in 2015. 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). Plant watermelons in raised beds with plastic mulch. Watermelon, however, is resistant to this disease and certain Cut stem, squeeze sap from cut ends, put 2 pieces together, then slowly pull them apart while looking for characteristic thin strands of sticky bacterial material. Brown streaking in the xylem tissue. To reduce the spread of bacterial wilt, treat for the striped or spotted cucumber beetles. On the right, is a research trial with plants showing wilting symptoms due to Phytopthora root and crown rot. The fresh flavor and water content make it perfect for experimenting in the summer heat. N.C. Pot experiments were carried out to investigate the effect of intercropping with aerobic rice on Fusarium wilt in watermelon. Unilateral wilting of single, green vines due to Fusarium wilt. Plant resistant varieties of watermelon if the field has a history of Fusarium wilt. Erwinia tracheiphila . commitment to diversity. Bacterial wilt is mainly caused by Enterobacteriaceae, Erwinia tracheophyta, and Burkholderiaceae, Ralstonia solanacearum. Read our Lamb’s quarter, when allowed to grow alongside watermelon, improves its vigor and amount of minerals in watermelon. N.C. This is the bacterial ooze that clogs the plant. Watermelon diseases like Anthracnose , Downy Mildew , Gummy Stem Blight , Bacterial Wilt and Powdery are main in watermelon farming. The fungus invades the vascular tissue through the root system, which can cause wilting of the whole plant. Image: Howard F. Schwartz, Colorado State University, Bugwood.org. The bacteria are carried from plant to plant by striped or spotted cucumber beetles. However, bacterial wilt occurs on muskmelon and cucumber, but does not affect watermelon. For the latest fungicide recommendations for Fusarium wilt of watermelon see the Southeastern US Vegetable Crop Handbook. Find more information at the following NC State Extension websites: There is an alternate Spanish language version of this document here: Marchitez de Fusarium en sandía. It is commonly transmitted by Cucumber Beetles (they transport the bacteria and create wounds for it to enter the plant). Pseudomonas, Erwinia species. Garden vertically this year, trellis tomatoes, cucumbers, melons, beans, and peas. All leaves are wilted or necrotic. Bacterial wilt causes watermelon to wilt and die immediately when fruit production begins. First Frost Date (FFD) refers to the approximate date of the first killing frost of winter. If watermelons are wilting, this might indicate that there's a fungal problem coming from the soil. Example first frost date on April 08. Last Frost Date (LFD) refers to the approximate date of the last killing frost of spring. Pumpkins and squash are much less susceptible to bacterial wilt than cantaloupe or cucumbers. of bacterial wilt, especially in pumpkin and squash. Initial symptoms of wilt are pale, wilted sections of leaves that are often associated with feeding injury (Figure 1). Use good sanitation practices (removal of infected plant tissue away from the field site, using clean equipment, etc.). One way to determine if bacterial wilt has infected a plant is to cut the stem and squeeze both cut ends. This publication printed on: Dec. 08, 2020, Skip to Favorable Environmental Conditions for the Disease, Skip to Disease Control for Conventional Growers, Skip to Disease Control for Organic Growers, Skip to Disease Control for Home Gardeners, NC State Extension Plant Pathology portal, NC Although infection occurs when spring weather is cool and damp, fusarium wilt can show up on the plant at any stage of growth, any time during the growing season. Figure 1. This disease is severe on cucumber and melon, but is less damaging to squash and watermelon. The pathogen infects in the cool and wet weather when the plants are young and overtakes the vasculature. Rotate crops away from watermelon for 5-10 years if disease is found in the field. A&T State University, in all 100 counties and with the Eastern Band of Cherokee Tricia shows you how to build a variety of quick and easy vegetable trellises. A&T State University. that each was susceptible to the pathogen when the plants were at the 1-leaf stage, but plants inoculated at the 10-leaf stage exhibited no bacterial wilt symptoms, although isolations of Fungicide labels are legal documents, always read and follow fungicide labels. Bacterial colonies recovered from inoculated plants were identical to those recovered from field infected plants. Verticillium wilt of watermelon, caused by Verticillium dahliae has similar symptoms to Fusarium wilt of watermelon. You might also grow your plants under row covers. The causal fungus is