Temperature and relative humidity shape white leaf spot ( Neopseudocercosporella capsellae ) epidemic development in rapeseed ( Brassica napus )

2021 ◽  
Author(s):  
Tamsal Murtza ◽  
Ming Pei You ◽  
Martin J. Barbetti
Keyword(s):  
Brassica Napus ◽  
Relative Humidity ◽  
Leaf Spot ◽  
White Leaf ◽  
Epidemic Development

scholarly journals Interactions in the Brassica napus ‐ Pyrenopeziza brassicae pathosystem and sources of resistance to P . brassicae (light leaf spot)

2021 ◽  
Author(s):  
C. S. Karandeni Dewage ◽  
A. Qi ◽  
H. U. Stotz ◽  
Y. J. Huang ◽  
B. D. L. Fitt
Keyword(s):  
Brassica Napus ◽  
Leaf Spot ◽  
Sources Of Resistance

Experimental Study on Hygroscopicity of Rapeseed (Brassica Napus)

2012 ◽  
Vol 479-481 ◽  
pp. 2275-2278
Author(s):  
Ming Jin Yang ◽  
Wu Ming Xu ◽  
Tian Tang ◽  
Ling Yang ◽  
Feng Liu
Keyword(s):  
Experimental Study ◽  
Brassica Napus ◽  
Relative Humidity ◽  
Moisture Absorption ◽  
Early Period ◽  
Critical Relative Humidity ◽  
Temperature And Humidity ◽  
Higher Temperature

The hygroscopicity property of the rapeseed at different temperature and humidity was experimental studied in this paper. Tested results show that: the moisture absorption rates increase with the increase of relative humidity at the early period of absorption, and higher temperature leads to earlier reach of moisture equilibrium; the critical relative humidity(CRH) increases with the increase of temperature; the optional relative humidity for safety storage of rapeseed should be controlled less than 60%.

Septoria cannabis. [Descriptions of Fungi and Bacteria].

1980 ◽  
Author(s):  
E. Punithalingam
Keyword(s):  
North America ◽  
Geographical Distribution ◽  
Leaf Spot ◽  
Crop Residues ◽  
New Records ◽  
Cannabis Sativa ◽  
Leaf Blight ◽  
White Leaf ◽  
Rain Splash

Abstract A description is provided for Septoria cannabis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Cannabis sativa (hemp). DISEASE: White leaf spot or leaf blight of hemp. Symptoms usually appear on basal leaves as round or ellipsoidal to polygonal, whitish or ochraceous yellow lesions with a conspicuous dark brown border. Affected leaves become curled and withered up towards the edges and fall prematurely leaving much of the lower part of the stem defoliated (15, 97, 805). GEOGRAPHICAL DISTRIBUTION: Asia, Europe and North America (CMI Map No. 477, ed. 1, 1971). New records not mapped are: Asia (Kashmir, Pakistan). TRANSMISSION: Detailed studies have not been reported but conidia are presumed to be disseminated by rain-splash and wind blown water. The fungus could also be carried over in crop residues.

scholarly journals Identification and characterization of maize lines resistant to leaf diseases

2019 ◽  
Vol 40 (2) ◽  
pp. 517
Author(s):  
Kaian Albino Corazza Kaefer ◽  
Adilson Ricken Schuelter ◽  
Ivan Schuster ◽  
Jonatas Marcolin ◽  
Eliane Cristina Gruszka Vendruscolo
Keyword(s):  
Genetic Diversity ◽  
Leaf Spot ◽  
Block Design ◽  
Snp Markers ◽  
Gray Leaf Spot ◽  
Leaf Blight ◽  
Yield Reduction ◽  
Northern Leaf Blight ◽  
Sources Of Resistance ◽  
White Leaf

