Blumeria graminis (powdery mildew of grasses and cereals)

Notes on Taxonomy and Nomenclature

Top of pageThis fungus is the only species of the genus Blumeria but it has previously been treated as a species of Erysiphe. According to Braun (1987), it differs from all species of Erysiphe because its anamorph possesses unique features, for example, digitate haustoria, secondary mycelium with bristle-like hyphae and bulbous swellings of the conidiophores, and because of the structure of the ascocarps. Braun (1987) considers that, because of these differences, there should be a separation at generic level. Molecular sequence analyses proved the separate position of the powdery mildew on Poaceae and showed that Blumeria takes a basal position in the phylogenetic trees of the Erysiphales. Hence, Blumeria is only distantly related to Erysiphe and all other genera of the powdery mildew fungi (Saenz and Taylor, 1999; Mori et al., 2000; Braun et al., 2002).

Description

Top of pagePrimary mycelium branched, hyaline and uninucleate; hyphal cells (35-)40(-55) x 3-6 µm; appressoria nipple-shaped, solitary or in opposite pairs, 3.5-7 µm diam.; secondary mycelium consisting of bristle-like hyphae which are straight to falcate, thick-walled, 200-400 x 4-7 µm, hyaline, later ochraceous to rusty or reddish brown; conidiophores arising from the mycelium at a right angle with the host surface, erect, 60-90 x 4-7 µm, foot-cells 20-40 x 5-7 µm, with a basal bulbose swelling, ca 10-15 µm wide, followed by shorter cells, ca 12.5-25 µm long; conidia in chains, mostly uninucleate, occasionally binucleate, hyaline, ellipsoid-ovoid, limoniform, (20-)25-35(-45) x (8)12-16(-20) µm, germinating by a simple germ tube, terminal to lateral, straight to somewhat flexuous, ca 12-50 x 2.5-4 µm, after germination germ tube forming an appressorium in juxtaposition with the host cuticle, a hyphal peg penetrating the cuticle and the subcuticular wall and forming an haustorium in the epidermal cell; haustoria ellipsoid with long, finger-shaped appendages radiating from both ends (the fungus advances no further in plant tissue and the remainder of the mycelium, as well as the ascomata, are entirely extramatrical i.e. on the exterior of the host substratum). Ascomata (chasmothecia) immersed in the mycelial felt, at first globose, becoming strongly depressed, often cupulate, 110-280 µm diam., peridial cells obscure, irregularly polygonal, 8-20 µm diam., with simple, rarely branched appendages, few to numerous, in the lower half, usually shorter than the ascomatal diam., mycelioid, septate, hyaline to pigmented, thin-walled, smooth, asci 6-30, saccate-ovate to subcylindrical, short-stalked, 50-110 x 20-45 µm; usually 8-spored, sometimes 4-spored, but ascospores rarely fully developed; ellipsoid-ovoid, subhyaline to pale brown, 20-24 x 10-14 µm.

See also Kapoor (1967) and Braun (1987, 1995).

Distribution

Top of pageAlthough powdery mildew of cereals and grasses has a genuinely worldwide distribution, there appear to be fewer reports of it in South America than elsewhere. Powdery mildew is distributed widely in Europe and North America, and in China.

Risk of Introduction

Top of pageThere are no known quarantine regulations on B. graminis perhaps because of its widespread distribution and airborne dissemination.

Hosts/Species Affected

Top of pageB. graminis is found on numerous species comprising more than 100 genera of Poaceae, with the exception of the Maydeae, Andropogoneae, Zoysieae, Paniceae and Oryzeae (Dickson 1956; Amano, 1986).

Growth Stages

Top of pageFlowering stage, Fruiting stage, Seedling stage, Vegetative growing stage

Symptoms

Top of pagePowdery mildew appears in the form of white, later grey-tan areas on all aerial parts of cereals and grasses i.e. leaves, stems and ears, although leaves are most commonly infected. Initial symptoms are easily overlooked and take the form of chlorotic flecks on plant tissue. This is quickly followed by the development of white patches which produce masses of conidia (asexual spores) and assume a powdery appearance. If the plant is shaken even gently, clouds of conidia are released from the patches. Ascomata (fruit bodies forming sexual spores) may or may not form, but when they do, they occur late in the season and can be found embedded in the mildew colonies as tiny, dark-coloured dots.

Biology and Ecology

Top of pageB. graminis overwinters mainly as a mycelial mat on leaves of grasses and autumn-sown cereals. Although the ascomata produced during the late summer are fairly resistant to cold and drying out, they appear to be of secondary importance in overwintering and as a source of inoculum in the spring. This is because in temperate regions, fresh host plant material is nearly always available over the winter period. Nevertheless, in humid weather, ascomata release ascospores which can start infections on autumn-sown crops in the autumn and perhaps also in the spring. As temperatures rise in the spring, dormant mycelium commences growth and conidia are produced rapidly. Conidia usually germinate over a range of temperatures from about 3 to 31°C, although 15°C is probably optimal for germination, together with a relative humidity about 95%. Conidial germination is inhibited by free water. Under favourable conditions, fresh conidia can be found in about 7 days and are dispersed within the crop and further afield in the wind. Crucially, therefore, epidemics of powdery mildew will tend to occur during conditions of alternating wet and dry weather, with some wind to ensure dispersal on the conidia.

