Does Pestalotiopsis royenae Cause Leaf Streak of Large Cardamom?

Leaf streak caused by Pestalotiopsis royenae (Guba) Steyaert has been reported as a new disease of large cardamom (Amomum subulatum). It is characterized by rectangular spots running parallel to the veins. P. royenae was isolated onto potato dextrose agar from the infected portion of the plant. In the pathogenicity test, disease symptoms were not present on inoculated plant and on detached leaf in vitro after 20 days. During 2014–2016, a survey in various large cardamom plantations of Sikkim revealed the presence of tea mosquito bugs on the infected parts of A. subulatum. The spots did not show any growth. Different sized spots have been noticed on the infected leaf produced by different instars. At the initial stage, these symptoms appear on the young and tender leaves of large cardamom. Tea mosquito bugs were collected from the infested leaves and allowed to feed under controlled conditions, which produced similar type of leaf streak symptoms in large cardamom and also in other non-host crops like maize and turmeric. The results reveal that the cause of leaf streak is due to feeding injury of tea mosquito bugs and rule out P. royenae as a pathogen causing leaf streak disease symptoms. Pestalotiopsis sp. was also isolated as endophyte from large cardamom.