Alternaria blight of sunflower TNAU

early blight (Alternaria solani ) on potato (Solanum

TNAU Agritech Portal :: Crop Protectio

The disease is a destructive one, widely distributed wherever the crop is grown. Severe reduction in seed and oil yield reported. The most affected components are number of seeds per head and the seed yield per plant. The disease also affects the quality of sunflower seeds by affecting germination and initial vigour of the seedlings Crop: Sunflower, Scientific Name: Helianthus annus, Family: Asteraceae : Alternaria blight: Rust : Charcoal rot : Rhizopus head rot : Sclerotium wilt or rot: Downy. Keywords: Alternaria, sunflower, screening, leaf spot Sunflower (TNAU), Coimbatore (Table 1). The field experiments were carried out at Department of Oilseeds, TNAU, Coimbatore during kharif, 2014. The trial was conducted with two replications in a Alternaria leaf blight caused by Alternaria helianthi is Alternaria leaf blight of sunflower is characterised by irregular dark, necrotic lesions with a greyish brown centre surrounded by a chlorotic halo on the leaves, stem, petioles and capitulum (Kim and Mathur, 2006)

The pathogen produces cylindrical conidiophores, which are pale grey-yellow coloured, straight or curved, geniculate, simple or branched, septate and bear single conidium. Conidiaare cylindrical to long ellipsoid, straight or slightly curved, pale grey-yellow to pale brown, 1 to 2 septate with longitudinal septa Life Cycle: Alternaria on stem There are several species of Alternaria which all overwinter on diseased stalks. Disease development is promoted by extended warm and moist conditions. Extended wet periods can hasten the disease significantly. Damage: Excessive leaf loss will lead to yield loss.Reports of yield loss up to 90% have been reported in subtropical areas Alternaria occurs in all sunflower producing areas and is currently a potential disease threat to sunflower production in South Africa. Alternaria survives between sunflower crops in and on infested crop debris, on weed hosts and on seed In order to manage the most important disease of sunflower, Alternaria leaf blight, management practices were taken up and also to know the effective among the chemical fungicides, botanicals, and entophytes abiotic inducers tested. In the present investigation, it is evident that Pseudomonas sp. under study was found to be effective in controlling the disease, which in turn reflected on higher yield Wang TY, Zhao J, Sun P, Wu XH (2014) Characterization of Alternaria species associated with leaf blight of sunflower in China. Eur J Plant Pathol 140:301-315. CAS Google Scholar Wang TY, Zhao J, Ma GP, Bao SW, Wu XH (2019) Leaf blight of sunflower caused by Alternaria tenuissima and A. alternata in Beijing, China. Can J Plant Pathol 41:372-37

• Seldom a problem in drier sunflower-production areas • Can be confused with Alternaria leaf blight and bacterial leaf spot. Larger rounded lesions with pycnidia help distinguish Septoria leaf spot from Alternaria leaf spot Alternaria leaf blight first infects mature leaves near the crown of the plant. Leaf spots start as small brown spots, often with a yellow halo, and grow into irregular brown spots (up to 3/4). Leaf spots sometimes develop a target-like pattern of rings. Severely infected leaves turn brown, curl upward, wither and die Alternaria Leaf Blight Disease: In India, Alternaria leaf blight is the major disease since the introduction of sunflower crop. It appears in the entire sunflower growing areas of India in low to severe form. The disease has been reported to reduce the seed yield by 27 to 80% and oil yield by 17 to 33% Keywords: Sunflower, Alternaria leaf blight, Alternaria alternata, culture medium, Growth, sporulation Introduction Sunflower is one of the major oil seed crops grown in India. Its production can be limited by blight disease caused by A. alternata, which decreases seed germination and seedling survival (Udayashankar et al., 2011) [9]. It causes. Various fungi of the genus Alternariacan cause Alternaria leaf spot. Stem spotting and a head rot can also occur. A. helianthi is the most common pathogen responsible for the disease, but A. zinniae and A.alternata can occasionally attack sunflower