Among the maize leaf diseases, white leaf spot, northern leaf blight, gray leaf spot, and southern rust are recognized not only by the potential for grain yield reduction but also by the widespread occurrence in the producing regions of Brazil and the world. The aim of this study was to characterize common maize lines for resistance to white leaf spot, northern leaf blight, gray leaf spot, and southern rust and suggest crosses based on the genetic diversity detected in SNP markers. The experiment was conducted in a randomized block design with three replications in order to characterize 72 maize lines. Genotypic values were predicted using the REML/BLUP procedure. These 72 lines were genotyped with SNP markers using the 650K platform (Affymetrix®) for the assessment of the genetic diversity. Genetic diversity was quantified using the Tocher and UPGMA methods. The existence of genetic variability for disease resistance was detected among maize lines, which made possible to classify them into three large groups (I, II, and III). The maize lines CD 49 and CD50 showed a good performance and can be considered sources of resistance to diseases. Therefore, their use as gene donors in maize breeding programs is recommended. Considering the information of genetic distance together with high heritability for leaf diseases, backcrossing of parent genotypes with different resistance levels, such as those of the lines CD49 x CD69 and CD50 x CD16, may result in new gene combinations, as they are divergent and meet good performances.

scholarly journals First Report of Nigrospora osmanthi Causing Leaf Spot on Tartary Buckwheat in China

Plant Disease ◽  
2020 ◽  
Author(s):  
Quan Shen ◽  
Xixu Peng ◽  
Feng He ◽  
Shaoqing Li ◽  
Zuyin Xiao ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Leaf Spot ◽  
Plant Pathogens ◽  
Hunan Province ◽  
Tartary Buckwheat ◽  
Tween 20 ◽  
Pathogenicity Test ◽  
Conidial Suspension ◽  
Sterile Water ◽  
First Report

Buckwheat (Fagopyrum tataricum) is a traditional short-season pseudocereal crop originating in southwest China and is cultivated around the world. Antioxidative substances in buckwheat have been shown to provide many potential cardiovascular health benefits. Between August and November in 2019, a leaf spot was found in several Tartary buckwheat cv. Pinku1 fields in Xiangxiang County, Hunan Province, China. The disease occurred throughout the growth cycle of buckwheat after leaves emerged, and disease incidence was approximately 50 to 60%. Initially infected leaves developed a few round lesions, light yellow to light brown spots. Several days later, lesions began to enlarge with reddish brown borders, and eventually withered and fell off. Thirty lesions (2×2 mm) collected from three locations with ten leaves in each location were sterilized in 70% ethanol for 10 sec, in 2% sodium hypochlorite for 30 sec, rinsed in sterile water for three times, dried on sterilized filter paper, and placed on a potato dextrose PDA with lactic acid (3 ml/L), and incubated at 28°C in the dark for 3 to 5 days. Fungal colonies were initially white and later turned black with the onset ofsporulation. Conidia were single-celled, black, smooth, spherical to subspherical, and measured 9.2 to 15.6 µm long, and 7.1 to 11.6 µm wide (n=30). Each conidium was terminal and borne on a hyaline vesicle at the tip of conidiophores. Morphologically, the fungus was identified as Nigrospora osmanthi (Wang et al. 2017). Identification was confirmed by amplifying and sequencing the ITS region, and translation elongation factor 1-alpha (TEF1-α) and partial beta-tublin (TUB2) genes using primers ITS1/ITS4 (Mills et al. 1992), EF1-728F/EF-2 (Carbone and Kohn 1999; O’Donnell et al. 1998) and Bt-2a/Bt-2b (Glass et al. 1995), respectively. BLAST searches in GenBank indicated the ITS (MT860338), TUB2 (MT882054) and TEF1-α (MT882055) sequences had 99.80%, 99% and 100% similarity to sequences KX986010.1, KY019461.1 and KY019421.1 of Nigrospora osmanthi ex-type strain CGMCC 3.18126, respectively. A neighbor-joining phylogenetic tree constructed using MEGA7.0 with 1,000 bootstraps based on the concatenated nucleotide sequences of the three genes indicated that our isolate was closely related to N. osmanthi. Pathogenicity test was performed using leaves of healthy F. tataricum plants. The conidial suspension (1 × 106 conidia/ml) collected from PDA cultures with 0.05% Tween 20 buffer was used for inoculation by spraying leaves of potted 20-day-old Tartary buckwheat cv. Pinku1. Five leaves of each plant were inoculated with spore suspensions (1 ml per leaf). An equal number of control leaves were sprayed with sterile water to serve as a control. The treated plants were kept in a greenhouse at 28°C and 80% relative humidity for 24 h, and then transferred to natural conditions with temperature ranging from 22 to 30°C and relative humidity ranging from 50 to 60%. Five days later, all N. osmanthi-inoculated leaves developed leaf spot symptoms similar to those observed in the field, whereas control leaves remained healthy. N. osmanthi was re-isolated from twelve infected leaves with frequency of 100%, fulfilling Koch’s postulates. The genus Nigrospora has been regarded by many scholars as plant pathogens (Fukushima et al. 1998) and N. osmanthi is a known leaf blight pathogen for Stenotaphrum secundatum (Mei et al. 2019) and Ficus pandurata (Liu et al. 2019) but has not been reported on F. tataricum. Nigrospora sphaerica was also detected in vegetative buds of healthy Fagopyrum esculentum Moench (Jain et al. 2012). To our knowledge, this is the first report of N. osmanthi causing leaf spot on F. tataricum in China and worldwide. Appropriate strategies should be developed to manage this disease.