Mildew is encouraged by very early autumn sowing, especially in barley. In the autumn, heavily infected plants may be less resistant to winter frosts and plants may die. Cereals grown late in the autumn and spring may also be more prone to attack. Powdery mildew is also encouraged by excessive use of nitrogen fertilizer and can be particularly severe in dense crops grown in a sheltered, humid environment.

For further information, see Spencer (1978), Parry (1990) and Manners (1993).

Seedborne Aspects

Top of page

Seed treatment

Seed treatment with difenoconazole, followed by flutriafol, triticonazole and triadimenol was shown to achieve the highest fungal protection in wheat (Reis et al. 2008).

Impact

Top of pagePowdery mildew is one of the most common and destructive diseases of cereals. Actual losses depend on the time of disease epidemic onset and its severity, and can at the extreme reach up to 60% (James, 1991; Oerke, 1994). Although it occurs in most, if not all, parts of the world where cereals are grown, it is not considered to be a major problem in every region. This disease can be very destructive to cereals, but generally seems to cause most damage in temperate latitudes, where economically important cereals are more frequently cultivated. However, powdery mildew can also be a limiting factor for cereal production in subtropical and tropical areas. Yield losses by powdery mildews are generally complex to estimate and depend on several factors such as climate, year, cropping system, cereal species and cultivar.

In some parts of Europe, powdery mildews are a limiting factor to the yield of cereals. In the UK, the Agricultural Development and Advisory Service (ADAS, 1980) estimated that increases in yield of winter barley achieved by controlling B. graminis infection in 1978 and 1979 ranged from 0.11 to 0.65 t/ha. Although Cook and King (1984) ranked B. graminis infection as the principal pathogen of spring barley in England and Wales, yield losses vary on a yearly basis. Cock (1975) estimated that losses in spring barley in 1974 and 1975 were 1.3% and 0.5%, respectively. From 1975 to 1978, powdery mildew was the most frequent foliar pathogen in barley and caused yield losses ranging from 2.8 (James et al., 1991) to 8.7% (King, 1977b). In the period 1976-1986, yield losses of 4-9% were recorded for powdery mildew in spring barley in England and Wales (Polley et al., 1993). Field tests in England have suggested that the effects of B. graminis f.sp. hordei infection on grain-filling in spring barley may be determined partly by temperature during the grain-filling period. Fungicides that controlled mildew increased the total grain yield much more in a warm environment (58.2%) than in a cool environment (17.7%). These results illustrated the potential risks involved in using data obtained under one set of circumstances to predict what will happen in another, especially when environments differ so greatly (Jenkyn, 1984).

Estimated yield losses for wheat grown in England and Wales in the period from 1970 to 1975 were 2.8% (King, 1977a), but from 1981 to 1988 yield losses of only 0.5% were estimated (James et al., 1991). In organic wheat, mildew led to yield losses of around 7% in 1991 (Yarham and Turner, 1992). Yield decreases of up to 30% (-1.61 t/ha) were correlated with the severity of mildew on leaf 2 between the watery and milky ripe (GS 71-75) development stages of wheat (Hardwick et al., 1994).

In Scotland, powdery mildew was by far the most important disease from 1970 to 1973, being responsible for average yield losses of 7.0% in barley (James et al., 1991). In wheat, studies carried out between 1970 and 1974 revealed losses due to powdery mildew of 1.7% (James et al., 1991).

The principal disease of barley in central Europe is powdery mildew (Oerke et al., 1994). Field trials with winter barley in Germany between 1975 and 1981 revealed yield losses of 11% due to powdery mildew (Kolbe, 1982). Despite the use of crop protection measures, Lutze et al. (1982) calculated that the average yield loss due to powdery mildew over 6 years was 5.3% (a range of 3.3 to 6.2% was estimated) in barley cultivated in the east of Germany. Based on a yield level of 7.5 t/ha, heavy infections by powdery mildew resulted in losses of 4.8% in wheat during 1969-79 in Germany (Anderl et al., 1984). In the Czech Republic, yield losses of 17% were reported in wheat growing under a severe infection pressure of powdery mildew (Benada and Vanova, 1984). The crop loss in wheat in the Netherlands despite control practices against powdery mildew in 1980 was 1% (Daamen, 1981). Analysis of epidemics showed mildew damage at growth stages GS 32-83 (second node to early dough) to be described by the simple function D = -0.0013 t/ha per colony-day of mildew per leaf, at yield levels of 7-9 t/ha and independently of wheat cultivar, year or nitrogen supply (Daamen, 1989). In Romania, crop losses due to B. graminis f.sp. tritici varied from 1 to more than 20% depending on the region in which it occurred (Ciurdarescu et al., 1987).

