Sulfentrazone efficiency on Ipomoea hederifolia and Ipomoea quamoclit as influenced by rain and sugarcane straw

Abstract

-The aim of this study was to assess the capacity of sulfentrazone applied in preemergence in controlling Ipomoea hederifolia and Ipomoea quamoclit as a function of the time interval between herbicide application and the occurrence of rain, and the presence of sugarcane straw on the soil surface. Two greenhouse experiments and one field experiment were conducted. For the greenhouse experiments, the study included three doses of sulfentrazone applied by spraying 0, 0.6, and 0.9 kg ha -1 , two amounts of straw on the soil (0 and 10 t ha -1 ), and five time intervals between the application of herbicide and rain simulation (0, 20, 40, 60, and 90 days). In the field experiment, five herbicide treatments (sulfentrazone at 0.6 and 0.9 kg ha -1 , sulfentrazone + hexazinone at 0.6 + 0.25 kg ha -1 , amicarbazone at 1.4 kg ha -1 , and imazapic at 0.147 kg ha -1 ) and two controls with no herbicide were studied. Management conditions with or without sugarcane straw on the soil were also assessed. From the greenhouse experiments, sulfentrazone application at 0.6 kg ha -1 was found to provide for the efficient control of I. hederifolia and I. quamoclit in a dry environment, with up to 90 days between herbicide application and rain simulation. After herbicide application, 20 mm of simulated rain was enough to leach sulfentrazone from the straw to the soil, as the biological effects observed in I. hederifolia and I. quamoclit remained unaffected. Under field conditions, either with or without sugarcane straw left on the soil, sulfentrazone alone (0.6 or 0.9 kg ha -1 ) or sulfentrazone combined with hexazinone (0.6 + 0.25 kg ha -1 ) was effective in the control of I. hederifolia and I. quamoclit, exhibiting similar or better control than amicarbazone (1.4 kg ha -1 ) and imazapic (0.147 kg ha -1 ).Keywords: Boral ® , raw sugarcane, morning glory, herbicide retention, Saccharum officinarum.RESUMO -Objetivou-se neste trabalho avaliar o controle em pré-emergência de Ipomoea hederifolia e Ipomoea quamoclit pelo herbicida sulfentrazone em função do intervalo de tempo entre a aplicação e a ocorrência de chuva e da manutenção ou não de palha de cana-de-açúcar na superfície do solo. Três experimentos foram desenvolvidos: dois em casa de vegetação e um em campo. Nos experimentos em casa de vegetação, foram estudadas três doses de sulfentrazone (0, 0,6 e 0,9 kg ha -1 ) pulverizado em duas quantidades de palha na superfície do solo (0 e 10 t ha -1 ) e cinco intervalos de tempo entre a sua aplicação e a simulação de chuva (0, 20, 40, 60 e 90 dias). No experimento em campo, foram avaliados cinco tratamentos de herbicida (sulfentrazone a 0,6 e 0,9 kg ha -1 ; sulfentrazone + hexazinone a 0,6 + 0,25 kg ha -1 ; amicarbazone a 1,4 kg ha -1 ; e imazapic a 0,147 kg ha -1 ) e duas testemunhas sem aplicação. A manutenção ou não da palha de cana sobre o solo também foi estudada. Em casa de vegetação, a aplicação de 0,6 kg ha -1 de sulfentrazone foi suficiente para o controle adequado de I. hederifolia e I. quamoclit num ambiente seco com até ...

Chemical Control of Morning Glory Species in Sugarcane Harvested in the Dry and Semi-Wet Seasons1

“…In other studies, among the evaluated herbicides, sulfentrazone was minimally affected by environmental conditions and by the applied dosages (Viator et al, 2002;Jones & Griffin, 2008) and remained on sugarcane straw for up to 90 days without losing the potential on controlling I. hederifolia and I. quamoclit after the occurrence of rain (Correia et al, 2013). However, depending on the infestation level (seed bank in the soil), the species and spray dosage, the use of herbicides in the sugarcane fields in the dry season is not effective, requiring complementation with other herbicides in the wet season, due to the new plant emergency flows in the area (Correia et al, 2010).…”

“…Depending on the physical and chemical properties of the herbicide, such as solubility, vapor pressure and polarity, the straw will have more or less influence on its effectiveness (Rodrigues, 1993;Selim et al, 2012). The amount and period in which rainfall or irrigation occur after application, in addition to the degree of decomposition or the age of the plant residues, can also greatly influence the adsorption of the herbicide straw (Mersie, 2006;Selim & Naquin, 2011;Correia et al, 2013;Giori et al, 2014). The herbicide will be exposed to losses due to photodegradation and volatilization even at adsorption plant residues while its removal from the straw to the soil does not occur.…”

Dinâmica de herbicidas em pré-emergência em sistemas de produção com palha

“…For sulfentrazone, the first 20 mm of simulated rainfall after application of the herbicide in the straw were sufficient to ensure the arrival of the herbicide to the soil, and even with a 90-day period of drought good levels of weed control were found (Correia et al, 2013). However, when herbicides flumioxazin and clomazone + hexazinone applied to the straw were exposed to 60 days without rainfall there was a downward trend in weed control even after simulation of 20 mm of rain (Carbonari et al, 2010a;Carbonari et al, 2010b).…”

Manejo de >i<Cyperus rotundus>/i< L. em cana-de-açúcar no sistema de mudas pré-brotadas (MPB)

“…A eficácia de controle do sulfentrazone é comprovada para várias espécies de plantas daninhas como: I. hederifolia L. e I. quamoclit L. (Correia et al, 2013), E. heterophylla, I. nil (L.) Roth, I. hederifolia, I. quamoclit, I. triloba e M. aegyptia (L.) Urb. (Azania et al, 2009), M. cissoides (Lam.)…”