Terpene based biopesticides as potential alternatives to synthetic insecticides for control of aphid pests on protected ornamentals

The biopesticide products tested gave statistically similar levels of control of M. persicae populations on pansy plants as the conventional synthetic insecticide flonicamid (500 g/kg active ingredient, formulated as a wettable granule) and spirotetramat (150 g/l active ingredient, formulated as an oil dispersion). All products reduced numbers of aphids by at least 85% during the experimental period. Orange oil also gave a similar speed of kill to flonicamid and was faster acting than spirotetramat, two conventional synthetic insecticides that are widely used to control aphid pests of ornamental crops. Against A. gossypii on Hebe, orange oil gave similar levels of control (90% reduction in aphid numbers) as flonicamid (98% reduction in aphid numbers), when applied with a spray interval of three days (as per label recommendation). The essential oil from Chenopodium ambrosioides variety nr. ambrosioides was not as effective as flonicamid but did significantly reduced (80% reduction in aphid numbers) numbers of A. gossypii on Hebe compared to a water control when applied with a spray interval of five days. Neem oil was not effective against A. gossypii. Importantly, there was little evidence of any phytotoxicity caused by any of the biopesticide products tested. The potential to use these products as part of an Insecticide Resistance Management (IRM) programme are discussed.