title: A multi-year field study to evaluate the environmental fate and agronomic effects of insecticide mixtures.
abstract: A mixture of insecticides used in corn production was monitored over a three-year period in a field study to determine how long each persists in the environment, where each insecticide travels within the corn field, and the efficacy of using soil-applied insecticides with genetically modified corn. The genetically modified corn contained the insecticidal Cry1Ab and Cry3Bb1 proteins (Bt corn) and the Cry1Ab protein was found to persist only during the corn growing season in soil, runoff water, and runoff sediment with highest concentrations measured during pollination. Very low concentrations of Cry1Ab proteins were measured in soil collected in the non-Bt corn field, and no Cry1Ab proteins were detected in shallow groundwater or soil pore water. Clothianidin, a neonicotinoid insecticide used as a seed coating, was detected in all matrices and remained persistent throughout the year in soil pore water. Tefluthrin, a pyrethroid insecticide applied at planting to control corn rootworm larvae (Diabrotica spp., Coleoptera: Chrysomelidae) populations, was consistently detected in soil, runoff water, and runoff sediment during the corn growing season, but was not detected in groundwater or soil pore water. Tefluthrin did not have an effect on root damage from corn rootworm larvae feeding to Bt corn, but did prevent damage to non-Bt corn. A slight reduction in grain yield was observed in the non-Bt, no tefluthrin treatment when compared to all other treatments, but no significant difference in grain yield was observed among Bt corn treatments regardless of soil insecticide application. In the current study, the use of tefluthrin on Bt corn did not significantly affect crop damage or yield, and tefluthrin may travel off-site in runoff water and sediment.
authors.affiliation: Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: whitings@abclabs.com.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Whiting
authors.affiliation: Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: katie.strain@siu.edu.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Strain
authors.affiliation: Plant, Soil, and Agricultural Systems Department, 1205 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: lacampbell@dow.com.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Campbell
authors.affiliation: Plant, Soil, and Agricultural Systems Department, 1205 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: bryanyoung@purdue.edu.
authors.forename: Bryan G
authors.initials: BG
authors.lastname: Young
authors.affiliation: Center for Fisheries, Aquaculture, and Aquatic Sciences and Department of Zoology, 1125 Lincoln Dr., Southern Illinois University, Carbondale, IL 62901, USA. Electronic address: mlydy@siu.edu.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lydy
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000633:toxicity*; D001517:Coleoptera / Q000187:drug effects; D004731:Endotoxins / Q000633:toxicity*; D004777:Environment; D004784:Environmental Monitoring; D006460:Hemolysin Proteins / Q000633:toxicity*; D007306:Insecticides / Q000633:toxicity*; D007814:Larva / Q000187:drug effects; D030821:Plants, Genetically Modified; D012621:Seasons; D003313:Zea mays / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis
keywords: Clothianidin; Cry1Ab; Genetically modified corn; Insecticide; Tefluthrin