Chemical control of morning glory as a function of water restriction levels

Among the herbicides recommended for the dry season and registered to sugarcane crop, amicarbazone, isoxaflutole and the association diuron + hexazinone + sulfomethuron-methyl can be highlighted. These are pre-emergence herbicides efficient against broad-leaved weeds. Morning glory causes large losses in infested sugarcane fields by bending the stalks and interfering in harvesting. In this study the effectiveness of pre-emergence herbicides for two species of morning glory (Ipomoea hederifolia and Ipomoea grandifolia) was evaluated. Treatments were arranged in completely randomized factorial design (4 x 7). There were four periods of water restriction (0, 30, 60 and 90 days), seven chemical treatments [diuron + hexazinone + sulfometuron-methyl (1387 + 391 + 33.35 g a.i. ha-1), diuron + hexazinone + sulfometuron-methyl (1507.5 + 425 + 36.25 g a.i. ha-1), diuron + hexazinone + sulfometuron-methyl (1658.25 + 467.5 + 39.87 g a.i. ha-1), diuron + hexazinone + sulfometuron­methyl (1809 + 510 + 43.5 g a.i. ha-1), amicarbazone (1190 g a.i. ha-1), amicarbazone + isoxaflutole (840 + 82.5 g a.i. ha-1)] and a control with no application. At 7, 14, 21 and 28 days after the restoration of moisture, control was visually evaluated. After the final evaluation, the dry mass of morning glories was measured. At 90 days of water restriction, diuron + hexazinone + sulfometuron-methyl was more effective to control I. hederifolia than the amicarbazone + isoxaflutole tank mixture. The four diuron + hexazinone + sulfometuron­methyl doses have reduced morning glory dry mass to zero; whereas treatments with amicarbazone have not. The most effective treatment for morning glory control was diuron + hexazinone + sulfometuron-methyl. This result may be due to a possible synergistic interaction.

Translocação dos herbicidas glyphosate e imazamox em plantas de aguapé

Eichhornia crassipes is one of the main weeds found in aquatic environments, being undesirable for many activities. The aim of this study was to evaluate the translocation of glyphosate and imazamox in E. crassipes. Eight intervals were studied for cutting leaves that received herbicides: 2, 4, 6, 8, 12 and 24 hours after application (HAA), and a treatment with no cutting (untreated). The glyphosate dose was 2,160 g a.e. ha-1 (commercial product - Rodeo) + 0.5% v v-1 Aterbane adhesive spreader and imazamox at 290.4 g i.a. ha-1 (commercial product - Clearcast). The treatments were installed in a completely randomized design with four replications. Glyphosate showed a bad control for all the periods of leaf cutting. The imazamox did not provide control within 12 HAA, while from 24 HAA onward the control was effective. There was not a great mobility of the glyphosate molecule in water hyacinth plants, a period above 24 hours being needed for a satisfactory translocation. For imazamox at least 24 hours were needed after herbicide application for the translocation to occur along with subsequent control.

Evolução de CO2 e atividades enzimáticas em amostras de solo tratado com herbicidas

Effects of bentazon, metolachlor, trifluralin, imazethapyr, imazethapyr+lactofen, haloxyfop-methyl, glyphosate and chlorimuron-ethyl at rates of 2 and 10 times the equivalent commercial dose on soil microbial activity was evaluated in soil samples extracted from a field never treated before. Global soil microbe respiration, estimated by CO2 production at 2, 4, 8, 12, 16, 20, 24 and 28 days of soil incubation and enzymatic activities (dehydrogenase and fluorescein diacetate hydrolysis) at 8 and 28 days were used as bioindicators. Bentazon and mixture imazethapyr+lactofen at the highest rate and haloxyfop-methyl at both rates, inhibited soil respiration although with differences in timing and duration. None of the herbicides affected FDA hydrolysis. Dehydrogenase activity was inhibited at 8 days of incubation with bentazon and imazethapyr at high rates but it was stimulated by metolachlor and imazethapyr at low rate and glyphosate at the highest rate. Herbicide effects on soil microbial activity was detected with higher sensitivity by global soil microbe respiration and dehydrogenase activity than by FDA hydrolysis. Only dehydrogenase activity and soil respiration estimations at 8 days of soil incubation had significant correlation. Results indicated the need of multiple estimations when evaluating herbicides effects on soil microbiota

Adjuvantes na deriva de 2,4-D + glyphosate em condições de campo

The aim of the research was to evaluate the effect of adjuvants on the spray drift applications from mixture of 2,4-D + glyphosate. The trial was carried out in field conditions in a completely randomized design. The treatments corresponded to solutions containing mixture of the herbicides 2,4-D + glyphosate (670 and 1068g ha-1, respectively) adding the adjuvants (v v-1): mineral oil (0.5%); anti-drift agent (0.09%); spreader-sticker A (0.1%); liquid fertilizer (0.05%); spreader-sticker B (0.25%); and only herbicides without adjuvantes (control). Nylon strings were used to drift determination outside the application area (1, 5, 10, 20, 50, 100 and 200 m away) with 4 replications and six foam cylinders placed on the boom of the sprayer were used to collect the droplets subject to drift. The applications were performed simultaneously, using a specific salt tracer for each spray solution to quantify the deposits by spectrophotometer. It was not possible to verify effect of the adjuvants on drift at different distances of the application area. Based on droplets collected above the boom spray, it was found that susceptibility to drift was lower with the mineral oil and the anti-drift agent. The drift risk was higher with the liquid fertilizer and the spreader-sticker B.

