scholarly journals Influence of Gibberellic Acid on Carrot Growth and Severity of Alternaria Leaf Blight

Plant Disease ◽  
2000 ◽  
Vol 84 (5) ◽  
pp. 555-558 ◽  
Author(s):  
P. Santos ◽  
J. J. Nunez ◽  
R. M. Davis
Keyword(s):  
Gibberellic Acid ◽  
Growth Habit ◽  
Leaf Length ◽  
Leaf Blight ◽  
Root Weight ◽  
Root Cortex ◽  
Alternaria Leaf Blight ◽  
Alternaria Dauci ◽  
Plant Emergence ◽  
Root Quality

Applications of gibberellic acid (GA) to carrot foliage consistently reduced the percentage of leaf area affected by Alternaria dauci compared with nontreated plants. The degree of leaf blight reduction with two applications of GA was similar to that achieved with four applications of the fungicide iprodione. At the rates examined (GA at 2.5 to 250 mg/liter), foliage dry weights were generally increased by GA. Although root weight was significantly reduced by rates of 250 mg/liter, applications of lower rates (40 mg/liter or less) reduced leaf blight severity without affecting root quality. Applications of GA usually resulted in plants with longer leaves, wider petioles, and a more upright growth habit. In one trial, leaf length and petiole diameter increased linearly with increasing rates (20, 30, and 40 mg/liter). When applied twice at 30 mg/liter, GA did not affect cuticle, epidermal, or leaf thickness. In general, the initial timing of two applications of 20 to 40 mg/liter (4, 6, or 8 weeks after plant emergence) did not influence the effects of GA. However, in one trial, there was a greater incidence of core separation from the root cortex when 40 mg/liter was applied initially at 4 weeks. GA at 30 mg/liter slightly but significantly decreased inner root color in one of two trials.

Influence of rate of soil fertilization on alternaria leaf blight (Alternaria dauci) in carrots

1999 ◽  
Vol 27 (3) ◽  
pp. 193-200 ◽  
Author(s):  
H. Vintal ◽  
E. Ben-Noon ◽  
E. Shlevin ◽  
U. Yermiyahu ◽  
D. Shtienberg ◽  
...  
Keyword(s):  
Leaf Blight ◽  
Soil Fertilization ◽  
Alternaria Leaf Blight ◽  
Alternaria Dauci

scholarly journals First report of alternaria leaf blight caused by Alternaria dauci on carrot in Turkey

2005 ◽  
Vol 54 (2) ◽  
pp. 252-252 ◽  
Author(s):  
S. Soylu ◽  
S. Kurt ◽  
E. M. Soylu ◽  
F. M. Tok
Keyword(s):  
Leaf Blight ◽  
First Report ◽  
Alternaria Leaf Blight ◽  
Alternaria Dauci

scholarly journals Optimization of Chemical Suppression of Alternaria dauci, the Causal Agent of Alternaria Leaf Blight in Carrots

Plant Disease ◽  
2001 ◽  
Vol 85 (11) ◽  
pp. 1149-1156 ◽  
Author(s):  
E. Ben-Noon ◽  
D. Shtienberg ◽  
E. Shlevin ◽  
H. Vintal ◽  
A. Dinoor
Keyword(s):  
Field Experiments ◽  
Threshold Model ◽  
Disease Onset ◽  
Leaf Blight ◽  
Copper Hydroxide ◽  
Control Efficacy ◽  
Alternaria Leaf Blight ◽  
Major Constraint ◽  
Action Threshold ◽  
Alternaria Dauci

Alternaria leaf blight, caused by Alternaria dauci, is a major constraint to carrot production in Israel. Israeli carrot growers apply prophylactic sprays at 3- to 10-day intervals throughout the season until harvest, up to 30 sprays in a growing season. In this study, we attempted to optimize the chemical suppression of the disease, in order to reduce fungicide use. The efficacy of nine fungicides was determined in two field experiments. All fungicides reduced disease severity, but there were significant differences in efficacy among them. The most effective were difenoconazole and chlorothalonil; less effective were copper hydroxide, tebuconazole, trifloxystrobin, and mancozeb; the least effective in our experiments were flutrifol, propineb, and iprodione. The effect of the time of spray initiation on fungicide efficacy was determined in three field experiments. Qualitative (analysis of variance) and quantitative (regression) analyses of the data revealed that initiating sprays after disease onset reduced control efficacy. Thus, an action threshold model could not be developed for A. dauci in carrots. The time before harvest at which sprays could be terminated was tested in two field experiments and it was found that terminating sprays 14 days before harvest did not significantly affect the overall control efficacy. The main conclusions derived from these experiments were tested and corroborated in two additional field experiments.

