Premium
Geographical distribution of Vip3Aa20 resistance allele frequencies in Spodoptera frugiperda (Lepidoptera: Noctuidae) populations in Brazil
Author(s) -
Amaral Fernando S A,
Guidolin Aline S,
Salmeron Eloisa,
Kanno Rubens H,
Padovez Fernando E O,
Fatoretto Júlio C,
Omoto Celso
Publication year - 2020
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.5490
Subject(s) - spodoptera , noctuidae , biology , lepidoptera genitalia , fall armyworm , crop , genotype , allele , pest analysis , pesticide resistance , veterinary medicine , agronomy , botany , genetics , gene , pesticide , medicine , recombinant dna
BACKGROUND The use of Bt plants has been the main strategy for controlling the fall armyworm Spodoptera frugiperda (J. E. Smith) in Brazil. However, many resistance cases were already registered. The resistance of S. frugiperda to the Vip3Aa20 protein was recently characterized under laboratory conditions but it is still efficient under field conditions. Here, resistance monitoring studies were conducted using phenotypic (purified protein and Bt maize leaves) and genotypic (F 1 and F 2 screen) methods to support insect resistance management (IRM) programs and preserve Vip3Aa20 technology on maize. RESULTS Phenotypic monitoring with purified protein showed two populations significantly different from the susceptible strain on the second crop season in 2016. This number increased for the first and second crop seasons in 2017 in several regions. The genotypic monitoring estimated a mean frequency of the resistance allele of 0.0027 for the F 1 screen and 0.0033 for the F 2 screen. Three new resistant strains to Vip3Aa20 were selected from F 2 screen assays. Complementation tests on these new resistant strains were positive with the previous resistant strain. CONCLUSION Here we showed that the resistance allele of S. frugiperda to Vip3Aa20 protein is widely distributed in maize‐producing regions in Brazil and its frequency increases throughout crop seasons. © 2019 Society of Chemical Industry