Powdery mildew is a destructive disease of wheat in the mid-Atlantic states of the USA in most years. For example, yield losses in Virginia ranging from 12 to 20% have been observed in susceptible cultivars (Griffey et al., 1993). In North Carolina, yield reductions of ca 17% were reported in the susceptible cultivar Saluda when disease severity reached 10% on the flag leaf by heading stage. It has been concluded that powdery mildew can limit yield in modern soft red winter wheat cultivars, although current levels of resistance in certain cultivars are sufficient to prevent large yield reductions (Leath and Bowen, 1989). In Kentucky, USA, an average yield loss of 20% was associated with powdery mildew over two experimental years in soft red winter wheat (Pearce et al., 1996).

Among the pathogens of wheat in Argentina, powdery mildew practically occurs every year in the wheat cropping area, particularly in the first growth stages and less frequently in later stages. In general, it is not economically important in the crop area of La Pampa Humeda, in contrast to areas with higher temperatures such as Santa Fe, Entre Rios and Chaco, where the disease also occurs at later growth stages and can therefore cause significant yield losses. However, no precise data on losses by powdery mildew is available for wheat in Argentina (Molteni, 1996). In field experiments carried out in the south of Brazil during 1981, powdery mildew reduced the yield of a wheat susceptible cultivar by 8% (Luz, 1984). In 1986, experimental results showed that yield losses attributed to the lack of fungicide control of powdery mildew varied from 20-23% (in susceptible cultivars) to 55% (in a highly susceptible wheat cultivar), when compared with conditions where the control was situated (Linhares, 1988).

Based on figures from the Chinese crop protection authorities, Teng (1986) quoted losses nationwide due to powdery mildew in wheat as 3.4%. According to the average wheat yield in China, the permissible loss was 1.7% (Lu and Gong, 1986).

In New Zealand, Cromey et al. (1992) reported losses in winter wheat of up to 63% following wheat diseases including powdery mildew infection. Infection of up to 70% leaf area damage resulted in a 40-60% reduction in grain yield in barley grown in Australia (Chan et al., 1990).

Diagnosis

Top of pageBecause, under favourable conditions, powdery mildew can infect leaves and commence sporulating within 7-8 days, and is easily identified, specific diagnostic methods are usually not required. B. graminis is an obligate biotroph and cannot be cultured axenically.

Detection and Inspection

Top of pagePowdery mildew is easily detected in the crop since the white, fluffy colonies are easily seen on the foliage.

Prevention and Control

Top of pageCultural Control and Sanitary Methods

Since volunteer cereals act as overwintering sources of inoculum and stubble and crop debris may be infested with cleistothecia, eradication of volunteers and disposing of stubble and debris are important aspects of cultural control. Isolation of autumn-sown and spring-sown cereals (i.e. not growing them too close together) will reduce the risk of infection of the autumn-sown crop spreading to the spring-sown crop. In addition, because nitrogen fertilizer promotes lush crop growth and encourages mildew development, excessive use of nitrogen should be avoided.

Host-Plant Resistance

Host-plant resistance is very important in the control of powdery mildew on cereals. A wide range of resistance to powdery mildew is exhibited by varieties of wheat, barley and oats, and in those countries where mildew is widespread, it is prudent to choose a variety with a good disease resistant rating. If the variety grown has poor resistance to powdery mildew, careful crop monitoring will be necessary in order to optimise the timing of fungicide applications.

Spread of mildew from one field to another can be reduced by the correct diversification of varieties. In the UK, the National Institute of Agricultural Botany (NIAB) produces a leaflet on Diversification Schemes which gives information on good combinations of varieties. Growing mixtures of varieties is also an option to reduce mildew (Chin and Wolfe, 1984).

Rubiales et al. (2001) found that chromosomal addition lines of Hordeum vulgare and Hordeum chilense possessed resistance to wheat powdery mildew. This resistance was expressed as a reduction of disease severity and is of broad genetic basis, conferred by gene (s) present on different chromosomes of both H. vulgare and H. chilense. This resistance may be useful in breeding new wheat varieties with resistance to powdery mildew. In addition, a powdery mildew resistance gene, originating from wild emmer wheat (Triticum dicoccoides) accession C20, from Israel, was successfully transferred to hexaploid wheat through crossing and backcrossing (Lin et al., 2002). Genetic analyses revealed that a single dominant gene controls the powdery mildew resistance at the seedling stage. The gene was assigned to chromosome area 5BS and appears to be a new gene, designated PM30.