Impact of carrot resistance on development of the Alternaria leaf blight pathogen (Alternaria dauci)

2008 ◽  
Vol 121 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Cora Boedo ◽  
Valérie Le Clerc ◽  
Mathilde Briard ◽  
Philippe Simoneau ◽  
Michel Chevalier ◽  
...  
Keyword(s):  
Leaf Blight ◽  
Alternaria Leaf Blight ◽  
Alternaria Dauci

scholarly journals Relationship Between Nitrogen Fertilization and Cercospora Leaf Spot and Alternaria Leaf Blight of Carrot

HortScience ◽  
2008 ◽  
Vol 43 (5) ◽  
pp. 1522-1527 ◽  
Author(s):  
Sean M. Westerveld ◽  
Alan W. McKeown ◽  
Mary Ruth McDonald
Keyword(s):  
Leaf Spot ◽  
Field Experiments ◽  
Field Trials ◽  
Application Rate ◽  
Leaf Blight ◽  
Cercospora Leaf Spot ◽  
N Application ◽  
Alternaria Leaf Blight ◽  
N Application Rate ◽  
Alternaria Dauci

Alternaria leaf blight (ALB) and Cercospora leaf spot (CLS) are economically important diseases of carrot in Ontario. Field experiments were conducted in the Holland Marsh, Ontario, to determine the effect of nitrogen (N) application rates on both diseases. Five rates of N were applied to organic and mineral soils in which two carrot cultivars, Idaho and Fontana, were grown in each of 2002, 2003, and 2004. Both diseases were rated every 2 weeks on a scale of 0 (healthy) to 10 (tops destroyed), and the number of live (green) leaves per plant was assessed at harvest. In addition, three N rates were applied to carrot plants grown in the greenhouse, and the plants were inoculated with Alternaria dauci (Kühn) Groves and Skolko. Disease severity, senescence, and sap nitrate-N concentration were assessed. In the field trials, the response of ALB and CLS to N application rate was relatively consistent across cultivar, soil type, and year. Area-under-the-disease-progress curves typically increased with decreasing N rate for both diseases. In lower N treatments, this resulted in fewer live leaves per plant at harvest. In the greenhouse, ALB severity increased with increasing amount of leaf senescence at final assessment. The results suggest that N application rate could be used to reduce the need for fungicide applications to control these diseases in the field.

scholarly journals Development of a weather-based forecasting model for Alternaria leaf blight of carrot

2019 ◽  
Vol 45 (4) ◽  
pp. 413-414
Author(s):  
Leandro Luiz Marcuzzo ◽  
Carolina Maria Tomasoni
Keyword(s):  
Linear Regression Analysis ◽  
Beta Function ◽  
Logistic Function ◽  
Leaf Blight ◽  
Forecasting Model ◽  
Leaf Wetness ◽  
Leaf Wetness Duration ◽  
Influence Of Temperature ◽  
Alternaria Leaf Blight ◽  
Alternaria Dauci

ABSTRACT In the present study, under controlled conditions, the influence of temperature (10, 15, 20, 25 and 30°C) and leaf wetness duration (6, 12, 24 and 48 hours) was studied on the severity of Alternaria leaf blight of carrot caused by Alternaria dauci. The relative density of lesions was influenced by temperature and leaf wetness duration (P<0.05). The disease was more severe at the temperature of 25°C. Data underwent non-linear regression analysis. The generalized beta function was used for fitting the data on disease severity and temperature, while a logistic function was chosen to represent the effect of leaf wetness duration on the severity of leaf blight. The response surface resulting of the product of the two functions was expressed as ES = 0.004993 * (((x-8)1.13125) * ((36-x)0.53212)) * (0.39219/(1+25.93072 * exp (-0.16704*y))), where: ES represents the estimated severity value (0.1); x, temperature (ºC) and y, leaf wetness duration (hours). This model must be validated under field conditions to be used as a forecasting model for Alternaria leaf blight of carrot.

scholarly journals Foliar spray of gibberellic acid influences morphological attributes and foliage yield of coriander (Coriandrum sativum L.)

