ORIENTATION RESPONSE OF OXYA NITIDULA (WALKER) TO SOME RICE CULTIVARS

Experiments were conducted to evaluate the orientation response of Orya nitidula (Walker) the small rice grasshopper in response to the odours of different rice cultivars First instar nymphs were used for this investigation. The insects were subjected to cut plants as well as Intact plants of six rice cultivars in a mixed combination basis. The six cultivars were IR50, TRYI, co43, ASD17, TKM9 and TKM11. An orientation chamber was devised and the insect was introduced into the chamber to observe its orientation towards the plant odeurs. It was interesting to note that more than 50% insects responded to that particular side of the chamber, where the cut plants were placed. This reflects the fact that insects were more attracted towards the internal chemicals of the plants than the surface chemicals.