Relative natural resistance of Populus deltoides clones against defoliatorClostera cupreata (Lepidoptera : Notodontidae) in northern India

Populus deltoides (poplar) that is extensively being planted commercially i n agroforestry combinations in northern India is prone to attack by a defol iating insect, Clostera cupreata. In order to evaluate the relative suscept ibility/resistance of different clones and to identify the resistant ones, 80 clones of American origin were evaluated in Dehra Dun, India. The feedin g potential of the pest on different clones varied significantly. The clone s were grouped into six categories depending on their susceptibility as mos t resistant or R1 (12 clones), moderately resistant or R2 (14 clones), marg inally resistant or R3 (10 clones), marginally susceptible or S1 (17 clones ), moderately susceptible or S2 (18 clones) and most susceptible or S3 (nin e clones). Clone '110120' of Tennessee was most resistant where as Oklahoma clone '104' was most susceptible to this pest. Amongst the most resistant clones (R1), only three clones, WSL-4, WSL-12 and WSL-18 (source: WIMCO See dlings Ltd, India) were found to be superior, in terms of growth increment, as compared to the standard and most widely planted clones in northern Ind ia i.e. G-3 and G-48, and are promising clones for plantation in defoliator prone areas.