Cytochrome P450 enzymes inhibitor in the control of Digitaria insularis

Abstract

ABSTRACT Herbicide interactions can be synergic, additive, or antagonist when mixed in the spray tank. A good example is an association between 2,4-D and graminicides. One hypothesis is that 2,4-D contributes to increasing the Cytochrome P450 activity, which may be one of the causes of antagonism. This study aimed to investigate the use of CYP450 enzymes inhibitor associated with the herbicide mixtures 2,4-D and ACCase inhibitors in vivo on the control of Digitaria insularis. The experiment was performed using a randomized block design in a factorial scheme of 6x2 with four replications. Factor A consisted of untreated check, 2,4-D (1005 g a.e ha-1), clethodim (192 g a.i ha-1) and haloxyfop (62.4 g a.i ha-1), 2,4-D + clethodim (1005 g a.e ha-1+192 g a.i ha-1), and 2,4-D + haloxyfop (1005 g a.e ha-1 +62.4 g a.i ha-1). Factor B represented the presence or absence of malathion (1000 g ha-1) applied two hours before applying the herbicides. A physicochemical test was performed to verify the compatibility of the herbicides in the tank. Malathion application performed two hours before applying the herbicide mixtures (2,4-D and clethodim/haloxyfop) did not provide adequate control of sourgrass, suggesting that CYP450 enzymes inhibited by malathion are not involved in the antagonistic effect between 2,4-D and both graminicides in the management of sourgrass. The 2,4-D + haloxyfop in tank mix demonstrated less efficacy in controlling sourgrass than 2,4-D + clethodim, but both mixtures were incompatible in the tank mix, which may be associated with reduced efficacy in sourgrass management.