Leaf Rust

10 Key excerpts on "Leaf Rust"

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  eBook - ePub

  Biocontrol Of Plant Diseases

  • K. G. Mukerji, K.L. Garg(Authors)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  Chapter 1

  BIOCONTROL OF RUST AND LEAF SPOT DISEASES *

  J. K. Sharma and K. V. Sankaran

  TABLE OF CONTENTS

  I.	Introduction
  II.	Biological Control in Nature A.  Hyperparasitism 1.  Rust 2.  Leaf Spots B.  Antagonism 1.  Naturally Occurring Antagonists 2.  Foreign Antagonists C.  Immunization D.  Hypovirulence
  III.	Future Prospects

  Acknowledgment References

  I. INTRODUCTION

  Among the greatest hazards in crop production, unfavorable weather conditions, insect pests, and diseases are the main factors. Any one of them can upset the crop yields with catastrophic suddenness. Of all the plant diseases, foliar diseases, especially rusts and leaf spots, are the important group of diseases causing large-scale destruction of agricultural and horticultural crops. There are about 4000 species of rust fungi belonging to 100 genera, many of which are capable of causing widespread epidemics. A few notable examples are those of cereal rusts (Puccinia graminis f. sp. tritici, P. graminis f. sp. secalis), cedar rust of apple (Gymnosporangium juniperi-virginianae), and white pine blister rust (Cronartium ribicola), which are well known for causing economic losses. Cereal rusts are known to have changed the cropping pattern of different regions and food habits of the population. Wheat Leaf Rust created an economic disaster in 1916 in the U.S. and Canada. An even worse disaster struck in 1935 when about 100 million bushels of wheat were lost. In India, according to an estimate during 1971 to 1972, a brown rust (Puccinia recondita) epidemic in northwestern India resulted in a loss of 1.5 million tonnes of wheat.79 Epidemics of the coffee rust compelled Sri Lanka to bring more land into tea plantations and to abandon coffee cultivation for years. This way coffee rust changed the entire economy of Sri Lanka in 1875 due to the widespread rust epidemic. Leaf spot diseases are equally significant in causing economic disasters. To name a few, late blight of potato (Phytophthora infestans), blast of rice (Pyricularia oryzae), Helminthosporium leaf spot of maize (H. turcicum, H. maydis, H. carbonum), and bean anthracnose (Colletotrichum lindemuthianum) are known to have affected crop yields drastically. The potato famine of Ireland in 1845, due to late blight, which gradually spread to the whole of the European continent, is the most cited example to indicate destruction and aftereffects of diseases on a large population. Rice blast disease, reported from 70 countries has affected up to 90% of the yield depending upon the part of the plant infected. In the 1950s in Florida, losses of winter-grown sweet corn due to leaf spot caused by H. turcicum

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  QTL Mapping in Crop Improvement

  Present Progress and Future Perspectives

  • Shabir Hussain Wani, Dechun Wang, Gyanendra Pratap Singh, Dechung Wang(Authors)
  • 2022(Publication Date)
  • Academic Press

    (Publisher)

  Gustafson et al., 2009 ).

  Fungal pathogens of genus Puccinia cause rust diseases in plants (Table 2 ; Bolton et al., 2008 ). Three rust diseases infect wheat: 1. Pgt (Puccinia graminis f. sp. tritici) causes stem rust. 2. Puccinia triticina Eriks causes Leaf Rust. 3. Pst (Puccinia striiformis f. sp. tritici) causes stripe rust or yellow rust. These viruses are biotrophic, indicating that they need living host to reproduce, resulting in lower yields of crop (Chakraborty et al., 2011 ). One of the most quickly evolving disease pathogens are of rust. They have huge populations, airborne spore distribution over great distances, and reproduce through sexually and asexually (McDonald and Linde, 2002 ). These features allow rust infections to spread across continents and throughout the globe in complex and quickly changing populations, generally containing many races and so defeat host resistance genes (Kolmer, 2005 ).

  Table 2

  Classification of wheat rust fungal pathogen (Puccinia sp.).

