scholarly journals Temporal and Spatial Development of Cercospora Leaf Spot of Faba Bean Influenced by In Situ Inoculum

Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1823-1830 ◽  
Author(s):  
R. B. E. Kimber ◽  
J. G. Paull ◽  
E. S. Scott ◽  
C. B. Dyson ◽  
J. A. Davidson
Keyword(s):  
Leaf Area ◽  
Faba Bean ◽  
Leaf Spot ◽  
Soil Surface ◽  
Infested Soil ◽  
Cercospora Leaf Spot ◽  
Soil Zone ◽  
Temporal And Spatial ◽  
Over Time

The temporal and spatial dynamics of Cercospora leaf spot on susceptible and resistant lines of faba bean grown in or at defined distances from soil with residues infested by Cercospora zonata were examined in South Australia in 2005 and 2006. The disease was first observed on susceptible seedlings 49 days after sowing (DAS) in soil that had been sown with faba bean every 3 years since 1997 (positive soil zone for C. zonata) but was delayed by 1 week in adjacent soil (0 to 16 m away) with no history of cultivation of faba bean (negative soil zone). The incidence of diseased seedlings from 49 to 63 DAS showed a gradient from 4 to 16 m from the infested soil and was significantly greater for susceptible plants grown in the positive versus negative soil zones in field trials conducted in 2005 and 2006 (92 versus 30% in 2005, χ21 = 32.2, P < 0.001; 98 versus 55% in 2006, χ21 = 12.1, P < 0.001). The incidence of Cercospora leaf spot on the resistant line 1322/2 was significantly less (χ26 = 171.7; P < 0.001) than on the susceptible line ‘Farah’ at that time in both years, with fewer than 5% of the seedlings showing the disease. However, a gradient was shown at 70 to 84 DAS, where disease incidence was significantly greater on line 1322/2 in the positive soil zone than on plants in the negative soil zone in both years (62 and 18%, respectively, with χ21 = 27.9, P < 0.001 in the 2005 trial; and 47 and 6%, respectively, with χ21 = 33.3, P < 0.001 in the 2006 trial). At peak disease severity on Farah, Cercospora leaf spot mean leaf area diseased (%LAD) was severe (85 ± 4.3%) on leaves of the three nodes closest to the soil surface, and much less severe (1 ± 0.6%) in the upper canopy. Defoliation combined with %LAD was used to describe the loss of photosynthetic leaf area (%LPLA) in both cultivars, on both soil zones, in each year. Nonlinear regression analyses using a logistic model described disease development over time on susceptible plants grown in infested soil (e.g., for +12-m blocks within infested soil, y = 2.66 + 46.08/[1 + exp(−0.23 × [X − 40.92])] in 2005 and y = 0.49 + 5.02/[1 + exp(−0.14 × [X − 28.30])] in 2006, where X = DAS and y = %LPLA, with both regressions significant at P < 0.001), whereas an exponential model (e.g., for −12-m blocks from infested soil, y = 0.23 + 0.77 × 1.04X in 2005 and y = 0.44 + 0.56 × 1.04X in 2006, both at P < 0.001) best described disease gradients with increasing distance from the inoculum source. Paired t tests of %LPLA at 77 and 98 DAS showed significant differences in disease severity in the positive versus negative soil zones and a steep gradient in %LPLA from 0 to 4 m from the inoculum source. The role of infested faba bean residue in survival of C. zonata over time was also examined using a pot-bioassay and in situ field assay. When residues were removed from the soil surface or depleted rapidly by animal grazing, the amount of C. zonata inoculum in the soil was significantly less (P < 0.001) than for soil with residue remaining on the soil surface. C. zonata survived in soil and remained infective for at least 30 months after harvest of an infected faba bean crop.

scholarly journals Extending the CSM-CERES-Beet Model to Simulate Impact of Observed Leaf Disease Damage on Sugar Beet Yield

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1930
Author(s):  
Emir Memic ◽  
Simone Graeff-Hönninger ◽  
Oliver Hensel ◽  
William D. Batchelor
Keyword(s):  
Sugar Beet ◽  
Leaf Area ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Root Weight ◽  
Storage Root ◽  
Cercospora Leaf Spot ◽  
Area Index ◽  
Spot Disease ◽  
The Impact

