Description

Cotton and wheat are the major cash crops of Pakistan and mainly cotton-wheat crop rotation is followed in the Punjab province of Pakistan. Aphid (Aphis gossypii) attacks on both of these crops including wheat (Triticum aestivum) and cotton (Gossypium hirsutum). Lady bird beetle Coccinella septempunctata is the local key predator of aphid. Food preference of predator C. septempunctata towards different kinds of aphid and semio-chemical effect of different crops including cotton (Gossypium hirsutum) , wheat (Triticum aestivum), brassica (Brassica oleracea), dumbi siti (Phalaris minor) and oat (Avena sativa) on aphid were studied by using olfacto-meter. From the results it is clear that cotton, wheat and brassica are the natural host plants of aphid but other tested plants are factitious hosts. Preference of C. septempunctata is also more on cotton and wheat aphid followed by brassica crop and brassica aphid, however there is further need to explore the role of semio-chemicals that may affect the food preference of predator.