  Taxonomy of wheat rust pathogens
  Phylum	Basidiomycota
  Class	Urediniomycetes
  Order	Uredinales
  Family	Pucciniaceae
  Genus	Puccinia

  Leaves and stems of wheat related to specific genera are mostly affected by rust fungus. Several different types of Puccinia produce rust disease in all grass species. Fungus species also have a variety of races also known as physiological races and pathotypes that exclusively infected specific host species and can be recognized using differential cultivars (Roelfs, 1992 ). Rust infections are still one of the most serious dangers to wheat plants. Grain quality has deteriorated as a result of considerable yield losses. The development of new wheat stem rust strains (Ug99) has raised concern among wheat production around the world (Singh et al., 2011

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  Diseases of Small Grain Cereal Crops

  A Colour Handbook

  • T.D. Murray(Author)
  • 2013(Publication Date)
  • CRC Press

    (Publisher)

  In similar sur-veys of winter barley (1981–1991), brown rust was considered as one of the major foliar diseases, with epidemics in 1989 and 1990 when average flag leaf areas affected by the disease were 4.6 and 3.0%, respectively. It was estimated that annual losses due to brown rust on barley averaged 1.2% of the United Kingdom national yield over the survey period. In the United States, it was estimated that an average grain yield loss of 0.42% occurred for each 1% increment of Leaf Rust severity on the upper two leaves at the early dough stage of plant development. Control Cultural control methods include the eradica-tion of volunteer cereals, which can harbour inoculum over winter, together with the dis-posal of crop debris. Avoiding very early sowing and excess nitrogen fertilizer applica-tions also helps to reduce the disease. The deployment of genetic resistance in varieties and chemical control methods are also similar to those used for yellow rust. RUSTS 51 82. Photomicrograph of urediniospore pustules of brown rust on a wheat leaf. 82 The major economic host of yellow rust is wheat, particularly in cool, maritime regions of the world. In semi-arid areas, only very susceptible varieties are at risk during wet periods. Typical symptoms of yellow rust on mature wheat leaves consist of yellow–orange rust pustules arranged between the veins in stripes – hence the alternative name stripe rust ( 83–86 ). On young leaves such pustules are scattered at random and may be difficult to distinguish from those of brown rust (Leaf Rust) caused by Puccinia recondita on wheat or P. hordei on barley. Later in the season, yellow rust may occur on cereal heads, result-ing in the formation of masses of spores lodged between the glume and the lemma. At the end of the season, black telia may form in necrotic tissue patches killed by the yellow rust pustules. As with many obligate parasites, e.g. mildew, P. striiformis is further differentiated within the f.

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  Diseases of Sugarcane

  Major Diseases

  • C. Ricaud, B.T. Egan, A.G. Gillaspie, C.G. Hughes(Authors)
  • 2012(Publication Date)
  • Elsevier Science

    (Publisher)

  In such cases, the number of live leaves per plant can be seriously reduced, while, in very susceptible varieties, there may be fewer stalks per stool and reduced diameter and length of the stalk (Taylor, Croft and Ryan, 1986). Affected crops take on a distinctive rusty to brown colour, depending on variety, as disease intensity builds up. The discolouration of these crops is readily seen from a distance, so that monitoring of the rust disease situation in susceptible varieties may be made from natural vantage points such as hills, or from the air. Disease symptoms may develop rapidly under favourable conditions, since the latent period for pustule development is only 8-18 days, depending on varietal susceptibility and environmental conditions (Sahni and Chona, 1965; Srinivasan and Muthaiyan, 1965; Hsieh and Kuo, 1983). The density of initial infection as shown by small yellow lesions, and the percentage of these which develop into reddish-brown spots and pustules, are influenced by the inoculum load, varietal susceptibility and environment. In some cases, bands of lesions may occur, resulting from intermittent heavy infection while the leaf is in the partially unrolled spindle. Rust can also cause wilting, some leaf tip death and accelerated death of leaves. Rust is most severe in the young stages of plant and ratoon crops ( 1 -6 months), and it generally declines with increasing crop age (Anon., 1977, 1979; Scarlett, 1979; Liu, 1980b; Purdy et al., 1983; Sandoval, Picornell, Chavez and Ramos, 1983), but this is not true for all varieties, or under some circumstances. Rust is more prevalent in cooler weather and in cooler districts of cane-growing countries (Hsieh et al., 1977; Bailey, 1979; Burgess, 1979; Liu, 1980a; Purdy et al., 1983). Orange rust Symptoms of orange rust (Plate XII, Fig. 1) are similar in many ways to those of common rust, hence the confusion which has occurred so frequently.