A CSM-CERES-Beet pest damage routine was modified to simulate the impact of Cercospora leaf spot disease effects on sugar beet yield. Foliar disease effects on sugar beet growth and yield were incorporated as daily damage to leaf area and photosynthesis, which was linked to daily crop growth and biomass accumulation. An experiment was conducted in Southwest Germany (2016–2018) with different levels of disease infection. Data collected included time-series leaf area index, top weight, storage root weight and Cercospora leaf spot disease progress. The model was calibrated using statistical and visual fit for one treatment and evaluated for eight treatments over three years. Model performance of the calibration treatment for all three variables resulted in R2 values higher than 0.82 and d-statistics higher than 0.94. Evaluation treatments for all three observation groups resulted in high R2 and d-statistics with few exceptions mainly caused by weather extremes. Root mean square error values for calibration and evaluation treatments were satisfactory. Model statistics indicate that the approach can be used as a suitable decision support system to simulate the impact of observed Cercospora leaf spot damage on accumulated above-ground biomass and storage root yield on a plot/site-specific scale.

scholarly journals Effect of Bion and Amistar in inducing resistance against Cercospora leaf spot of banana

2018 ◽  
Vol 16 (3) ◽  
pp. 380-385
Author(s):  
Fahmida Akter ◽  
Md. Mijanur Rahman Mejan ◽  
Mst. Arjina Akter ◽  
Ismail Hossain
Keyword(s):  
Plant Pathology ◽  
Leaf Area ◽  
Leaf Spot ◽  
Spot Size ◽  
Diseased Plant ◽  
Diseased Leaf ◽  
Cercospora Leaf Spot ◽  
Banana Variety ◽  
And Control ◽  
Inducing Resistance

Bion (benzothiadiazole) and Amistar (azoxystrobin) were applied for controlling Cercospora leaf spot of banana variety Amrita Sagarin at the field laboratory, Department of Plant Pathology, Bangladesh Agricultural University (BAU), Mymensingh by applying different treatments viz. dipping bottom of sucker for 6 hrs. in Bion (0.005%) before planting, dipping bottom of sucker for 6 hrs. in Bion (0.01%) before planting, spraying of Bion @ 0.005% once on leaves after 80 days of planting, spraying of Bion @ 0.01% once on leaves after 80 days of planting, spraying of Amistar @ 0.05% once on leaves after 80 days of planting, spraying of Amistar @ 0.05% only on leaves after 80 and 140 days of planting, spraying of Bion @ 0.005%) once on leaves and pseudostem after 80 days of planting, spraying of Bion @ 0.01% once on leaves and pseudostem after 80 days of planting and control (without chemical). From these above treatments it is revealed that dipping of bottom of banana sucker for 6 hrs. in Bion either @ 0.005% or 0.01% significantly reduced plant height, while Bion and Amistar did not exert any effect on number of leaf/ plant. Bion @ 0.005% and 0.01% (dipping of bottom of sucker before planting), Bion @ 0.01% (on leaves, 1 spray) and 0.01% (on leaves and pseudostem, 1 spray) and Amistar @ 0.05% (on leaves, 2 spray) showed significant effect in reducing number of diseased leaf/ plant, number of diseased spot/ plant, percent leaf area (cm2) diseased/ plant, mean spot size (mm2)/ plant of banana var. Amrita sagar. J.Bangladesh Agril. Univ. 16(3): 380–385, December 2018

Alternaria and Cercospora Leaf Spot Diseases of Niger (Guizotia abyssinica Cass.) – A Traditional Tribal Crop of South Gujarat, India, with Cost Benefit Ratio in Relation to Different Fungicides

2018 ◽  
Vol 51 (3) ◽  
pp. 89-99
Author(s):  
P.B. Sandipan ◽  
P.K. Jagtap ◽  
M.C. Patel
Keyword(s):  
Field Experiment ◽  
Seed Yield ◽  
Leaf Spot ◽  
Foliar Spray ◽  
Cost Benefit ◽  
Research Station ◽  
Guizotia Abyssinica ◽  
Cercospora Leaf Spot ◽  
Benefit Ratio ◽  
Cost Benefit Ratio

