Current situation of pests targeted by Bt crops in Latin America

BLANCO, C. A; FARIAS, J. R; CHIARAVALLE, W; MOTA SANCHEZ, D; GARCÍA DEGANO, M. F.; PIERALISI, B. K; MURUA, M. G.; RODRIGUEZ, J.; TERÁN-SANTOFIMIO, H.; DALLA-RIZZA, M.; TERÁN-VARGAS, A. P.; WILLINK, E.; GASTAMINZA, G. A.; OMOTO, C.; RODRIGUEZ- MACIEL, J,C. ; VALENCIA, S. J.

INSECT SCIENCE

WILEY-BLACKWELL PUBLISHING, INC

Año: 2016 vol. 15 p. 131 - 138

1672-9609

Transgenic crops producing Bacillus thuringiensis- (Bt)insecticidal proteins (Bt crops) have provided useful pestmanagement tools to growers for the past 20 years. Planting Btcrops has reduced the use of synthetic insecticides on cotton,maize and soybean fields in 11 countries throughout LatinAmerica. One of the threats that could jeopardize thesustainability of Bt crops is the development of resistance bytargeted pests. Governments of many countries requirevigilance in measuring changes in Bt-susceptibility in order toproactively implement corrective measures before Btresistanceis widespread, thus prolonging the usefulness of Btcrops.A pragmatic approach to obtain information on theeffectiveness of Bt-crops is directly asking growers, cropconsultants and academics about Bt-resistance problems inagricultural fields, first-hand information that not necessarilyrelies on susceptibility screens performed in laboratories. Thistype of information is presented in this report.Problematicpests of cotton and soybeans in five Latin Americancountries currently are effectively controlled by Bt crops.Growers that plant conventional (non-Bt) cotton orsoybeans have to spray synthetic insecticides againstmultiple pests that otherwise are controlled by these Btcrops. A similar situation has been observed in six LatinAmerican countries where Bt maize is planted. No syntheticinsecticide applications are used to control corn pestsbecause they are controlled by Bt maize, with the exceptionof Spodoptera frugiperda. While this insect in somecountries is still effectively controlled by Bt maize, in othersresistance has evolved and necessitates supplementalinsecticide applications and/or the use of Bt maize cultivarsthat express multiple Bt proteins. Partial control of S.frugiperda in certain countries is due to its natural toleranceto the Bt bacterium. Of the 31 pests targeted and controlledby Bt crops in Latin America, only S. frugiperda has showntolerance to certain Bt proteins in growers? fields, the mostreliable indication of the status of Bt-susceptibility in most ofthe American continent.