Tea mosquito bug (Helopeltis spp.) – A devastating pest of cashew plantations in India: A review

More than 32 countries are growing cashew in the world, wherein India occupies largest area under cashew plantations (20%) and earning foreign exchange of over 5 000 crores per annum through export of cashew kernels and cashew nut shell liquid. Often, there is a serious loss in cashew nut yield due to attack of tea mosquito bug (Helopeltis spp., Heteroptera: Miridae) which is a major sucking pest of cashew plantations in India. Under severe out break conditions, yield losses are as high as 40-50%. There are three common species of Helopeltis, viz. H. antonii Signoret, H. bradyi Waterhouse and H. theivora Waterhouse found in west coast and H. antonii is most predominant in the east coast, though in east coast its occurrence is prevalent from Tamil Nadu to Odisha. Whereas, H. theivora is predominant species in north-east region. Besides cashew, a large number of host plants like, tea, guava, cocoa, neem, cinchona etc. are reported. The seasonality study suggested that the population of tea mosquito bug reaches its peak during the flushing, flowering and fruiting season in cashew, i.e. from November to February. As a management strategy, varietal screening suggested that no cashew varieties are resistant to tea mosquito bug infestation but Dhana and Bhaskara varieties are moderately susceptible. Therefore, even today only chemical means of tea mosquito bug management is adopted under commercial cashew plantation. As a biological control strategy, the solitary egg parasitoids, viz. Telenomus cuspis, Chaetostricha sp. and Erythmelus helopeltidis Gahan were specifically promising against Helopeltis. The adult parasitoid, Leiophron sp. is additional asset for natural control strategies of Helopeltis spp. on cashew. Recent researches have incorporated 117 species of spiders and 18 species of reduviids into cashew management strategies. Laboratory mass culture techniques of reduviids have also been standardized using wax moth larvae as prey. Adults of H. antonii and H. theivora were found to be infested by predatory mite, Leptus sp. attached ecdysial line from head and thorax. Moreover, sex pheromone based technology development is the need of the hour to manage this pest. In this paper, efforts have been made to review the literature pertaining to the pest taxonomy, biology, distribution, host plants, nature of damage, seasonality and management strategy of Helopeltis spp. focusing on Indian subcontinent, so as to bring out non-chemical based management strategies.