scholarly journals Response of cotton genotypes against the incidence of Alternaria leaf blight of cotton under field conditions

2021 ◽  
Vol 42 (4) ◽  
pp. 1002-1007
Author(s):  
G. Rajesha ◽  
◽  
S. Nakkeeran ◽  
T. Indumathi ◽  
P. Adhipathi ◽  
...  

Aim: To identify the resistant source present in the breeding materials against Alternaria leaf blight disease of cotton (Gossypium spp.). Methodology: Breeding entries were sown in a randomized complete block design in the experimental site. Disease intensity on each genotype at 45, 90, 135 and 180 days after sowing (DAS) were recorded from leaves of lower, middle and upper parts of plants and graded. According to 0 - 4 disease scoring scale, per cent disease index (PDI) was calculated and genotypes were categorized into different categories based on disease reaction Results: Development of Alternaria disease was noticed at early days of crop growth in few genotypes and the disease increased upto 135 days after sowing. The maximum mean per cent disease index of 41.17 and 40.06 were recorded in Br.14a (ZT)1333 and Br.14a (ZT)1332 respectively. The least PDI of 0.58 was recorded in Br.03a (ZT)1303. Disease incidence of <11.00% of was reported in 37 entries at 45 days after sowing. None of the genotypes showed apparently immune reaction, twenty-one genotypes showed resistant reaction, eleven genotypes were moderately resistant and five showed moderately susceptible reaction. Interpretation: Twenty-one breeding lines showed resistant reaction against Alternaria leaf blight disease under field conditions, however, further utilization of these lines may be carried out in breeding programmes for the development of resistant source against this disease.

2021 ◽  
Vol 23 (1) ◽  
pp. 54-59
Author(s):  
SANTOSH KUMAR ◽  
MD. NADEEM AKHTAR ◽  
SANTOSH KUMAR ◽  
MAHESH KUMAR ◽  
TRIBHUWAN KUMAR

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.


Author(s):  
K. Alekya ◽  
B. Laxmi Prasanna ◽  
M. Balram ◽  
N. Balram ◽  
P. Gonya Nayak ◽  
...  

Biotic stresses are major threat to rice production. Among biotic stresses, bacterial leaf blight is one of the major diseases affecting rice grain production in rice growing areas. Present investigation was conducted to evaluate phenotypic effect of 50 breeding lines from a cross (Pranahitha//ISM/MTU1010) in glass house at Regional Agricultural Research Station, Jagtial by inoculating Bacterial leaf blight culture (DX-020) by leaf clipping method. Out of these 50 F4 lines evaluated, twenty nine breeding lines showed resistant reaction with disease score of 1. Eleven lines showed moderately resistant reaction with disease score 3. Twenty nine breeding lines that were resistant with disease score 1, had excellent grain yield. Hence, these lines can be advanced to further generations. Thus the present study has demonstrated that phenotypic selection is successful in the glass house and these breeding lines with higher yield levels are expected to perform better in the field trials and further in the farmers fields with the good level of bacterial blight resistance.


Plant Disease ◽  
2021 ◽  
Vol 105 (1) ◽  
pp. 60-70 ◽  
Author(s):  
Guoping Ma ◽  
Shuwen Bao ◽  
Juan Zhao ◽  
Yuan Sui ◽  
Xuehong Wu

Watermelon is an economically important crop in China and is commonly affected by Alternaria-like leaf blight that can result in significant economic losses. In this study, 830 Alternaria isolates, recovered from symptomatic watermelon leaves, were identified based on morphological traits, pathogenicity, and multilocus sequence analyses of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone 3 (HIS3), the internal transcribed spacer of ribosomal DNA (rDNA ITS), and the RNA polymerase II second largest subunit (RPB2). Watermelon isolates grouped to five Alternaria species and one unclassified Alternaria species. They were A. tenuissima, A. alternata, A. cucumerina, A. infectoria, A. gaisen, and Alternaria sp. Notably, A. tenuissima was the most prevalent (73.5%) of the six isolated species, followed by A. alternata (25.0%), A. cucumerina (1.1%), Alternaria sp. (0.2%), A. infectoria (0.1%), and A. gaisen (0.1%). Pathogenicity tests demonstrated that all six Alternaria species could produce brown necrotic lesions on detached leaves of watermelon. The average disease incidence (75.1%) and average disease index (60.8) of watermelon resulting from inoculation of leaves with A. cucumerina were significantly higher than levels resulting from A. alternata (52.9% and 37.2) and A. tenuissima (47.5% and 30.8). Inoculation with Alternaria sp. resulted in a disease incidence (70.0%) and disease index (51.5), which were lower than those of A. cucumerina. The disease incidence and disease index in watermelon leaves inoculated with the one isolate of A. infectoria and the one isolate of A. gaisen present in the inoculated leaves were 28.9% and 16.4, and 48.9% and 31.4, respectively. Results of the study indicate that Alternaria species associated with watermelon leaf blight in China are more diverse than that has been previously reported. This is the first report globally of A. infectoria, A. gaisen, and an unclassified Alternaria species as causal agents of leaf blight on watermelon.