early blight (Alternaria solani ) on tomato (Lycopersicon

Alternaria panax: Primarily attacks ginseng as an alternaria blight. Alternaria radicina: Causes black rot in carrots both in soil and in later storage of crops. Alternaria solani: Extremely common, causing early blight in tomatoes and potatoes. Can cause stem lesions/fruit rot in tomato and tuber blight on potatoes, as well as visible. Susceptibility of sunflower breeding material to Alternaria sp. KarolinaVrandecic 1, Drazenka Jurkovic1, Jasenka Cosic , Tomislav Duvnjak2, Jelena Postic1 1Faculty of Agriculture, Svaciceva 1d, Osijek 31000, Croatia, karolina.vrandecic@pfos.hr 2Agricultural Institute in Osijek, Juzno predgradje 17, Osijek 31000, Croatia ABSTRACT In Croatia the leaf and stem spot disease caused by Alternaria. Effect of TNAU-Pf1 seed biopriming and foliar spray of newer fungicides on the incidence of leaf blight of sunflower Seed biopriming followed by foliar spray of different newer fungicide molecules to manage sunflower leaf spot under field conditions have been tried in Coimbatore, Tamil Nadu, India for three consecutive years (2014-2016) Table 1: Potential and actual losses estimated for the major diseases of sunflower in India Disease Potential (%) Actual (%) Alternaria blight 90 10-40 Downy mildew 80 2-25 Rust 35 1-10 Soil borne 30 1-10 Seed borne 23 2-7 Sunflower necrosis disease 90 5-7 Safflower leaf spot / blight caused by Alternaria carthami (Chowdhury) is serious diseases in India. Considering the economic importance and seriousness of the disease, the present cost effective management practices against the test pathogen present in vitro studies were conducted during 2012-13

Alternaria leaf blight (Alternaria helianthi (Hanford) Tubaki and Nishihara and Alternaria alternata (Fries) Keissler)Description and symptoms . Alternaria species affects all aerial parts of the plant such as the leaf, petiole, stem, floral parts and seeds of sunflower plants during emergence and throughout the growing stages of the plant (Malone and Muskett, 1997) Genus: Alternaria • Is a fungus causing leaf blight and other diseases on over 380 host species of plant. • It is an opportunistic pathogen on numerous hosts causing leaf spots, rots and blights on many plant parts Disease symptoms: Alternaria leaf spot with concentric rings All the aerial parts of the plant, i.e., stem, leaves, inflorescence and capsules are liable to be attacked. These may appear on any portion of the leaf and are irregular, scattered, and have concentric rings. These are brown and later become covered with bluish-green or sooty growth Alternaria helianthi is a fungal plant pathogen causing a disease in sunflowers known as Alternaria blight of sunflower

Control of Alternaria leaf blight caused by Alternaria

  1. Among biotic stresses Alternaria blight caused by Alterneria lini and A. linicola is the most important disease in eastern India and known to inflict 40-60 % of theoretical yield losses in linseed [ 3 - 5] The crop has poor resistance base against this disease in national gene pool [ 6, 7 ]
  2. g followed by foliar spray of different newer fungicide molecules to manage sunflower leaf spot under field conditions have been tried in Coimbatore, Tamil Nadu, India for three consecutive years (2014-2016). The result indicated that among the different treatments tested, seed biopri
  3. Theory . Symptoms, etiology, disease cycle and management of following diseases. Diseases of field crops: Diseases of Wheat: Rusts, loose smut, karnal bunt, powdery mildew, alternaria blight, and ear cockle.Diseases of Sugarcane: Red rot, smut, wilt, grassy shoot, ratoon stunting and Pokkah Boeng Diseases of Sunflower: Sclerotinia stem rot and Alternaria blight Diseases of Mustard: Alternaria.
  4. The disease attacks on the lower leaves as small circular brown necrotic spots which slowly increase in size. Many concentric spots coalesce to cover large patches showing blightening and defoliation in severe cases. Circular to linear, dark brown lesions also develop on stems and pods, which are elongated at later stage

Sunflower :: Major Disease :: Leaf Bligh

Alternaria leaf blight of sunflower is currently one of the major potential disease threatening of sunflower and capable of causing yield losses in all production regions. Once infected, the symptoms appear on the bottom leaves and consist of small, irregular, dark necrotic spots; gradually, the spots spread to the stem, petiole, and also. Sunflower is an important oilseed crop of Pakistan, comprising 20% proteins and 38-45% oil contents. Alternaria leaf blight (ALB) caused by Alternaria alternata, is one of the devastating diseases of sunflower.Six different fungicides viz., difenoconazole, hexaconazole, azoxystrobin, dimethomorph + mancozeb, myclobutanil and Sulphur were tested at different concentrations (10, 20, 30 ppm) in. Sunflower (Helianthus annuus L.) is an important oilseed seed crop in India. Sun flower is susceptible to a large variety of devastating disea ses. But Alternaria blight caused by the fungus Alternaria helianthi (Hansf.) Tubaki & Nishhara is a serious disease of sunflower in many parts of the world including India Alternaria leaf blight (ALB) has been shown in recent years to be one of the major potential disease threats of sunflower capable of causing yield losses in all major production areas. The aim of this study was to determine the causal agent, prevalence and geographical distribution of ALB in the major sunflower production areas of South Africa In South Africa there are no registered foliar fungicides on sunflowers that can be used legally to control these diseases. For more information on sunflower Alternaria leaf blight, brown rust and Septoria leaf spot, contact the authors at. 018 299 6100 or RamusiM@arc.agric.za and FlettB@arc.agric.za. Publication: February 2014

