A head infested with sunflower moth larvae looks trashy and has webbing across the face of the head. The infection may . The head becomes brown and soft. As the rhizopus head rot develops in sunflower, a watery soft rot will develop on the backs of the heads. The sunflower hybrids in the Carrington site had head rot incidence levels of 26% to 97%, while the same hybrids at Morden ranged from 11% to 54% infection. Fusarium oxysporum, Myrothecium roridum Quinisulcius acutus, Sunflower Chlorotic Mottle virus (SuCMoV), Common Names of Diseases, The American Phytopathological Society, https://en.wikipedia.org/w/index.php?title=List_of_sunflower_diseases&oldid=963255109, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License, Alternaria leaf blight, stem spot and head rot, Phymatotrichum root rot (cotton root rot), Sclerotinia basal stalk rot and wilt, mid-stalk rot, head rot, Sclerotium basal stalk and root rot (southern blight), This page was last edited on 18 June 2020, at 19:43. Alternaria helianthi Large sclerotia mixed in with seed confirms that a field contained head rot. Head rot infection is favoured by extended periods of rain, several weeks prior to and during flowering. = Sclerotinia libertiana PP1727-4 The combined analysis indicates that 7 hybrids had head rot infection levels that were numerically lower than the best resistant check. The first symptoms of head rot usually are the appearance of water-soaked spots or bleached areas on receptacles (the fleshy back of the head). develop and pops (empty seed hulls) may occur. AUTHORS: Sam Markell, Tom Gulya, Charlie Block and Bob Harveson SYMPTOMS • Lesions begin as large, soft (mushy), brown areas on the back of heads that turn tan-cream, typically odorless On the average, infected plants yield less than 50 per cent of healthy plants. Plants missing or cut at base. Rhizopus head rot is more serious in southern sunflower production regions including Kansas, Nebraska, Colorado, and the Texas Panhandle. The Sclerotinia diseases are some of the most important diseases of sunflower in the Northern Great Plains.Three diseases are recognized in the field: Sclerotinia wilt, middle stalk rot, and head rot. Leptosphaeria lindquistii Septoria leaf spot, powdery mildew, Rhizopus head rot, and charcoal stem rot are diseases which, although occasionally observed, seldom reach severe proportions. Recently this disease has spread in the local sunflower production areas with really high incidences of up to 90% being recorded in fields in the North West Province and northern Free State of South Africa. = Fusarium tabacinum Sclerotinia wilt and head rot are generally the most important diseases affecting sunflowers. Bacterial stalk rot Pectobacterium carotovorum, subsp. Head Rot Disease. Sclerotinia sclerotiorum. Never compost diseased sunflowers. Diseased plants may occur singly or in patches. White mold is easily identified by the characteristic white cottony mycelium of the pathogen that grows on the surfaces of infected aerial tissues (Fig. Heads are predisposed to rot as a result of injury caused by hail, birds, or the sunflower head moth. Head rot resistance is tested by spraying sunflower heads with lab-produced ascospores, an infectious stage of Sclerotinia. = Phoma oleracea var. = Helminthosporium helianthi Sclerotinia head rot in sunflower. The Rhizopus head rot pathogens require free moisture and a wound to successfully infect sunflower heads. Sclerotinia survives in the soil for up to four years as irregularly-shaped fungal bodies called sclerotia. Sclerotinia head rot. It has historically been considered to be of minor importance, however, it was documented as causing severe losses in Israel, and a recent survey of sunflower diseases in California found that Rhizopus head rot was the most common disease of sunflower. Fusarium solani Sclerotinia Diseases of Sunflower. Sclerotinia head rot • Dries down stalks and green matter to facilitate a timely harvest • Increases combine efficiency and speed while lessening wear and tear • Reduces foreign matter, seed moisture and dockage For more information and product labels, visit sunflowers.farmassist.com. Nectria haematococca [teleomorph] Athelia rolfsii [teleomorph], Verticillium albo-atrum Both mid-stalk head rot occur when ascospores settle on dead plant tissue. Sunflower crops grown in Nebraska are susceptible to diseases caused by bacteria, viruses, and