named Fusarium oxysporum forma specialis (“special form”) niveum , which is commonly abbreviated as FON. It is very common in moist sandy soils and humid environments, such as the conditions of the coastal south of the US. Figure 2. To our knowledge, this is the first report of bacterial wilt on pumpkin and watermelon in New Mexico. It is commonly transmitted by Cucumber Beetles (they transport the bacteria and create wounds for it to enter the plant). The pathogen can be transported long distances in infected plant tissue, infested soil from transplants, or seed. Flooding in the field can also serve to spread inoculum within a localized area. If the sap is stringy and viscous it is probably wilt. Copper fungicide can control symptoms if it’s applied as soon as symptoms of bacterial fruit blotch are detected. The watermelon has a thick smooth outer rind and a fleshy sweet juicy interior with a high water content (it may be up to 95% water). bacterial wilt is to prevent large numbers of beetles from feeding on small plants. Receive Email Notifications for New Publications. Bacterial Wilt is primarily a disease of the Cucurbits, particularly cucumbers and melons, though it can also attack the Solanum crops (tomato, pepper, potato, eggplant) and corn. Cooperative Extension is based at North Carolina's two land-grant institutions, Bacterial wilt is most severe on cucumber and cantaloupe and less severe on squash, pumpkin and watermelon. It is an excellent desert fruit and their juices contain 92% water along with proteins, minerals and carbohydrates. Fusarium wilt is a patchy disease and healthy plants can be found in between diseased plants. 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. Lamb’s Quarter. Life Cycle of Bacterial Wilt These bacteria cannot live in a dry atmosphere. It was introduced in the Americas in the early 1600s. Infected watermelon vines stay behind and remain green for a short period, then turn yellow and progressively desiccate until wilted plant is completely brown. Bacterial Wilt. commitment to diversity. The disease is favored by cool wet conditions in the spring when infection occurs, but symptoms are observed during the hot and dry conditions in the summer. Hot and dry summer temperatures can stress the plant and cause the wilting symptoms that are typical for the disease. Home gardeners have no chemical control options that are effective and need to completely rely on host resistance and cultural strategies for disease control. Bacterial Wilt. Verticillium wilt of watermelon is not common in North Carolina. When the stem is cut, a white bacterial ooze will often come out of the stem, which does not happen in Fusarium wilt. Indians. A watermelon field with 100% loss in yield due to Phytophthora fruit rot is to the left. This disease is caused by the bacterium Erwinia tracheifila. Few fungicides are available for Fusarium wilt control, but a soil application at transplant with prothioconazole (Proline 480 SC) can reduce disease in the field. This succulent tropical fruit originated in Southern Africa, but was cultivated in North Africa by the ancient Egyptians 4,000 years ago (it is depicted in hieroglyphs). It is recommended that certified clean seed is utilized in the field. Bacterial Wilt of Cucurbits This vascular wilt disease caused by the bacterium Erwinia tracheiphila affects only certain members of the cucumber family including cucumber, squash, muskmelon, pumpkin, and gourd. Bacterial wilt of cucurbits also exhibits wilting that begins in only a few leaves. Wilt progresses to individual runners of a plant. niveum (F. oxysporum). Leave this to dry for a few minutes, then put your finger on it and slowly remove. Bacterial Wilt is primarily a disease of the Cucurbits, particularly cucumbers and melons, though it can also attack the Solanum crops (tomato, pepper, potato, eggplant) and corn. Infected fruits with no symptoms can have post-harvest decay during transit. This wilting eventually spreads to the whole plant and the leaves start to die off, usually without turning yellow first. Bacterial Wilt is primarily a disease of the Cucurbits, particularly cucumbers and melons, though it can also attack the Solanum crops (tomato, pepper, potato, eggplant) and corn. Fusarium wilt causes wilting of the aboveground tissue and general vine decline. Adult cucumber beetles harbor bacterial wilt organism (Pseudomonas lachrymans) in winter and transmit it during the growing season. The first sign of this disease is when one or two leaves wilt in the afternoon, but then recover in the evening. The tested soil was classified as a loam soil, previously planted with watermelon and collected from Hexian county, Anhui province, China. Bacterial