Chemical management for late soybean sowing and its influence on the fomesafen action sprayed in post-emergence soybean crop

Abstract

The aim of this research was to evaluate the efficacy of sequences management systems in late soybean, Glycine max (L.) Merril (Leguminosae-Faboideae), sowing and its influence on the fomesafen application. The experiment was carried out at São João de Ivaí-PR (1998/99), using: (M1) sulfosate + 2,4-D/sulfosate; (M2) sulfosate + 2,4-D/(paraquat+diquat); (M3) sulfosate/(paraquat+diuron); (M4) sulfosate/diquat; (M5) sulfosate/(paraquat+diquat), where M1 was developed 26 days before the sowing (DBS) and during the sowing, and the other systems at 40 DBS and during the sowing. The anticipation of the management systems (40 DBS) allowed a reduction in the use of herbicides and better control of Commelina benghalensis. Fomesafen (125 g i.a./ha), applied in single dose at 19 days after sowing (DAS), made possible sequencial management systems that reached high control level. Its sequence (19 DAS/27 DAS) was satisfactory even when the management was not efficient. M1 was faulty in the C. benghalensis control, allowing the replacement of 2,4-D for sulfosate/diquat or sulfosate/(paraquat+diuron) sequence, both for Ipomoea grandifolia and for C. benghalensis