Efficacy and market potential of biopesticides developed from saponins and essential oils

Citation

Nicol, R., M. Berhow, M. Charbonneau, I. Scott, K. Tamming, S. Lachance. 2022. Efficacy and market potential of biopesticides developed from saponins and essential oils. Poster presentation at the Ontario Pest Management Conference, Guelph, November 1, 2022.

Plain language summary

Plant natural products have been identified as sources of bioactive compounds used as medicines and pesticides. In Ontario, agri-food waste streams, including tomato skins and pea processing waste have been identified as an appreciable source of natural chemicals, including saponins. The objective of the collaborative project between Lambton College, Sarnia ON, the University of Guelph, Ridgetown ON and AAFC London was to investigate saponins as biopesticides against greenhouse pests and diseases. The saponin preparations caused mortality in two-spotted spider mites larvae and reduced the in vitro growth of several important plant pathogens. In greenhouse experiments where tomato plants were inoculated with a fungus, saponins reduced disease symptoms, reduced plant mortality and had no effect on plant biomass or tomato harvest. Saponins likely exert their anti-fungal effects by disrupting the fungal membrane, but future research will explore the possibility that saponins induce host resistance.

Abstract

The global market for biopesticides, crop protection products based on living microbes, microbial products or plant natural chemicals, is predicted to represent 20% of total pesticide use in 2025. For those biopesticides that are based on plant chemicals, the chemical active ingredient generally falls within the category of vegetable oils and fatty acids, or small molecules also known as secondary plant metabolites. We are evaluating the use of saponins and essential oils, secondary metabolites found in a variety of plants, as active ingredients in innovative biopesticide formulations. The effect of essential oils on behaviour and mortality of melon aphid, Aphis gossypii, was assessed in a fumigant bioassay. The antifungal activity of saponins and hop essential oils, alone and as mixtures, was assessed using in vitro as well as using whole plant bioassays. Hop essential oil and, to a lesser extent, geranium essential oil, were found to have a profound effect on the behavior of aphids on cucumber plants, in addition to causing aphid mortality at higher doses. Saponins and essential oils were found to have in vitro antifungal activity against a broad range of fungal pathogens and were also found to protect tomato plants from infection by Fusarium oxysporum. The extrapolated retail value of new saponin and essential oil biopesticides for use in Canadian strawberry production alone was estimated to be potentially over $3 million annually. Additional tests of the fumigant effects and antifungal activity should be conducted in a commercial greenhouse setting.

Publication date

2022-11-01

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