Núbia Maria Correia

Herbicide detection in groundwater in Córrego Rico-SP watershed

Due to the large amount of pesticides applied in agriculture, mainly herbicides, there is a growing concern about a possible environmental contamination with these products, including water bodies. Given the above, the aim of the present work was to detect and quantify herbicides through multiresidue analysis in water samples collected in semi-artesian wells and springs in a rural area of the city of Jaboticabal (SP). Samples were collected from 32 wells and 13 water springs, in three different seasons: October 2010, February 2011 and May 2011. Additionally, samples at a residence in the urban area were also collected. Analysis using high performance liquid chromatography coupled to mass spectrometry was performed and herbicides ametryn, amicarbazone, clomazone, diclosulan, diuron, hexazinone, imazapic, imazapyr, isoxaflutole, S-metolachlor, sulfentrazone, sulfometuron-methyl, and tebuthiuron were evaluated. In semi-artesian wells, an incresed quantity of herbicides was found in comparison with the water springs. Among the tested herbicides, hexazinone, imazapyr and sulfentrazone were detected in measurable amounts in accordance with the analytical method applied, while clomazone was the most common herbicide being detected in more than 60% of the samples. Ametryn, diuron and amicarbazone herbicides were also detected. Diclosulan, imazapic, isoxaflutole, S-metolachlor, sulfometuron-methyl, and tebuthiuron were not detected in any sample. Inappropriate use of these products without prior knowledge of the behavior of the soil can lead to groundwaters and water springs contamination, thus an ongoing monitoring of this resource becomes very important.

Chemical control of different Digitaria insularis populations and management of a glyphosate-resistant population

This study aimed to control different populations of Digitaria insularisby glyphosate herbicide, isolated and mixed, besides the combination of methods (chemical and mechanical) to manage resistant adult plants. Three experiments were conducted, one in pots which were maintained under non-controlled conditions and two under field conditions. In the experiment in pots, twelve populations of D. insularis were sprayed with isolated glyphosate (1.44 and 2.16 kg a.e. ha-1) and mixed (1.44 and 2.16 kg a.e. ha-1) with quizalofop-p tefuryl (0.12 kg i.a. ha-1). The treatment of 1.44 kg a.e. ha-1 of glyphosate plus 0.12 kg a.i. ha-1 of quizalofop was sufficient for adequate control (>95%) of all populations. Population 11 (area of grain production in Itumbiara, GO) was considered sensitive to glyphosate. Others populations were moderately sensitive or tolerant to the herbicide. In the field, the plants of D. insularis of one of the experiments were mowed and, in the other, there were not. Eight treatments with herbicides [isolated glyphosate (1.44 and 2.16 kg a.e. ha-1) and mixed (1.44 and 2.16 kg a.e. ha-1) with quizalofop-p-tefuryl at 0.12 kg a.i. ha-1), clethodim at 0.108 kg a.i. ha-1) or nicosulfuron at 0.06 kg a.i. ha-1)] were assessed, in combination with or without sequential application of the standard treatment, sprayed 15 days after the first application. The combination of the mechanic control with the application of glyphosate (2.16 and 1.44 kg a.e. ha-1) plus quizalofop-p-tefuryl (0.12 kg a.i. ha-1) or clethodim (0.108 kg a.i. ha-1), associated to the sequential application, was the most effective strategy for the management of adult plants of resistant D. insularis.

