First Report of Alternaria Leaf Blight in Bael (Aegle marmelos (L.) Corr.) from Eastern Plateau and Hill Region of India (original) (raw)
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Alternaria alternata causes leaf and fruit blight in makhana
Current Science
Makhana (Euryale ferox) is a high-value commodity of nutritional, medicinal and ritualistic significance. North Bihar has occupied a prominent position in terms of both production and productivity of makhana not only in India, but across the globe. Leaf blight disease on makhana was noticed in April 2018, with a severity of 15-20% in a survey of farmers' ponds in North Bihar. Symptoms of the disease were circular, small, lightbrown, necrotic, sunken lesion that later turned into a large, dark, blighted area in the leaves. Blighting of fruits was also noticed during June and July 2018. Blighted fruits were small, distorted and twisted with less seed. Alternaria alternata was identified as the pathogen causing the disease based on morphological and cultural characteristics of the culture maintained on potato dextrose agar from symptomatic leaf and fruit samples. The fungus gave rise to greyish to greyblack colonies with obclavate to obpyriform, catenulate conidia in chains. Conidia consisted of 2-5 horizontal and 0-2 vertical septa and measured 15-60 × 5-9 μm in dimension. Molecular confirmation was done by sequence analysis of the internal transcribed spacer (ITS) regions of rDNA using ITS1 and ITS4 primers. Eventually, pathogenicity test inferred that leaf and fruit blight in makhana are due to A. alternata infection.
Studies of alternaria black spot disease of pomegranate caused by Alternaria alternata in Punjab
Journal of Applied and Natural Science, 2017
Alternaria black spot of pomegranate caused by Alternaria alternata pose significant economic losses in India as it reduce the crop yield. Farm survey was undertaken at Punjab Agricultural University, Pomegranate Research Block, Fruit Research Station, Jallowal- Lesriwal Jalandhar during 2015. Among all the five cultivars highest disease incidence (70%) and severity (30%) was registered in cultivar Bhagwa. Twenty two isolates of A. alternata were recovered from infected fruits and clustered using UPGMA (unweighted pair group method with arithmetic averages) on the basis of disease score produced in five cultivars (Ganesh, Ruby, Bhagwa, Jyoti and Mridula). It was revealed that five isolates namely AL14, AL15, AL20, AL21 and AL22 were highly virulent on almost all the pomegranate cultivars. Two cultivars viz. Bhagwa and Mridula were found to be most susceptible as 45.45 % isolates were found to be highly virulent on them.Thein vitro antifungal effects of the six fungicides on mycelial...
Bangladesh Journal of Plant Pathology, 2022
Watermelons (Citrullus lanatus) were severely affected by leaf blight disease in different parts of Nayabazar, Gorudaspur upazila, and Natore district of Bangladesh. The watermelon leaves those were affected by the leaf blight disease had numerous irregularly shaped dark brown patches that eventually blighted the leaves. The morphological, microscopic, and rDNA sequencing analyses supported the association of Alternaria alternata f. sp. cucurbitae with the leaf blight disease of watermelon. The pathogenicity of Alternaria alternata in watermelons was also proven by Koch's postulates. The pathogen Alternaria alternata causing leaf blight of watermelon was seemed to be the first time in Bangladesh.
2021
The present study was on management of Alternaria leaf spot caused by Alternaria alternata in Asalio. The disease was found to be very severe in all Asalio growing areas causing heavy destruction. The main aim of this investigation was to find out effect of age of the host, inoculum density in Alternaria leaf spot disease development and molecular identification of pathogen. The result shows that the susceptibility in Asalio increased with increase in age on inoculatios of A. alternata. Maximum disease was obtained in the plants ageing 40 DAS with PDI 55.60 per cent. Among the variously examined levels of inoculum concentrations. The two lower concentrations 1 × 101 and 1 × 102 conidia ml-1 exhibited significant difference in the PDI (20.00 and 31.20 respectively) within each other. 1 × 103 and 1 × 104 conidia ml-1 inoculum levels were found to be significantly at par to each other with PDI (39.20 and 40.80 respectively). 1 × 103 conidia ml-1 inoculum concentration was optimum for c...
Cultural, morphological and pathogenic studies revealed a wide range of variability of among the 20 isolates of A. carthami of safflower which represented four geographic regions of the state of Maharashtra. All 20 test isolates exhibited a great cultural variability in mycelial growth, colony colour, growth speed, colony shape and sporulation. Significantly highest mycelial growth was found in isolate AcHl (90.00 mm), followed by AcBl (89.67 mm) and AcAn (88.83 mm). Among morphological variability in respect of mycelial width, conidial dimensions, beak length and number of vertical and horizontal septa eight isolates exhibited large mycelial width (7.05 to 9.80 µm), six isolates with medium sized with mycelium width (5.40 to 6.46 µm) and six with small sized mycelium width (3.25 to 4.86 µm). On the basis of average conidial dimensions (length X breadth), the test isolates were categorized into three groups viz., large, medium and small sized conidia were found in nine isolates of which average length ranged from 36.37 to 50.32 µm and width from 13.06 to 17.19 µm; seven isolates were with medium sized conidia (26.80-35.37 X 9.94-14.73 µm) and rest four isolates with small sized conidial (22.45-25.17 X 7.28-9.27 µm). About eight isolates exhibited long beak length (11.05 to 16.43 µm), seven isolates with medium beak length (8.13 to 11.27 µm) and rest five isolates were of short beak length (6.04 to 7.46 µm). Among the test isolates, horizontal septation on conidia was ranged from 1 to 12 and vertical septation from 0 to 3. All of the 20 isolates of A. carthami exhibited a wide range of pathogenic variability. However, the aggressive isolates (viz., AcHl, AcBl, AcAn, AcJg, etc.) showed least incubation period, highest leaf spot frequency with maximum sized leaf spots.
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First report of leaf blight of noni caused by Alternaria alternata (Fr.) Keissler
Journal of General Plant Pathology, 2010
A severe outbreak of leaf blight was observed in noni crop for the first time in Tamil Nadu and Karnataka states of India during 2008-2009. Based on pathogenicity, morphology and ribosomal DNA spacer sequences, the pathogen was identified as Alternaria alternata (Fr.) Keissler. This report is the first of Alternaria leaf blight of noni.
Alternaria leaf spot of broccoli caused by Alternaria alternata in Bangladesh
Plant Protection Science
This study aimed to isolate and characterise the pathogen associated with Alternaria leaf spot on broccoli and to evaluate the inhibitory effects of fungicides against it. We isolated and identified the fungal pathogen as Alternaria sp. using morphological and cultural methods. Based on the aligned sequences of the internal transcribed spacer (ITS) and molecular phylogenetic analysis by the neighbour-joining method, the isolates (Ab1 and Ab2) were confirmed as Alternaria alternata. The conidia of the isolates were dark brown, cylindrical, obclavate to muriform. The conidiophores were olivaceous brown, septate, and branched. The conidial morphology of the isolates ranged from 52.4–92.4 × 10–20 μm with 2–6 transverse and 0–3 longitudinal septa. Both isolates yielded positive results in the pathogenicity test on broccoli leaves by developing brown and circular spots with concentric rings on the leaves surrounded by yellow halos. The culture studies revealed that the maximum growth of t...