Characterization of Phytophthora de Bary inciting capsule rot/azhukal and leaf blight disease of cardamom (Elettaria cardamomum Maton)
Bhai. S. R Sarma. Y. R
Journal of Plantation Crops ; 2005 [Vol.33] Pages:187-197
Abstract
A detailed study was carried out to characterize the Phytophthora species associated with capsule rot and leaf blight diseases in cardamom. Phytophtliora was isolated from rot affected plant parts such as leaf, capsule and pseudostem collected from different cardamom growing tracts of ldukki and Wyanad districts of Kerala during the monsoon and post monsoon periods. Morphological and physiological studies such as colony morphology, growth rate, morphology of sporangia, pedicel length, caducity, chlamydospores, sex organs, compatibility type, growth on synthetic medium and temperature relationship was studied using 25 Phytophthora isolates from cardamom. Two groups of Plrytophthora could be identified from infected capsules, leaves and pseudo stem. The group one having pigmentation, chlamydospore production and growth at >35 °C where as the group two having no pigmentation, no chlamydospore production and no growth at 35 °C. The group one is identified as P. nicotianae var. nicotianae and group two as P. meadii. From the studies it has been confirmed that two species of Phytophthora viz. P. meadii, and P. nicotianae var. nicotianae are involved in initiating capsule rot occurring during the monsoon season of which P. meadii is the predominant one, The leaf blight occurring during the post monsoon season is due to P. nicotianae var. nicotianae. However, there is certain amount of overlapping of these in initiating the disease in cardamom. P. palnaivora could not be isolated from the infected plant parts as reported earlier.
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