Abstract Niger (Guizotia abyssinica Cass.) is an important minor oil seed crop grown in dry areas grown mostly by tribal and interior places as life line of tribal segment. Tribal people mainly use its oil for cooking purpose, above than that there were also other uses. Hence, the niger crop should be protected from the infection. The crop is affected by number of fungal diseases. Therefore, a field experiment was formulated for three years with the four replications at the Niger Research Station (NRS) at Navsari Agricultural University (NAU), Vanarasi, Navsari (Gujarat) on the foliar diseases of GN-1 variety of niger crop. In this experiment, six different fungicides along with one control have been evaluated to control the Alternaria and Cercospora leaf spot diseases, out of which all the fungicidal treatments were significantly superior over the control. Here, foliar spray on the incidence of diseases was compared with the control (without any treatment). All the fungicidal treatments were significantly superior over the control to reduce Alternaria and Cercospora leaf spot diseases of Niger crop. Treatment of Carbendazim + Mancozeb (0.2 %) with two sprays first from the initiation of the disease and second after the interval of 15 days recorded the lowest incidence of Alternaria (14.56) and Cercospora (14.94) leaf spot diseases of niger and recorded the highest seed yield 337 seed yield kg/ha along with the net return with cost benefit ratio graph.

On the Damage of Cercospora Leaf Spot of Sugar Beets Caused by Cercospora beticola Sacc.

1968 ◽  
Vol 34 (1) ◽  
pp. 1-6
Author(s):  
Wataru IIDA ◽  
Kazuichi KUDO ◽  
Takashi KIMIGAFUKURO
Keyword(s):  
Leaf Spot ◽  
Cercospora Beticola ◽  
Cercospora Leaf Spot ◽  
Sugar Beets

scholarly journals Air Concentrations of Gaseous Elemental Mercury and Vegetation–Air Fluxes within Saltmarshes of the Tagus Estuary, Portugal

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 228
Author(s):  
Rute Cesário ◽  
Nelson J. O’Driscoll ◽  
Sara Justino ◽  
Claire E. Wilson ◽  
Carlos E. Monteiro ◽  
...  
Keyword(s):  
Leaf Area ◽  
Elemental Mercury ◽  
Ambient Air ◽  
Tagus Estuary ◽  
Contaminated Site ◽  
Gaseous Elemental Mercury ◽  
Mercury Flux ◽  
Sarcocornia Fruticosa ◽  
Air Concentrations

In situ air concentrations of gaseous elemental mercury (Hg(0)) and vegetation–atmosphere fluxes were quantified in both high (Cala Norte, CN) and low-to-moderate (Alcochete, ALC) Hg-contaminated saltmarsh areas of the Tagus estuary colonized by plant species Halimione portulacoides (Hp) and Sarcocornia fruticosa (Sf). Atmospheric Hg(0) ranged between 1.08–18.15 ng m−3 in CN and 1.18–3.53 ng m−3 in ALC. In CN, most of the high Hg(0) levels occurred during nighttime, while the opposite was observed at ALC, suggesting that photoreduction was not driving the air Hg(0) concentrations at the contaminated site. Vegetation–air Hg(0) fluxes were low in ALC and ranged from −0.76 to 1.52 ng m−2 (leaf area) h−1 for Hp and from −0.40 to 1.28 ng m−2 (leaf area) h−1 for Sf. In CN, higher Hg fluxes were observed for both plants, ranging from −9.90 to 15.45 ng m−2 (leaf area) h−1 for Hp and from −8.93 to 12.58 ng m−2 (leaf area) h−1 for Sf. Mercury flux results at CN were considered less reliable due to large and fast variations in the ambient air concentrations of Hg(0), which may have been influenced by emissions from the nearby chlor-alkali plant, or historical contamination. Improved experimental setup, the influence of high local Hg concentrations and the seasonal activity of the plants must be considered when assessing vegetation–air Hg(0) fluxes in Hg-contaminated areas.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

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