0000005057 00000 n Sixty indigenous and exotic inbred lines were evaluated under artificial epiphytotic conditions at two identified hot spot locations, Almora and Nagenahalli. 1. Turcicum leaf blight on maize Maize leaf showing elongated, spindle-shaped necrotic lesions caused by turcicum leaf blight (Setosphaeria turcica, anam. Under these terms infestations developed in France. 0000000796 00000 n Similar patches can also be found on maize husks. Maize is a crop of strategic national interest and contributed 46 % GDP of the agricultural products in Tanzania (Gabagambi, 2009). This disease is often found in Central Europe, but cost-effective damages have not been caused yet. Maize rust (Puccinia sorghi) is widespread especially in tropical and subtropical areas. First symptoms on maize plants appear on the lower leaves. Exserohilum turcicum is the causal organism of northern corn leaf blight of maize, as well as Exserohilum leaf blight of sorghum (Photo 1). The major control measure for this maize disease also is ploughing under of straw. In Central and Southern Europe the disease mostly occurs in individual years and in restricted areas (as in Austria 1995). 0000000016 00000 n 1) Turcicum Leaf blight: causal organism: Helminthosporium turcicum. 4) Banded leaf and sheath blight. In the past the anamorph (production of asexual spores called conidia) of the pathogen was named Helminthosporium turcicum. Under these terms infestations developed in France. Therefore variety choice is most relevant in controlling leaf blight of maize. At the beginning of the infestation small, longish, watery stains arise which can grow into elongated bands of grey-green to light brown lesions. With favourable weather conditions initial infections take place beginning from the 8 leaf stage. It is a major constraint to maize production in many maize growing regions worldwide with a growing season characterized by high humidity and moderate temperatures (17 to 27°C). Whether they cause cost effective damage primarily depends on the annual weather trend. 0000002955 00000 n Cochliobolus carbonum (formerlly known as Helminthosporum carbonum); this pathogen causes, in contrast to Setosphaeria turcica, much smaller, light green or yellow round patches, later up to maximal 3 cm elongate brown patches. Epidemiology and Management of Turcicum leaf Blight of Maize Caused by Exserohilum turcicum (Pass.) They begin as small, diamond-shaped lesions and elongate within the veins to become larger and rectangular. Even with favourable weather conditions for the fungi yield losses can be avoided by growing less susceptible varieties along with appropriate cultivation measures. The patches converge and can reach a size of up to 20 cm long and 5 cm wide. The book gives an insight into the ecology and biology of the fungus. symptoms first appear on the leaves at any stage of plant growth, but usually at or after anthesis. The characteristic symptom of turcicum leaf blight on a susceptible cultivar is one-to-six inch long cigar-shaped gray- to tan-colored lesions on the leaves (Figure 2). These carbon sources were amended in Richard's medium in place of sucrose. In maize resistance to Turcicum leaf blight is both qualitative and quantitative. 0000002380 00000 n Growth and sporulation of E. turcicum isolates were studied in different carbon sources namely the sucrose, glucose, lactose, mannitol, glycerin and maltose. Leonard and Suggs}, author={Sharanappa I. Harlapur}, year={2005} } Symptoms vary depending on which race is present. The disease scores were taken bi-weekly from the onset of the symptoms up to grain filling stage. The maneb formulations were most effective in minimising the E. turcicum severity under field conditions followed by ziram, vacide and Z-65. saff 0.25% recorded the lowest percent disease index (PDI) The disease is more prevalent in humid weather with temperature between 20–28 °C and causes small cigar-shaped lesions to complete destruction of the foliage. Only highly susceptible varieties, which are not recommended though, show losses of over 30 percent. 0000002921 00000 n 0000005746 00000 n Krankheiten und Schädlinge: Blattfrüchte, Mais, Blattfleckenkrankheiten an Mais (German version), Factors that were found to have an effect and possible control methods. Penetration of maize leaves by Helminthosporium turcicum. 0000003462 00000 n In Austria (Styria) yield losses were assessed in susceptible varieties. Starting point of the leaf blight disease are maize residues remaining on the soil surface. Karnataka Journal of Agricultural Sciences, 23(2):372-373. Exserohilum turcicum). Turcicum leaf blight of maize in Uttarakhand, attaining epidemic proportions which resulted in 83 per cent yield reduction. Spots that occur later, caused by spores distributed by wind, show on upper leaves. TLB, caused by E. turcicum, is considered a serious disease where climatic conditions are cool with high relative humidity. Symptoms. If the infection takes place 5-6 weeks after flowering yield reduction is marginal. Figure 7. Sohi et al. Turcicum leaf blight of maize caused by the fungus Setosphaeria turcica is a serious foliar disease of maize distributed widely throughout the world and causing significant yield losses. H����n�6����� ����is^lu�ݠ���;��]���� ۛ��&�MQ��Ǚ�>:��d���ɔլ�e�JR��i&mY��nj�H[&5�h�. In the USA it occurs mainly in the northern Corn Belt. Lodging as a result of NCLB & GLS infection. 