Trichogramma pretiosum Riley is an important parasitoid of heliothis (Helicoverpa spp.) eggs throughout the Darling Downs. In the past heliothis have been managed using broad spectrum insecticides such as pyrethroids and organophosphates. These insecticides usually cause high mortality of Trichogramma and other beneficial insects. Increasingly farmers and consultants are looking for soft chemistry to control pests without killing the beneficial arthropods in the farming system. Paraffin oils are now being explored as an option to control heliothis in cotton without causing high mortality of beneficial arthropods. Trichogramma are particularly sensitive to chemical insecticides and can act as bioindicators of the toxicity of insecticidal products. If an insecticide does not impact on Trichogramma it is likely that it will be conducive to most of the beneficial fauna in the farm ecosystem. This report documents the impact of two paraffin oils (Biopest' and Canopy') on Trichogramma pretiosum during larval, pupal and adult stages of development.