Leaf Blight Of Maize Research Articles

Effect of Different Natural Products Against Leaf Blight Diseases of Maize

This experiment was conducted during kharif seasons (June to September) of 2016 and 2017 at District Seed Farm, Kalyani Simanta of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India. The objective of the study was to find out the performance of natural products against maydis leaf blight of maize under artificial epiphytotic condition. The eleven natural products were namely; Neem leaves, Karanj leaf, Milkweed / Calotropis leaf, Datura leaf, Parthenium leaf, leaves of Umbelanterna / Lantana camara, leaves of False Ashoka, leaves of tulsi, bulb of garlic, cow urine and Hexaconazole as standard check. The experiment was laid out in Randomized Block Design with 12 treatments with three replications. The extracts of Plant products at 10% concentrations were then applied by spraying to plants in the field just after 24 h of inoculation. 2nd inoculation was done seven days after first inoculation. Severity was calculated for each replication of each treatment by using the Percent Disease Index (PDI). Allium sativum (garlic) bulb @ 10% resulted lowest Percent Disease Index i.e. 28.4% against the Maydis leaf blight and 25.8% against Turcicum leaf blight of maize with the concurrent 61.13% and 65.08% control of diseases. Cow urine @ 50% resulted 29.8% and 28.6% PDI which was statistically equally effective with Allium sativum (garlic) bulb @ 10%. Likewise, this Allium sativum (garlic) bulb @ 10% also produced highest yield (2910 kg ha-1) which was 34 higher than the chemical, Hexaconazol used for these diseases.

CHEMICAL CONTROL OF SOUTHERN LEAF BLIGHT OF MAIZE CAUSED BY HELMINTHOSPORIUM MAYDIS

Southern Leaf Blight of maize (SLBM) is a severe disease affecting maize crop in Pakistan. This disease causes considerable losses in maize crop every year. To avoid this loss, a study was conducted to check the efficacy of four fungicides and one control, tested against maize variety Malka-2016. The experiment was conducted at Plant Pathology AARI Research area, Faisalabad, during 2021-22. The result showed that Propiconazole (Tilt 25% WP) was found to be the most effective fungicide to control the leaf Blight of maize followed by Dithane M-45 (Mancozeb 80%WP) and Kavach (Chlorothalonil 75%WP). The Blitox-50 (Copper oxychloride 50%WP) was the least effective against the disease. The Propiconazole (Tilt 25% WP) control the disease 80 % over the check. Similarly, Dithane M-45 (Mancozeb 80 %) controls the disease 70.83 % and Chlorothalonil by 59 %. The least effective fungicide was Blitox-50 (Copper oxychloride 50 %) which control the disease 42.5% over the check.

Integrated Management of Maize Leaf Blight Caused by Helminthosporium maydis

Leaf blight (Helminthosporium maydis Nisikado) is one of the most devastating diseases in maize. The innovative idea to manage crop diseases is the integrated method (chemical and bio-control agents), as it involves the least amount of fungicidal load in the environment. Thus, in the present study, the objectives were formulated to screen the different systemic and non-systemic fungicides against the mycelial growth of leaf blight pathogen under in vitro conditions and to investigate the effect of different fungicides and bio-agents against leaf blight disease under field conditions. Among fungicides, systemic fungicides viz., propiconazole, tebuconazole and hexaconazole were best (100%) and significantly superior in inhibiting the mycelial growth of the fungus at 0.1 per cent concentration. Mancozeb (0.2%) was recorded 92.78 per cent inhibition over control followed by propineb at 0.2 per cent (93.33%). In the field experiments, seed treatment (ST) with TNAU-Pf1 @ 10 g/kg seed + foliar spray of propiconazole (0.1%) and ST with TNAU-Pf1 @ 10 g/kg seed + foliar spray of tebuconazole (0.1%) at 40 DAS recorded the lowest incidence of leaf blight and maximum grain yield in maize.

Omnivorous Notoxus trinotatus Pic (Coleoptera: Anthicidae) is a newly recognized vector of northern leaf blight in maize.

