Association of adjuvants with culture filtrate from Fusarium Fujikuroi for increasing the control of Conyza sp.

Abstract

Metabolites from Fusarium fujikuroi were used as a bioherbicide product for the control of Conyza sp., a weed that causes considerable losses in the cultivation of soybean worldwide. Formulations containing distilled water or culture filtrate and different adjuvants (palm, soybean or mineral oil, Span® 80 and Tween® 80) were evaluated in order to increase the bioherbicidal activity through post-emergence bioassays. The herbicidal activity of culture filtrate was improved using different combinations of adjuvants. The best formulation was 3% (w/v) of mineral oil, 5.5% (w/v) of surfactant (Span® 80 and Tween® 80) and a hydrophilic-lipophilic balance (HLB) of 15, which resulted in a higher herbicidal activity (100%) (complete death of plants) and lower phytotoxicity (0%). The suitable combination of adjuvants in association with culture filtrate from F. fujikuroi increased up to 2.5 times the efficiency of bioherbicide for the post-emergence control of Conyza sp.