Population Dynamics of Tea Mosquito Bug, Helopeltis antonii Signoret (Hemiptera: Miridae), in Young Cashew Plantation of Cashew Research Station, Madakkathara, Kerala

摘要

Tea mosquito bug (TMB) is a serious pest of commercially grown cashew in India. Yield loss of up to 40% is reported from India due to TMB infestation in cashew. The age of the trees was found to influence the severity of TMB infestation in cashew. Young trees are affected by TMB throughout the year, as they produce flushes almost continuously. A survey was carried out in young cashew plantation of cashew Research Station, Madakkathara, Kerala during October 2009 to September 2010 to study the occurrence and damage potential of TMB. Regular monthly observations were recorded on the population and damage of TMB from five trees each of eleven cashew cultivars released from Madakkathara namely; 'K-22-1', 'Madakkathara-l', 'Madakkathara-2', 'Kanaka', 'Dhana', 'Priyanka', 'Sulabha', 'Amrutha', 'Damodar', 'Raghav' and 'Poornima'. The number of nymphs and adults were counted visually from 20 tender shoots on each tree. TMB damage was also recorded in 0-4 scale from 20 tender shoots on each tree. Phenological phase of crop growth namely flushing and flowering were recorded during the survey. Generally two peaks of TMB population were recorded in the plantation, one during December and another during June, coinciding with flowering and flushing, respectively. Maximum population of TMB was recorded during June which coincided with maximum flushing in all the cultivars. The extend of shoot damage in young cashew plants was high during July to September. Among the weather parameters studied, rainfall showed significant positive correlation with the population of TMB and extent of shoot damage.