Alternaria - National Sunflower Association Hom

FOLIAR DISEASES OF SUNFLOWER: Alternaria leaf blight

  1. Alternaria leaf blight sampling. Alternaria species were recovered from sunflower seeds and symptomatic leaves. The leaves were sampled from the major sunflower production areas of South Africa; North West, Limpopo, Free State, Mpumalanga and Gauteng provinces during surveys in 2013 and 2014 (Table 1).Samples of diseased sunflower leaves were placed in individual paper bags to prevent rapid.
  2. Sunflower (Helianthus annuus L.), belonging to the family Asteraceae, is one of the most important oilseed crops in China.Leaf blight, caused by Alternaria species, is a serious and potentially destructive disease on sunflower, resulting in premature defoliation when warm temperature and high relative humidity prevail (Prathuangwong et al. 1991).The disease significantly reduces sunflower head.
  3. Alternaria leaf and stem spot is caused by the fungus Alternaria.Two species of Alternaria cause disease on sunflowers, Alternaria helianthi (now known as Alterniaster helianthi) and Alternaria zinniae with A. helianthi being more common. Symptoms include irregular leaf spots, stem lesions, and dark brown spots on the seed heads

Characterization of Alternaria species causing leaf spot

Sunflower Disease Diagnostic Series — Publication

Field experiment was carried out to assess the efficacy of plant oils, plant extracts and antagonistic microorganisms against leaf blight disease of onion caused by Alternaria alternata.Two sprays of neem oil (3%) given on onion plants at the first appearance of the disease and the second on 15 days later recorded significantly the lowest percent disease index (22.22%) and besides increasing. Alternaria Blight. It is caused by Alternaria brassicae. The pathogen perpetuates through seed and affected plant portion (refuse) in the soil. Characterized by the appearance of concentric black spots on leaves, stem and pods. Such pods contain shriveled, undersized seeds. Control Measures : Use healthy seeds. Spray Duter or Difolatan or. Based on field evaluation of different fungicides against foliar diseases, the fungicide propiconzole was found to be very effective in controlling all foliar diseases (Alternaria blight, leaf spot, grey mildew and bacterial blight) and recorded the maximum seed cotton yield (Sub Project)

Alternaria leaf blight UMN Extensio

(Dabbas and Bais, 1977) on mungbean for Alternaria leaf spot on brinjal for Alternaria leaf spot, (Ratan et al., 2003) marigold for Alternaria blight, (Khan et al., 2004) on linseed for Alternaria blight. The results of all these workers fully supported present findings damping off, early blight, late blight, Fusarium wilt, Verticillium wilt, bacterial wilt and tomato mosaic virus. Among the diseases early blight caused by Alternaria solani (Ellis and Martin) Jones and Grout is one of the most severe disease in India can cause direct loss by th The leaf blight disease of sunflower (Helianthus annuus) caused by Alternaria helianthi is a serious threat to its cultivation worldwide. Early and accurate detection of the pathogen is critical to efficient disease management and in avoiding further losses due to epidemics in sunflower. Conventional methods of detection and identification are time consuming, labour intensive, and lack. Under artificial screening in green house condition both at TNAU, Coimbatore and Indian Institute of Rice Research, Hyderabad, it showed high resistance to bacterial blight. Out of the 12 pathogenic races tested, the culture is resistant to almost all (11) races of the BB pathogen As regards the sunflower disease situation in this region of Maharashtra State, a major survey was conducted during 1995-96. The survey results revealed that after Alternaria blight, downy mildew is the second major disease. Downy mildew incidence was registered in about 36% of sunflower fields (Shirshikar, 1997). * Corresponding autho

