Pronotal color morphs and influence of weather parameters on population trends of the Capsid bugs, Helopeltis antonii and H. bradyi in cashew ecosystem
Srikumar, Kodakkadan Kotian; Bhat, Pollali Shivarama
Abstract Tea mosquito bugs (TMB) Helopeltis spp. are major sucking pests of cashew (Anacardium occidentale L.). The present study, carried out over three consecutive years (2009–2012), identified three pronotal color morphs in the adults of the capsid bugs, Helopeltis antonii Signoret and H. bradyi Waterhouse (Heteroptera: Miridae): dark red, black and brownish black. In H. antonii, the frequency of dark red morphs was significantly (p < 0.05) higher than the black, and the black was significantly (p < 0.05) higher than the brownish black. In contrast, the black colour variant dominated in the males of H. bradyi. In H. bradyi females the frequency of the dark red color morph was significantly higher than the brownish black and was on par with the frequency of the black. For H. antonii the highest number of dark red individuals was recorded in October and the lowest was found in February for males and June for females. In both males and females the incidence of black was higher in June. Brownish black morphs had a low incidence ranging from 11% to 21%. The population abundance of both sexes of H. bradyi was very low most of the year and they were completely absent during the months of July to September. The highest number of male black color morphs was recorded during the month of January and February. The frequencies of dark red and black individuals were significantly (p < 0.05) higher than brownish black in the female population. Minimum temperature and sunshine hours had significant effects (p < 0.05) on the size of H. antonii population. The largest populations were observed in December and January. The size of H. bradyi population was affected by minimum temperature. Minimum temperature and number of sunshine hours could be used to predict the size of Helopeltis spp. populations and to plan appropriate control measures.