The Population Structure and Presence of Helopeltis bradyi on the Tea Plant Parts at Various Times during the Day

Behavioural characteristics of the tea mosquito bug, Helopeltis bradyi, are important to be understood to support the control efforts of the pest. The study was aimed to describe population structure and behaviour of H. bradyi on the tea plant parts. The field study was conducted at Pagilaran tea plantation located in Batang Regency, Central Java Province, at 870 m asl, in early dry season of March - April, 2018. All developmental stages of H. bradyi on tea plant parts of 20 sample plants were observed and recorded in situ in the morning, at noon, and in the afternoon. Results showed that nymphs dominated the H. bradyi population structure. Population density in the morning (06.00-08.00 a.m.) was 45.1 individuals/20 plants (5.54 eggs, 80.71 nymphs, 13.75adults), at noon (11.00 a.m.-13.00 p.m.) was 41.7 individuals/20 plants (3.40 eggs, 84.00 nymphs, 12.60 adults), and in the afternoon was 37.0 individuals/20 plants (0 eggs, 88.38 nymphs, 11.62 adults). The H. bradyi was mostly present on tea shoots at upper leaf surface namely 97.08 in the morning, 79.27 at noon, and 88.14 in the afternoon, the rest was on lower leaf surface, shoot internodes, and other plant parts. The eggs were only found on tender internodes of shoots.