HOST PLANT PREFERENCE FOR LOOPER CATERPILLAR ON THREE CLONAL VARIETIES (TV1, TV18, AND TV25) OF TEA FROM DARJEELING FOOTHILLS

Tea is one of major cash crop of Darjeeling foothills and adjoining areas. Herbivore Insects prefer to feed on that sort of food to which it can best suit. The nutritive quality of tea plant is probably seldom optimal in terms of meeting the herbivores nutritional requirements. The present study reveals that the late instar of looper caterpillar prefers to feed on TV1, variety specifically on 3rd and 4th mature leaves. The percentage study also revealed the presence of non-digestible matter mostly in 3rdand4thleaf of TV1.The feeding of the 1stinstar caterpillar which among the 3 varieties feed in least quantity on TV1. TV1 leaves are known to contain tough fibres rather than TV18and TV25. One reason regarding the non-preference of TV1 may be due to its poorly developed jaw apparatus of the earlier instars to appropriate foliage with tough fibers. Whereas in case of middle instar preference to TV25 has been found as compared to TV1and TV18.Though the cellulose content of the 3rd& 4th leaves of TV18 is alike or higher than TV25 but may be due feeding stimulant or some other reasons the middle instars have to prefer the leaves of TV25 than TV1 and TV18. So, a study of host plant selection and basis of selection plays a significant role in phytophagous insects for better utilization of their resources.