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Sălaşu de Sus, Romania

Melo M.S.C.,Graduando em Engineering Agronomica | Carvalho S.J.P.,ESALQ USP | Nicolai M.,ESALQ USP | Crhistoffoleti P.J.,University of Sao Paulo
Planta Daninha | Year: 2010

After successive years, glyphosate applications on São Paulo-Brazil citrus orchards selected resistant biotypes of Conyza bonariensis and C. canadensis. The occurrence of herbicide-resistant weed biotypes at some agricultural area makes it necessary to change the management practices to reach effective control of the selected resistant populations, as well as to reduce selection pressure on the other species. Thus, this work aimed to identify the alternative herbicides to control glyphosate-resistant biotypes of Conyza spp., with applications at different weed phenological stages. Three trials were developed under field conditions: in citrus orchards under formation, in plants with phenological stages of ten leaves and at pre-flowering. For plants at the ten leaf stage, satisfactory control was reached with applications of glyphosate + bromacil + diuron (1,440 + 1,200 + 1,200 g ha -1), glyphosate + atrazine (1,440 + 1,500 g ha -1) and glyphosate + diuron (1,440 + 1,500 g ha -1). For Conyza spp. plants at the pre-flowering stage, ammonium- glufosinate application, at the rate of 400 g ha -1, isolated or associated to MSMA, bromacil+diuron, metsulfuron, carfentrazone and paraquat, was a viable alternative to control glyphosate-resistant biotypes.


de Freitas R.M.O.,Graduando em Engineering Agronomica | Nogueira N.W.,Graduando em Engineering Agronomica | de Oliveira F.N.,Graduando em Engineering Agronomica | da Costa E.M.,Graduando em Engineering Agronomica | Ribeiro M.C.C.,UFERSA
Revista Caatinga | Year: 2010

This work has, as its goal, to evaluate the effect of diverse concentrations of salt in irrigation water in the germination and initial growth of seedling of Jucá. The experiment was developed in the greenhouse of the Vegetable Sciences Department of the Federal Rural University of the Semiarid (UFERSA). The statistic delimitation was entirely casualized, with four treatments. To obtain the concentrations, we added NaCl and the electric conductivities (C.E.) T2-1.5; T3-3.0; T4-4.5 dS m -1 which, along with the standard (wellwater, T1-0,5 dS m -1) formed the treatments. The variables we analysed were: percentage of emergency (E), levels of emergency speed (IVE), the seedling's height (AP), and the seedling's dry matter mass (MSP). It was not possible to obtain an expressive result to the seedling dry matter mass variable. On the results, it appears that the salinity interferes in all the evaluated parameters, except dry matter, proportionally to the increase in salinity on the irrigation water. The evaluated characteristics are more sensible to salinity levels of 3dS m-1 or higher.

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