Fatores ambientais que afetam a eficácia de herbicidas inibidores da ACCase: revisão

Abstract

Palavras-chave: variáveis ambientais, temperatura do ar, umidade relativa do ar, luminosidade.ABSTRACT -Understanding the factors that limit herbicide performance would allow selecting the appropriate time to spray the compounds, optimizing the dose applied, and reducing the production costs. The objective of this review was to synthesize the information available on the literature on the effect of the environmental conditions (air temperature, relative humidity, and irradiance) on the efficacy of the ACCase-inhibiting herbicides. Air temperature and relative humidity are the most important environmental variables altering the performance of these herbicides on weed control. Under natural conditions, these variables, along with irradiance, interact with one another, making it difficult to decide the best time to select herbicide application. Under controlled conditions, it is possible to identify the individual influence of each factor on herbicide efficacy. Increased relative humidity and air temperature increase the efficacy of ACCase-inhibitors to a certain extent, because of increased uptake and translocation of the herbicides by the plants. Light intensity, when increased, also provides these benefits, but sometimes shading provides better performance of these herbicides. To optimize the efficacy of ACCase-inhibitors on weed control, it is necessary to analyze the influence of each of the variables mentioned above.

Fluazifop-P-Butyl Efficacy as a Function of Application Time and Herbicide Dose

“…This herbicide belongs to the chemical family aryloxy-phenoxy propionate, which is a strong inhibitor of the enzyme acetyl-coenzyme A carboxylase (ACCase). Inhibition of ACCase by fluazifop precludes the synthesis of malonyl-CoA, the committed step of fatty acid biosynthesis in plants, thus controlling the grass weeds (Cieslik et al, 2013).…”

“…Environmental conditions, such as air temperature and relative humidity, as well as irradiation, affect several steps on the herbicide-plant interaction, mainly interception, absorption and the translocation of the chemical within the weed (Cieslik et al, 2013(Cieslik et al, , 2014. The environmental variables during the herbicide spray are affected by the time of the day.…”

“…Therefore, the time of the day which the herbicide is sprayed may affect the herbicide efficacy (Cieslik et al, 2014). There is enough theoretical knowledge about the impact of the environment on the efficacy of ACCase inhibitors (Cieslik et al, 2013). However, most of available information was developed with experiments conducted in growth-chambers to study the impact of each factor isolated.…”

Environmental and physiological factors that affect the efficacy of herbicides that inhibit the enzyme protoporphyrinogen oxidase: a literature review

“…However, in the field these factors can not be separated from each other and must be considered for choosing the best time of herbicide application, in order to optimize their activity (Cieslik et al, 2013;Queiroz et al, 2013). The activity of flumiclorac or fluthiacet, when applied at 6:00 am in the morning, was 17 and 33% higher, compared to the effects of the herbicides applied at 2:00 pm or 10:00 pm, respectively.…”

“…In summer, during the first hours of the day, the usual conditions are reduced temperatures, low light intensity and high relative humidity, when compared to the conditions shortly after noon (Cieslik et al, 2013). In addition to environmental aspects, the physiological condition of weeds can affect the herbicide efficacy due to the presence of enzymes responsible for herbicide detoxification or for antioxidant metabolism in plants, which can compromise the agronomic performance of the products.…”