Submitted to: Plant and Soil
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 19, 2010
Publication Date: April 13, 2010
Citation: Lehman, R.M., Osborne, S.L., Prischmann-Voldseth, D., Rosentrater, K.A. 2010. Insect-Damaged Corn Stalks Decompose at Rates Similar to Bt-Protected, Non-Damaged Corn Stalks. Plant and Soil Journal. 333:481-490. DOI 10.1007/s11104-010-0364-8. Interpretive Summary: We investigated potential differences in plant residues from Bt corn hybrids and non-Bt hybrids that were cultivated under insect pressure from corn rootworms or corn borers. We found no differences between Bt and non-Bt corn hybrids in the above ground biomass produced or the relative decomposability, composition, and physical strength of the residues. We conclude that while individual hybrids may vary in their residue composition, stalk strength, and decomposability, these characteristics do not systematically vary with the presence of the Bt gene, even under conditions of insect pressure.
Technical Abstract: The relative decomposability of corn (Zea mays L.) residues from insect (Bt)-protected hybrids and conventional hybrids cultivated under insect pressure was investigated in two studies. Above-ground biomass, residue macromolecular composition, and stalk physical strength were also measured. In the first decomposition study, chopped residues (stalks and leaves) were used from a corn rootworm-protected (Cry3Bb1) hybrid and its non-Bt near isoline that were grown in replicated plots infested with corn rootworms (Diabrotica spp.). In the second study, residue (intact stalk sections) was used from three European Corn Borer (ECB, Ostrinia nubilalis Hübner)-resistant (Cry1Ab) hybrids representing different seed manufacturer/maturity date series, their non-Bt near isolines, two Cry3Bb1-protected isolines, and three additional conventional hybrids, all cultivated in replicated plots under conditions of elevated ECB pressure. In both studies, insect-resistant residues decomposed at rates similar to their non-protected near isolines. No evidence was found that insect-protected hybrids produced more above-ground biomass, or had distinct residue composition, or had physically-stronger stalks than unprotected hybrids. We conclude that while individual hybrids may vary in their residue composition, stalk strength, and decomposability, these characteristics do not systematically vary with the presence of the Bt gene, even under conditions of insect pressure.