The silverleaf whitefly is characterised by a huge host range, high fecundity, the ability to induce physiological responses in plants, transmit plant viruses, the copious production of honeydew, and an extreme ability to develop insecticide resistance. The whitefly damages cotton crops by direct feeding (yield can be reduced by 60% under heavy infestation), copious production of honeydew (which contaminates cotton lint and reduces the photosynthetic efficiency of cotton leaves) and by virus transmission.

B-biotype B. tabaci came into Australia with insecticide resistance to most pyrethroids, organophosphates and carbamates. Explosion of the silverleaf whitefly into horticultural crops in north Queensland during the late 1990’s ensured development resistance to other insecticides (bifenthrin, endosulfan, amitraz and imidacloprid) to which they initially susceptible. Field selection experiments in horticultural crops in North Queensland (DAN 106C) showed a very rapid rate in the selection of resistance to insecticides.

At the commencement of this project, B-biotype B. tabaci was not a pest of cotton but was considered to be a major threat to the Australian cotton industry needing pre-emptive research. The aims of this project were therefore, to monitor silverleaf whitefly numbers on cotton, secondly to monitor insecticide resistance levels and to investigate novel insecticides and insecticides combinations as candidates for whitefly control. In December 2001, the silverleaf whitefly exploded on cotton in central Queensland and reached economically damaging levels.