ABSTRACT The use of tank mixtures has long been a practice in the phytosanitary management of agricultural crops. However, when different molecules are mixed in a tank, interactions may occur that reduce the efficiency of the products and cause a loss of selectivity in the crops. The aim of this study was to evaluate selectivity in maize, with a tank mixture of different phytosanitary products recommended for use with the crop. The following products were used: herbicides - Sanson®, Soberan®, Callisto®, Zapp Pro®; fungicides - Priori Xtra®, Nativo®, Tebufort®, Aproach Prima®; insecticides - Connect®, Lorsban® 480 BR, Karate Zeon®; and nutrition - Kellus Manganese®, Kellus Blindex®. The experimental units consisted of 5-litre pots, containing two plants per pot, with the products applied at phenological stage V6. Assessments were made of phytotoxicity, transient chlorophyll a fluorescence, chlorophyll content and shoot dry weight. The data obtained in the experiment were submitted to ANOVA (p ≤ 0.05), and when significant, to the Scott-Knott test (p ≤ 0.05). The maize crop suffered phytotoxicity of up to 30%, with the plants recovering from 28 DAA. The phytotoxicity was caused by mixing the different products in the spraying solution, mainly due to the synergism caused by the mixture of the herbicides nicosulfuron and tembotrione with the insecticide chlorpyrifos and the fertiliser Kellus Manganese®, which aggravated the incompatibility of some treatments. The results of this study defined which phytosanitary products recommended for use with maize should not be mixed in the same spraying solution due to the possibility of damaging the crop. crops However used Sanson Sanson® Soberan Soberan® Callisto Callisto® Pro® Pro Xtra Xtra® Nativo Nativo® Tebufort Tebufort® Prima® Prima Connect Connect® Lorsban 48 BR Zeon® Zeon Manganese Manganese® Blindex Blindex® 5litre litre 5 pots pot V6 V fluorescence weight p 0.05, 005 0.05 , 0 05 0.05) significant ScottKnott Scott Knott 0.05. . 30 30% 2 DAA treatments 4 00 0.0 3 0.

RESUMO As interações entre herbicidas quando misturados na calda de pulverização podem ser sinérgicas, aditivas ou antagônicas. Um exemplo de antagonismo está na associação entre os herbicidas 2,4-D e graminicidas. Há a suspeita de que o 2,4-D contribui para o aumento da atividade do Citocromo P450, podendo ser esta uma das causas do antagonismo. O objetivo deste estudo foi investigar o uso do inibidor das enzimas CYP450 in vivo, associado às misturas de herbicidas 2,4-D e inibidores da ACCase, no controle de Digitaria insularis. O experimento foi realizado em delineamento de blocos casualizados em esquema fatorial 6x2 com quatro repetições, sendo o fator A os herbicidas: controle 2,4-D (1005 g a.e. ha-1); cletodim (192 g a.i ha-1) e haloxifope (62,4 g a.i ha-1), 2,4-D+cletodim (1005 g a.e ha-1+192 g a.i ha-1), 2,4-D+haloxifope (1005 g a.e ha-1 +62.4 g a.i ha-1); e o fator B a presença ou não de malation (1000 g ha-1) aplicado duas horas antes dos herbicidas. Foi realizado um teste físico-químico para verificar a compatibilidade dos herbicidas no tanque. A aplicação do malation duas horas antes das misturas dos herbicidas 2,4-D+clethodim ou haloxyfop, não proporcionou controle satisfatório do capim-amargoso, sugerindo que as enzimas CYP450 inibidas pelo malation não estão envolvidas no efeito antagônico observado. A mistura de 2,4-D+haloxyfop demonstrou menos eficácia no controle do capim-amargoso quando comparada com 2,4-D+clethodim, porém ambas foram incompatíveis na mistura em tanque, o que pode estar associado à eficácia reduzida no manejo do capim-amargoso.

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.