Trinexapac-Ethyl and Sulfometuron-Methyl Selectivity to Young Eucalyptus Plants

Entre os maturadores, o trinexapac-ethyl e o sulfometuron-methyl sao os mais usados nos canaviais. A pulverizacao e aerea, de modo que, se as condicoes meteorologicas nao forem favoraveis, podera ocorrer deriva para culturas vizinhas. Assim, objetivou-se neste trabalho avaliar a seletividade dos reguladores vegetais trinexapac-ethyl e sulfometuron-methyl, utilizados como maturadores em cana-de-acucar, para plantas jovens de eucalipto (Eucalyptus urograndis). O experimento foi instalado em area de producao comercial de eucalipto, no municipio de Tambau, SP, Brasil. O delineamento experimental foi o de blocos ao acaso, em esquema fatorial 2 x 8, com quatro repeticoes. Os tratamentos estudados foram trinexapac-ethyl e sulfometuron-methyl, pulverizados em oito dosagens: 0; 1,0; 2,5; 5,0; 10; 25; 50; e 100% da dose utilizada em cana-de-acucar como maturador (200 g ha-1 de trinexapac-ethyl e 15 g ha-1 de sulfometuron-methyl). Os reguladores de crescimento foram aplicados sobre as plantas de eucalipto com 48 cm de altura, 10,1 ramos, 4,5 mm de diâmetro de caule e 44,3 cm de diâmetro de copa, aos 46 dias apos o plantio. O trinexapac-ethyl foi seletivo para o eucalipto e estimulou o crescimento do diâmetro de copa. Ja o sulfometuron-methyl, nas maiores doses testadas, ocasionou injurias visuais severas as plantas de eucalipto, como a morte de gemas apicais. Contudo, no decorrer das avaliacoes, as plantas recuperaram-se, nao sendo observados sintomas visuais de fitointoxicacao ou alteracao do crescimento aos 60 dias apos a aplicacao. Os reguladores vegetais trinexapac-ethyl e sulfometuron-methyl foram seletivos para plantas jovens de eucalipto.

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

The control of morning glory (Ipomoea spp. and Merremia aegyptia) was evaluated in five commercial sugarcane-production fields receiving applications of the herbicides sulfentrazone (0.9 kg ha-1), amicarbazone (1.4 kg ha-1), imazapic (0.147 kg ha-1), and hexazinone + tebuthiuron (0.325 + 0.75 kg ha-1) applied pre-emergence in either the dry season (July and August) or in the semi-wet season (early October); mesotrione alone (0.192 kg ha-1) or in combination (0.12 kg ha-1) with atrazine (1.5 kg ha-1) or diuron + hexazinone (0.491 + 0.139 kg ha-1) applied post-emergence in the wet season (November), and the phytointoxication of the chemical treatments for sugarcane. Five species of morning glory (Ipomoea hederifolia, Ipomoea nil, Ipomoea quamoclit, Ipomoea triloba and Merremia aegyptia) were assessed in the experiments. The applications during the dry, semi-wet, and wet seasons resulted in similar levels of control of I. hederifolia, I. nil, I. quamoclit, and I. triloba. The herbicides imazapic and mesotrione alone resulted in lower levels of control of M. aegyptia. Imazapic and the combination of mesotrione + (diuron + hexazinone) caused greater visible phytotoxicity to sugarcane than other herbicides applied during the dry and semi-wet seasons. However, the greatest loss of production was attributed to amicarbazone.

Selectivity of linuron herbicide for carrot when sfrayed in post-emergence.

Objetivou-se aqui estudar a seletividade do herbicida linuron para a cultura da cenoura, influenciada por genotipo, dosagem do produto e estadio de desenvolvimento das plantas no momento da aplicacao. O trabalho englobou a realizacao de quatro experimentos, um em casa de vegetacao e tres em campo, em area de producao comercial de cenoura.

Seletividade do Herbicida Linuron para Cenoura Quando Pulverizado em Pós-Emergência

Among the herbicides registered for carrot crop in Brazil, linuron is the most used one, according to horticulturists. However, there are few reports in the literature on its selectivity for the carrot plants. Therefore, the aim of this work is to study the selectivity of linuron herbicide for growing carrots, influenced by genotype, product dosing, and plant development phase at the time of application. This work included four experiments, one in greenhouse, and three in the field, in area of commercial carrot production. In the greenhouse, the experimental design was completely randomized in factorial scheme 4 x 2 x 3, with four replications. Linuron, at doses 0, 225, 450 and 675 g a.i. ha-1 was sprayed in plants with 1 and 2-3 true leaves of cultivars Brasilia, Kuronan and Verano. In the field, two experiments were carried out, one with the cultivar Verano and the other with BRS Planalto. In three experiments, the experimental design was a randomized block in factorial 2 x 5, with four replications. Verano or BRS Planalto plants were sprayed, in two stages of development (1 and 3 true leaves for Verano, and 1 and 2 true leaves for BRS Planalto), with 0, 225, 450, 675 and 990 g a.i. ha-1 of linuron. Post-emergence herbicide linuron was selective for growing carrots, regardless of cultivar, product dosage and plant development stage at the time of application.