Don't know the exact translation of this worm, but the reports on Globo Rural this morning had video of fields absolutely devastated by what looked like army worms or cotton bollworms.  

On Globo Rural, no good approved insecticides are available.  They are going to try some non-approved insecticides as an emergency measure.

Videos showed populations of 3 or 4 per plant, which is hard to believe.  

I don't grow or trade soya, BTW.





http://exame.abril.com.br/meio-ambiente-e-energia/noticias/governo-declara-emergencia-em-mt-por-ataque-de-lagartas