園芸ジャーナル
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概要

Canker disease a new threat to tomato cultivation in Sri Lanka

R G A S Rajapaksha, M P T Premarathna and Shyamalee Kohombange

Tomato production of some locations in central and southern areas in Sri Lanka has suffered in the recent past, due to emergence of canker disease caused by Clavibacter michiganensis Subsp. michiganensis (Cmm). Recently, leaf and fruit symptoms of Cmm has observed in some exotic tomato cultivars grown in hot (350C – 400C) and humid areas. Now it has become a problem constraining production of healthy seeds, nursery seedlings at commercial scale and profitable tomato cultivation. Earlier it was suspected that the symptoms of leaves resemble damage caused by fungal pathogens and attempts have been made to control this problem by foliar spraying of fungicides. However, it was failed and at present this disease has limited to some of the locations in tomato cultivations of the country. Canker disease has been first identified in year 2015 in tomato cultivation of exotic varieties in central province with the technical collaboration of JAICA, Sri Lanka. It was noted that symptoms of tomato canker disease initiate warm and moist condition and the main symptoms observed in the effected plants were leaf yellowing and necrosis around leaf margins. Fruit symptoms were occasionally observed as small dark spots on the fruit surrounded by a white halo. Tomato cultivars with some tolerance to canker have been introduced, but there is little significant tolerance in commercial tomato varieties