Current situation of pests targeted by Bt crops in Latin America

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

Current Opinion in Insect Science

Elsevier

Año: 2016

2214-5745

Bacillus thuringiensis-expressing (Bt) crops have been useful tools for growers for the past 20 years. Planting Bt crops has reduced the use of synthetic insecticides on cotton, maize and soybean fields in 11 countries of Latin America. One of the threats that could jeopardize the use of Bt crops is the development of resistance by certain pests to B. thuringiensis. Governments of many countries require vigilance of the levels of Bt-susceptibility in order to proactively implement corrective measures before Bt-resistance is widespread, thus prolonging the usefulness of Bt crops.A pragmatic approach to obtain information on the effectiveness of Bt-crops is directly asking growers, crop consultants and academics about Bt-resistance problems in agricultural fields, first-hand information that not necessarily rely on susceptibility screens performed in laboratories. This type of information is presented in this report.Problematic pests of cotton and soybeans in five Latin American countries currently are effectively controlled by Bt-crops. Growers that plant conventional (non-Bt) cotton or soybeans have to spray synthetic insecticides against multiple pests that otherwise are controlled by these Bt-crops. A similar situation has been observed in six Latin American countries where Bt-maize is planted. No synthetic insecticide applications are aimed to pests because they are controlled by Bt-maize, with the exception of Spodoptera frugiperda. While this insect in some countries is still effectively controlled by Bt-maize, in others necessitates supplemental insecticide applications and/or the use of Bt-maize cultivars that express multiple Bt proteins. Partial control of S. frugiperda in certain countries is due to its natural tolerance to the bacterium. Of the 31 pests targeted and controlled by Bt-crops in Latin America, only S. frugiperda has shown tolerance to certain Bt proteins in growers? fields, the most reliable indication of the current situation of Bt resistance in most of the American continent.