This project was based on the results of extensive research on fruits, ornamentals, vegetables and cotton (in NSW) in which the effectiveness of petroleum-derived spray oils (PDSOs) on insect and mite pests has been unequivocally demonstrated. Oils kill susceptible pests through suffocation (e.g., mites, thrips, aphids and scales). They also influence the feeding and oviposition behaviour of some pests that are not generally susceptible to suffocation (e.g., Helicoverpa armigera and H. punctigera). This has led to behavioural effects on a very broad range of pests becoming much more important than suffocation, the traditionally accepted mode of action, of a much narrower range of pests. Contemporary PDSOs classed as either horticultural mineral oils or agricultural mineral oils are not toxic and pose no threat to human health or the environment. Their impact on natural enemies is generally negligible and arthropod resistance to PDSOs has not been empirically demonstrated in over 100 years of use.