Canola Growth Stage at Time of Infection Determines Magnitude of White Leaf Spot (Neopseudocercosporella capsellae) Impact

Plant Disease ◽  
2020 ◽  
Author(s):  
Tamsal Murtza ◽  
Ming Pei You ◽  
Martin John BARBETTI
Keyword(s):  
Plant Growth ◽  
Seed Yield ◽  
Leaf Spot ◽  
Growth Stage ◽  
Disease Incidence ◽  
Leaf Spot Disease ◽  
Leaf Stage ◽  
Spot Disease ◽  
White Leaf ◽  
Field Plots

White leaf spot (Neopseudocercosporella capsellae) is a persistent and increasingly important foliar disease for canola (Brassica napus) across southern Australia. To define the role of plant growth stage on development of the disease epidemic, we first investigated the response of different canola cultivars (Scoop and Charlton) at five Sylvester-Bradley growth stages against N. capsellae. White leaf spot disease incidence and severity was dependent upon plant growth stage and cultivar (both P < 0.001), with plants being most susceptible at plant growth stage 1,00 (cotyledon stage) followed by plant growth stage 1,04 (4th leaf stage). Then, second, to quantify the impact of this disease on canola yield, we investigated the in-field relationship of white leaf spot disease incidence and severity with seed yield loss following artificial inoculation commencing at growth stage 1.04 (4th leaf stage). White leaf spot significantly (P < 0.001) reduced seed yield by 24% in N. capsellae inoculated field plots compared with non-inoculated field plots. We believe that this is the first time that serious seed yield losses from this disease have been quantified in-field. The current study demonstrates that N. capsellae disease incidence and severity on canola is determined by host growth stage at which pathogen infestation occurs. Emerging seedling cotyledons were highly susceptible, followed by less susceptibility in first true leaves to emerge but then increasing susceptibility as plants subsequently age towards the 4th leaf stage. This explains field observances where white leaf spot readily establishes on emerging seedlings and subsequently becomes more prevalent and severe as plants age.

scholarly journals Predicting light leaf spot (Pyrenopeziza brassicae) risk on winter oilseed rape (Brassica napus) in England and Wales, using survey, weather and crop information

2004 ◽  
Vol 53 (6) ◽  
pp. 713-724 ◽  
Author(s):  
S. J. Welham ◽  
J. A. Turner ◽  
P. Gladders ◽  
B. D. L. Fitt ◽  
N. Evans ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Leaf Spot ◽  
Winter Oilseed Rape ◽  
England And Wales
Sign in / Sign up

Export Citation Format

Share Document