Inoculum survival of Exserohilum turcicum on corn between and during growing periods

1995 ◽  
Vol 17 (2) ◽  
pp. 144-146 ◽  
Author(s):  
Yehouda Levy
Keyword(s):  
Exserohilum Turcicum ◽  
Inoculum Survival

scholarly journals Assessment of physiological races of Exserohilum turcicum isolates from maize in Argentina and Brazil

2021 ◽  
Author(s):  
Barbara Ludwig Navarro ◽  
Lucia Ramos Romero ◽  
María Belén Kistner ◽  
Juliana Iglesias ◽  
Andreas von Tiedemann
Keyword(s):  
Exserohilum Turcicum ◽  
Breeding Programs ◽  
Physiological Races ◽  
Maize Leaves ◽  
Race 1 ◽  
Resistance Reaction ◽  
Qualitative Resistance ◽  
Maize Plants ◽  
Corn Leaf Blight ◽  
Resistant Genotypes

AbstractNorthern corn leaf blight (NCLB) is one of the most important diseases in maize worldwide. It is caused by the fungus Exserohilum turcicum, which exhibits a high genetic variability for virulence, and hence physiological races have been reported. Disease control is based mainly on fungicide application and host resistance. Qualitative resistance has been widely used to control NCLB through the deployment of Ht genes. Known pathogen races are designated according to their virulence to the corresponding Ht gene. Knowledge about of E. turcicum race distribution in maize-producing areas is essential to develop and exploit resistant genotypes. Maize leaves showing distinct elliptical grey-green lesions were collected from maize-producing areas of Argentina and Brazil, and 184 monosporic E. turcicum isolates were obtained. A total of 66 isolates were collected from Argentina during 2015, 2018 and 2019, while 118 isolates from Brazil were collected during 2017, 2018 and 2019. All isolates were screened on maize differential lines containing Ht1, Ht2, Ht3 and Htn1 resistance genes. In greenhouse experiments, inoculated maize plants were evaluated at 14 days after inoculation. Resistance reaction was characterized by chlorosis, and susceptibility was defined by necrosis in the absence of chlorosis. The most frequent race was 0 in both Argentina (83%) and Brazil (65%). Frequencies of race 1 (6% and 24%) and race 23N (5% and 10%) were very low in Argentina and Brazil, respectively. The high frequency of race 0 isolates provides evidence that qualitative resistance based on the tested Ht genes is not being used extensively in Argentina and Brazil to control NCLB. This information may be relevant for growers and breeding programs as the incidence of NCLB is increasing in both countries.

scholarly journals Resistance of Corynebacterium pseudotuberculosis in the Brazilian semiarid environment

2018 ◽  
Vol 38 (6) ◽  
pp. 1091-1096 ◽  
Author(s):  
Maria C.A. Sá ◽  
Samily A.S. Oliveira ◽  
Edmilson M. Dantas Jr ◽  
Gisele V. Gouveia ◽  
João J.S. Gouveia ◽  
...  
Keyword(s):  
Survival Rates ◽  
Control Measures ◽  
Corynebacterium Pseudotuberculosis ◽  
Maximum Temperature ◽  
Caseous Lymphadenitis ◽  
Biofilm Production ◽  
Brazilian Semiarid ◽  
Higher Temperature ◽  
Inoculum Survival

ABSTRACT: The semiarid northeast of Brazil contains a unique biome known as caatinga, with a maximum temperature of 40 ºC and a relativity humidity of 56%. The caatinga is characterized by a variety of plants, including Cereus jamacaru Dc (mandacaru), Poincianella microphylla Mart. ex G. Don (catingueira), Pilosocereus gounellei FAC Weber (xique-xique) and Mimosa tenuiflora (Willd.) Poir (jurema preta). Sheep and goat industries are economically strong in that region, despite the fact that caseous lymphadenitis is highly prevalent. The aim of the present study was to assess the survival and biofilm production of Corynebacterium pseudotuberculosis isolates in the environment and under controlled temperatures (28°C, 37°C and 42°C) under different surfaces (plants, soil, wood, wire and thorns). In addition, we investigated the effects of applying the disinfectants chlorhexidine, hypochlorite and quaternary ammonia in soil, tiles, wood and vegetation cover. Four strains of C. pseudotuberculosis were selected (two from goats and two from sheep) for inoculation according to their in vitro biofilm production. Adherence to microplates was used to assess the biofilm-forming ability of the bacteria. Lower survival rates were observed when isolates of C. pseudotuberculosis were subjected to a temperature of 42°C. In terms of caatinga biome plants, contamination of jurema-preta plants resulted in the lowest survival rates. The disinfectant quaternary ammonia promoted a lower inoculum survival in all surfaces. The disinfectants and the higher temperature contributed to the reduction of biofilm production in isolates of C. pseudotuberculosis. knowledge of these patterns is important for the establishment of disease control measures, given the questionable efficacy of the treatment and the immuno-prophylaxis of caseous lymphadenitis.