nematodes, but the most economically damaging is head rot, caused by the fungal pathogen Rhizopus. Of these, only six (downy mildew, rust, Sclerotinia stalk and head rot, Verticillium wilt, Phoma black stem, and Alternaria leaf and stem spot) threatens sunflower yields. Fungicides are not currently effective in controlling sclerotinia rot. head rot, and Rhizopus head rot. The affected heads decay, become soft, and black sclerotia form within the heads. Several species of the genus Rhizopus have been implicated in causing head rot, including R. arrhizus A. Fischer, R. stolonifer (Ehrenb.:Fr.) Rhizopus Head Rot of Sunflower in Nebraska Robert M. Harveson, Extension Plant Pathologist Sunflower crops grown in Nebraska are sus-ceptible to diseases caused by bacteria, viruses, and nematodes, but the most economically damaging is head rot, caused by the fungal pathogen Rhizopus. Puccinia xanthii carotovorum and P. atrosepticum Figure 1 Figure 2 Figure 3 PP1727-4 Sunflower Disease Diagnostic Series. (Photos by Bob Harveson) Figure 2. ADVERTISEMENTS: Here is a list of nine major diseases of Sunflower: 1. = Cystopus tragopogonis, Coleosporium helianthi Fungal structures: mycelium, sporangia, and sporangiospores. Cool, moist weather conditions, especially during the ripening period, are unsuitable, because they encourage rust and head rot, while very hot dry conditions cause charcoal rot. A warm and somewhat dry climate is considered optimal for sunflower production. Head rot (Figure 3) is caused by wind-borne spores of the same fungus. This article is a list of diseases of sunflowers (Helianthus annuus) and jerusalem artichoke (H. tuberosus). The disease is most severe in rainy or humid weather during or shortly after flowering. Sclerotinia basal stalk rot and wilt, mid-stalk rot, head rot Sclerotinia sclerotiorum = Sclerotinia libertiana = Whetzelinia sclerotiorum. Sunflower Necrosis Disease 2. The infected head … It usually occurs late in the season, after initial flowering and extended periods of wet weather. In addition to feeding damage, sunflower moth larvae predispose the sunflower head to Rhizopus head rot (Fig. In North Carolina, the sunflower moth is a sporadic pest of sunflowers and other composites such as coneflower. The disease can appear on the flower side of the sunflower head as a grayish, fuzzy substance covered with sporangia, the small, black reproductive fruits of the fungus. Rust Puccinia helianthi Puccinia xanthii Uromyces junci. helianthi-tuberosi [teleomorph], Phomopsis spp. Infested heads are disfigured with dark frass pellets and tangled mats of webbing. Small, irregularly-shaped, sclerotia can be found inside the stem, near the soil line. These are found primarily in the High Plains. Disease Management in Sunfl ower . Although no resistant hybrids are available, progress is being made in reducing the susceptibility of sunflowers to sclerotinia. Rhizopus is the most common. The affected heads turn brown and mushy, and then brittle and hard as they dry out. Damage usually patchy, not uniform throughout field. The sclerotia germinate in the summer, producing either mycelia that infect sunflower roots causing wilt or mushroom-like structures (apothecia) that release wind-borne spores that infect the head causing head rot. In general, the symptoms of damage include drooping, brown or dead upper leaves; plants that turn brown or black and die prematurely (Figure 1); fungal bodies (sclerotia) in the stem at the soil line; (Figure 2) soft, rotting heads (Figure 3) with only fibrous tissue remaining; and black sclerotia in the heads. The fungus can decay the entire receptacle and the seed layer falls away leaving only a bleached, shredded skeleton interspersed with large sclerotia. Also, on the head, large sclerotia develop and infected seeds fall out (Figure 2). Alternaria zinniae, Botrytis cinerea Wilt is distinct because it begins as a root rot, whereas Sclerotinia head rot and middle stalk rot are above-ground diseases caused by airborne spores. DOI: 10.1094/PHI-I-2020-1201-01 AuthorsFebina Mathew, South Dakota State University, Brookings, SD, … Pseudomonas syringae pv. Myrothecium verrucaria, Phoma macdonaldii Dead petals on the back of the heads provide a place for the spores to germinate. As the disease develops, the infection spreads down the stalk and the head looks like a straw broom (Figure 1). Head rot also causes a decrease in