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Made available in DSpace on 2022-04-28T19:44:49Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 The aim of this study was to assess the efficacy of imazamox for control of S. molesta and to assess the effects of plant decomposition on environmental indicators after application of this herbicide in microcosm conditions. The following rates were used: 600, 700, 800 and 900 g ai ha−1 and spray volume 50 L ha−1. Control efficacy was determined as the percentage (from 0 to 100%) of visible injury symptoms in the plants, biochemical and chemical oxygen demand (BOD5 and COD), water quality variables, chlorophyll a and pheophytin a at 0, 7, 15, 30, 45 and 60 days after application (DAA) and fresh and dry biomass at 60 DAA. Imazamox was effective in controlling 94% of S. molesta with 900 g ai ha−1; it reduced 95% of fresh weight and 92% of dry weight of plant at 60 DAA, and reduced chlorophyll a of the plants for all rates. For BOD5, there was an increase for all rates at 15, 30 and 45 DAA with restoration of the parameters at 60 DAA, and for COD, there was an increase at 60 DAA with 700 and 900 g ai ha−1. For temperature, pH, dissolved oxygen and electrical conductivity, there was no significant effect after spraying. Imazamox was effective in controlling S. molesta with 900 g ai ha−1 without causing significant effects on the physical-chemical parameters of water quality. College of Agricultural and Veterinary Science São Paulo State University University Center of the Barretos Educational Foundation Ecosafe - Agriculture and Environment Department of Plant Health College of Agricultural and Veterinary Science São Paulo State University College of Agricultural and Veterinary Science São Paulo State University Department of Plant Health College of Agricultural and Veterinary Science São Paulo State University

The aim of this study was to assess the efficacy of imazamox for control of

This study aimed to assess, in a microcosm condition, the efficacy of electrostatic spraying of herbicide imazamox in the control of

Made available in DSpace on 2021-06-25T23:35:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-12-08 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Companhia Energetica de Sao Paulo (CESP) This study aimed to assess, in a microcosm condition, the efficacy of electrostatic spraying of herbicide imazamox in the control of Salvinia molesta and the effects of decomposition of plant material on water quality. The herbicide rates used were 600, 700, 800, and 900 g ai ha(-1) and spray volume of 50 L ha(-1) in electrostatic application. Control effectiveness was assessed at 7, 15, 30, 45, and 60 days after application (DAA), expressed in percentage (0-100%) of visible injury symptoms in the plants, biochemical oxygen demand (BOD5), chemical oxygen demand (COD), chlorophyll a and pheophytin a contents at 0, 7, 15, 30, 45, and 60 DAA, and fresh and dry biomass at 60 DAA. Imazamox was effective in controlling 63% of S. molesta with 900 g ai ha(-1) in 45 DAA and 30% with 800 g ai ha(-1) in 30 DAA, and reduced 82.3% and 17.5% of fresh weight and 62.6% and 9.3% of dry weight of plant at 60 DAA, respectively. The imazamox spray reduced chlorophyll a with all doses applied and increased BOD5 in 45 DAA with 900 g ai ha(-1) and COD in all assessment periods, but for temperature, dissolved oxygen, electrical conductivity, and pH, there was no significant effect after spraying. The herbicide imazamox reduced S. molesta plants with 900 g ai ha(-1), without causing significant effects on environmental indicators of water quality. Electrostatic spraying of herbicide can be used in management strategies of aquatic plants to reduce plant density in water bodies and maintain the colonization of plants at a level not harmful to the aquatic biota. Sao Paulo State Univ, Coll Agr & Vet Sci, Jaboticabal, SP, Brazil Univ Ctr, Barretos Educ Fdn, Sao Paulo, Brazil Ecosafe Agr & Environm, Sao Paulo, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Plant Hlth, Sao Paulo, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Jaboticabal, SP, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, Dept Plant Hlth, Sao Paulo, Brazil CAPES: 001 CNPq: 156212/2019-6 Companhia Energetica de Sao Paulo (CESP): PD-00061-0052/2016