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  Diseases of Field Crops and their Management

  • S. Parthasarathy, G. Thiribhuvanamala, K. Prabakar(Authors)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  Chapter - 2

  Diseases of Wheat - Triticum aestivum L.

  S. No.	Disease	Pathogen
  1.	Black (stem) rust	Puccinia graminis var. tritici
  2.	Orange brown (leaf) rust	Puccinia triticina
  3.	Yellow (stripe) rust	Puccinia striiformis
  4.	Loose smut	Ustilago tritici
  5.	Flag smut	Urocystis tritici
  6.	Rough spored bunt	Tilletia tritici
  7.	Smooth spored bunt	Tilletia laevis
  8.	Dwarf bunt	Tilletia controversa
  9.	Karnal bunt	Tilletia indica
  10.	Powdery mildew	Blumeria graminis f.sp. tritici
  11.	Leaf blight	Alternaria triticina
  12.	Pythium foot rot	Globisporangium abappressorium
  13.	Pink snow mold	Microdochium nivale
  14.	Fusarium foot rot	Fusarium culmorum
  15.	Tan spot	Pyrenophora tritici-repentis
  16.	Tundu	Clavibacter tritici + Anguina tritici
  17.	Bacterial leaf streak and black chaff	Xanthomonas translucens
  18.	Soil borne mosaic disease	Soil-borne mosaic virus
  19.	Take all disease	Gaeumannomyces graminis
  20.	Scab (The Fusarium Head Blight)	Fusarium graminearum
  21.	Leaf blotch	Mycosphaerella graminicola; Leptosphaeria nodorum; Leptosphaeria avenaria
  22.	Molya disease	Heterodera avenae

  Wheat Rust

  Aristotle (384–322 B.C.) writes of rust being produced by the “warm vapors” and mentions the devastation of rust and years when rust epidemics took place. Theophrastus reported that rust was more severe on cereals than legumes.

  Wheat rust pathogens belong to genus Puccinia, family Pucciniaceae, order Uredinales and class Basidiomycetes. These rust fungi are highly specialized plant pathogens with narrow host ranges. The Italians Fontana and Tozzetti independently provided the first unequivocal and detailed reports of wheat stem rust in 1767 (Fontana, 1932; Tozzetti, 1952). Chester (1946) provided one of the first detailed histories of the literature on the rust of wheat. In the early records, wheat Leaf Rust is not distinguished from stem rust (Chester, 1946).

  The first stem rust epidemic record goes back to 1786 A.D. in central India. Widespread occurrence of Leaf Rust was observed during 1971–73 in popular cultivar Kalyansona in northern plains. Both Leaf Rust and stripe rust occurred each year from 1967 to 1974 but the losses were estimated only twice.

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  Crop Diseases

  Identification,Treatment and Management

  • Darwin, Henry(Authors)
  • 2020(Publication Date)
  • NEW INDIA PUBLISHING AGENCY (NIPA)

    (Publisher)

  Excess of nitrogen favor disease occurrence. Potash and phosphorus confer high degree of resistance to this disease. Application of balanced dose of fertilizers helps to reduce the incidence of the disease. Chemical control . Spraying the crop with wettable sulfur - 1000 gm. or mancozeb - 500 gm. or caboxin - 250 gm. or oxycarboxin - 250 gm. in 250 lit. of water per acre affords good control of the disease. Spraying should commence, as soon as the symptoms are manifested and 3 - 4 sprayings, at 10 - 14 days interval should be given. 3. Brown rust or orange rust or Leaf Rust of wheat Puccinia triticina (P. recondita) ‘Brown rust’ occurs in all wheat growing countries of the world. The disease is mainly confined to the leaves and hence, it is also known as ‘Leaf Rust’ . However, rarely the rust pustules appear on the stems and heads. In India, the disease occurs in the states of Punjab, Bihar and Uttar Predesh and causes more extensive damage than the other rusts. In Tamil Nadu, the disease is found in the hilly tracts, as well as in the plains. Symptoms . The disease appears earlier than the other two rusts, by the time the crop is 5 - 6 weeks old. Heavy infection of leaves greatly retards photosynthetic activity of the leaves and when the disease appears 50 CROP DISEASES 1. Uredosori on leaf 2. Uredium 3. Uredospores 4. Germinating uredospore 5. Telia 6. Teliospores 7. Paraphysis 8. Germinating teliospore 9. Basidium 10. Basidiospore Fig. 11: Yellow rust of wheat Puccinia striiformis Fig. 12: Brown rust of wheat Puccinia triticina 51 DISEASES OF FIELD CROPS early, entire leaves turn yellow and wither within a short time. Increased transpiration, as a result of infection, cause the plants to take a much longer time to head and mature. Heavy rusting of the foliage, retards normal maturity and leads to reduction in yield and quality of grain and straw.