A range of spring barley mixtures including one set made from cultivars grown in the UK and one from cultivars grown in Poland, were examined, along with their component cultivars, in nine trials at Scottish Crop Research Institute, Dundee, UK, or at the Experimental Plant Breeding Station of the IHAR, Bakow near Kluczbork, Poland, over five seasons. In four trials where inoculum pressure was controlled, mixtures reduced infection more at lower inoculum pressures, but this did not translate into yield benefit. Smaller plots increased mildew in monocultures but not mixtures. Fertilizer levels increased mildew levels but did not affect mixture efficacy. There were large differences between both Polish and UK germplasm, and between Polish and UK trial sites, but the performance of the mixtures compared with their respective monoculture components was similar within both germplasm groups and trial sites. Mixtures reduced lodging and affected plant height and heading date. The advantages of mixtures for improving yield, reducing fungicide applications and improving agronomic characteristics was demonstrated and there seems to be great potential for their further improvement and exploitation.

Chemical Control

Fungicides are widely used in the control of powdery mildew in cereals. Mildew on wheat and barley can be controlled using morpholines (e.g., fenpropidin), triazoles (e.g., tebuconazole and cyproconazole) and the more recent strobilurin fungicides. Differences in the efficacy of fungicides used in mildew control are due, in large part, to the development of isolates of B. graminis which are tolerant to fungicide groups. Tolerance has been detected to the triazoles, for example, flutriafol, propiconazole and triadimefon. However, these are often combined with another active ingredient, commonly a morpholine such as tridemorph, in order to increase efficacy and reduce pressure on the pathogen to produce triazole-tolerant isolates. Resistance to strobilurin fungicides has been detected in isolates from B. graminis f.sp. tritici from commercial crops in England and Germany (Fraaije et al., 2002). These workers developed a quantitative real-time PCR diagnostic procedure for the early detection of resistance genes at low frequency which, if used with risk evaluation, would be invaluable for further resistance risk assessment and validation of anti-resistance strategies.

Mildew infection on oats can also be controlled using morpholines and triazoles, although in some countries such as the UK, the range of fungicides approved for oats is limited compared to other cereals. A new fungicide, Falcon 460 EC containing the new active ingredient spiroxamine, was introduced in Slovenia in 2000 for the control of a range of diseases including powdery mildew on cereals (Kraner, 2001). In addition, simeconazole (2-[4-fluorophenyl)-1-(1H-1,2, 4-triazol-l-yl)3-trimethylsilylpropan-2-01), a novel triazole fungicide with broad spectrum activity was launched as a new seed treatment (Tsuda et al., 2000). It has activity against powdery mildew (B. graminis) and has been shown to increase wheat yields by 10% compared to untreated crops.

Computer based decision support systems (DSS), for example, EPIPRE, have been developed to aid fungicide spray recommendations for the main diseases on wheat including powdery mildew (Forrer, 1992) and a DSS for disease in spring barley is under development

For further information, see Parry (1990).

References

Top of page

+ssveen M, Gunnarstorp T, 1996. Effects of barley cultivar mixture on certain agronomically important characteristics. Norsk Landbruksforsking, 10(2):149-158; 28 ref.

Abkhoo J, 2015. Powdery mildews causing fungi in Iran. Mycopath, 13(1):51-55. http://111.68.103.26/journals/index.php/mycopath/article/viewFile/673/354

Al-Mughrabi KI, Gray AB, 1996. Build-up of resistance to triadimefon for isolates of Erysiphe graminis f.sp. tritici from Nova Scotia, Canada. Canadian Plant Disease Survey, 76(1):9-14; 27 ref.

Amano K, 1986. Host range and geographical distribution of the powdery mildew fungi. Tokyo, Japan; Japan Scientific Societies Press, 741 pp.

Anderl A, Mangstl A, Reiner L, 1984. The effect of fungicides on yield and yield structure in winter wheat, investigated on the database or ISPFLANZ. Bayerisches Landwirtschaftliches Jahrbuch, 61(6):816-849

Anon, 1994. Winter triticale: Tridel. Revue Suisse d'Agriculture, 26(6):380.

Arifi A, 1995. Evolution and importance of fungal diseases of wheat in Morocco. Al Awamia, No. 90:19-30; 11 ref.

Basandrai AK, Sharma SC, Munshi GD, 1996. Race specific genes for powdery mildew resistance in wheat. Crop Improvement, 23(1):83-88; 6 ref.

Benada J, Vanova M, 1984. Bayleton protection of winter wheat against powdery mildew. Sbornk UVTIZ, Ochrana Rostlin, 20(1):29-38

Braun U, 1987. A monograph of the Erysiphales (powdery mildews). Beihefte zur Nova Hedwigia, 89:700 pp.

Braun U, 1995. The Powdery Mildews (Erysiphales) of Europe. Jena, Germany: Gustav Fischer Verlag, 337 pp.

Braun U, Cook RTA, Inman AJ, Shin HD, 2002. The taxonomy of the powdery mildew fungi. The powdery mildews: a comprehensive treatise, 13-55; many ref.

CABI/EPPO, 2004. Blumeria graminis. Distribution Maps of Plant Diseases, No. 924. Wallingford, UK: CAB International.

