Occurrence of maize detritus and a transgenic insecticidal protein (Cry1Ab) within the stream network of an agricultural landscape.
Widespread planting of maize throughout the agricultural Midwest may result in detritus entering adjacent stream ecosystems, and 63% of the 2009 US maize crop was genetically modified to express insecticidal Cry proteins derived from Bacillus thuringiensis. Six months after harvest, we conducted a synoptic survey of 217 stream sites in Indiana to determine the extent of maize detritus and presence of Cry1Ab protein in the stream network. We found that 86% of stream sites contained maize leaves, cobs, husks, and/or stalks in the active stream channel. We also detected Cry1Ab protein in stream-channel maize at 13% of sites and in the water column at 23% of sites. We found that 82% of stream sites were adjacent to maize fields, and Geographical Information Systems analyses indicated that 100% of sites containing Cry1Ab-positive detritus in the active stream channel had maize planted within 500 m during the previous crop year. Maize detritus likely enters streams throughout the Corn Belt; using US Department of Agriculture land cover data, we estimate that 91% of the 256,446 km of streams/rivers in Iowa, Illinois, and Indiana are located within 500 m of a maize field. Maize detritus is common in low-gradient stream channels in northwestern Indiana, and Cry1Ab proteins persist in maize leaves and can be measured in the water column even 6 mo after harvest. Hence, maize detritus, and associated Cry1Ab proteins, are widely distributed and persistent in the headwater streams of a Corn Belt landscape.
Tank
Jennifer L
JL
Department of Biological Sciences, University of Notre Dame, Notre Dame, IN 46556, USA. tank.1@nd.edu
Rosi-Marshall
Emma J
EJ
Royer
Todd V
TV
Whiles
Matt R
MR
Griffiths
Natalie A
NA
Frauendorf
Therese C
TC
Treering
David J
DJ
D000383:Agriculture; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000032:analysis*; D004731:Endotoxins / Q000032:analysis*; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D040362:Geographic Information Systems; D006460:Hemolysin Proteins / Q000032:analysis*; D007196:Indiana; D007306:Insecticides / Q000032:analysis*; D035261:Plant Components, Aerial / Q000737:chemistry*; D030821:Plants, Genetically Modified / Q000235:genetics*; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D003313:Zea mays / Q000235:genetics*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D014874:Water Pollutants, Chemical; C030956:insecticidal crystal protein, Bacillus Thuringiensis