Spodoptera frugiperda

Resende, Daniela Chaves, Mendes, Simone Martins, Marucci, Rosangela C., Silva, Alessandra de Carvalho, Campanha, Mônica Matoso & Waquil, José Magid, 2016, Does Bt maize cultivation affect the non-target insect community in the agro ecosystem?, Revista Brasileira de Entomologia 60 (1), pp. 82-93 : 84

Abundance of S. frugiperda

The abundance of S. frugiperda larvae of different sizes collected in whorl samples was dependent on the location (N = 252, F = 1.56, p <0.05, Fig. 1 ). The abundance of S. frugiperda in the cornfield with Bt maize was lower in the three studied counties – Inhaúma, Três Corações and Nazareno. In Inhaúma, the difference occurred only for larvae with a body size smaller than 1 cm, in Três Corações,

Três Corações Iguatama Iraí de Minas Nazareno Varjão de Minas

Conv. crops Cry1Ab Cry1F Cry(1A105+2Ab2)

where the difference was for larvae smaller than 2 cm, and finally in Nazareno, where the conventional treatment showed higher abundance of S. frugiperda independent of larval size.

The treatment effects on frequency of the different larval sizes of S. frugiperda in the ears were significantly different among the sampling sites (N = 162, F = 1.96, p <0.01, Fig. 2). In Três Corações, for larvae smaller than 1 cm, the abundance of S. frugiperda was higher in the cornfield with conventional maize. For larvae larger than 2 cm, the abundance of S. frugiperda was higher in the conventional cornfield than in the field with Bt maize, except in the Bt cornfield with Cry1Ab protein. In Iraí de Minas, for larval body size smaller than 1 cm in the cornfield with conventional maize, the abundance of S. frugiperda was lower than the in cornfield with transgenic maize. Moreover, in the cornfield with Cry1F protein, the abundance of S. frugiperda was higher than in the cornfield with Cry1Ab protein. For larval body size between 1 and 2 cm, the abundance of S. frugiperda was higher in the cornfield with Cry1Ab protein, whereas for larval body size greater than 2 cm, the conventional cornfield had quite a high abundance of S. frugiperda . And finally, in Varjão de Minas for larvae smaller than 1 cm, the cornfield cultivated with the Bt hybrid expressing Cry1Ab protein showed higher abundance of S. frugiperda than the other treatments, whereas for larvae larger than 2 cm, the conventional cornfield had a higher abundance of S. frugiperda than the cornfield with Cry1F transgenic maize.

Figures

Fig. 1. Abundance of different sizes of larvae of Spodoptera frugiperda in whorls of conventional and transgenic maize (Cry1Ab, Cry1F and combined Cry2Ab2 and Cry1A105 proteins) from cornfields of different counties in Minas Gerais. Bars represent a 95% confidence interval.