Location: Screwworm ResearchTitle: Non Target Effect of Cry1 Ab and Cry Ab x Cry3 Bb1 Bt Transgenic Maize on Orius Insidiosus (Hemiptera: Anthocoridae) Abundance) Author
Submitted to: Entomology, Ornithology, & Herpetology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/28/2013
Publication Date: 7/1/2013
Citation: Palizada, S.A., Belay, D.K., Tiroesele, B., Mustafa, F., Ullah, M.I., Hunt, T., Molina-Ochoa, J., Skoda, S.R., Clark, P.L., Foster, J.E. 2013. Non Target Effect of Cry1 Ab and Cry Ab x Cry3 Bb1 Bt Transgenic Maize on Orius Insidiosus (Hemiptera: Anthocoridae) Abundance. Entomology, Ornithology, & Herpetology. 2:2. Interpretive Summary: Developing crop varieties that are resistant to pest insects has been a practice of society ever since humans developed agriculture. This practice has reached new levels with the development and commercial release of genetically modified crops. Corn has been genetically modified to resist insect pests by inserting genes from bacteria; this corn is commonly called Bt corn. Many studies have been done to prove the effectiveness of Bt corn against pests, but relatively few have been done to determine if the non-target, beneficial insects are adversely affected. Here we compared the effect of two types of Bt corn, untreated corn and corn treated with two types of insecticides, on the abundance of a general insect predator called the insidious flower bug. We determined the number of insidious flower bugs by visual observations, collecting five corn plants and counting all insidious flower bugs, and by collecting them on sticky cards from all five treatment types of corn. The experiments were replicated at three locations over two years. Results showed that the Bt corn had no negative impact compared to untreated corn on the insidious flower bug. One of the insecticides had a significant negative impact on the insidious flower bug at all three locations over both years, while the other insecticide had a variable, negative impact. We concluded that using Bt corn to control pest insects has no impact on this non-target pest and less negative impact on the general environment.
Technical Abstract: Non-target effects of Cry1Ab x CP4 EPSPS and Cry1Ab + Cry3Bb1 x CP4 EPSPS Bt transgenic new maize hybrids on insidious flower bugs [Orius insidiosus (Say)] was studied in Nebraska (Mead, C lay Center, and Concord) during 2007 and 2008. The Bt effect was compared to CP4 EPSPS maize (isoline), conventional maize, and insecticide applications of permethrin (Pounce® 1.5G) and bifenthrin (Capture® 2EC) to control first and second generations of Ostrinia nubilalis (Hübner), respectively. Yellow sticky cards, visual observations, and destructive samplings were used to evaluate O. insidiosus abundance. The yellow sticky card data in 2007 showed that O. insidiosus abundance was lower on Pounce® 1.5G treated non-Bt isoline maize plots compared to the Bt transgenic hybrids at 60 and 90 days after planting (DAP). From visual observations, numbers of O. insidiosus were lower in Pounce® 1.5G treated plots and no adverse effects of the Bt hybrids was observed. In 2008, no significant differences were found among treatments in the sticky card data, but the O. insidiosus population significantly increased with increasing DAP, where the lowest and highest numbers were recorded at 30 and 120 DAP, respectively. In the visual observation and destructive samplings, numbers of O. insidiosus were lower at Concord compared to other sites. Results from the visual observation data in 2008 also revealed that O. insidiosus abundance was lower on Pounce® 1.5G treated plots compared to other treatments. This study showed no adverse effects of the new Bt transgenic hybrids that included stacked resistance genes on O. insidiosus compared to the non-Bt maize hybrids.