Studies on Cultural Characteristics and Management of Cercospora Leaf Spot of Mungbean [ Vigna radiata (L.) Wilczek]
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Date
2020-12-01
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Banda University of Agriculture & Technology, Banda-210001, Uttar Pradesh, India
Abstract
The pulses, mainly mungbean [Vigna radiata (L.) Wilczek] is an important crop grown extensively in Bundelkhand region of Uttar Pradesh. Despite the multifaceted importance of this crop, its production could not be stabilized in the Uttar Pradesh as well as in the country. There are several biotic constraints like diseases and insect-pests hampering the production of mungbean crop. Among the diseases, Cercospora leaf spot is the most important fungal disease occurring regularly in the mungbean growing areas. The disease is caused by Cercospora canescens Ellis and Martin. Cercospora leaf spot disease appears during warm and humid weather leading to Chlorosis, defoliation and low yield. Keeping in view of importance of disease, experiments were conducted to study the cultural characters of the pathogen and to find out the efficient management strategies for this disease.
The pathogen isolated onto potato dextrose agar medium was slow growing; white in colour and puffy growth was observed which was slightly raised on the upper side. Mycelium was hyaline to light brown in color and septate. Conidiophores were straight or flexuous, light brown to brown in color and multi-septate. Conidia were hyaline to light brown, straight to curved with 5-10 septate measuring 3-5 x 40-130 um with delicate tip. The inoculated leaves showed small brown spots in the initial stage which were turned into dark brown and enlarged spots. Closely located spots coalesced and formed large necrotic patches. Developed spots had grey colored center and brown margin. The size of the spots varied from 3- 10mm in diameter. Out of 5 media viz., potato dextrose agar, potato sucrose agar, oat meal agar, mungbean decoction agar and v-8 juice agar medium tested for growth of the C. canescens, the highest radial growth of mycelia (87.67mm) recorded in v-8 juice agar medium which was almost equal to growth of mycelia observed on potato dextrose agar (86mm), potato sucrose agar (86.50mm) and mungbean decoction agar (86.50mm). The least radial growth (41.17) of mycelia exhibited in oat meal agar medium. White color colony of C. canescens was seen in three media viz., potato dextrose agar, mungbean decoction agar and v-8 juice, while, creamy white and light yellow colored colony were observed in potato sucrose agar and oat meal agar medium, respectively.
During both of the crop seasons i.e. Kharif 2019 and 2020, twice sprays of Carbendazim at 1" appearance of symptoms and 15 days' interval gave the maximum reduction in incidence and severity i.e. 45.57% and 58.45%, respectively; of Cercospora leaf spot disease along with significant enhancement (53.39%) in seed yield (quintal/ha) as well as in yield components (except number of primary branches per plant and number of seed per pod) over the unprotected crop. It was followed by the twice sprays of Carbendazim + Mancozeb with respective parameters. Sprays of Captan + Hexaconazole were found to be least effective to reduce the disease incidence/ severity as well as to increase the yield and its components. Out of 190 mungbean genotypes evaluated against Cercospora leaf spot during two consecutive crop seasons, four genotypes viz., PDM 04-123, PDM 54, EC520034and EC 520022 were found to be resistant against Cercospora leaf spot disease.
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Gupta Kshitij 2020. Studies on Cultural Characteristics and Management of Cercospora Leaf Spot of Mungbean [ Vigna radiata (L.) Wilczek]. M.Sc. Thesis. 98p.