Sunflower, Helianthus annuus, is an herbaceous annual plant in the family Asteraceae, grown for its seeds.The plant has a thick, hairy, erect stem which gives rise to a large flower head. The plant has large, broad lower leaves which are oval and arranged alternately on the stem and smaller, narrower upper leaves which are attached individually to the stem Management of sunflower Alternaria blight with new fungicides. 219. Shreeshain Sonyal . The disease gaining national importance, pomgranate wilt complex. 220. Shweta Badoni et al. Study of Environment Factors on Rust of Field Pea and its Management through the application of fungicides and Botanicals. 221. Singh CB et a Pathogen biology The causal pathogen of early blight is the fungus Alternaria solani. There is no known sexual stage and hence it is classified as a Deuteromycete. The genus Alternaria is a large and important group of pathogenic fungi, which cause a significant number of important diseases. The fungus is readily cultured on artificial media such as V8 juice where it produces a deeply.

Hence, an in-vitro evaluation of selected fungicides on the Growth and Sporulation of Alternaria alternata causing blight disease of broad bean (Vicia faba L.) was under taken in the present investigation. A judicious application of Tricyclazole and Copper oxychloride at 1000ppm can effectively manages the blight disease of broad bean and. Sunflower (Helianthus annuus L.) is an important oilseed crop in China and is grown in rotation with potato in the northern parts of China, including Inner Mongolia, Hebei, Shaanxi, Shanxi, Gansu, Jilin, Liaoning and Heilongjiang provinces. Alternaria blight causes significant losses in tomato. High disease severity during fruiting stage.

SUMMARY Of the different integrated seed treatment options tested for the management of Alternaria blight of sunflower, highest benefit was obtained in the seed treatment with Carbendazim+Iprodione (Quintal) at 0.3% in water along with hexaconazole foliar spray (0.1%) followed by seed treatment with Pseudomonas fluorescens (0.8%) in jelly+hexaconazole foliar spray. Efficacy of Pseudomonas. A. triticina, the causal agent of Alternaria leaf blight of wheat [Triticum spp.], was described as a species from India by Prasada and Prabhu (1962).Their description is also available in Anahosur (1978), but Simmons (1981; 2007) provides a more detailed description based on Prasada and Prabhu's type and cultures derived from it.. Prasada and Prabhu (1962) distinguished the species as an. Management of sunflower Alternaria blight with new fungicides. 222. Shreeshain Sonyal . Student. The disease gaining national importance, pomgranate wilt complex. 223. Shweta Badoni et al. PhD scholar. Study of Environment Factors on Rust of Field Pea and its Management through the application of fungicides and Botanicals. 224. Singh CB et.

Alternaria blight (Alternaria dauci ) on carrot (Daucus

First report of Alternaria alternata causing fruit rot disease of Jatropha curcas from India. Journal of Mycology and Plant Pathology, 42 (2):265-266. Sain SK, Gour HN, Sharma P, Chowdhry PN, 2009. A new leaf spot disease of Calotropis gigantea caused by Alternaria alternata in Rajasthan, India Botany . Pea is a diploid with 2n=14. Field pea with coloured flowers belong . Pisum arvense to . and the garden pea with white flowers belong to . P. sativum. Pea is a herbaceous annual plant with tap root system Disease The important diseases of Pigeon pea are Wilt, Sterility mosaic disease, Phytophthora blight, Alternaria blight, Powdery mildew Radish, Raphanus sativus, is an herbaceous annual or biennial plant in the family Brassicaceae, grown for its edible taproot. The radish plant has a short hairy stem and a rosette (ground level horizontal and circular leaves) of oblong shaped leaves which measure 5-30 cm (2-12 in) in length. The top leaves of the plant are smaller and lance. Alternaria leaf blight (ALB) of sunflower is caused by Alternaria alternata, a seed-borne pathogen on sunflower, able to infect seedlings from a very young age. However, the majority of infections take place during head formation. In severe infections, lesions caused by ALB become irregular by coalescing, leading to blight and premature defoliation and can furthermore [ Key words: Alternaria blight, disease quantification, net photosynthetic rate INTRODUCTION Alternaria blight, one of the major diseases that affects sunflower in Brazil, is caused by the necrotrophic fungus A. helianthi Tub. Nish. According to Leite and Pascholati (1995), Agrios (1997) and Lucas (1998), the first symptom caused b

