The diamondback moth is the most destructive insect pest of brassica crops throughout the world. Reliance on chemicals as a control measure for the diamondback moth has resulted in the development of resistance to many insecticides. Resistance to synthetic pyrethroid insecticides has been detected in populations of diamondback moth in all Australian states. Since 1993, brassica growers in Victoria have had difficulty in controlling the caterpillars of diamondback moth and have experienced insecticide control failures. In extreme cases, damaged crops have been ploughed in and produce has been unmarketable.