Assessing the efficacy and persistence of rosemary oil as a miticide/insecticide for use on greenhouse tomato

Efficacy of rosemary essential oil was assessed against two-spotted spider mites (Tetranychus urticae) and greenhouse whiteflies (Trialeurodes vaporariorum) as well as its effects on the tomato host plant and bio-control agents. Laboratory bioassay results indicated that pure rosemary oil and EcoTrol ™ (a rosemary oil-based pesticide) caused complete mortality of spider mites and whiteflies at concentrations that are not phytotoxic to the host plant. The predatory mite, Phytoseiuluspersimilis, is less susceptible to rosemary oil and EcoTrol™ than twospotted spider mites both in the laboratory and the greenhouse, whereas the parasitic wasp, Encarsia formosa, is more susceptible to rosemary oil than whiteflies. Rosemary oil repels both spider mites and whiteflies and can affect oviposition behavior. Rosemary oil and rosemary oil-based pesticides are non-persistent in the environment and their lethal and sub-lethal effects fade within one or two days. EcoTrol ™ is safe to tomato foliage, flowers and fruits even at double the recommended label rate. A greenhouse trial indicated that a single application of EcoTrol ™ at its recommended label rate could reduce a twospotted spider mite population by 52%. At that rate, EcoTrol™ did not cause any mortality among predatory mites Phytoseiulus persimilis nor did it affect their eggs. Toxicity of individual and incomplete mixtures of constituents of rosemary oil to spider mites indicated significant synergy among the constituents. Highest mortality was only obtained when all constituents were present in the mixture. In general, EcoTrol ™ was found to be a suitable option for small-scale IPM programs for controlling spider mites and whiteflies in greenhouse tomato plants.Land and Food Systems, Faculty ofGraduat