Effect of different doses of post-emergence-applied iodosulfuron on weed control and grain yield of malt barley (Hordeum distichum L.), under Mediterranean conditions

Abstract

A study was carried out over a two year period (2009/2010 and 2012/2013) on an experimental farm in the Alentejo region (Beja), in southern Portugal where rainfed malt barley (Hordeum distichum L.) is sown at the end of autumn or beginning of winter (November- December). The aim of this experiment was to study the efficiency of the herbicide iodosulfuron-methyl-sodium to control post-emergence broadleaved weeds in this cereal crop. The malt barley crop was established using no-till farming. This technology provides the necessary machine bearing capacity of the soil to assure the post-emergence application of herbicides at two different weed development stages. The herbicide iodosulfuron-methyl-sodium was applied at three doses (5.0, 7.5, and 10.0 g a. i. · ha-1) and at two different broadleaved weed development stages (3 to 4 and 6 to 7 pairs of leaves), that also corresponded to two different crop development stages (beginning of tillering and complete tillering). The results indicated that early herbicide application timing provided a significantly higher efficiency for all the applied herbicide doses, but this better weed control was not reflected in a higher crop grain yield. The lack of a higher crop grain yield was probably due to a crop phytotoxicity of the herbicide, when used at an early application timing.

Iodosulfuron-Methyl-Based Herbicidal Ionic Liquids Comprising Alkyl Betainate Cation as Novel Active Ingredients with Reduced Environmental Impact and Excellent Efficacy

“…38 Additionally, NMR spectra confirmed the presence of both the herbicidal anion and the alkylated betaine cation in the obtained products. 1 H NMR spectra of the reactants (iodosulfuron-methyl sodium salt and heptyl betainate bromide (P6)) as well as the final product (6) are depicted in Figure 2.…”

“…General Considerations. 1 H NMR spectra were recorded on a Mercury Gemini 300 spectrometer operating at 300 MHz and a Varian VNMR-S 400 MHz spectrometer with TMS as the internal standard. 13 C NMR spectra were obtained with the same instruments at 75 and 100 MHz, respectively.…”

“…This compound belongs to the sulfonylurea compounds, which are used as postemergence herbicides. 1 The mechanism of action of these agrochemicals is based on the inhibition of the enzyme acetolactate synthase (ALS), which catalyzes the first branched-chain amino acid (BCAA) biosynthesis reaction—leucine, valine, and isoleucine. 2 According to recent reports, ALS-inhibiting herbicides are often characterized by high selectivity, high efficiency at low doses, and low toxicity to animals.…”

“…Iodosulfuron-methyl-sodium is known as a plant protection product that is widely applied to control monocotyledonous and dicotyledonous weeds in cereal cultivation. This compound belongs to the sulfonylurea compounds, which are used as postemergence herbicides . The mechanism of action of these agrochemicals is based on the inhibition of the enzyme acetolactate synthase (ALS), which catalyzes the first branched-chain amino acid (BCAA) biosynthesis reactionleucine, valine, and isoleucine .…”

Can Commercial Low-Cost Drones and Open-Source GIS Technologies Be Suitable for Semi-Automatic Weed Mapping for Smart Farming? A Case Study in NE Italy

“…One of the promising practices which increase sustainability of weed management is based on the so-called Site-Specific Weed Management (SSWM) strategies [18,19]. In fact, the ecological impacts of herbicides are generally the consequence of three main critical issues in weed management: (i) the application of herbicide during an inappropriate weed phenological stage; (ii) the lack of weed threshold assessment in terms of degree of infestation; (iii) the application of herbicides over the entire field, without considering the weed spatial distribution [20][21][22][23]. While the first depends on experiences and agronomic knowledge of the farmer, the latter could be addressed by developing SSWM strategies.…”