Vegetable oil formulation as biopesticide to control California red scale (Aonidiella aurantii Maskell)

During laboratory tests, mineral oil in water emulsion (2%), containing Brassicaceae seed meals (2 g l⁻¹), induced total mortality (100%) among adult female California red scales on detached orange fruits, whereas only 47.5% of insect mortality was observed with the same mineral oil when used alone. These results were partially confirmed by two preliminary field trials. With the aim of improving biodegradability and the environmental impact of the insecticidal formulation, mineral oil was replaced by a vegetable oil without observing any significant variation of the product’s efficacy. In addition, a clear “dose-effect” of meal in mineral and vegetable oil was also demonstrated. The formulation, essentially based on oil, meals and some minor additives, shows the following advantages: (1) high insecticidal activity against an insect pest difficult to control such as Aonidiella aurantii (Maskell); (2) simultaneous control of several pathogens seems to be possible; (3) non-appearance of resistance phenomena in plant pathogens; and finally, (5) absence of phytotoxicity.