Diseases of Sunflower: Necrosis, Leaf Blight, Mildew and

Symptoms of Alternaria Blight first appear on lower, shaded leaves and consist of small, round, yellow, brown or black spots, often with concentric rings. These spots slowly enlarge and join together and may eventually reach 3 inches in diameter. These infected areas may drop out and leave holes in the leaves, or the whole leaf may die and drop. Alternaria leaf blight and necrosis of Sunflower was conducted at Oilseeds Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola during kharif 2013 - 14 and 2015-16, to develop integrated module for foliar disease management in sunflower. The experiment was laid out in Randomized Block Design with seven treatments and thre combination for the sustainable management of Alternaria blight of sunflower. Acknowledgements The authors thank The Project Director, Directorate of Oil Seeds Research, Rajendranagar, Hyderabad, for providing facilities. PflKrankh. 5/97 Effect of botanicals and chemicals on the management of blight 52 Sunflower (Helianthus annuus L.) is cultivated in India over an area of 21.62 lakh ha with a production of 12.24 lakh tonnes. Karnataka occupies first position accounting 53 per cent of total area and 35 per cent of total production in India. Among the major diseases of sunflower, Alternaria blight caused by Alternaria helianthi (Hansf.) Tubaki.

Alternaria blight of mustard. Potential of chemical fungicides, bio-agents for substituting the recommended chemical fungicides applied as soil application at the time of sowing and foliar spray at critical stages of 45, 75 days after sowing against the Alternaria blight disease were tested in the present study Blight and Leaf Spot in Sunflower (Alternaria helianthi) As a result of this disease's attack, the plants are weakened as their veins are partially destroyed. This fungus attack the entire shoot system of a plant. Irregular, brown spots with yellow halos appear on the leaves. The attack on the stem can be seen as elongated and thin spots The leaves of fifty six F 1 s developed during kharif, 2004 along with parents were used for screening against Alternaria blight during rabi, 2004. Chopped leaf bits (200 g) of sunflower cv. CO-4 were boiled in 500 mL of water for about 10-15 min. In another 500 mL of water, 20 g of agar was melted Alternaria alternata causing Alternaria blight in pigeon- pea is a distinct species from other reported Alternaria spp. infecting different host. In our earlier findings, we [16] have reported Alternaria tenuissima causing Alter-naria blight in pigeonpea. REFERENCES [1] Van der Maesen, L.J.G. (1990) Pigeonpea: Origin, his-tory, evolution and. Among the fungal diseases of tomato, early blight caused by Alternaria solani (Ellis and Martin) Jones and Grout is an important disease-causing production losses varying from 10 - 80 per cent (Datar and Mayee, 1986) [5]

Diseases: Introduction :: Mustard Production Manual

Common Names of Plant Diseases - Diseases of Sunflower and Jerusalem Artichoke...R. M. Harveson, S. G. Markell, C. C. Block, and T. J. Gulya, primary collators (last update: 1/12/16) BACTERIAL DISEASES Apical chlorosis Pseudomonas syringae pv. tagetis (Hellmers) Young et al. Bacterial leaf spot Pseudomonas cichorii (Swingle) Stapp Pseudomonas syringae p.. THE CONTROL OF ALTERNARIA BLIGHT OF SUNFLOWERS IN EASTERN AUSTRALIA. S.J. I ALLENT, J.F. BROWNT, and J.IC KOCHMAN2. Departrnent of Botanv, univers.ity of New engtà1aÀrmidale, NSW.2351, Australia. 2 Departnent of prima'ry Industriei.ro*oor-ùi-qlà. -ïï3ô'â.[iirà. ABSTRACT Alternaria blight causes signiticant yield reductions in sunllower crops Alternaria, necrosis, leaf curl, powdery mildew, sunflower, screening INTRODUCTION Sunflower is one of the important oilseed crop grown in India, being cropped in an area of 2.47 lakh ha in 201819, having a production and productivity of 2.19 lakh tonn and 886 kg ha-1 (Directors report, 2019-20) there of respectively Alternaria blight (Alternaria helianthi Hansf) is one of the major diseases of sunflower during Kharif season in Maharashtra. Present Lab study was conducted at Department of Plant Pathology and field experiment at Oilseed Research Station, College of Agriculture, Latur, VNMKV, Parbhani, Maharashtra, India Sunflower No Pathogen Found Sweet potato Unknown, General Tomato Early Blight; Leaf Spot (Alternaria solani) Bacterial Leaf Spot (Xanthomonas sp./spp.) No Pathogen Found Septoria Leaf Blight (Septoria lycopersici) Rust Mites, Order acari Spider Mites, Family Tetranychidae.

