Symptom expression and ethylene production in leaf blight of cotton caused by Alternaria macrospora and Alternaria alternata alone and in combination

1994 ◽  
Vol 72 (11) ◽  
pp. 1574-1579 ◽  
Author(s):  
Yoav Bashan
Keyword(s):  
Disease Severity ◽  
Ethylene Production ◽  
Alternaria Alternata ◽  
Leaf Blight ◽  
Cotton Leaf ◽  
Symptom Expression ◽  
Leaf Shedding ◽  
Dual Inoculation ◽  
High Concentrations ◽  
Blight Disease

The interaction between the cotton leaf pathogens Alternaria macrospora and Alternaria alternata was studied using dual inoculation at dosages (≈ 103 spores/(mL ∙ pathogen)) that did not produce symptoms with either pathogen alone. This dual inoculation produced the typical disease symptoms (spots and shedding) and disease severity similar to inoculation with 104 spores/mL of A. macrospora alone. Neither pathogen produced ethylene in culture; however, they induced production of ethylene concentrations by diseased tissue that were correlated to both disease severity and leaf shedding. Plants infected by both pathogens produced the highest concentration of ethylene. Leaf discs either from leaves exhibiting symptoms or from symptomless infected leaves produced similarly high concentrations of ethylene. Inoculation of any site of the leaf with A. macrospora alone or with both pathogens resulted in shedding of the leaf. Pretreating inoculated plants with several ethylene inhibitors or an auxin decreased ethylene production, disease severity, and leaf shedding. Alternaria alternata apparently triggers symptom expression by A. macrospora in leaf blight disease of Pima cotton, and disease is manifested by the production of ethylene that leads to the typical leaf shedding symptom. Key words: Alternaria macrospora, Alternaria alternata, cotton leaf blight, defoliation, ethylene, fungus – fungus interaction, leaf spot of cotton, symptomless infections, virulence.

scholarly journals Influence of weather parameters on alternaria leaf blight severity of makhana under the agro-climate of Koshi region of Bihar

2021 ◽  
Vol 23 (1) ◽  
pp. 54-59
Author(s):  
SANTOSH KUMAR ◽  
MD. NADEEM AKHTAR ◽  
SANTOSH KUMAR ◽  
MAHESH KUMAR ◽  
TRIBHUWAN KUMAR
Keyword(s):  
High Temperature ◽  
Relative Humidity ◽  
Disease Severity ◽  
Infection Process ◽  
Leaf Blight ◽  
Alternaria Leaf Blight ◽  
Weather Parameters ◽  
Maximum Temperatures ◽  
Blight Disease ◽  
Cent Disease

Weather parameters play a pivotal role in the infection process and spread of pathogen. It also influences the expression of susceptibility/resistance of the host plant during post-infection phases. Therefore, an experiment was conducted for two consecutive cropping seasons (2018 &2019) to study the influence of weather parameters such as temperature, humidity, rainfall and wind direction on the emergence of alternaria leaf blight of makhana in Koshi region of Bihar. Maximum per cent disease severity of alternarialeaf blightwas observed during the peak monsoon months (June to August). Highest disease severity of leaf blight (14.80% & 15.7%) was observed in the mid June during crop season, 2018 and 2019. High temperature (36.9oC & 38.1oC), and relative humidity (94% & 96.4%) of both the year 2018 and 2019 were found correlated with higher severity to alternaria leaf blight. Similarly average HTR values (3.1) were also found correlated with the average high temperature and relative humidity of both years (2018 and 2019) in terms of severity of leaf blight disease. Maximum temperatures, relative humidity and rainfall exhibited strong positive linear relationship and influenced the occurrence of alternaria leaf blight disease significantly. We also developed a geo-phytopathological model for the prediction of alternaria leaf blight disease of makhana on the basis of congenial mean temperature and relative humidity.

scholarly journals Prevalence and Severity of Leaf Blight Disease of Chrysanthemum in Southern regions of Karnataka and in-vitro Fungicidal Effect on Alternaria alternata