2018 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Dhiman Das ◽  
Asim Kumar Bhadra ◽  
Mohd Moniruzzaman
Keyword(s):  
Gibberellic Acid ◽  
Vegetative Growth ◽  
Leaf Length ◽  
Distilled Water ◽  
Water Spray ◽  
Single Plant ◽  
Plant Weight ◽  
Morphological Attributes ◽  
Number Of Leaves ◽  
Different Doses

A field experiment was conducted at the research field of Sher-e- Bangla Agricultural University, Dhaka during the period from December 1, 2016 to January 11, 2017 to investigate the effect of gibberellic acid (GA3) on vegetative growth, morphological attributes and foliage (leaf) yield of coriander (Coriandrum sativum L.). The experimental treatments consisted of eight different doses of GA3 viz., 0 (distilled water spray), 5, 10, 15, 20, 25, 30 and 35 ppm. The variety Rosina (Pahuja Co., India) was used as planting material and different doses of GA3 were applied on the plants at 25 and 30 days after sowing. The experiment was laid out in Randomized Complete Block Design with three replications. GA3 had significant effect on vegetative growth, morphology, foliage yield and yield contributing characters of coriander. Plant height, number of leaves plant-1, leaf length, plant spread and single plant weight were found maximum from the application of GA3 at 20 ppm, which was closely followed by 25 ppm GA3. Application of GA3 at 20 ppm produced the highest weight of foliage m-2. A strong positive correlation of foliage yield was observed with plant height, number of leaves plant-1, leaf length, plant spread, single plant weight and weight of foliage m-2. Application of GA3 at 20 ppm gave maximum foliage yield (9.34 t ha-1) which was followed by GA3 at 15 ppm (8.46 t ha-1) and 25 ppm (8.06 t ha-1), and the minimum foliage yield was recorded from control (distilled water spray) (4.90 t ha-1). Application of GA3 at 20 ppm increased foliage yield over control by 47.54 %. A quadratic relationship between applied GA3 concentration and foliage yield was found; the regression equation was y = 4.87 + 0.375x – 0.009x2 from which it came up to be optimum dose of GA3 as 20.83 ppm.Res. Agric., Livest. Fish.5(1): 1-9, April 2018

Moderate Boron Concentration Beneficial for Flue-cured Tobacco Seedlings Growth and Development

2021 ◽  
Author(s):  
Mengxia Li ◽  
Xiaopeng Deng ◽  
Ke Ren ◽  
Rui Liu ◽  
Tao Wang ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
Dry Matter ◽  
Agronomic Traits ◽  
Photosynthetic Performance ◽  
Leaf Length ◽  
Internal Quality ◽  
Root Weight ◽  
Nicotine Content ◽  
Hydroponic Experiment ◽  
Tobacco Seedlings

Abstract Boron (B) is a micronutrient tobacco needs in minute amounts, and Boron insufficient supply can causes significant tobacco yield loss, however, the appropriate concentration for flue-cured tobacco seedlings to growth remains unknown. In this sense, a hydroponic experiment was conduct to measure the agronomic traits, dry matter mass, chlorophyll content, photosynthetic performance, antioxidant enzymes, boron ion and nicotine content of flue-cured tobacco seedlings K326 under different boron concentrations of 0.000mmol/L (B1, CK), 0.125mmol/L (B2), 0.250mmol/L (B3), 0.750mmol/L (B4), 5.000mmol/L (B5), 10.000mmol/L (B6), 20.000mmol/L (B7), 40.000mmol/L (B8) after 30 days. B significantly influenced flue-tobacco seedlings growth on agronomic traits, photosynthetic performance, the activities of antioxidant enzymes, boron ion and nicotine content aspects. B linearly enhanced the accumulation of boron ion by 24.00%~96.44%, and decreased nicotine content by 21.60%~82.03% in tobacco seedlings. Solution B concentration at 0.750 and 5.000mmol/L markedly improved tobacco seedlings maximum leaf length by 4.83%~82.03% and leaf width by 0.77%~24.36%, root weight by 13.64%~56.82%, stem weight by 12.26%~52.36%, leaf weight by 9.68%~36.56%, dry matter mass by 10.65%~38.92%, the Pn parameter by 1.22%~80.28%, the Cond paramete by 33.40%~75.86%, while decreased the activities of SOD by 10.44%~91.67%, POD by 21.32%~65.62% and CAT by 50.05%~96.44%, and MDA by 16.23%~75.16%. The B concentration concluded in this study enhanced the agronomy traits, photosynthetic and biochemical characteristics of flue-cured tobacco seedlings, which lays a scientific theoretical foundation for rational application of B in tobacco production and improve the internal quality of flue-cured tobacco.

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