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  Fungi

  Biology and Applications

  • Kevin Kavanagh(Author)
  • 2017(Publication Date)
  • Wiley-Blackwell

    (Publisher)

  Septoria tritici blotch of wheat is among the most serious diseases of cereals, particularly in maritime climates. This fungus produces sexual ascospores and asexual conidia called pycnidiospores (produced in a spore case called a pycnidia). Disease symptoms include elongate oval lesions on leaves, running parallel to the leaf. These become water‐soaked and brown, and a chlorotic halo may develop around the lesion. Black pycnidia develop on mature lesions and cirri may form on the lesions if the weather is dry for prolonged periods. The fungus overwinters on seed, stubble, debris, and overwintering cereal crops. In the spring, it reproduces sexually to form ascospores that are wind‐dispersed to wheat leaves. However, asexual pycnidiospores that are water‐splashed to host leaves provide the major source of inoculum for disease development. Spore germ tubes directly penetrate the plant or enter via stomata, where they colonize host tissue and produce pycnidia. Moisture in the form of rain, dew, or irrigation stimulates pycnidiospore release from conidia that are water‐splashed to leaves to cause new infections.

  Control of this disease is attempted by good sanitary practices such as removal of crop debris, crop rotation, using resistant wheat cultivars, and chemical control. As stated earlier (see Section 14.8.2 ), strains of the causal fungus have developed resistance to the fungicides that were used to control the disease and strains are emerging that have enhanced tolerance to the main fungicide group currently used to control the disease.

  14.14 Rusts, Smuts, and Powdery Mildew Diseases

  Rusts, smuts, and powdery mildew diseases are among the most common and devastating fungal diseases of plants. Control is achieved by good clean cultural practices, using resistant hosts, and fungicide application.

  Rust diseases have caused devastating losses on coffee and grain crops, but also of pine, apple, other field crops, and ornamentals. There are thousands of rust fungi that attack different plants. They are basidiomycetes and most are obligate parasites. The most destructive include stem rusts of wheat and other cereals caused by Puccinia graminis (Plate 14.12 ), coffee rust caused by Hemileia vastatrix, and Puccinia rusts of field crops, vegetables, and ornamentals. Rust diseases appear as yellow to brown, white or black rusty spots; the rusty appearance results from epidermal rupture by the emerging spore masses that often have a powdery appearance. Wheat stem rust caused by P. graminis threatens food security at present. International research efforts are focussed on developing new wheat varieties that resist the new aggressive rust strains that have evolved in the last few decades.

  Smut diseases, also caused by basidiomycetes, were a serious problem prior to the development of contemporary fungicides. These fungi are not obligate parasites; that is, they can be cultured on media, but in nature they exist almost exclusively as parasites. Most smut fungi attack and devastate the ovaries of cereal grains and grasses, turning seed to black powdery masses (e.g. covered smut of oats caused by Ustilago hordei and covered smut or “bunt” of wheat caused by Tilletia species; Plate 14.13

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  Plant Pathology

  • Stephen Burchett, Sarah Burchett(Authors)
  • 2017(Publication Date)
  • Garland Science

    (Publisher)

  Xanthomonas campestris that causes brassica black rot. This bacterial pathogen infects a wide range of plant species, many of which are of economic importance.

