Yield Losses in Transgenic Cry1Ab and Non-Bt Corn as Assessed Using a Crop-Life-Table Approach

• Published in: Journal of economic entomology Vol. 111; no. 1; pp. 218 - 226
• Main Authors: Silva, Gerson A, Picanço, Marcelo C, Ferreira, Lino R, Ferreira, Dalton O, Farias, Elizeu S, Souza, Thadeu C, Rodrigues-Silva, Nilson, G. Pereira, Eliseu José
• Format: Journal Article
• Language: English
• Published: US Entomological Society of America 09-02-2018; Oxford University Press
• Subjects: Abundance; Agricultural production; Animals; Arthropoda; Arthropods; Bacterial Proteins - adverse effects; Bacterial Proteins - pharmacology; Brazil; Bt toxin; Butterflies & moths; Corn; corn earworm; Cultivars; Diptera - drug effects; Diptera - growth & development; Endotoxins - adverse effects; Endotoxins - pharmacology; fall armyworm; FIELD AND FORAGE CROPS; Grain; Helicoverpa zea; Hemolysin Proteins - adverse effects; Hemolysin Proteins - pharmacology; Herbivory - drug effects; Hybrids; Insecticides - adverse effects; Insecticides - pharmacology; Insects; Larva - drug effects; Larvae; Lepidoptera; Life Tables; maize; Moths - drug effects; Moths - growth & development; Natural enemies; natural enemy; Pest control; Pest Control, Biological; Plants, Genetically Modified - growth & development; Predatory Behavior; silk fly; Spodoptera frugiperda; Toxins; Vegetables; Zea mays - growth & development; natural enemy; silk fly; maize; Bt toxin; corn earworm; fall armyworm
• ISSN: 0022-0493; 1938-291X
• DOI: 10.1093/jee/tox346

In this study, we constructed crop life tables for Bacillus thuringiensis Berliner (Bt) Cry1Ab and non-Bt corn hybrids, in which yield-loss factors and abundance of predaceous arthropods were recorded during 2 yr at two locations. Corn kernel/grain was the yield component that had the heaviest losses and that determined the overall yield loss in the corn hybrids across years and locations. Yield losses in both corn hybrids were primarily caused by kernel-destroying insects. Helicoverpa zea (Boddie) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) were the key loss factors at one location, while at the other, the key loss factor was the silk fly larvae, Euxesta spp. (Diptera: Ulidiidae). Although the realized yield of corn grains was not different (P > 0.05) between Cry1Ab and non-Bt corn hybrids, the Bt corn hybrid reduced (P < 0.05) the damage by H. zea and S. frugiperda in three of the four field trials, particularly at the location where Lepidoptera were the key loss factors. As expected, no reduction in the abundance of predaceous arthropods was observed in Cry1Ab corn fields. Various species of natural enemies were recorded, particularly the earwig Doru luteipes (Scudder) (Dermaptera: Forficulidae), which was the most abundant and frequent predaceous insect. These results indicate that integration of pest management practices should be pursued to effectively minimize losses by kernel-destroying insects during corn reproductive stages when growing non-Bt or certain low-dose Bt corn cultivars for fall armyworm and corn earworm, such as those producing Cry1Ab or other Cry toxins.