Molecular characterization of accessions of crabgrass (Digitaria nuda) and response to ametryn

Digitaria species are sugar cane crop weeds in Brazil and are being controlled with herbicides, although there are some reports of control failure, notably to the triazine group. Molecular techniques are recommended to analyze the genetic variability in weeds. RAPD (Random Amplified Polymorphic DNA), PCR-RFLP (Polymerase Chain Reaction - Restriction Fragment Length Polymorphism) and, in combination with sequencing, allow the localization of resistance genes, as well as possible mutations related to the onset of resistant individuals in some species. Thus, the objective of this work was to characterize ten accessions of Digitaria spp. by RAPD and PCR-RFLP markers, to sequence a conserved region of the psbA gene and evaluate the accessions response to ametryn. As showed by molecular analysis there was high genetic similarity among the accessions, all of them presented similar genetics profiles and were susceptible to ametryn.

Adubação nitrogenada e aplicação de herbicidas como reguladores de crescimento em grama esmeralda

Pós-graduação em Agronomia - FEIS

Influência da vinhaça e da palhada de cana-de-açúcar na sorção de herbicidas aplicados em diferentes solos

Pós-graduação em Agronomia (Agricultura) - FCA

Intoxicação e alterações metabólicas do algodão sensível e resistente ao amônio glufosinate

Pós-graduação em Agronomia (Agricultura) - FCA

Hormesis de herbicidas em soja

Pós-graduação em Agronomia (Agricultura) - FCA

Qualidade de sementes de soja convencional e transgênica em função da dessecação das plantas com glyphosate

Pós-graduação em Agronomia (Agricultura) - FCA

Influência de diferentes misturas em tanque contendo o herbicida 2,4-D no espectro de gotas da aplicação

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Métodos para identificação de moléculas com atividade herbicida com ênfase na rota de síntese de carotenóides

Pós-graduação em Agronomia (Proteção de Plantas) - FCA

Teores foliares de macro e micronutrientes em milho tolerante ao glyphosate submetido à herbicidas

A serial of factors related to development of glyphosate-tolerant corn should be approached and best studied. This work was developed to evaluate foliar levels of N, P, K, Ca, Mg, S, B, Cu, Fe, Mn and Zn, besides the grain yield of glyphosate-tolerant corn (DKB390 RR hybrid). An experiment was carried out under field conditions, during the crop year of 2010/2011. A randomized complete block design with four repetitions was used to distribute the treatments in the field. Twelve herbicide treatments were studied: glyphosate (720, 1200 and sequential application of 960 plus 720 g ha(-1) of the acid glyphosate equivalent), atrazine (2500 g ha(-1)), nicosulfuron (60 g ha(-1)), mesotrione (192 g ha(-1)), tembotrione (100,8 g ha(-1)), atrazine plus glyphosate (1000 + 960 g ha(-1)), atrazine plus nicosulfuron (1000 + 20 g ha(-1)), atrazine plus mesotrione (1000 + 144 g ha(-1)) and atrazine plus tembotrione (1000 + 75,6 g ha(-1)) and one control treatment without herbicide. The glyphosate and mesotrione alone did not cause no visible injury to corn. The other herbicides caused intoxication symptoms classified as light (<5%). The treatments studied did not affect foliar levels of N, P, K, Ca, Mg, S, B, Mn and Zn in the corn plants. But, the plants treated with atrazine plus nicosulfuron had more leaf Fe content, and the plants sprayed with glyphosate (in the three doses) and atrazine, more accumulation of Cu in the leaf. The Grain yield of corn was reduced with application single of glyphosate (1200 g ha(-1)), nicosulfuron, tembotrione and with the mixture atrazine plus nicosulfuron.

Espacialização do banco de sementes de plantas daninhas sob diferentes manejos de cana-de-açúcar em Rio Brilhante, Mato Grosso do Sul

The State of Mato Grosso do Sul is in full growth of this sector, thus the concern about harvesting systems are being studied, and these systems may influence the weed community interference of weeds in the cane sugar. The integrated management tool attached to geostatistics is to avoid productivity losses due to weed interference. The objective of this work was to study the spatial variability of the seed bank of weeds depending on the system for collecting cane sugar (raw and burning). The experiment was conducted in the area of commercial cultivation of the plant ETH Bioenergy S/A Eldorado Unity. Soil samples were taken with auger layer from 0.00 to 0.40 m depth in both cropping systems. The experimental plot was composed by a mesh consisting of 50 points georeferenced with irregular distances. Soil samples were taken to the greenhouse for germination. The number of weed species was analyzed using descriptive statistics and geostatistical techniques. The seeds of B. pilosa, dicots, bitter grass, nutsedge, dayflower monocots and spatial dependence of the seed bank in the collection system with burning of cane sugar. For the system of harvest only the raw sedge species present spatial dependence of distribution in the seed bank. In the harvest green cane enable the mapping of these species through the kriging maps produced, spot applications of herbicides in integrated management of Cyperus rotundus.

Procedures to Evaluate the Efficiency of Protective Clothing Worn by Operators Applying Pesticide

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)