The adaptations of omnivorous insects to food are manifested in a multifaceted manner, and the availability of food resources directly determines insect feeding tendencies, which contribute to a complex insect-food relationship and impact insect functionality in the environment. Stable isotope analysis was applied to test the feeding preference and further define the functional role of omnivorous beetles in cropland. Our results confirmed that as an omnivorous beetle, the fungivorous nature of Notoxus trinotatus accounted for a prominent proportion food selection at the adult stage, and more importantly, this dietary feature contributed to the dispersal of the northern corn leaf blight in maize (NLB) during the feeding trials. In addition to the preference for fungi, water supplementation was an essential element extending adult longevity, which directly prolonged the contact time of adults with pathogenic fungi in agricultural fields. Consistent with the herbivorous characteristics of beetles, before the emergence of NLB fungal pathogens, corn tissues served as the main food, which provided the beetles with more opportunities to transmit fungal pathogen propagules. We conclude that the role of N. trinotatus in carrying NLB pathogen is due to its feeding on this plant mycopathogen, and an increased abundance of beetles carrying the pathogen may increase the rate of NLB disease infestation. More focus should be concentrated on the functions of fungivorous beetles, not only as pathogen-transmitting pests, but also as an element among the balanced biotic factors in farmland.

Prevalence of Southern Leaf Blight of Maize in two major maize producing states of India

Southern corn leaf blight (SCLB) or Maydis leaf blight, caused by Bipolaris maydis, is an important disease of maize in the eastern and north-eastern part of India. Hence, to assess the severity and distribution of the disease in two distinct and major maize growing states i.e. Mizoram and West Bengal were selected. A roving survey was conducted under different agro-climatic conditions during the kharif season of 2019 and 2020 in three districts of West Bengal and as well as in Mizoram. The survey results revealed that SCLB was more prevalent in the plains of West Bengal in comparison to hilly areas of Mizoram. The mean SCLB incidence varied from 18.87% in Zemabawk, Mizoram to 63.22% in institutional farm, C-block, of BCKV, West Bengal. The mean disease severity ranged from 10.06 % in Muthi, Mizoram to 22.09% in Instructional Farm, Jaguli, BCKV, West Bengal. Both disease incidence and severity were highest at 99 DAS in all the locations surveyed. Successive surveys of SCLB in the maize growing belts across the country need to be conducted to develop a better understanding about the disease prevalence, intensity and severity under different agro-ecological conditions.

Evaluation of Fungicides, Botanicals and Biocontrol Agents for Management of Southern Leaf Blight of Maize (Bipolaris maydis)with Effective Benefit Cost Ratio

Southern leaf blight of maize (Bipolaris maydis) is one of the major disease in many countries including India. An experiment was conducted for two consecutive years during rabi 2019 and 2020 to develop an integrated management of southern leaf blight of maize using fungicides, botanicals and bioagents under natural field conditions. Propiconazole was found to be the best and showed 100% mycelial growth inhibition in vitro at 0.1%. Among the botanicals, citronella showed 99.70% mycelial growth inhibition and Trichoderma harzianum was found to be the best with 84.26% mycelial growth inhibition among the biocontrol agents. The results of the field trials showed the highest yield performance (2601.71 kg ha-1) and percent reduction in disease severity over control of 61.70 % in the treatment comprising of seed treatment+spraying with propiconazole 25% EC @ 1% which was followed by treatment comprised of spraying with citronella @ 0.1% (2445.33 kg ha-1) and spraying with propiconazole 25% EC @ 0.1% (2349.26 kg ha-1). Highest BC ratio was obtained in seed treatment+spraying with propiconazole 25% EC @ 1% (4.05) followed by spraying with Trichoderma harzianum @ 4 g (3.71) and seed treatment+spraying with Trichoderma harzianum @ 4 g (3.69). The results showed that seed treatment+spraying with propiconazole 25% EC @ 1% was significantly superior over other treatments.

SNP-based bulk segregant analysis revealed disease resistance QTLs associated with northern corn leaf blight in maize.