2015 ◽  
Vol 9 (3) ◽  
pp. 38-45 ◽  
Author(s):  
G. Shamala ◽  
G. R. Janardhana
Keyword(s):  
Alternaria Alternata ◽  
Disease Incidence ◽  
Life Sciences ◽  
Leaf Blight ◽  
Cut Flowers ◽  
In Vitro Evaluation ◽  
Karnataka State ◽  
Commercially Important ◽  
Blight Disease

Chrysanthemum is one of the commercially important flower crop with great potential both as loose and cut flowers in Karnataka state. In the present study, prevalence and incidence of leaf blight disease was studied in six major growing districts of South Karnataka during 2012 - 2013. The pathogen associated with leaf blight disease was isolated and identified as Alternaria alternata. The study revealed that, the disease was distributed in Southern districts of Karnataka wherever Chrysanthemum is grown. The varieties Chandini and Karnel were more susceptible to blight showing highest disease incidence (100%) and severity (100%) recorded from Mandya and Mysore regions. The lowest disease incidence, severity and PDI of 18.40%, 38.68% and 24.89% were recorded on Rajawhite variety in Bangalore region. During 2013, the highest disease incidence, severity and PDI with 100%, 98.47%, and 45.71% were recorded in Mysore district on Chandini variety. In vitro evaluation of four fungicides on Alternaria alternata revealed that Carbendazim+Mancozeb was most effective with 95.65% inhibition followed by Carbendazim, Mancozeb and Metalaxyl+Mancozeb with 68.26%, 91.30% and 91.30% inhibition of the mycelium at 2.0% concentration.DOI: http://dx.doi.org/10.3126/ijls.v9i3.12465   International Journal of Life Sciences 9 (3): 2015; 38-45

Association between Alternaria macrospora and Alternaria alternata, causal agents of cotton leaf blight

1991 ◽  
Vol 69 (12) ◽  
pp. 2603-2607 ◽  
Author(s):  
Yoav Bashan ◽  
Hanna Levanony ◽  
Reuven Or
Keyword(s):  
Gossypium Hirsutum ◽  
Alternaria Alternata ◽  
Leaf Surface ◽  
Gossypium Barbadense ◽  
Cotton Leaf ◽  
Optimal Dosage ◽  
Alternaria Blight ◽  
Cotton Species ◽  
Infested Field ◽  
Blight Disease

The association between Alternaria macrospora and Alternaria alternata, responsible for the development of alternaria blight disease in cotton, was evaluated in artificially inoculated greenhouse plants and in naturally infested field plants. When greenhouse plants were inoculated with suboptimal doses of both pathogens (< 1.2 × 104 spores/mL) infection was greater than when separately inoculated by each pathogen at optimal dosage. In field-grown, naturally infected plants (Gossypium barbadense), both pathogens were found together in more than 40% of the plants. A second field-grown cotton species (Gossypium hirsutum) exhibited infection mainly by either A. alternata or both pathogens together. When both cotton species were naturally infected by both pathogens together, the number of A. alternata spores (either airborne or on the leaf surface) was greater than that of A. macrospora. We propose that A. macrospora together with A. alternata create a disease composite responsible for alternaria blight symptoms in cotton. Key words: Alternaria, cotton diseases, Gossypium barbadense, Gossypium hirsutum.

scholarly journals Assessing Taro (Colocasia esculenta (L.) Schott) Leaf Blight Incidence, Severity, and Farmers’ Knowledge of the Disease in Fako Division of Cameroon

2020 ◽  
pp. 17-29
Author(s):  
Mandah Cicelia Takor ◽  
Ekwa Yawa Monono ◽  
Ojong Agbor Ntane ◽  
Jemimah Evenye Ngale ◽  
Lum A. Fontem
Keyword(s):  
Disease Severity ◽  
Disease Incidence ◽  
Management Strategies ◽  
Leaf Blight ◽  
Cultural Methods ◽  
Randomized Design ◽  
High Prevalence ◽  
Severity Of The Disease ◽  
Blight Disease ◽  
Taro Leaf Blight