Alternaria Blight: It is a serious disease, it cause reduction in seed and oil yield. Dark, brown black spots are developed first on lower leaves, later spread to middle and upper leaves. In severe infestation spots are observed on stem, petioles Alternaria blight in sunflower, caused by the fungus Alternaria helianthi, is one of the major diseases that affects sunflower in Brazil. The effect of this organism on net photosynthetic rate of four sunflower genotypes was measured under field experimental conditions. Through a mathematical approach the diseased leaf area and net photosynthetic rate were related and used to analyze the. 2008. Tamil Nadu Scientist Award (TANSA) in Agricultural Sciences. Tamil Nadu State Council for Science and Technology. 2005. Best paper award for the research paper entitled Induction of systemic resistance against die-back and fruit rot of chillies by Pseudomonas fluorescens in the National Seminar. KAU, Kerala

Alternaria Leaf Spot Sunflower - Bugwoodwik

Alternaria Leaf Spot: How To Wipe Out This Fungal Foe For

Alternaria alternata. Alternaria alternata is generally considered as a weak and opportunistic pathogen that follows different routes for penetrating plant tissue, like wounds (Pearson and Hall, 1975), natural openings such as lenticels, stem ends, and pedicels (Prusky, 1996), and by direct breaching of the host cuticle (Mersha et al., 2012), which enables the pathogen to enter the unripe. Alternaria blight, caused by the fungus Alternaria cucumerina, is a common disease of most cucurbits in warm, rainy weather. A similar cucurbit disease called Alternaria spot, caused by a related fungus (Alternaria alternata), is not known to occur in the High Plains Followed by two sprays of Propiconazole@ 1ml/L at 45 and 60 DAS. Intercropping sunflower with groundnut in the ratio of 6 : 2 reduces the disease incidence. Early planting of sunflower during kharif season results in low occurrence of leaf blight. Spacing of 60 x 30 cm or 45 x 30 out the source of resistance against Alternaria leaf blight of rapeseed- mustard caused by Alternaria barassicae, under artificial conditions. It is clear from the table 2 that's out of tested 30 genotype cultivars none were found free to this disease. Two genotype viz., UDN- 11-05 and UDN-11-29 on leaves and two genotype viz., UDN-11-12 and UDN Sunflower (Helianthus annuus L.) is an important oilseed crop in South Africa, and is grown in rotation with maize in some parts of North West, Limpopo, Free State, Mpumalanga and Gauteng provinces.Alternaria leaf blight is currently one of the major potential disease threats of sunflower and is capable of causing yield losses in all production regions

Tips & Information about Turnips - Gardening Know HowManagement of Alternaria leaf spot/blight through

The Deuteromycetes fungal genus Alternaria comprises of different saprophytic as well as endophytic species and is well known for its notoriously destructive plant pathogen members. It has been found to have a drastic effect on the members belongin Field evaluation of different fungicides against foliar diseases, the fungicide propiconazole was found to be very effective in controlling all foliar diseases (Alternaria blight, leaf spot, grey mildew and bacterial blight) and recorded the maximum seed cotton yield Coconut leaf blight caused by Biopolaris incuwata, Coleus root rot caused by Macrophomina phaseolina and Stevia root rot caused by Sclerotium rolfsii are identified and reported for the first time in India. Salient findings in bee research. Placing honey bee hives @ 4 Nos./ha was found to enhance seed set in sunflower by 15-20 per cent Alternaria leaf blight Alternaria alternata Downy mildew Plasmopara halstedii Powdery mildew Erysiphe cichoracearum Rust Puccinia helianthi Septoria leaf spot Septoria helianthi 7 8. Nematodes Pin Paratylenchus projectus Lesion Pratylenchus hexincisus Root knot Meloidogyne arenaria Spiral Helicotylenchus sp. Stunt Quinisulcius acutus 8 9 Alternaria leaf blight and seed infection: A common disease causing major damage. May 2017 PROF BRADLEY FLETT, ARC-Grain Crops, Potchefstroom. Alternaria leaf blight is caused by Alternaria alternata, which is the predominant Alternaria spp.Of sunflower responsible for significant yield losses in South Africa Early blight (Alternaria solani) Early blight: biology. Early blight is an endemic disease - it exists in virtually every potato field in Canada and can lead to yield losses if not treated. First, infected leaf tissue reduces the crop's photosynthetic capacity which on its own reduces yield, but then it also erodes the crop's ability to.