Bemisia tabaci is a serious agricultural pest and vector of many economically important plant viruses worldwide. We studied the role of alternate host plants in carry-over of B. tabaci to cotton crop in Punjab province of India. One hundred thirteen plants in twenty nine families harboured the whitefly, but plants in Asteraceae, Cucurbitaceae, Fabaceae, Solanaceae and Malvaceae were preferred hosts. During winter months, vegetables Solanum melongena, Solanum tuberosumm, Ipomoea batatus and perennial weeds namely Abutilon indicum, Solanum nigrum and Xanthium strumarium played major role in the overwintering of the pest. Cucurbits, S. melongena, Solanum lycopersicum, Abelmoschus esculentus and Vigna radiata had the highest potential for harbouring B. tabaci during spring season and carry- over of the pest to cotton crop. We recommended that weed hosts that harbour the B. tabaci should be removed, whereas cucurbits, brinjal, tomato, okra and moong should be monitored regularly during spring season. The insecticides should be applied sparingly on spring hosts to prevent population buildup and to reduce carry-over of B. tabaci to cotton and other kharif crops in north western India.