Taro leaf blight (TLB), a major disease of taro plant caused by Phytophthora colocasiae, a pseudo-fungus, that occurs in many taro producing areas, especially in the South West of Cameroon. A Survey was conducted to assess farmers’ knowledge, as well as to determine the incidence and the severity of the disease in taro fields. Structured questionnaires were administered in selected locations (Bokova, Ekona, Muea, Mile 16, Mutengene, and Likomba) of taro production. Two farms were selected with two quadrats of 64 m2 each were carved to assess disease incidence and severity on taro. The number of plants infected with taro leaf blight were counted and the area of the affected leaves measured was used to evaluate the disease incidence and disease severity. Data collected were subjected to ANOVA for complete randomized design and the means were compared using Tukey test at 0.05 probability levels. The results revealed that most of the farmers could identify the disease while practicing cultural methods in controlling the disease. The results also revealed significant differences (p = 0.001) in disease incidence and disease severity in all the localities, with Mile 16 showing the highest percentage mean of 96.53% and 85.59%, respectively. The severity scored showed high infection range of 3 – 3.95 in all locations except in Likomba (2.60).  It could be concluded from the results that there were high prevalence of taro leaf blight disease in Fako Division. Good management strategies are therefore required to control Taro leaf blight and improve taro production in the area.

Management of Alternaria Leaf Blight in Pigeonpea through Host Plant Resistance and Micronutrient Application

2021 ◽  
Author(s):  
E. Rajeswari ◽  
P. Akiladevi ◽  
P. Jayamani
Keyword(s):  
Alternaria Alternata ◽  
Untreated Control ◽  
Field Experiments ◽  
Leaf Blight ◽  
Plant Diseases ◽  
Grain Legume ◽  
Resistant Variety ◽  
Minor Importance ◽  
Fungicide Application ◽  
Blight Disease

Background: Pigeonpea [Cajanus cajan (L.) Millsp] is one of the primary grain legume crops grown in India for its high quality vegetable protein, animal feed and fodder. It is affected by various fungal and viral diseases. Among these, leaf blight caused by Alternaria alternata is one of the most destructive diseases and recently the disease of minor importance becomes major one in Tamil Nadu. Use of resistant cultivar is the most effective, economically viable and eco-friendly tool for combating the plant diseases. The micronutrients play a key role in many physiological and biochemical functions of the plants which influences plant pathogenic interaction. The micronutrients viz., Zn.Mn,Cu and Fe found to have greater impact on reducing the plant disease severity. Developing integrated disease management strategy involving disease resistant variety, micronutrient and fungicide application would be the best sustainable method for controlling the pigeonpea leaf blightMethods: Twenty four pigeonpea genotypes along with two local varieties viz., CO5 and CO6 were evaluated in the field for their resistance against Alternaria alternata leaf blight disease, consecutively for three years from 2015-16 to 2017-18 using the disease resistance scale ranging from 0 to 9. Field experiments were also conducted for three consecutive Kharif season from 2015 to 2018 to evaluate the efficacy of the foliar application of different micronutrients and combination fungicide viz., carbendazim 12% + mancozeb 63% on the incidence of leaf blight disease. Result: A total of 24 pigeonpea genotypes were screened for their resistance against leaf blight under field condition. Among these, four genotypes viz., BDN2, IPA 8F, IPA 15F and MA6 were found resistance and nine genotypes were moderately resistant and remaining 11 genotypes showed susceptible reaction to leaf blight. The results of the field experiment on micronutrient and fungicide application revealed that foliar spraying of MnSO 4 @0.2% on 30 days after sowing and carbendazim 12%+ mancozeb 63%@ 1g / lit on 45 days after sowing recorded the lowest leaf blight incidence of 8.1 PDI (Per cent Disease Index) with the highest disease reduction of 76.9% as against 35 PDI in the untreated control plot. The above treatments also recorded the highest grain yield of 905 kg/ ha as against 703 kg/ in the untreated control.

First report of leaf blight disease of Gloriosa superba L. caused by Alternaria alternata (Fr.) Keissler in India

2007 ◽  
Vol 73 (5) ◽  
pp. 377-378 ◽  
Author(s):  
Chandan Kumar Maiti ◽  
Surjit Sen ◽  
Amal Kanti Paul ◽  
Krishnendu Acharya
Keyword(s):  
Alternaria Alternata ◽  
Leaf Blight ◽  
Gloriosa Superba ◽  
First Report ◽  
Blight Disease
Sign in / Sign up

Export Citation Format

Share Document