Choosing Organic Pesticides over Synthetic Pesticides May Not Effectively Mitigate Environmental Risk in Soybeans

School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada.
PLoS ONE (Impact Factor: 3.23). 06/2010; 5(6):e11250. DOI: 10.1371/journal.pone.0011250
Source: PubMed


Selection of pesticides with small ecological footprints is a key factor in developing sustainable agricultural systems. Policy guiding the selection of pesticides often emphasizes natural products and organic-certified pesticides to increase sustainability, because of the prevailing public opinion that natural products are uniformly safer, and thus more environmentally friendly, than synthetic chemicals.
We report the results of a study examining the environmental impact of several new synthetic and certified organic insecticides under consideration as reduced-risk insecticides for soybean aphid (Aphis glycines) control, using established and novel methodologies to directly quantify pesticide impact in terms of biocontrol services. We found that in addition to reduced efficacy against aphids compared to novel synthetic insecticides, organic approved insecticides had a similar or even greater negative impact on several natural enemy species in lab studies, were more detrimental to biological control organisms in field experiments, and had higher Environmental Impact Quotients at field use rates.
These data bring into caution the widely held assumption that organic pesticides are more environmentally benign than synthetic ones. All pesticides must be evaluated using an empirically-based risk assessment, because generalizations based on chemical origin do not hold true in all cases.

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    • "This result was not completely unexpected because the total TFI values were similar between these three management strategies . In addition some insecticides used in organic orchards are broad-spectrum insecticides such as spinosad or pyretre (Bahlai et al. 2010). The two microbial insecticides, granulosis virus and Bacillus thuringiensis, mainly used under organic management strategies, are expected to have a low direct toxicity towards spider (Bajwa and Aliniazee 2001). "
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    • "Natural products are valuable for crop protection as stand-alone insecticides, or as templates for development of more efficacious synthetic insecticides. Nonetheless, the common perception that bioinsecticides are safer for humans and the environment due to their (natural) origin and consequently should benefit from ''fast-track'' registration is disputable (Coats, 1994; Kidd, 2000; Bahlai et al., 2010). Spinosad is a bioinsecticide made from spinosyns, which is generated as a fermentation product from the actynomycete species Saccharopolyspora spinosa (Mertz & Yao) (Sparks et al., 2001). "
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    • "Various pest and pathogen control measures are recommended to minimize damage , among which chemical control measures have been reported to be most effective. However, the side effects of these measures, such as insecticide resistance (Callaghan 1991; Matsumura & Sanada-Morimura 2010; Che et al. 2013), pest resurgence (Hardin et al. 1995), environmental pollution (Bahlai et al. 2010) and harm to natural enemies (Baur et al. 2003; Ohnesorg et al. 2009; Frewin et al. 2012; Macfadyen & Zalucki 2012), have increased in recent years. Therefore, nonchemical control technologies are now recommended, and an integrated pest management (IPM) strategy is widely accepted as an optimal strategy to control pest and pathogen problems in soybean fields (Brier et al. 2008). "
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