Maize (Zea mays L.) is the most important food security crop worldwide. Northern corn leaf blight (NCLB), caused by Exserohilum turcicum, severely reduces production causing millions of dollars in losses worldwide. Therefore, this study aimed to identify significant QTLs associated with NCLB by utilizing next-generation sequencing-based bulked-segregant analysis (BSA). Parental lines GML71 (resistant) and Gui A10341 (susceptible) were used to develop segregating population F2. Two bulks with 30 plants each were further selected from the segregating population for sequencing along with the parental lines. High throughput sequencing data was used for BSA. We identified 10 QTLs on Chr 1, Chr 2, Chr 3, and Chr 5 with 265 non-synonymous SNPs. Moreover, based on annotation information, we identified 27 candidate genes in the QTL regions. The candidate genes associated with disease resistance include AATP1, At4g24790, STICHEL-like 2, BI O 3-BIO1, ZAR1, SECA2, ABCG25, LECRK54, MKK7, MKK9, RLK902, and DEAD-box ATP-dependent RNA helicase. The annotation information suggested their involvement in disease resistance-related pathways, including protein phosphorylation, cytoplasmic vesicle, protein serine/threonine kinase activity, and ATP binding pathways. Our study provides a substantial addition to the available information regarding QTLs associated with NCLB, and further functional verification of identified candidate genes can broaden the scope of understanding the NCLB resistance mechanism in maize.

Fusarium Species Associated with Maize Leaf Blight in Heilongjiang Province, China.

Fusarium spp. are among the most important plant pathogens in the world. A survey on maize leaf blight was carried out in Heilongjiang province from 2019 to 2021. Based on morphological characteristics and a phylogenetic analysis on translation elongation factor (tef1) and second-largest subunit of RNA polymerase II (rpb2) genes, 146 Fusarium isolates were obtained and grouped into 14 Fusarium species, including F. ipomoeae (20.5%), F. compactum (17.1%), F. sporotrichioides (9.59%), F. graminearum (9.59%), F. citri (8.9%), F. asiaticum (6.85%), F. verticillioides (6.85%), F. acuminatum (5.48%), F. glycines (5.48%), F. temperatum (2.74%), F. armeniacum (2.74%), Fusarium sp. (2.05%), F. flagelliforme (1.4%), and F. annulatum (0.68%). The Fusarium incarnatum-equiseti species complex (FIESC, including F. ipomoeae, F. compactum, F. citri, and F. flagelliforme) was the most prevalent, indicating an evolving occurrence of the Fusarium species causing maize leaf blight. The typical symptoms observed on the maize leaves were oval to long strip lesions, with a gray to dark gray or brownish red coloration in the center and a chlorotic area at the edges. Based on the tef1 gene, seven haplotypes of FIESC were identified in Heilongjiang province, suggesting a population expansion. This is the first report of F. ipomoeae, F. compactum, F. flagelliforme, F. citri, F. sporotrichioides, F. graminearum, F. asiaticum, F. acuminatum, F. glycines, F. temperatum, F. armeniacum, Fusarium sp., and F. annulatum causing maize leaf blight in Heilongjiang province, China. The current research is informative for managing disease, exploring the phylogenetic relationship among Fusarium species, and clarifying the diversity of Fusarium species associated with maize leaf blight.

Confirmation of physiological race of Bipolaris maydis causing maydis leaf blight of maize in India

Maydis leaf blight (MLB) incited by Bipolaris maydis occurs in most of the maize growing regions. Present study revealed morphological divergence among 74 isolates of B. maydis collected from geographically distant places of India. Based on morpho-cultural features clustered by R software, 25 representative isolates of B. maydis were used for race identification. The internal transcribed spacer (ITS) sequence further confirmed the isolates as B. maydis. In recent concept, variation in disease incidence and infectivity denotes genetic shift in the pathogen or introduction of new pathogenic race(s) through germplasm exchange. For unveiling Indian race(s) of B. maydis, present exploration was made. Four genetically divergent maize genotypes with cytoplasmic male sterility (CMS), viz. -C (MGU- 161QPV-C), -T (MGU- 345PV-T), -S (MGU-150Q-S) and CM-119 (fertile cytoplasm) were assessed using 25 isolates of B. maydis during kharif 2018-19 at ICAR-IARI, New Delhi. The genotype MGU-161QPV-C associated with CMS-C was highly resistant followed by MGU-345PV-T (CMS-T) and MGU-150Q-S (CMS-S), whereas CM-119 showed high susceptibility. Present outcome confirmed prevalence of race 'O' of B. maydis in India and eliminated uncertainty about occurrence of other races, i.e. T and C.

Genetic characterization and comparative assessment of response of biparental and multi-parental populations to northern corn leaf blight in maize (Zea mays L.)