oil content and an increase in free fatty acid content. Rhizopus head rot is caused by various fungi in the genus Rhizopus, including R. arrhizus, R. stolonifer, and R. microsporus. = Rhizoctonia bataticola, Plasmopara halstedii Surviving plants may or may not produce seed, depending on when the infection occurs. Infected heads usually shatter during combining and any remaining seeds are lost. Leveillula compositarum f. helianthi Oidiopsis sicula [anamorph] Alternaria leucanthemi The sclerotia that form in diseased stalks and heads are returned to the soil at harvest and can cause sclerotinia diseases in sunflower or other susceptible crops in following years. Wilt occurs whenever sunflower is planted on sclerotinia-infested soil and can cause severe yield loss. Follow a crop rotation of 5 years between susceptible crops. Thanatephorus cucumeris [teleomorph], Rhizopus arrhizus The bleached, skeletonized heads associated with head rot are very obvious in the field, even from a distance. Gibberella intricans [teleomorph] Botryotinia fuckeliania [teleomorph], Macrophomina phaseolina The sclerotia germinate in the summer, producing either mycelia that infect sunflower roots causing wilt or mushroom-like structures (apothecia) that release wind-borne spores that infect the head causing head rot. Pseudomonas syringae pv. 171 . MIDDLE STALK ROT and HEAD ROT: Sclerotinia Head Rot Infestation Of these two infections, head rot is by far the most serious. Please refer to the report for project 5442-21220-010-00D, Sclerotinia Diseases, for additional information. 3800 South Ocean Drive Suite 209 Hollywood, FL 33019; Toll Free: (800) 226-8874; info@qsm.org; Become Q SM Wound Care Certified; PDPM Wound Seminar Immediately afterwards, the mist system is turned on, and it runs intermittently around the clock for the next 3 weeks. Oidium asteris-punicei [anamorph] Pratylenchus hexincisus, Rotylenchulus spp. Peridermium californicum [anamorph], Pratylenchus spp. The overall objective is to identify the time period of maximum sclerotinia infections to sunflower heads and to establish methodology for assessing wild sunflower species for head rot resistance. To minimize head rot, plant to maximize air circulation. Plasmopara helianthi f. helianthi, Fusarium equiseti = Sclerotium bataticola The key to managing these diseases is to plant in non-infested soil and prevent the buildup of sclerotia in soil. The first wilted plants are usually seen just before flowering but most appear in patches during and after flowering. The fungus has a large host range of more than 360 plant species in 225 genera in 64 families. Erysiphe cichoracearum var. The time required from incipient wilt to complete wilting may be four to seven days. mellea, Alternaria alternata The ultimate goal of the USDA Sunflower Unit breeding program is to combine resistance to both Sclerotinia head rot and stalk rot into the same lines, and couple this resistance with good agronomic characters, including high oil content, high oleic acid, downy mildew resistance, and tolerance to … The entire plant dies quickly. Meloidogyne javanica, Tylenchorhynchus nudus Sclerotinia survives in the soil for up to four years as irregularly-shaped fungal bodies called sclerotia. With sclerotinia wilt, young wilted plants often turn black. Locate new plantings as far away as possible from fields where sclerotinia was know to be a problem in the previous four years. Wet soil is required for sclerotia to germinate to produce apothecia. Rhizopus head rot Rhizopus arrhizus = Rhizopus nodosus Rhizopus microsporus Rhizopus stolonifer = Rhizopus nigricans. Uromyces junci, Sclerotinia sclerotiorum Under favorable c… Symptoms in sunflower heads occur at the end of flowering or later. Rhizopus head rot is a common and often severe fungal disease of sunflowers primarily in the high plains of the USA. Monitor fields for sclerotinia diseases and rotate crops. The characteristic symptoms of sclerotinia wilt include sudden wilting of leaves, root rot, and a basal stem canker. Meloidogyne incognita Fungal growth may be visible inside the flower head. = Rhizopus nigricans, Puccinia helianthi Phomopsis helianthi The large sclerotia in the heads may be 12 millimeters (1/2 inch) or greater in diameter and many are harvested along with the seed. Coleosporium pacificum = Phymatotrichum omnivorum, Phytophthora spp. Young wilted plants often turn black