Chan KC, Boyd WJR, Khan TN, 1990. Distribution, severity and economic importance of powdery mildew of barley in Western Australia. Australian Journal of Experimental Agriculture, 30(3):379-385

Cherif M, Harrabi M, Morjane H, 1994. Distribution and importance of wheat & barley diseases in Tunisia 1989-1991. Rachis, 13:25-34.

Chin KM, Wolfe MS, 1984. The spread of Erysiphe graminis f.sp. hordei in mixtures of barley varieties. Plant Pathology, 33(1):89-100

Ciurdarescu G, Csep N, Vonica I, 1987. Evolution of attacks of some wheat diseases in 1980-1983 and possibilities of their chemical control. Buletinul de Protectia Plantelor, No. 2-3:3-6

Cock LJ, 1975. The control of cereal diseases in the UK. In: Proceedings of the 8th British Insecticide and Fungicide Conference, Brighton, UK: BCPC, 859.

Cook RJ, King JE, 1984. Loss caused by cereal diseases and the economics of fungicidal control. In: Wood RKS, Jellis GJ, eds. Plant Diseases. Infection, damage and loss. Oxford, UK: Blackwell Scientific Publications, 237-245.

Cromey MG, Hanson R, 1992. Disease resistance in winter wheat cultivars and effects of foliar fungicides on yield. In: Popay AJ, ed. Proceedings of the forty fifth New Zealand plant protection conference, Wellington, New Zealand, 11-13 August, 1992. Rotorua, New Zealand: New Zealand Plant Protection Society, 75-78

Daamen RA, 1981. Surveys of diseases and pests of winter wheat in the Netherlands, 1979-1980. Mededelingen van de Faculteit Landbouwwetenschappen, Rijksuniversiteit Gent, 46(3):933-937

Daamen RA, 1989. Assessment of the profile of powdery mildew and its damage function at low disease intensities in field experiments with winter wheat. Netherlands Journal of Plant Pathology, 95(2):85-105

Dickson JG, 1956. Diseases of field crops. Bombay, India: Tata McGraw-Hill Publishing Co Ltd.

Dobrev D, Tufa F, 1995. Horizontal resistance of barley varieties to the powdery mildew pathogen. Rasteniev dri Naulei, 32:107-109.

Dreiseitl A, Jurecka D, 1997. Leaf disease occurrence on winter barley in the Czech Republic in 1989-1996. Ochrana Rostlin, 33(3):177-186; 8 ref.

Duan XiaYu, Sheng BaoQin, Zhou YiLin, Xiang QiJun, 1999. Field test of resistance sources against powdery mildew in wheat. Research progress in plant protection and plant nutrition., 94-98; 5 ref.

El-Meleigi MA, Al-Rokibah AA, 1996. Survey of wheat diseases in Central Saudi Arabia. Bulletin of Faculty of Agriculture, University of Cairo, 47(3):499-512; 21 ref.

El-Sayed AA, Ghobrial E, Noaman MM, Rizk RA, Mostafa EE, 1995. Evaluation of some barley varieties against major diseases in the Northwestern coastal region. Egyptian Journal of Agricultural Research, 73(4):897-911; 18 ref.

Felfcio JC, Camargo CEde O, Magno Cde PRdos S, Gallo PB, Pereira JCVNA, Pettinelli J·nior A, 1996. Evaluation of agronomic and technological quality of wheat genotypes under sprinkler irrigation in the state of Sao Paulo. Bragantia, 55(1):147-156; 16 ref.

Forrer HR, 1992. Experiences with the cereal disease forecast system EPIPRE in Switzerland and prospects for the use of diagnostics to monitor the disease state. Brighton Crop Protection Conference, Pests and Diseases - 1992. Volume 2 Farnham, UK; British Crop Protection Council, 711-720

Fraaije BA, Butters JA, Coelho JM, Jones DR, Hollomon DW, 2002. Following the dynamics of strobilurin resistance in Blumeria graminis f.sp. tritici using quantitative allele-specific real-time PCR measurements with the fluorescent dye SYBR Green I. Plant Pathology, 51(1):45-54; 40 ref.

Gao Sheng Gao, 1997. Identification and evaluation of disease resistant germplasm of wheat. Journal of the Hebei Agricultural University, 20:51-55.

Ghimire SR, Pradhanang PM, 1996. Response of lentil and wheat genotypes against major diseases 1993/1994. Working paper - Lumle Regional Agricultural Research Centre, 96-28:1-38.

Golebrink B, 1995. Susceptibility of cereals to Erysiphe graminis DC isolated from wild grasses. Materialg Sesji Instytute Ochrony Roslin, 35:238-240.

Gooding RW, Campbell KG, Herald LD, Lafever HN, 1997. Registration of 'Glory' wheat. Crop Science, 37(3):1008.

Griffey CA, Das MK, Stromberg EL, 1993. Effectiveness of adult-plant resistance in reducing grain yield loss to powdery mildew in winter wheat. Plant Disease, 77(6):618-622

Hanisovß A, Hanis M, 1997. Winter wheat Samara. Genetika a S^hacek~lechte^hacek~ni^acute~, 33(1):79-80.

