A review on the mode of action and current use of petroleum distilled spray oils

Abstract

Oils have a long history of effective use on fruit trees, with a good performance for pests small in size and restricted to a small area during its lifecycle. They are particularly effective against insects from the orders Lepidoptera and Hemiptera, as well as the non insect arthropods Acari. The action mechanisms identified as well the factors influencing the efficacy of these products on different insect species are discussed. Oils target multiple sites given that their toxicity is mainly due to narcosis, depending on the interaction between their properties with the insect characteristics. Their toxic effects include disruption of cuticle wax layer, cuticle softening, epidermal teratogenicity, tracheal blockage, receptor coating, deterrence and neurotoxicity, upon contact. A summary of database records indicates that petroleum distilled spray oils (PDSOs) are as current today as mineral oils were before the advent of broad spectrum insecticides. Future research should explore structure-toxicity relationships for each oil type, and standardize assessment methodology and experimental design to allow comparable results across insect taxa and oil types as well as providing a guide of recommended practices for PDSOs use against different pests.