  Figure 1.13

  Rust pustules on leaves of wheat (Triticum species). A color version of this figure can be found in the color plate section at the end of the book.

  Another important group of pathogens that cause significant damage to plants during the vegetative growth phase consists of the vascular wilts (Fusarium species) and other root and vascular diseases, such as take-all (Gaeumannomyces graminis) of wheat. If these organisms infect the plant before it has completed the vegetative growth phase they can significantly reduce its photosynthetic efficiency by reducing water uptake, and also restrict plant growth due to loss of root area.

  The final stage in the wheat life cycle consists of flowering, pollination, and grain filling, and for the grower this is a key economic stage that has to be managed carefully, as a number of pathogens can infect the grain, such as ergots, the smuts, bunts, and glume blotch. These pathogens will cause reductions in grain yield and final grain quality. For example, glume blotch (Septoria species) invades the flower spike late in the life cycle of the crop, producing resting spores known as pycnidia, which eventually produce conidia that can then reinfect a new crop. In the UK, S. tritici is the key pathogen of wheat crops grown in the south-west region of England. Another problematic disease of cereal grains is loose smut (Ustilago nuda and U. tritici). The mycelium of Ustilago species keeps pace with the growing point of the cereal plant, and eventually the mycelium invades the flower spike and subsequently the young kernels of the ear. As the kernels mature, the mycelium of Ustilago

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  Advances in Plant Pathology

  • Josphert Ngui Kimatu(Author)
  • 2018(Publication Date)
  • IntechOpen

    (Publisher)

  , wheat stripe rust (WSR) caused by Puccinia striiformis Westend. f. sp. Tritici Eriks. , and Fusarium Head Blight (FHB) caused mainly by Fusarium graminearum . The control of the diseases caused by these pathogens is a high priority to minimize yield and grain quality losses. 3.1. Septoria leaf blotch The majority of the SLB disease prediction systems proposed for the management of Z. tritici assume that the main risk of infection of the upper leaves (the most critical for grain fill [15]) comes from the inoculum that developed on the leaves during the winter and spring before the extension of the stem [ 16 ]. These prediction systems are based solely on rainfall occurring during stem extension, without considering the development of individual leaves [ 17–19 ]. The importance of rain and splash dispersal for development of severe SLB has been demon -strated in several studies (e.g., [ 16 , 20 – 22]). Shaw and Royle [ 19 ] suggested that the amount of Septoria inoculum at GS31 (first node detectable) [23] was only a partial guide to forecast the inoculum available during the expansion of the last two leaves. The progression of the disease on the upper leaves depends on the sensitivity of the cultivar, and the period of infec -tion (infections occurring during and/or just after the emergence of these leaves could lead to severe impacts if the weather conditions are favorable) [24]. The mechanisms by which the pathogen population increases on the upper leaves are determined by the interaction of plant growth, the meteorological conditions allowing the dispersal of the inoculum and thus oppor -tunity for new infections, and the availability of that inoculum in sufficient proximity to the upper leaves [ 19 ]. El Jarroudi et al. [20] suggested that the greatest risk to a wheat crop occurs Advances in Plant Pathology 6

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  The Cereal Rusts

  Origins, Specificity, Structure, and Physiology

  • William Bushnell(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  Green, G. J., Johnson, T., and Conners, I. L. (1980). Pioneer leaders in plant pathology: J. H. Craigie. Annu. Rev. Phytopathol. 18, 19-25. Grove, W. B. (1913). The British Rust Fungi (Uredinales). Their Biology and Classifica-tion. Cambridge Univ. Press, London and New York. Hamilton, L. M., and Stakman, E. C. (1967). Time of stem rust appearance on wheat in the western Mississippi basin in relation to the development of epidemics from 1921-1962. Phytopathology 57, 609-614. Harrar, J. G., Loegering, W. Q., and Stakman, E. C. (1944). Relation of physiologic races of Puccinia graminis tritici to wheat improvement in southern Mexico. Phytopathol-ogy 34, 1002 (abstr.). 1. Contributions of Early Scientists 35 Hayes, H. K., Parker, J. H., and Kurtzweil, C. (1920). Genetics of rust resistance in crosses of varieties of Triticum vulgäre with varieties of T.

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