wilt is a tomato disease that is caused by the pathogen bacterium Ralstonia Solanacearum. When the stem is cut, a white bacterial ooze will often come out of the stem, which does not happen in Fusarium wilt. When one of these bacteria infects a plant, it spreads by its vessels from the point of contamination to the main stem, then in all the plants. The bacteria resides in the soil and works its way very quickly through the roots and up the stem of … Verticillium wilt of watermelon is not common in North Carolina. ):S10, 1999. vention of bacterial wilt of cucurbits, which affects cucumber, squash, muskmelon, pumpkin, and gourds. Watermelon, however, is extremely resistant to bacterial wilt. However other soil-borne vascular pathogens can also cause this symptom. The fungus colonizes the vasculature in the root and crown, and cutting open the crown can show brown streaking within the xylem (Figure 2). Watermelon are not susceptible to bacterial wilt. Fusarium oxysporum is a soilborne fungus not transported on air currents. The causal agent must be isolated from the infected tissue to discern which pathogen is causing the disease. Bacterial wilt also causes infected plants to rapidly wilt and collapse (Figure 9). This disease is caused by the bacterium Erwinia tracheifila. References: (1) B. Bruton et al. Removing potentially infected crop debris and rotating crops will help to reduce the source of infection. If you suspect Bacterial Wilt, cut a stem near the crown and pull it apart. Watermelons do not get infected with bacterial wilt or squash vine borer. Fusarium wilt is a patchy disease and will cause disease in plants that appear to be randomly scattered around the field (Figure 3). Figure 3. The vascular wilt disease caused by the bacterium . Copyright © 2019 Green Living Solution, Inc. Smart Gardener® is a registered trademark of Green Living Solution, Inc. All rights reserved. Bacterial wilt, a disease caused by the bacterium Erwinia tracheiphila, attacks melons, with particular intensity on cantaloupes. Watermelon is immune and certain varieties of cucumber and squash show varying degrees of resistance to this disease. It is commonly transmitted by Cucumber Beetles (they transport the bacteria and create wounds for it to enter the plant). affects members of the cucurbit family, includ-ing cucumber, squash, muskmelon, pumpkin, and gourd. Symptoms of bacterial wilt progress from localized leaf symptoms to collapse of individual vines and eventually to plant death Prevention & Treatment: There is no chemical control for bacterial wilt once plants become infected. If bacteria are present strands will adhere to the skin and may stretch up to 1/4 inch long. Example first frost date on November 01. The disease is of minor concern on the foliage, but severely affects fruit and renders them unmarketable. Watermelon should be planted in full sun and heavy feeders. Vascular discoloration of the stem at the base of the plant is a characteristic symptom of Fusarium wilt. Both diseases also cause the same dark brown staining of the vascular tissue. Fusarium wilt of watermelon is caused by the fungus Fusarium oxysporum f. sp. Bacterial wilt Once the initial early flush of beetles is gone, any further foliar insecticide applications should be unnecessary, unless they are feeding in large numbers on developing fruit. Plants may wilt at any growth stage, but wilting is often most severe during periods of rapid growth. To test for Bacterial Wilt in cucumber cut a stem near the ground and squeeze until the sticky sap oozes out. Use yellow sticky traps in order to minimize the damage. Dr. Lina Quesada, NC State Vegetable Pathology Lab. Because watermelon is not susceptible to bacterial wilt, insecticides should only be applied when an average of 5 or more beetles are feeding on each plant (Table 2). Fruit produced on a wilting plant usually is not marketable. Lamb’s quarter, also known as Chenopodium album, is a weed, but we would call it a beneficial weed at this point. The watermelon is best eaten fresh all by itself, however it can also be used in, salads, drinks, soup, sorbets, and Granita. Yield losses up … Fusarium wilt of watermelon is the most widespread and destructive disease of watermelon in the southeastern United States and other areas of the world. Of course you should remove infected plants immediately (and wash your hands with soap and water afterwards). Symptoms of Fusarium wilt are similar on all cucurbits and are dependent on several factors It pairs well with arugula and goat cheese for a crunchy summer salad. — Read our Bacterial fruit blotch is a sporadic disease of watermelon in Oklahoma. 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