To compare the efficiency of multiparental and biparental progenies to northern corn leaf blight (NCLB) resistance, F3 progenies were evaluated during two seasons. A total of 418 F3 progenies derived from multiple founder parents and 248 F3 progenies derived from two parents, namely, SKV50 (Resistant) and CM202 (Susceptible) were phenotyped for their response to the NCLB during summer and kharif 2020. A wide range of disease severity was observed among F3 progenies derived from multiple parents ranging from 28.12 to 62.93%. The difference in the variances between multiparent and biparental progenies was indicated by the significance of Levene’s test. High genotypic and phenotypic coefficient of variation was observed among multi-parental progenies than those derived from the biparental population. Reaction to NCLB showed moderate heritability of 57% and high genetic advance as per cent mean (20.70%) in the case of biparental population, whereas, multi-parental population exhibited a high heritability (68%) and high genetic advance as per cent mean (28.57%). The distribution of F3 progenies was found to be positively skewed and platykurtic indicating that the trait was under the control of large number of genes with complementary gene action.

Physiological and Molecular Characteristics of Southern Leaf Blight Resistance in Sweet Corn Inbred Lines

Southern corn leaf blight is one of the most widespread foliar diseases in maize-producing areas worldwide and can seriously reduce the yield and quality of sweet corn. However, the molecular mechanisms underlying the disease in sweet corn have not been widely reported. In this study, two sweet corn inbred lines, resistant K13 (RK13) and susceptible K39 (SK39), were used to explore the disease resistance mechanism of southern leaf blight. We observed morphological characteristics and assessed the changes in protective enzymatic activity in sweet corn leaves after inoculation of C. heterostrophus. RNA-seq was performed to elucidate the transcriptional dynamics and reveal the key pathways involved in southern leaf blight resistance without pathogens (Mock) and at 1 and 3 days post inoculation (1 and 3 dpi). Differentially expressed genes (DEGs) were identified in the SK39 group (including three pairwise combinations: SK39−0d_vs_SK39−1d, SK39−1d_vs_SK39−3d and SK39−1d_vs_SK39−3d), the RK13 group (including three pairwise combinations: RK13−0d_vs_RK13−1d, RK13−1d_vs_RK13−3d and RK13−1d_vs_RK13−3d), and the SK39_vs_RK13 group (including three pairwise combinations: SK39−0d_vs_RK13−0d, SK39−1d_vs_RK13−1d, and SK39−3d_vs_RK13−3d). In our study, 9455 DEGs from the RK13 group, 9626 from the SK39 group, and 9051 DEGs from the SK39_vs_RK13 group were obtained. Furthermore, 2775, 163, and 185 DEGs were co-expressed at SK39_vs_RK13, RK13, and SK39, respectively. A functional analysis of the DEGs revealed that five pathways—i.e., photosynthesis, plant hormone signal transduction, MAPK signaling pathway, phenylpropanoid biosynthesis, and biosynthesis of secondary metabolites—and transcription factor families play crucial roles in disease resistance. The results from the present study enabled the identification of the JA and SA signaling pathways, which are potentially involved in the response to southern leaf blight in maize. Our findings also highlight the significance of ZIM transcription factors and pathogenesis-related (PR) genes during pathogen infection. This study preliminarily explored the molecular mechanisms of the interaction between sweet corn and C. heterostrophus and provides a reference for identifying southern leaf blight resistance genes in the future.

Inhibitory Potentialities of Bio-control Agents on Cochliobolus heterostrophus Inciting Maydis Leaf Blight of Maize in Manipur

The antagonistic potentialities of seven species of native Trichoderma viz., T. atroviride, T. koningiopsis, T. ovalisporum, Hypocrea lixii, T. harzianum, T. asperellum and T. harzianum were evaluated in vitro against Cochliobolus heterostrophus causing maydis leaf blight of maize. The current study of dual culture assay, revealed the percentages of mycelial growth inhibition of C. heterostrophus by Hypocrea lixii, T. harzianum, T. atroviridae, T. koningiopsis, T. ovalisporum, T. asperellu and T. harzianum were 80.4%, 83.80%, 83.80%, 82.85%, 85.23%, 83.33% and 82.38% respectively. Each species significantly slowed the Cochliobolus heterostrophus pathogen's expansion. The findings indicate that C. heterostrophus, a common pathogen associated with maize leaf blight, is capable of being inhibited to a significant degree by all seven species of Trichoderma, using them as effective potential antagonists.

