Tea clonal preference by Helopeltis theivora (Hemiptera: Miridae)
Purnima Das, Surajit Kalita and Lakshmi Kanta Hazarika
Helopeltis theivora Waterhouse (Miridae : Hemiptera) is a polyphagous insect having a characteristic diet preference, as revealed through ex situ and in situ screening of Tocklai Vegetative (TV) clones. Second instars caused the most feeding lesions (193.00 ± 8.91), but not the damage, amongst the developmental stages, and were capable of discriminating tested TV clones. Stadia of five instars were almost similar but were significantly different from adult longevity (15.58 to 18.25 days); adults exhibited not only female-biased sexual dimorphism in longevity but also of feeding potential. In situ screening resulted in identification of TV1 and TV7 as the susceptible clones, while TV6, TV12, TV14 and TV19 as resistant ones; these data were at par with that of ex situ screening in the laboratory, therefore, this method may be useful for large scale screening.