scholarly journals Development of a new maize hybrid for the Ecuadorian lowland

2018 ◽  
Vol 36 (2) ◽  
pp. 174-179
Author(s):  
Ricardo Limongi-Andrade ◽  
Daniel Alarcón-Cobeña ◽  
Eddie Zambrano-Zambrano ◽  
Marlon Caicedo ◽  
Paúl Villavicencio-Linzan ◽  
...  
Keyword(s):  
Zea Mays L ◽  
Regression Coefficient ◽  
Yield Potential ◽  
Curvularia Lunata ◽  
Exserohilum Turcicum ◽  
Maize Production ◽  
Maize Hybrid ◽  
Puccinia Sorghi ◽  
Feed Production ◽  
Self Sufficiency

Yellow maize (Zea mays L. var. indurata) is mainly produced in the Ecuadorian lowlands (less than 1,200 m a.s.l.), primarily for feed production. Although Ecuador has recently increased maize production, new genotypes are needed for self-sufficiency and in order to avoid costly imports. Maize is sown mostly from December to January during the rainy season. However, the irregularity of rainfall has become a constraint on production. “INIAP H-603 Superior” is a new single-cross maize hybrid developed for the Ecuadorian lowlands with improved yields, which could contribute to domestic food security. The new hybrid had an average yield of 8.48 t ha-1 with outstanding performance under the rainfall, sustained moisture, and irrigation conditions, outperforming the commercial hybrids INIAP H-602, DEKALB-7088 and INIAP H-553. Additionally, the new hybrid showed tolerance to the principal foliar diseases: leaf blight (Exserohilum turcicum), rust (Puccinia sorghi), and leaf spot (Curvularia lunata), as well as good adaptability and stability, with a regression coefficient (bi) of 0.98 when it was evaluated in 29 locations from 2010 to 2013. The greatest yield potential of the new hybrid (10.82 t ha-1) was obtained with irrigation during the dry season.

scholarly journals Mono-/Bis-Alkenoic Acid Derivatives From an Endophytic Fungus Scopulariopsis candelabrum and Their Antifungal Activity

2022 ◽  
Vol 9 ◽  
Author(s):  
Jun Tang ◽  
Xueshuang Huang ◽  
Ming-Hang Cao ◽  
Zhiyan Wang ◽  
Zhiyin Yu ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
High Resolution Mass Spectrometry ◽  
2D Nmr ◽  
Positive Control ◽  
Diffusion Method ◽  
Exserohilum Turcicum ◽  
Chemical Structures ◽  
Alkenoic Acid

During a screening for antifungal secondary metabolites, six new mono-/bis-alkenoic acid derivatives (2–7) and one known alkenoic acid derivative (1) were isolated from an endophytic fungi Scopulariopsis candelabrum. Their chemical structures were identified by 1H-NMR, 13C-NMR, 2D NMR, and high-resolution mass spectrometry, as well as comparisons with previously reported literatures. Among them, fusariumesters C‒F (2–5) are bis-alkenoic acid derivatives dimerized by an ester bond, while acetylfusaridioic acid A (6) and fusaridioic acid D (7) are alkenoic acid monomers. All the isolates were submitted to an antifungal assay against Candida albicans and the corn pathogen Exserohilum turcicum using the filter paper agar diffusion method. As a result, only compound 1 decorating with β-lactone ring turned out to be active against these two tested fungi. The broth microdilution assay against Candida albicans showed the minimum inhibitory concentration (MIC) value of 1 to be 20 μg/ml, while the minimum inhibitory concentration value of the positive control (naystatin) was 10 μg/ml. And the half maximal inhibitory concentration (IC50) value (21.23 μg/ml) of 1 against Exserohilum turcicum was determined by analyzing its inhibition effect on the mycelial growth, using cycloheximide (IC50 = 46.70 μg/ml) as the positive control.

scholarly journals Cultural, Morphological and Pathogenic Variability of Exserohilum turcicum causing Turcicum Leaf Blight in Maize

2019 ◽  
Vol 8 (11) ◽  
pp. 302-313
Author(s):  
Gee ta ◽  
D.S. Aswathanarayana ◽  
M.K. Naik ◽  
Mallikarjun Kenganal ◽  
Prakash H. Kuchanur
Keyword(s):  
Leaf Blight ◽  
Exserohilum Turcicum ◽  
Pathogenic Variability
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