Major diseases of field and horticultural crops in Northern Bihar region of India

A survey was conducted to determine the status of major diseases of field and horticultural crops grown in Saharsa, Supaul, Madhepura and Khagaria districts of northern Bihar, India. Three blocks in each district and three villages in each block were surveyed through a random field survey method. Per cent disease incidence was recorded on randomly selected plants in a particular field of selected location. The incidence of diseases was observed on the basis of typical field symptoms and later the association was confirmed through microscopic examinations in the laboratory. In view of maximum diseases incidence; foliar blight of wheat, sheath blight of rice, turcicum leaf blight of maize, mungbean yellow mosaic virus, Alternaria blight of mustard were recorded with >50% incidence in these districts. However, dry root rot and wilt of chickpea and lentil, wilt of pigeonpea, powdery mildew of pea, Alternaria leaf spot of linseed, Fusarium wilt and red rot of sugarcane and root rot of jute were noticed with 10 to 50% incidence. In fruit crops; sigatoka disease of banana was noticed with >50% incidence, while, anthracnose/ die back and floral malformation of mango, wilt of banana, foot rot of papaya and anthracnose of guava and citrus canker were observed with 10-50% incidence. Diseases viz., late blight, bacterial wilt, black leaf spot/ rot, leaf curl, yellow vein mosaic virus, die back and late blight were recorded with >50% incidence in tomato, brinjal, cauliflower, cucurbits, okra, chilli and potato, respectively. The purple blotch of onion, black leaf rot of cabbage and collar rot of elephant foot yam were noticed with 10-50% incidences.

Ascorbate peroxidase 1 confers resistance to southern corn leaf blight in maize.

Southern corn leaf blight (SCLB), caused by Bipolaris maydis, is one of the most devastating diseases affecting maize production. However, only one SLCB resistance gene, conferring partial resistance, is currently known, underscoring the importance of isolating new SCLB resistance-related genes. Here, we performed a comparative proteomic analysis and identified 258 proteins showing differential abundance during the maize response to B. maydis. These proteins included an ascorbate peroxidase (Zea mays ascorbate peroxidase 1 (ZmAPX1)) encoded by a gene located within the mapping interval of a previously identified quantitative trait locus associated with SCLB resistance. ZmAPX1 overexpression resulted in lower H2 O2 accumulation and enhanced resistance against B. maydis. Jasmonic acid (JA) contents and transcript levels for JA biosynthesis and responsive genes increased in ZmAPX1-overexpressing plants infected with B. maydis, whereas Zmapx1 mutants showed the opposite effects. We further determined that low levels of H2 O2 are accompanied by an accumulation of JA that enhances SCLB resistance. These results demonstrate that ZmAPX1 positively regulates SCLB resistance by decreasing H2 O2 accumulation and activating the JA-mediated defense signaling pathway. This study identified ZmAPX1 as a potentially useful gene for increasing SCLB resistance. Furthermore, the generated data may be relevant for clarifying the functions of plant APXs.

An Improved Genome Sequence Resource of Bipolaris maydis, Causal Agent of Southern Corn Leaf Blight.

An Improved Genome Sequence Resource of Bipolaris maydis, Causal Agent of Southern Corn Leaf Blight.

Mapping of quantitative trait loci for resistance to turcicum leaf blight in maize (Zea mays L.)

Turcicum Leaf Blight (TLB) is a common foliar disease of maize. The aim of this study was to find quantitative trait loci (QTL) for TLB resistance in maize. By crossing two inbred lines, CM 212 (susceptible) and CM 145 (resistant), a mapping population was developed, which was evaluated in two environments namely E1 (Varanasi, U.P., India; 250 N, 830 E) and E2 (Nagenahalli, Karnataka, India; 120 N, 760 E). Data on four disease severity traits viz., Percent Disease Index (PDI), Area Under Disease Progress Curve based on PDI (AUDPC-PDI), Lesion Area (LA), and Area Under Disease Progress Curve based on LA (AUDPC-LA) were generated for locating QTLs. Fifteen QTL intervals for resistance to TLB were located on chromosomes 1, 2, 4, 5, 6 and 9. Out of these fifteen QTLs, two QTLs were reported for trait PDI on chromosomes 1 and 5 for TLB resistance at E1; seven QTLs were identified at E2, where two QTLs were reported for PDI on chromosome 4, four QTLs for trait area under disease progress curve based on PDI and one QTL was reported for trait lesion area. Additionally, identified at pooled environment, six QTLs exhibited the LOD values in the range of 2.64 and 7.77, and corresponding R2 in the range of 10.80 and 17.74 in the individual environments and across the environments