Hardwick NV, Jenkins JEE, Collins B, Groves SJ, 1994. Powdery mildew (Erysiphe graminis) on winter wheat: control with fungicides and the effects on yield. Crop Protection, 13(2):93-98

Herman JL, Couvreur L, 1994. Phytotechnical approach to fungicidal control in winter wheat. Mededelingen - Faculteit Landbouwkundige en Toegepaste Biologische Wetenschappen, Universiteit Gent, 59(3a):1035-1045

Higginbotham S, Clark JH, David DHK, Dampney PMR, Froud-Williams RJ, Griffith PJ, Lane A, Sim L, Steven DB, 1996. The monitoring of disease levels in organically and conventionally grown wheat. Aspects of Applied Biology, 47:167-172.

Hirara K, 1966. Host Range and Geographical Distribution of the Powdery Mildews. (MIMEO). Niigata, Japan: Niigara University.

James WC, Teng PS, Nutter FW, 1991. Estimated losses of crops from plant pathogens. In: Pimentel D, ed. CRC Handbook of Pest Management in Agriculture. Boca Raton, USA: CRC Press.

Jenkyn JF, 1984. Effects of powdery mildew on grain filling in spring barley in contrasting environments. Annals of Applied Biology, 105(2):195-212

Johnson JW, Buntin GD, Cunfer BM, Roberts JJ, Bland DE, 1996. Registration of 'GA-Dozier' wheat. Crop Science, 36(3):801; 1 ref.

Jorgensen LN, Hovmoller MS, Secher BJM, Christensen K, 1995. Mildew in barley and wheat: the national disease in Denmark. 12th Danish Plant Protection Conference - Pests & Diseases SP - Rapport Staters Planteavlsfarsog, 4:57-83.

Kapoor JN, 1967. CMI Descriptions of Pathogenic Fungi and Bacteria No. 155. Wallingford, UK: CAB International.

Kari AG, 1996. Yield losses of spring barley induced by foliar diseases under semi-acid conditions. Technical Bulletin of the Cyprus Agricultural Research Institute, 177.

Kasha KJ, 1996. Barley. Agri-food Research in Ontario, 19(2):9-10.

King JE, 1977. Surveys of diseases of winter wheat in England and Wales, 1970-75. Plant Pathology, 26(1):8-20

King JE, 1977. Surveys of foliar diseases of spring barley in England and Wales, 1972-75. Plant Pathology, 26(1):21-29

Kolbe W, 1982. Further studies on the fungicidal activity of Baytan cereal seed treatment and its effect on yield (1975-1981). Pflanzenschutz-Nachrichten Bayer, 35(1):72-103

Kong Lin Rung, Dong Yu Chen, 1997. Studies on the genetic diversity for powdery mildew resistance genes for Aegilops tauschii. Acta Agronomica Sinica, 23:176-180.

Koric B, 1994. Occurrence and frequency of the pathotypes of Blumeria graminis D.C. f.sp. tritici March. in Croatia from 1988 to 1992. Fragmenta Phytomedica et Herbologica, 22(1/2):5-12; 9 ref.

Kraner A, 2001. Falcon 460 EC - excellent efficacy in diseases control of cereals and grape powdery mildew are now proved in practice. Proceedings of the 5th Slovenian Conference on Plant Protection, 180-181.

Leath S, Bowen KL, 1989. Effects of powdery mildew, triadimenol seed treatment, and triadimefon foliar sprays on yield of winter wheat in North Carolina. Phytopathology, 79(2):152-155

Lee TS, Kim SH, 1990. Virulence and race survey of Erysiphe graminis f.sp. hordei in Korea. Korean Journal of Plant Pathology, 6(1):28-34

Lindblad M, 1994. Agricultural pests and diseases in Sweden 1993. Vaxtskyddsnotiser, 58(1):27-32

Linhares WI, 1988. Yield losses caused by wheat powdery mildew. Fitopatologia Brasileira, 13(1):74-75

Lisovoy MP, Parphenyuk AI, 1997. Pathogenicity of Puccinia recondita, Erysiphe graminis and Pseudocercosporella spp. in the Ukraine and sources of group resistance of the winter wheat to these pathogens. Archives of Phytopathology and Plant Protection, 31(1):45-49; 4 ref.

Liu ZY, Sun QX, Ni ZF, Nevo E, Yang TM, 2002. Molecular characterization of a novel powdery mildew resistance gene Pm30 in wheat originating from wild emmer. Euphytica, 123(1):21-29.

Lu XK, Gong CG, 1986. Studies on gradation of disease severities and yield loss of wheat caused by Erysiphe graminis DC. Plant Protection, 12(2):5-7

Lutze G, Schott H, Trommer R, Amelung D, 1982. On the economic assessment of damage caused by major cereal diseases. Nachrichtenblatt fur den Pflanzenschutz in der DDR, 36(10):198-201

Luz WCda, 1984. Yield losses caused by fungal foliar wheat pathogens in Brazil. Phytopathology, 74(12):1403-1407

Manners JG, 1993. Principles of Plant Pathology. Ed. 2. Cambridge, UK: Cambridge University Press, 343 pp.

