Epidemics of leaf blotch disease (phaeodactylium alpiniae) of small cardamom

Leaf blotch disease of small Cardamom (Elettaria cardamomum) caused by the fungal pathogen Phaeodactylium alpiniae was reported first in the year 1969. The disease appears during monsoon months at mild levels and never occurred at epidemic proportions. However there was an unusual and serious incidence of leaf blotch disease during 2010 and 2011 at various Cardamom plantations in Idukki Dist, Kerala. A detailed survey of leaf blotch disease was made at 31 localities. The disease incidence was found to be high in Mali region (92.1%) and least in Cumbummettu (15.8%). Various accessions maintained at ICRI germplasm were screened for disease incidence. The disease incidence was highest in accession MCC86 (39.87%) and lowest in accession MCC161 (6.25%). The popular land race Njallani recorded 34.7% disease incidence. Out of the 139 accessions observed, 17 had disease incidence in the range of 1-10%; 72 had incidence in the range of 11-20%; 40 had disease incidence in the range of 21-30% and the rest 10 had the incidence in the range of 31-40%. Under artificial conditions the pathogen was able to infect leaves which are intact or injured. Besides, the pathogen was able to infect pseudostems and also on capsules which is the first report of its kind. Under field conditions, Bordeaux mixture (1.0%) recorded followed by the fungicide, Propiconazole (0.1%). The fungicides, Trifloxystrobin+Tebuconazole (0.1%), Thiophanate Methyl (0.2%), Mancozeb (0.2%) and Tebuconazole (0.1%) were also effective and were on par with each other.