Indirect effects of transgenes on resistance to northern leaf blight of maize under chemical and manual management practices of weeds

The effects of transgenes on plant resistance to non-target diseases caused by foliar fungi are still poorly studied. This study aimed to evaluate the indirect effects of the TC1507 event, isolated and in combination with NK603, on the maize genetic resistance to northern leaf blight, in the presence and absence of chemical control of weeds. Three isogenic hybrids were used as treatments in this study: the non-genetically modified conventional hybrid BG7060 (NGM); the genetically modified hybrid BG7060H (Hx), carrying transgenes cry1F and pat (TC1507 event); and the genetically modified hybrid BG7060HR (Hxrr), carrying transgene cp4epsps (NK603 event) combined with the TC1507 event. To evaluate the resistance of the three isogenic hybrids to that pathogen, three experiments were carried out in Florianópolis, southern Brazil, in complete randomized blocks with three replications in experiment 1 (2012/2013 harvest) and four replications in experiments 2 and 3 (2016/2017 harvest). The control of weeds was done by manual weeding, in experiments 1 and 2, and with the application of the herbicide Finale in a single dose, in experiment 3. The severity of northern leaf blight was evaluated under natural conditions of disease occurrence, in experiment 1, and from inoculation of the pathogen, in experiments 2 and 3. The isogenic hybrid Hxrr showed higher incidence and shorter incubation and latency periods than the Hx and conventional isogenic hybrids in the two management environments of weeds. Pathogen resistance, measured from these three variables, tended to be lower in the genetically modified hybrid Hxrr, which contains two events (TC1507 and NK603), followed by the hybrids Hx and NGM, in increasing order of resistance. The addition of the herbicide for the control of weeds increased the susceptibility of the genetically modified hybrids Hx and Hxrr, as well as the conventional hybrid not submitted to this control, but cultivated close to the hybrids Hx and Hxrr managed with the use of the herbicide.

Alternaria spp. Associated with Leaf Blight of Maize in Heilongjiang Province, China.

Maize (Zea mays L.) is a major economic crop worldwide. Maize can be infected by Alternaria species causing leaf blight that can result in significant economic losses. In this study, 168 Alternaria isolates recovered from symptomatic maize leaves were identified based on morphological characteristics, pathogenicity, and multilocus sequence analyses of the genes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), the internal transcribed spacer of ribosomal DNA (rDNA ITS), the RNA polymerase II second largest subunit (RPB2), and histone3 (HIS3). Maize isolates grouped to four Alternaria species including Alternaria tenuissima, A. alternata, A. burnsii, and Alternaria sp. Notably, A. tenuissima (71.4%) was the most prevalent of the four isolated species, followed by A. alternata (21.5%), Alternaria sp. (4.1%), and A. burnsii (3.0%). Pathogenicity tests showed that all four Alternaria species could produce elliptic to nearly round, or strip, lesions on leaves of maize, gray-white to dry white in the lesion centers and reddish-brown at the edges. The average disease incidence (58.47%) and average disease index (63.55) of maize leaves inoculated with A. alternata were significantly higher than levels resulting from A. tenuissima (55.28% and 58.49), Alternaria sp. (55.34% and 58.75), and A. burnsii (56% and 55). Haplotype analyses indicated that there were 14 haplotypes of A. tenuissima and five haplotypes of A. alternata in Heilongjiang Province and suggested the occurrence of a population expansion. Results of the study showed that Alternaria species associated with maize leaf blight in Heilongjiang Province are more diverse than those that have been previously reported. This is the first report globally of A. tenuissima, A. burnsii, and an unclassified Alternaria species as causal agents of leaf blight on maize.

Setosphaeria turcica (maize leaf blight)

Setosphaeria turcica (maize leaf blight)

Mycosphaerella zeae-maydis (yellow leaf blight of maize)

Mycosphaerella zeae-maydis (yellow leaf blight of maize)