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Performance of Seed Treatments Applied on Bt and Non-Bt Maize Against Fall Armyworm (Lepidoptera: Noctuidae)

Authors :
Daniela N. Godoy
Ivair Valmorbida
Oderlei Bernardi
Cínthia G Garlet
Matthew E. O'Neal
Dionei Schmidt Muraro
Gisele E Cossa
Regis F Stacke
Source :
Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual), Universidade de São Paulo (USP), instacron:USP
Publication Year :
2020
Publisher :
Oxford University Press (OUP), 2020.

Abstract

Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), is the main pest of maize in Brazil, attacking plants from emergence to reproductive stages. Here, we conducted studies to evaluate the efficacy of two seed treatments (chlorantraniliprole alone and imidacloprid combined with thiodicarb) on Bt and non-Bt maize in laboratory bioassays with distinct FAW strains that are susceptible, selected for resistance to Bt-maize single (Cry1F) or pyramided (Cry1A.105 + Cry2Ab2) events and F1 hybrids of the selected and susceptible strains (heterozygotes), and in the field against a natural infestation. In the laboratory, leaf-discs from seed treated Bt-maize plants at 7 d after emergence (DAE) increased the mortality of FAW resistant, heterozygote, and susceptible strains up to 24.8%, when compared with the respective maize grown without a seed treatment. In the field against natural infestations of FAW, Bt maize with a seed treatment had ~30% less FAW damage than non-Bt maize with the same seed treatment at 7 and 14 DAE. No differences in FAW damage was observed between Bt and non-Bt maize grown with and without a seed treatment at 21 DAE. Maize seeds treated with chlorantraniliprole alone or imidacloprid and thiodicarb combined presented limited protection against early infestations of FAW strains under laboratory and field studies.

Details

ISSN :
19382936 and 0046225X
Volume :
49
Database :
OpenAIRE
Journal :
Environmental Entomology
Accession number :
edsair.doi.dedup.....f5fded4098cb72904af2c29bec85cb3c
Full Text :
https://doi.org/10.1093/ee/nvaa088