The efficacy of imazamox to control Eichhornia crassipes with a centrifugal energy spray nozzle at doses and volumes of spray solution and the costs of mechanical and chemical control of aquatic plants were evaluated in this study. Imazamox doses consisted of 200, 400, and 600 g a.i. ha-1, and spray solution volumes consisted of 25, 50, and 100 L ha-1, with a control (without herbicide application) and ten replications. Applications were performed with a centrifugal energy spray nozzle. The evaluations were carried out considering the percentage of control at 7, 15, 21, and 30 days after application (DAA), and plant dry matter was measured at 30 DAA, as well as leaf retention of spray solutions. An efficacy from 96 to 100% and plant dry matter reduction from 88 to 100% was observed at 30 DAA using imazamox doses of 200, 400, and 600 g a.i. ha-1 and a spray solution volume of 50 L ha-1. Imazamox doses and spray solution volumes were effective in controlling E. crassipes, except for 200 g a.i. ha-1 and 25 L ha-1, respectively. The highest leaf retention of E. crassipes was 0.010 mL cm2 at an imazamox dose of 400 g a.i. ha-1 and volume of 50 L ha-1. The cost of chemical control was 20 times lower when compared to mechanical control, making it economically more viable. These results are important for decision-making on which method and application technology should be used to control E. crassipes. RESUMO: Neste estudo foi avaliada a eficácia do imazamox para controle de E. crassipes, com bico de pulverização de energia centrífuga em doses e volumes de calda de pulverização e comparação do custo de controle mecânico e químico de plantas aquáticas. Foram utilizadas as doses de 200, 400 e 600 g i.a. ha-1 de imazamox e volumes de calda de 25, 50 e 100 L ha-1, além de um controle (sem aplicação do herbicida), com dez repetições. As aplicações foram feitas com bico de pulverização de energia centrífuga. As avaliações foram realizadas por porcentagem de controle em 7, 15, 21 e 30 dias após a aplicação (DAA), e a massa seca das plantas foi mensurada aos 30 DAA, assim como a retenção foliar das caldas de pulverização. Aos 30 DAA, em 200, 400 e 600 g i.a. ha-1 e 50 L ha-1, ocorreu eficácia de 96% a 100% e redução da massa seca das plantas de 88% a 100%. As doses e volumes de calda do imazamox foram eficazes no controle de E. crassipes, exceto 200 g i.a. ha-1 e 25 L ha-1. A maior retenção foliar do aguapé foi de 0,010 mL cm² na concentração de 400 g i.a. ha-1 e 50 L ha-1. O custo do controle químico foi 20 vezes menor que o mecânico, o que o torna economicamente mais viável que este. Esses resultados são importantes para a tomada de decisão sobre qual método e tecnologia de aplicação devem ser utilizados no controle de E. crassipes.

Made available in DSpace on 2022-04-28T19:05:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 The aim of this research was to evaluate the feasibility for the use of the organisms Lemna minor, Azolla caroliniana, Hyphessobrycon eques, Pomacea canaliculata and Daphnia magna as exposure bioindicators for ethanol (lethal and effective concentration 50%-LC50(I)/EC50(I)). Thus, the following concentrations were used 5.0; 10.0; 20.0; 30.0; 40.0 and 50.0 mg L-1 ethanol on L. minor; 25.0; 50.0; 75.0; 100.0; 150.0 and 200.0 mg L-1 on A. caroliniana; 0.3; 0.5; 1.0; 2.0 and 3.0 mg L-1 on H. eques; 0.05; 0.10; 0.20; 0.40 and 0.80 mg L-1 on P. canaliculata; and 40.0; 60.0; 80.0; 100.0; 120.0 and 140.0 mg L-1 on D. magna. An untreated control was also kept for all organisms, with three repetitions. The increase in the ethanol concentration elevated the electrical conductivity and decreased the water dissolved oxygen and pH. The ethanol LC50 for L. minor and A. caroliniana were 12.78 and 73.11 mg L-1, respectively, and was classified as slightly toxic; 1.22 mg L-1 for H. eques (moderately toxic); 0.39 mg L-1 for P. canaliculata (highly toxic) and 98.85 mg L-1 for D. magna (slightly toxic). Thus, H. eques and P. canaliculata have showed good potential for the use as ethanol exposure bioindicators on water bodies. Núcleo de Estudos e Pesquisas Ambientais em Matologia Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista “Júlio de Mesquita Filho”, Via de acesso Paulo Donato Castellane, s/n Fundação Educacional de Barretos Ecosafe-Agricultura e Meio Ambiente Núcleo de Estudos e Pesquisas Ambientais em Matologia Faculdade de Ciências Agrárias e Veterinárias Universidade Estadual Paulista “Júlio de Mesquita Filho”, Via de acesso Paulo Donato Castellane, s/n

