Maria Conceição Peres Young Pessoa

Estimativa da deposição de agrotóxicos por análise de gotas

The available methodologies for analysing the pesticide reaching the target are sophisticated or expensive. The objective of this work was to compare two methods to quantify the pesticide deposition. One of them by droplets analysis and the other by chemical tracer analysis. The droplets of a fungicide spray were sampled using water sensitive papers, slides with oxide magnesium and cards of filter paper. In the droplet analysis method, the volume of spray deposited on a delimited area was estimated considering the diameters of stains or craters, spread factors and droplet density. In the chemical tracer analysis method the volume was calculated by the residue deposited on sampling target and spray concentration. There were no statistic differences in the volumes estimated by the two methods.

Herbicide Leaching on a Recharge Area of the Guarany Aquifer in Brazil

Abstract The region of Ribeirão Preto City, located in Southeast of Brazil, São Paulo State, is an important sugarcane, soybean, and corn producing area with a high level of pesticides utilization. This region is also an important recharge area for groundwater supply of the Guarany aquifer. Since the past ten years atrazine, simazine, ametryn, tebuthiuron, diuron, 2,4-D, picloram, and hexazinone are the main herbicides used in this area. In order to study a possible leaching of some of these herbicides into the aquifer, surface, and groundwater samples were collected in a watershed during the years of 1996 to 2003, from different locations. To detect and quantify the herbicides a GC-MS (gas chromatograph/mass spectrometry) method was used. The response of the herbicides analyzed was linear over the concentration range of 0.02 to 2.0 μg/L. Analysis of groundwater revealed that the herbicides tebuthiuron, diuron, atrazine, simazine, and ametryn were not present in the samples. In the surface water collected in 1997, ametryn was present in two out of nine locations with concentrations ranging from 0.17 and 0.23 μg/L, which is above the allowable 0.1 μg/L according to the European safety level. The leaching potential of tebuthiuron, diuron, atrazine, simazine, 2,4-D, picloram, and hexazinone has been evaluated using CMLS-94, “Chemical Movement in Layered Soil,” as simulation model. No leaching into the depth of the water table at 40 m was found.

Eficiência de deposição de agrotóxicos obtida com bocal eletrostático para pulverizador costal motorizado

O grande desperdicio das atuais tecnicas de aplicacao de agrotoxicos tem estimulado a procura por alternativas tecnologicas para aumentar sua eficiencia e a pulverizacao eletrostatica tem se revelado uma tecnologia promissora. O objetivo deste trabalho foi avaliar um bocal eletrostatico adaptavel em pulverizador costal motorizado, e verificar a influencia da tensao de inducao e vazao de liquido na intensidade da carga das gotas, bem como o efeito da carga na deposicao de tracador. O estudo da deposicao foi realizado com alvo artificial esferico. A carga maxima obtida com o bocal eletrostatico foi de 4,0 mC/kg para uma vazao de calda de 0,3 L/min e tensao de 8,0 kV. O aumento na vazao da calda de pulverizacao reduziu a carga das gotas. Gotas sem carga apresentaram uma eficiencia de deposicao de 18% de tracador, mas as gotas com intensidade de carga de 4,0 mC/kg aumentaram significativamente a deposicao para 62% do total do tracador aplicado.

Comparação de método microscópico e programa computacional para a estimativa da deposição de agrotóxicos pela pulverização aérea

(2) Abstract _ The main objective of this work was to compare two methods to estimate the deposition of pesticide applied by aerial spraying. Hundred and fifty pieces of water sensitive paper were distributed over an area of 50†m length by 75†m width for sampling droplets sprayed by an aircraft calibrated to apply a spray volume of 32†L/ha. The samples were analysed by visual microscopic method using NG†2 Porton graticule and by an image analyser computer program. The results reached by visual microscopic method were the following: volume median diameter, 398-62 μm; number median diam- eter, 159-22†μm; droplet density, 22.5-7.0†droplets/cm 2 and estimated deposited volume, 22.2-9.4†L/ha. The respective ones reached with the computer program were: 402-58†μm, 161-32†μm, 21.9-7.5†drop- lets/cm 2 and 21.9-9.2†L/ha. Graphs of the spatial distribution of droplet density and deposited spray volume on the area were produced by the computer program.

Priorização de regiões do Cerrado brasileiro para o monitoramento de Helicoverpa armigera (Lepidoptera: Noctuidae)

The objective of this work was to detect priority regions of the Brazilian Cerrado for monitoring of Helicoverpa armigera (Lepidoptera: Noctuidae). Municipalities with high production of cotton, soybean, corn, tomato, beans, coffee, orange, pine, and eucalyptus, based on data from the Brazilian Institute of Geography and Statistics, were considered in 2012. This information was spatialized and crossed with the occurrence of Cerrado areas, using ArcGIS 10.3. One hundred forty‑one municipalities located in eight states and in the Federal District were prioritized. The crops evaluated and found in these sites should be under constant monitoring, even when out of action range, because they are potentially subject to the migration of moths.

Estimativa de estádios ninfais do psilídeo-de-concha em função dos tamanhos das conchas

O psilideo-de-concha, Glycaspis brimblecombei, e considerado praga quarentenaria de elevada importância economica para o setor florestal no Brasil pela preferencia a Eucaliptus camaldulensis – especie mais plantada no pais. A insuficiencia de metodos quimicos, aceitaveis pelas empresas certificadas internacionalmente, para o controle da praga vem tornando a estrategia de controle biologico pelo parasitoide Psyllaephagus bliteus a opcao mais apropriada no momento. Por esta razao, a disponibilidade de metodos que ajudem a detectar fases de desenvolvimento da praga mais apropriadas ao parasitismo e de grande importância tanto para a identificacao precisa do seu ciclo de vida quanto a proposicao de estrategias de seu controle biologico. O objetivo deste trabalho foi identificar faixas de tamanhos de concha de G. brimblecombei, de modo a utiliza-las como padrao de referencia para um metodo inedito de estimativas de estadios ninfais de desenvolvimento da praga em funcao do seu respectivo tamanho de concha amostrado. Essas faixas (ou classes de tamanhos) foram obtidas atraves de minucioso trabalho entomologico realizado em laboratorio, onde os diâmetros das conchas e seus respectivos insetos foram medidos com auxilio de lupa e avaliados quanto aos estadios de desenvolvimento. Posteriormente, foram realizadas analises estatisticas e de tendencias. As seguintes classes de tamanhos de concha foram determinadas como resultado: Ninfa 1 – de 0,7 mm a 0,9 mm; Ninfa 2 – de 0,8mm a 1,1 mm; Ninfa 3 – de 1,1 mm a 1,7 mm; Ninfa 4 – de 1,6 mm a 2,2 mm;e Ninfa 5 – de 2,2 mm a 2,8 mm.