Isolation, Pathogenicity and Effect of Different Culture Media on Growth and Sporulation of Alternaria brassicae (berk.) Sacc. causing Alternaria Leaf Spot Disease in Cauliflower

A field experiment was laid out in randomized complete block design with three replications and seven cultivars of Radish as treatments for screening against Alternaria leaf spot for seed production. Disease scoring was done as percentage of leaf area infected on individual plant at 7 and 10 days intervals on leaf and siliqua respectively for 3 times, and disease severity and mean AUDPC were calculated and yield was recorded. Disease symptoms appeared first in Long Chetki 22 DAS and last in Green Neck Miyashige 38 DAS. Maximum mean AUDPC (886.7) on foliage was recorded in Long Chetki while minimum mean AUDPC (690.7) was recorded in Green Neck Miyashige Similarly, highest and lowest total mean AUDPC on siliqua were seen on cultivars 40 Days (1080) and Green Neck Miyashige (66.67) respectively. Highest yield was recorded in Green Neck Miyashige (695.2kg/ha) and lowest yield was recorded in cultivar Long Chetki (477.4kg/hac). Similarly, highest test weight was recorded in cultivar Mino Early (10.28gm) and lowest was recorded in cultivar 40-Days (8.4gm). Cultivar, All Season Green Long failed inflorescence formation hence no evidence of siliqua formation therefore bears value 0 for seed yield. Similarly, highest biomass yield excluding root was found in cultivar Subhra-32 (613.3gm/m2) and lowest biomass yield was recorded in cultivar Green Neck Miyashige (341.7gm/m2). Green Neck Miyashige was found resistant to Alternaria leaf spot disease with maximum seed yield (695.2kg/ha). The cultivars Subhra-32 and 40 days were highly susceptible to Alternaria leaf spot disease with minimum seed yield.Int J Appl Sci Biotechnol, Vol 4(3): 318-324

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Curvularia sp. Jamur Patogen Baru Penyebab Penyakit Bercak Daun pada Tanaman Sawi

Agrikultura ◽

10.24198/agrikultura.v29i3.21645 ◽

2018 ◽

Vol 29 (3) ◽

pp. 119

Author(s):

Tarkus Suganda ◽

Dinda Y Wulandari

Keyword(s):

Brassica Juncea ◽

Leaf Spot ◽

Fungal Pathogen ◽

Causal Agent ◽

Leaf Spot Disease ◽

Alternaria Brassicae ◽

Spot Disease ◽

Leaf Spots ◽

Green Production ◽

Mustard Green

ABSTRACTCurvularia sp. a new fungal pathogen causing leaf spot on the leaf of mustard greenA new diseases symptom as small spots of 1.5 - 1 mm diameter has been found on mustard green's leaf of farmer's field at Tanjungsari Regency of Sumedang. This symptom is different from those previously known incited by Alternaria brassicae and A. brassicola, Pseudocercosporella capsellae as well as by Myscosphaerella brassicicola. Although the spots are small, they are abundant and accompanied with yellowing, making these symptoms detrimental to mustard green production which has to be green and healthy. A Koch Postulate has been performed and successfully identified that the fungal causal agent was of the genera of Curvularia. Previously, curvularia leaf spot disease has never been reported on mustard green in Indonesia.Keywords: Curvularia, Leaf spots, Mustard green, Brassica junceaABSTRAKGejala penyakit baru, berupa bercak hitam berukuran diameter 0,5 - 1 mm ditemukan pada daun tanaman sawi milik petani di daerah Tanjungsari Kabupaten Sumedang. Gejala demikian berbeda dengan gejala-gejala penyakit bercak yang selama ini dikenal disebabkan oleh Alternaria brassicae dan A. brassicola, Pseudocercosporella capsellae dan Myscosphaerella brassicicola. Walaupun gejalanya berukuran kecil, namun karena jumlahnya banyak dan menyebabkan daun menguning, menjadikan gejala penyakit ini merugikan tanaman sawi yang harus hijau dan sehat. Uji Postulat Koch telah dilaksanakan, dan berhasil mengidentifikasi bahwa berdasarkan morfologi mikroskopiknya, jamur tersebut adalah dari genus Curvularia. Penyakit bercak daun curvularia, sebelumnya, belum pernah dilaporkan terdapat pada tanaman sawi di Indonesia.Kata Kunci: Curvularia, Bercak daun, Sawi, Brassica juncea

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