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: 3.53). 06/2010; 5(6):e11250. DOI: 10.1371/journal.pone.0011250
Source: PubMed

ABSTRACT 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.

Download full-text


Available from: Art William Schaafsma, Jul 08, 2015
1 Follower
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Apple orchards are agro-ecosystems managed with high levels of inputs and especially pesticides. Epigeal spider communities were sampled in three seasons using pitfall traps in 19 apple orchards with four different management strategies (abandoned, under organic, Integrated Pest Management or conventional protection) and thus significantly different pesticide usage. The abundance and diversity of the spider communities was the highest in abandoned orchards. Higher diversity and evenness values were the only difference in spider communities from the organic orchards compared to the other commercial orchards. The analysis of five ecological traits (proportion of aeronauts, type of diet, overwintering stages, body size and maternal care), however, clearly showed differences in the spiders from the organic orchards. The spider species in the other commercial orchards were smaller and have higher dispersal abilities. Seven bioindicator species were identified in abandoned orchards, two species in organic ones (only Lycosidae) and one species in conventional orchards (Linyphiidae).
    Ecotoxicology 01/2015; 24(3). DOI:10.1007/s10646-014-1409-1 · 2.50 Impact Factor
  • Source
    • "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). "
    [Show abstract] [Hide abstract]
    ABSTRACT: The risks imposed by novel insecticides, mainly bioinsecticides, are largely unknown despite their increased use and their perceived environmental safety, which is based on their natural origin. Furthermore, unlike honeybees, native pollinator species have received little attention. In the present study, the lethal and sublethal effects of the neonicotinoid imidacloprid and the bioinsecticide spinosad were assessed in the stingless bee species Melipona quadrifasciata, an important native pollinator in the Neotropical region. The adult stingless bee workers exhibited high oral insecticide susceptibility, with LD50s of 23.54 and 12.07 ng a.i./bee for imidacloprid and spinosad, respectively. Imidacloprid also impaired worker respiration and overall group activity and flight, while spinosad significantly impaired only worker flight despite exhibiting higher oral toxicity to adult workers than imidacloprid. These findings indicate the hazardous nature not only of imidacloprid but also the bioinsecticide spinosad to adult workers of the native pollinator M. quadrifasciata. Therefore, bioinsecticides should not be exempted from risk assessment analysis due to their lethal and sublethal components.
    Chemosphere 12/2014; 121. DOI:10.1016/j.chemosphere.2014.11.038 · 3.50 Impact Factor
  • Source
    • "- tional studies are warranted to determine if increased biological control services in reduced - risk program may eventually narrow this gap over time . However , sublethal reproductive and developmental effects of some reduced - risk pesticides may also minimize or inhibit such increases in biological control services ( Biddinger and Hull 1995 , Bahlai et al . 2010 , He et al . 2012 , Planes et al . 2012 , Biondi et al . 2013 ) ."
    [Show abstract] [Hide abstract]
    ABSTRACT: We developed new integrated pest management programs for eastern U.S. peaches with minimal use of organophosphates. From 2002‐2005, we assessed the ecological impacts of these reduced-risk programs versus grower standard conventional programs that still relied primarily on the use of organophosphorous and carbamate insecticides. Using a split-plot design replicated at four commercial Pennsylvania peach orchards, we quantified pesticide rates, environmental impact, and arthropod community response. We used Environmental Impact Quotient (EIQ) analysis based on the growers' pesticide records from each orchard to calculate seasonal cumulative EIQ field ratings for all years. Ecological effects of the reduced-risk and conventional program were also measured as the abundance and diversity of nontarget arthropod predators, parasitoids, and selected pest taxa. Pesticide inputs and EIQ values were substantially lower in reduced-risk programs compared with conventional spray programs. Arthropod arrays differed significantly between pest management programs: most beneficial predator and parasitoid taxa were positively associated with the reduced-risk program and negatively associated with the standard grower program. Regardless of the pest management program, we observed significant differences in species arrays in the peach tree canopy compared with the ground cover of the orchards, but the arthropod community did not differ among the field sites or based on distance from the edge of the orchard. We conclude that reduced-risk programs not only provide control comparable with that of conventional programs, but they also reduce negative environmental effects while conserving key arthropod biological control agents within eastern U.S. peach orchards.
    Journal of Economic Entomology 06/2014; 107(3). DOI:10.1603/EC13441 · 1.61 Impact Factor