Marin JP, Segarra J, Almacellas J, 1994. Modelling epidemics of powdery mildew of barley using an accumulated number of conidia as an independent variable. Investigacion Agraria, Produccion y Proteccion Vegetales, Fuera de Serie, 2:315-341

Mellado ZM, Matus TI, Madariaga BR, 1994. Importance of foliar diseases for grain yield of wheat varieties in Cauquenes dryland area of Chile. Agricultura Te^acute~cnica (Santiago), 54(2):106-111; 7 ref.

Mercer PC, Ruddock A, 2003. Disease management of spring barley with reduced doses of fungicides in Northern Ireland. Crop Protection, 22(1):79-85; 16 ref.

Molteni J, PTrez B, Wright E, L=pez V, 1996. Seedling reaction to powdery mildew, Blumeria graminis f.sp. tritici, of tetraploid wheat cultivars, differential cultivars and wild relatives. Revista de la Facultad de Agronomi^acute~a (Universidad de Buenos Aires), 16(1/2):111-117; 14 ref.

Mori Y, Sato Y, Takamatsu S, 2000. Evolutionary analysis of the powdery mildew fungi using nucleotide sequences of the nuclear ribosomal DNA. Mycologia, 92(1):74-93; 2 pp. of ref.

Morikawa T, 1995. Transfer of mildew resistance from the wild oat Avena prostrata into the cultivated oat. Bulletin of the University of Osaka Prefecture. Series B, Agriculture and Life Sciences, 47:1-10; 9 ref.

Mtisi E, Mashiringwani NA, 1995. An overview of wheat production in Zimbabwe with emphasis on some phytopathological aspects. Breeding for disease resistance with emphasis on durability. In: Danial DL, ed. Proceedings of a regional workshop for eastern, central and southern Africa, held at Njoro, Kenya, October 2-6, 1994. Wageningen, Netherlands: Landbouwuniversiteit Wageningen (Wageningen Agricultural University), 55-59

Oerke EC, Dehne HW, Schönbeck F, Weber A, 1994. Crop production and crop protection: estimated losses in major food and cash crops. Crop production and crop protection: estimated losses in major food and cash crops., xxii + 808 pp.; [ref. at ends of chapters, available from publishers at PO Box 1991, Amsterdam, Netherlands or PO Box 945, Madison Square Station, NY 10160-0757, USA].

O'Hara RB, Brown JKM, 1996. Immigration of the barley mildew pathogen into field plots of barley. Plant Pathology, 45(6):1071-1076; 24 ref.

Parry D, 1990. Plant Pathology in Agriculture. Cambridge, UK: Cambridge University Press, 385 pp.

Pasquini M, Serini L, Casulli F, Siniscalco A, Lendini M, Mameli L, Gallo G, Monti M, Re FLlo, Coppolino F, Padovan S, Arduini F, Jenabzadeh P, 1996. The principal fungal diseases of wheat in Italy in 1995-96. Informatore Agrario, 52(35):47-54.

Pearce WL, Sanford DAvan, Hershman DE, 1996. Partial resistance to powdery mildew in soft red winter wheat. Plant Disease, 80(12):1359-1362; 16 ref.

Peusha H, Hsam SLK, enno T, Zeller FJ, 1996. Identification of powdery mildew resistance genes in common wheat (Triticum aestivum L. em. Thell.) VIII. Cultivars and advanced breeding lines grown in Finland. Hereditas (Landskrona), 124(1):91-93; 16 ref.

Polley RW, King JE, Jenkins JEE, 1993. Surveys of diseases of spring barley in England and Wales, 1976-1980. Annals of Applied Biology, 123(2):271-285

Priilinn O, Enno T, Knnts H, Peusha H, 1996. Genetic resources for the adaptive breeding of wheat. Agraarteadus, 7(1):84-89; 13 ref.

Reis EM, Moreira EN, Casa RT, Blum MMC, 2008. Efficiency and persistence of fungicides in the control of powdery mildew of wheat through seed treatment. (Eficiência e persistência de fungicidas no controle do oídio do trigo via tratamento de sementes.) Summa Phytopathologica, 34(4):371-374. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-54052008000400016&lng=en&nrm=iso&tlng=pt

Rubiales D, Carver TWL, Martfn A, 2001. Expression of resistance to Blumeria graminis f.sp. tritici in 'Chinese Spring' wheat addition lines containing chromosomes from Hordeum vulgare and H. chilense. Hereditas (Lund), 134(1):53-57; 26 ref.

Ruzgas V, Liutkevicius G, 1996. Winter wheat varieties and lines of distant origin under Lithuanian conditions. Biologija, No. 3:63-65; 6 ref.

