Author(s):

Katakam Mounika, Birendranath Panja and Jayanta Saha

Abstract: Painted evergreen or Chinese evergreen [Aglaonema crispum (Pitcher & Manda) Nicolson] is an economically important foliage ornamental plant grown in the garden of Agri-Horticultural Society of India at Kolkata, West Bengal. These were found to be attacked severely by anthracnose disease leading to devastating foliar damage. The leaves showed characteristic blighting like symptoms with light brown to grey necrotic areas bordered by dark brown wavy margins. On the necrotic areas, black, erumpent, dot like acervuli, 320.7 – 540.1µ wide appeared to be arranged in the form of concentric zonations on the upper surface of the leaf. Setae were numerous, 1 - 2 septate, 126.0 – 176.3 x 3.5 – 6.8 µ in size with pointed tips. Conidia were hyaline, single celled, cylindrical to short rod shaped with rounded ends and 18.5 – 24.8 x 2.7 – 4.4µ in size. On the peptone agar medium (PAM) identified as ideal medium for acervuli production and sporulation, acervuli were pale brown to black, 426.5 - 920.5 µ in size. Setae were numerous, black to dark brown, 1 – 3 septate, unbranched, 198.5 – 245.1 x 6.0 – 7.8 µ in size with pointed tips. Conidia were hyaline, 1-celled, smooth walled, eguttulate, cylindrical with rounded ends measuring 23.7– 28.5 x 3.0 – 5.0 µ in size. Pathogenicity test of the isolated fungus had been established under laboratory condition following detached leaf technique. On comparison of the isolated fungus with Gloeosporium graffi and Colletotrichum dematium which were known to attack the host, it was found that acervuli and conidial characteristics of causal fungal pathogen of the present study differed from Gloeosporium due to the presence of setae and also from Colletotrichum dematium due dissimilarity in spore shape and size but exhibited gross similarity with Colletotrichum gloeosporioides. So, the causal fungus of presently described anthracnose disease of Aglaonema crispum is being proposed as Colletotrichum gloeosporioides.

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