0 The pathogen E. Turcicum was isolated by standard tissue isolation technique. Although the lesions produced on these two crops are very similar, an interesting fact is that not all isolates from this pathogen can infect sorghum and maize equally well. 0000012920 00000 n The brownish red centre is surrounded by a considerably larger yellow halo. Eventually the growing lesions can lead to complete burning of the foliage. Thus big parts of the leaf blade can … 0000003200 00000 n Proper crushing and ploughing under of infested plant residues avoids economically relevant yield losses due to this fungal disease. Typical symptoms of Turcicum leaf blight of maize Collection of diseased samples The leaves of affected maize plants showing typical Turcicum leaf blight necrotic lesion type symptoms were collected from susceptible genotype CM-202 grown at Zonal … These fungicides increased the grain yield and seed quality (Cox, 1956). 0000010346 00000 n Temperatures between 24°C to 30°C and humid leaves during a period of 10 hours are optimal requirements for the spores to germinate and to penetrate the leaf tissue. Both susceptible and resistant lesions Figure 5. Spots that occur later, caused by spores distributed by wind, show on upper leaves. startxref These start out as slightly oval, water-soaked, small spots, and may first appear on lower leaves. The patches are surrounded by a dark seam too and partly show concentric zones. 3. This paper presents identification of sources of Turcicum Leaf Blight (TLB) resistance in maize. Here we present a real-time quantitative PCR (qPCR) assay specific for E. turcicum detection and biomass quantification in sorghum and maize. Mature symptoms of Turcicum leaf blight are characteristic cigar shaped lesions that are 3 to 15cm long. They may appear first on If the weather stays warm and humid for a long time during spring and summer, several cycles of infection can develop and Setosphaeria-leaf blight of maize can spread out. Maize is not only utilized as a staple food by the lower strata of the society, but it is also used as a crop par excellence for industrial use. At the beginning of the infestation small, longish, watery stains arise which can grow into elongated bands of grey-green to light brown lesions. Figure 6. 23 25 Leonard and Suggs. In midsummer 1 to 3 mm big yellow pustules develop on upper and lower surfaces of leaves which rupture shortly after and release brown spores. In years with a warm humid growing season (as in 2002) higher infestation rates have been recorded. Keywords: maize, turcicum leaf blight, resistant, screening Introduction In Indian agriculture, maize occupies an important place after wheat and rice. A laboratory experiment was conducted to study the physiological variation of the thirteen isolates of maize TLB caused by Exseohilum turcicum. Two QTLs conferring resistance to northern leaf blight were identified for this mapping population Balint-Kurti et al., 2010). But if the preventive measures mentioned above are not followed consistently the variety alone can not save the day. After 10 to 14 days already new spores (conidia) are released from the underside of the leaves and are distributed by wind to neighbouring fields. A study was carried out to identify the sources of resistance to Turcicum leaf blight (TLB) and polysora rust in maize. The fungus affects the maize plant at a young stage. Helminthosporium turcicum) An early symptom is the easily recognized, slightly oval, water-soaked, small spots produced on the leaves. 0000008036 00000 n Small, only a few millimetres big, round spots appear on leaves. %PDF-1.4 %���� Lesions are elliptical and tan in color, developing distinct dark areas as they mature that are associated with fungal sporulation. 0000016713 00000 n These grow into elongated, spindle-shaped necrotic lesions (Photo 20). CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): ABSTRACT: Northern corn leaf blight or turcicum leaf blight caused by Exserohilum turcicum (Pass.) Symptoms can range from small cigar shaped lesions to complete destruction of the foliage (Welz and Reiger, 2000). Turcicum leaf blight causes extensive defoliation during grain filling period, reduce succulence of leaves and stalk necrosis resulting in grain yield losses (Perkins and Pederson, 1987). Welz and Geiger (2000) described that symptoms of the disease can range from small cigar-shaped lesions to complete destruction of the foliage and mid- altitude regions, about 900-1600 m above sea level, have particularly favourable climate for the disease as dew periods are long and temperature moderate. The pathogen is spread worldwide. Trichometasphaeria turcica) (Anamorph: Exserohilum turcicum, syn. In the region of Inn and Danube, which were the most affected areas, we estimated that yield losses stayed below 10 percent. Typical symptoms of Turcicum leaf blight of maize Collection of diseased samples The leaves of affected maize plants showing typical Turcicum leaf blight necrotic lesion type symptoms were collected from susceptible genotype CM-202 grown at Zonal Agricultural Research Station (ZARS), V.C. And biomass quantification in sorghum and maize with high relative humidity spots leaves. 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