Sachs E, 1995. Barley disease research in Germany. Rachis, 14:54-56.

Saenz GS, Taylor JW, 1999. Phylogeny of the Erysiphales (powdery mildews) inferred from internal transcribed spacer ribosomal DNA sequences. Canadian Journal of Botany, 77(1):150-168; 50 ref.

Schotman CYL, 1989. Plant pests of quarantine importance to the Caribbean. RLAC-PROVEG, No. 21:80 pp.

Sears RG, Martin TJ, Hatchett JH, Cox TS, Bequette RK, Curran SP, Chung OK, Heer WF, Long JH, Witt MD, 1997. Registration of '2137' wheat. Crop Science, 37(2):628.

Sekerkova M, 1996. The effect of row spacing, nutrition and sowing date on disease occurrence in winter wheat. Bedecke Prace Vgskumaeho Ustava Rustlinnej Vyroby v Piest'ang, 28:63-72.

Sharma BK, Busandrai AK, Verma BR, 1996. Disease Resistance Status of Commonly Grown Wheat Varieties in Himachal Pradesh. Plant Disease Research, 11:66-68.

Sheng BQ, Zhou YL, Duan XY, Xiang QJ, 1993. The host range of wheat powdery mildew (Erysiphe graminis f.sp. tritici) in Shanxi Province. Acta Phytophylacica Sinica, 20(2):105-112

Spencer DM, ed., 1978. The powdery mildews. The powdery mildews. Academic Press. London; New York and San Francisco, USA UK, xix + 565 pp.

Srivastava LS, 1996. Relative efficacy of fungitoxicants against powdery mildew of black gram in Sikkim. Journal of Hill Research, 9(2):296-298; 4 ref.

Steden C, Ramback O, Forster B, 1997. Powdery mildew of wheat: split applications contribute to selection of tolerant strains. Phytoma, 49:35-38.

Stojanovic S, Stojanovic J, Jevtic R, 1995. Efficacy of barley resistance genes to powdery mildew. Zastita-Bilja, 46:183-187.

Sykora M, Krippel E, Miklovicova M, Plesnik S, 1995. Sensitivity of barley powdery mildew (Erysiphe graminis f.sp. hordei) populations against some fungicidal substances in central Europe. Zeitschrift fur Pflanzenkrankheiten und Pflanzenschutz, 102(2):211-214

Tanda S, Su CT, 1995. A new variety of Uncinula ehretiae and anamorphs of powdery mildew fungi found on new host plants from Taiwan. Journal of Agricultural Science, Tokyo Nogyo Daigaku, 40(2):77-89

Teng PS, 1986. Crop loss appraisal in the tropics. Journal of Plant Protection in the Tropics, 3(1):39-50

Terekhov VI, Bessmel'tsev VI, Gavrilov SA, Dudnik SK, Timakov AA, 1997. With the minimal use of fungicides. Zashchita i Karantin Rastenii^breve~, No. 4:18.

Timmer RD, 1996. Growing malting barley without using pesticides. Publicatie - Proefstation voor de Akkerbouw en de Groenteteelt in de Vollegrond, Lelystad, No. 81A:79-84.

Tsuda M, Itoh H, Wakabayashi K, Ohkouchi T, Kato S, Masuda K, Sasaki M, 2000. Simeconzole (F-155), a novel systemic fungicide with broad-spectrum activity for seed treatment. The BCPC Conference: Pests and diseases, Volume 2. Proceedings of an International Conference held at the Brighton Hilton Metropole Hotel, Brighton, UK 13-16 November 2000, 337-562.

UK, Ministry of Agriculture, Fisheries and Food, 1980. ADAS Annual Report 1979. ADAS Annual Report 1979. HM Stationery Office. London UK, 69 pp.

Wang XF, Zhang ZS, He JB, Liu HY, 1992. Identification of physiological races of Erysiphe graminis f.sp. tritici in Henan Province. Acta Phytophylacica Sinica, 19(4):303-308

Whisson DL, 1996. Molecular characterization and pathogenicity of Erysiphe graminis f.sp. hordei in Australia. Australasian Plant Pathology, 25:55-63.

Yahyaoui AH, Reinhold M, Scharen AL, 1997. Virulence spectrum in populations of the barley powdery mildew pathogen, Erysiphe graminis f.sp. hordei in Tunisia and Morocco in 1992. Plant Pathology, 46(1):139-146; 20 ref.

Yarham D, Turner J, 1992. ADAS organic wheat survey. New Farmer & Grower, No. 34:31-33.

Zhang FL, Zhang Y, Zhang J, Xu KD, Liu K, Wang Y, Lu YJ, Xiang J, Zhang L, Shi XY, Wang H, Tan GX, Cao P, Li CW, 2014. First report of powdery mildew caused by Blumeria graminis on Festuca arundinacea in China. Plant Disease, 98(11):1585-1586. http://apsjournals.apsnet.org/loi/pdis

Distribution Maps

Top of page