2015 ◽  
Vol 9 (3) ◽  
pp. 38-45 ◽  
Author(s):  
G. Shamala ◽  
G. R. Janardhana

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


2020 ◽  
Vol 8 (3) ◽  
pp. 2906-2908
Author(s):  
P Vidyashree ◽  
ST Yenjerappa ◽  
D Pramesh ◽  
Gururaj Sunkad ◽  
Vikas Kulkarni

2020 ◽  
Vol 28 (2) ◽  
pp. 255-265
Author(s):  
J.F. Ogunsola ◽  
B. Ikotun ◽  
K.E. Ogunsola

Egusi melon (Citrullus lanatus (Thumb) Mansf.) is an important vegetable crop grown for edible seeds and oil in West Africa. Leaf Blight Disease (LBD) is one of the major constraints to its production, with potential to cause economic damage. The objective of this study was to investigate the incidence and distribution of leaf blight on Egusi melon in Southwestern Nigeria. A survey of LBD of Egusi melon was conducted in 2015 and 2016, in five southwestern States of Nigeria (Ogun, Oyo, Osun, Ekiti and Ondo States). Twenty plants each, were randomly sampled from 150 farms comprising 30 farms each, from each State. The distribution of different Egusi melon varieties planted was recorded. “Bara” cv. was the most cultivated variety (51.6%); followed by “Bojuri” (30.4%) and “Serewe” (18%). Leaf blight was observed in most farms in the five States, from 73% in Osun and Oyo states to 83% in Ondo State. Disease incidence and severity varied with locations and cultivars, and ranged from 0.0-87.5±18% and 1.0±0-4.5±0.8 in Osun State to 20.0±19 - 95.0±4.5% and 2.3±1.5 - 5.0±0 in Ondo State. Out of the twelve fungal pathogens from ten genera isolated from infected plants, only Colletotrichum truncatum, C. gloeosporioides and Lasiodiplodia theobromae caused Leaf blight on Egusi melon. Key words: Colletotrichum gloeosporioides, Colletotrichum truncatum, Lasiodiplodia theobromae


Author(s):  
Mandah Cicelia Takor ◽  
Ekwa Yawa Monono ◽  
Ojong Agbor Ntane ◽  
Jemimah Evenye Ngale ◽  
Lum A. Fontem

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.


2017 ◽  
Vol 29 (2) ◽  
pp. 257 ◽  
Author(s):  
Muhammad R. Bashir ◽  
Abid Mehmood ◽  
Muhammad Sajid ◽  
Muhammad A. Zeshan ◽  
Muhammad Mohsin ◽  
...  

The current research was conducted to find out the most appropriate concentrations of six fungicides for the management of sesame charcoal rot caused by Macrophomina phaseolina under lab and field conditions. The treatments viz. Antracol, Topsin-M, Mancozeb, Score, Topas, Nativo and Control with concentrations of 150, 250 and 350ppm were used with three replications under completely randomized design and randomized complete block design in Lab. and field conditions respectively. The mean colony growth of all treatments expressed that Nativo exhibited minimum colony growth of (0.93 cm) as compared to Score (1.14 cm), Topsin-M (1.42 cm), Mancozeb (1.77 cm), Antracol (2.04 cm), Topass (2.33 cm) correspondingly. The interaction between treatments and concentrations (T×C) showed that  used concentrations 150 ppm, 250 ppm and 350 ppm of Nativo abundantly inhibit fungal colony growth upto 1.26 cm, 0.86 cm and 0.66 cm respectively whereas the interaction between treatments and days expressed that after day ninth the minimum colony growth (1.23 cm) was observed for Nativo as compared to all other treatments. Similarly, the interaction between concentrations and days expressed highest fungal colony growth at concentration 150 ppm on day third (2.06 cm), sixth (3.02 cm) and ninth (3.65 cm) but the interaction of treatments, days and concentrations expressed that at 150 ppm concentration, all treatments exhibited minimum colony growth (1.70 to 3.30) cm at third, sixth and ninth day as compared to 250 and 350 ppm concentration respectively with respect to control (6.90 cm). In filed conditions, Nativo exhibited minimum Mean Disease Incidence (12.55%) whereas the interaction between treatments and days showed minimum of 14.95%, 12.82% and 9.90% disease incidence by Nativo as compared to all other treatments including control (66.86%, 77.57% and 87.22%) after day tenth, twenty and thirty. It was concluded that Nativo is significantly inhibiting the colony growth under lab and filed conditions.


2014 ◽  
Vol 6 (2) ◽  
pp. 541-544 ◽  
Author(s):  
P. N. Meena ◽  
A. Roy ◽  
B. S. Gotyal ◽  
S. Mitra ◽  
S. Satpathy

Field experiment was conducted for disease management with seven eco-friendly treatments in Corchorus olitorius jute during 2012-2013 under randomized block design (RBD) in three replications with variety JRO-524. The ecofriendly treatment 50% N: P: K + seed treatments with Azotobacter and phosphorus solubilizing bacteria (PSB) @ 5g/Kg+ Trichoderma viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha at 21DAS) + Psuedomonas fluorescens spray @ 0.2% at 45DAS was found superior with minimum per cent disease incidence (3.46 and 1.43%) as compared to control (13.17 and 4.96%). The second best treatment was found with Farm yard manure (FYM) @ 5t/ha + seed treatment with Azotobecter and PSB @ 5g/Kg+ T. viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha 21DAS)+ P. fluorescencs spray @ 0.2% at 45DAS and showed 3.61 and 2.0% disease incidence. The treatment with N: P: K @ 60:30:30 and seed treatment with carbendazim 50WP @ 2g/Kg at 45DAS showed 4.56 and 2.10 % disease incidence. Dry fibre yield was highest (30.33q/ha) in the plots treated with FYM @ 5t/ha + seed treatment with Azotobacter and PSB @ 5g/Kg+ T. viride (seed treatment @ 5g/Kg of seed and soil application @ 2Kg/ha at 21DAS) + P. fluorescencs spray @ 0.2% at 45DAS) and it was lowest in untreated control (15.69 q/ha).Variation in yield was attributed due to difference in plant height.


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