whereas mature plants usually remain light brown. However, Sclerotinia head rot of sunflower can cause major damage particularly in late-planted crops that ripen in cool, wet conditions. • Sunflower rust Strong disease control for Verticillium wilt and sclerotinia head rot, however, wilt your sunflowers, form dead patches on the leaves or stems and may affect nearby plants. Head rot reduces seed quality and lead to rancidity. Rust Disease 5. When it comes to sunflowers getting infected through the roots (sclerotia germinating to produce mycelia), there is no requirement for wet soil. Keeping your garden clean and free of weeds and debris, however, is your best line of defense in preventing these sunflower problems from occurring. If a sunflower dies from disease, pull it immediately and dispose of it in the trash. Verticillium dahliae, Albugo tragopogonis The disease appears first as dark spots on the back of ripening heads. Sclerotium Wilt and Collar Rot Disease 6. 0 20 40 60 80 100 % incidence head rot, Aug. 27 % incidence head rot, Sept. 9 Reduction in sunflower Sclerotinia head rot by Vertisan® fungicide applied at early and/or late flowering — Manitoba, Canada, 2014 For the Aug. 27 evaluation, all three application timings for Vertisan® reduced head rot significantly over the untreated and better than the standard latispora P. cichorii = Whetzelinia sclerotiorum, Sclerotium rolfsii Rhizopus (Head Rot) Home » Growers » Diseases » Rhizopus (Head Rot) Rhizopus on back of sunflower head There are several headrots other than Sclerotinia that affect sunflower. Monographella cucumerina [teleomorph], Fusarium moniliforme 5). Secondary symptoms such as Rotylenchulus reniformis, Meloidogyne arenaria For this to occur weather conditions have to be ideal as indicated in the disease cycle description above. Sclerotinia Wilt and Rot Disease 8. Alternaria tenuissima While sunflower problems are few, you may encounter them on occasion. • Can be confused with Rhizopus head rot PP1727-3 Sunflower Disease Diagnostic Series Card 3 of 20. Sclerotinia wilt also leads to increased levels of sclerotia in the soil which, in turn, can result in the removal of fields from sunflower production for many years. Figure 1. Alternaria Leaf Blight Disease 3. These fungi are cosmopolitan in soil and decaying organic matter. Usually, the seeds are not decayed but many are empty. When it comes to sunflowers getting infected through the roots (sclerotia germinating to produce mycelia), there is n… Plant Health Instructor. While both are widely distributed, white mold is a more serious problem in northern production areas, such as North Dakota, South Dakota, and Minnesota. Furthermore, their feeding damage may lead to infection by Rhizopus, a head rot fungus that requires physical injuries to infect the plant. Pythium debaryanum Sunflowers, canola, mustard, dry beans, field peas, lentils, potatoes. This disease can reduce yields up to 50 percent and lower seed oil content as well. . Pythium irregulare, Rhizoctonia solani The upper leaves droop, dry out, and die. Rhizopus stolonifer Leveillula taurica Phytophthora drechsleri, Erysiphe cichoracearum Small irregularly-shaped bodies can be found inside the stem near the soil line. Downy Mildew Disease 4. 1). = Coleosporium madiae Powdery Mildew Disease 9. Head rot is a fungus disease caused by Rhizopus spp. helianthi These spores are carried by wind and infect the sunflower heads to cause head rot. Pythium aphanidermatum Mature plants usually remain light brown. Diseases of Sunflower: […] rotate to sunflower. Rhizopus microsporus = Alternaria tenuis The symptoms of sclerotinia wilt usually appear during flowering. There are 30 or more known diseases of sunflowers, but only 10 are commonly seen. Oidium latisporum[anamorph] Introduction Sunflower production in Nebraska and other areas The heads on wilted plants generally are smaller than those on healthy plants and seed weights are lower. Alternaria helianthicola Chewing injury may be present on leaves. Charcoal Rot Disease 7. Microdochium tabacinum Vuill., and R. microsporusTiegh. = Rhizopus nodosus Sphaerotheca fuliginea, Pythium spp. For further information, contact your GO representative. G1677 Rhizopus Head Rot of Sunflower in Nebraska. Sunflowers are popular mainstays in many home gardens and growing them can be especially rewarding. 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