author(s)
Bismillah Shah, Faisal Ayub, Nazeer Ahmed

abstract
To study the population dynamics of aphids on turnip (brassica rapa) in Peshawar, the present research work was carried out at New Developmental Farm (Malakandher), The University of Agriculture, Peshawar during 2014. Turnip Brassica rapa subsp. rapa (Brassicaceae: Brassicales) is a root vegetable commonly grown in temperate climates worldwide for human consumption and as feed for livestock. It is an herbaceous annual or biennial plant in the family Brassicaceae grown for its edible roots and leaves. The turnip's root is high in vitamin C. The green leaves of the turnip top are a good source of vitamin A, folate, vitamin C, vitamin K and calcium. Losses occur in turnips are due to weeds, diseases, predators, and insects. Weeds are generally not a problem once the turnip crop is established. Flea beetles, Wireworms and Root maggots. Besides these the most serious pest of the Turnip is the Turnip aphid Lipaphis erysimi Kaltenbach (Aphididae: Homoptera). The aphid population generally makes its appearance sometimes during winter and it continues to breed parthenogenetically till the end of spring when winged individuals are produced and large-scale dispersal takes place. From the experiment, it was concluded that the aphids appear and fluctuate throughout during the growing season. Overall mean density of aphids was higher on Purple Top White Globe of Jerryseeds (Pak.) than on Purple Top White Globe of Chriseeds (USA).