The objective of this study was to evaluate the feasibility of the use of macrophytes Lemna minor and Azolla caroliniana as biomarkers of exposure (acute toxicity) for atrazine, bentazon + imazamox and clomazone, insecticide alpha cypermethrin + teflubenzuron and fungicides pyraclostrobin and mixture pyraclostrobin + epoxiconazole, as well as the risk for environmental intoxication. For this purpose, four plants of L. minor and five of A. caroliniana were selected in a 50 mL Hoagland medium. For both plants, the following concentrations were used: 0.10; 1.07; 3.44; 11.16; 36.40 and 118.0 mg L-1 of each test product and a control with three replicates. The results of this study demonstrated higher sensitivity of L. minor to the tested pesticides, when compared to A. caroliniana. L. minor can be used in the monitoring of herbicides bentazon, atrazine and clomazone and pyraclostrobin-based fungicide, and A. caroliniana can be used for pyraclostrobinbased fungicides, due to the sensitivity of these organisms when exposed. RESUMO O objetivo deste estudo foi avaliar a viabilidade na utilização das macrófitas Lemna minor e Azolla caroliniana como bioindicadores de exposição (toxicidade aguda) dos herbicidas atrazina, bentazon + imazamox e clomazone, do inseticida alfacipermetrina + teflubenzuron e dos fungicidas piraclostrobina e mistura piraclostrobina + epoxiconazol, bem como o risco de intoxicação ambiental. Para isso, foram selecionadas quatro plantas de L. minor e cinco de A. caroliniana em 50 mL de meio de cultivo Hoagland. Em ambas as plantas foram utilizadas as concentrações de 0,10, 1,07, 3,44, 11,16, 36,40 e 118,0 mg L-1 de cada produto testado e um controle, com três réplicas. Os resultados obtidos neste estudo demonstraram maior sensibilidade da planta L. minor, comparada a A. caroliniana, aos agrotóxicos testados. L. minor pode ser empregada no monitoramento de herbicidas à base de bentazon, atrazina e clomazone e do fungicida à base de piraclostrobina, e A. caroliniana, do fungicida à base de piraclostrobina, devido à sensibilidade desses organismos quando expostos.

The aim of this study was to assess the effectiveness of glyphosate, as Rodeo(r) formulation, to control Eichhornia crassipes, Pistia stratiotes, Salvinia molesta, Salvinia herzogii and Urochloa subquadripara, under greenhouse conditions. The doses assessed were (480, 960, 1440, 1920, 2400, 2880, 3360 and 3840 g ha-1 of glyphosate) with 0.5% of the Aterbane(r) BR surfactant and a control, with no herbicide application. All experiments were conducted in a completely randomized experimental design with ten replications. Applications were carried out by precision backpack sprayer at a CO2 constant pressure of 25 psi and spray solution consumption of 200 L ha-1. Product effectiveness was determined by assessing the growth inhibitions and phytotoxicity signals during the periods of 3, 7, 15, 21, 30 and 45 days after application (DAA). At 45 DAA, the highest glyphosate dose (3840 g ha-1) displayed 100% effectiveness for all four macrophyte species. Under greenhouse conditions, the glyphosate in formulation Rodeo(r) with 0.5% of Aterbarne(r) BR surfactant showed excellent effectiveness, inhibiting the growth of the floating aquatic macrophytes. This procedure can be included on the tillage plans for these species. O objetivo deste estudo foi avaliar a eficácia do herbicida glyphosate na formulação Rodeo(r) para controle da Eichhornia crassipes, Pistia stratiotes, Salvinia molesta, Salvinia herzogii e Urochloa subquadripara, em condição de casa de vegetação. As doses avaliadas foram: 480, 960, 1440, 1920, 2400, 2880, 3360 e 3840 g ha-1 de glyphosate, com adição de 0,5% do surfatante Aterbane(r) BR e um controle sem aplicação do herbicida. Todos os experimentos foram instalados no delineamento experimental inteiramente casualizado com dez repetições. As aplicações foram efetuadas com pulverizador costal de precisão em pressão constante de CO2 de 25 p.s.i. e consumo de calda de 200 L ha-1. A eficácia do produto foi determinada avaliando-se inibições no crescimento e os sinais de fitotoxicidade durante os períodos de 3, 7, 15, 21, 30 e 45 dias após a aplicação (DAA). Aos 45 DAA, a maior dose do glyphosate (3840 g ha-1) apresentou 100% de eficácia para as quatro macrófitas. Em condições de casa de vegetação, o glyphosate na formulação Rodeo(r) acrescido de 0,5% de surfatante Aterbarne(r) BR apresentou excelente eficácia, com inibição do crescimento de macrófitas aquáticas flutuantes, e pode ser incluído em um plano de manejo dessas plantas.

The fish Hyphessobrycon eques and Piaractus mesopotamicus, the snail Pomacea canaliculata, the aquatic plant Lemna minor and the microcustacean Daphnia magna were selected to evaluate the lethal or effective concentration (LC50/EC50) and the environmental risk of florfenicol (FLO), enrofloxacine (ENR), thiamethoxan (TH) and toltrazuril (TOL). For this, the organisms were acclimated in a bioassay room under controlled temperature and photoperiod, and then exposed to increasing drugs concentrations according to specific standard for each organism. L. minor is the sole organism which showed toxicity to FLO LC50; 48 h of 97.03 mg/L, which causes medium environmental risk. P. canaliculata was more sensible to ENR (14.64 mg/L), which causes high risk to the bioindicators. P. mesopotamicus was more sensible to TH toxicity (16.97 mg/L), which causes high risk also; followed by H. eques. TOL causes medium risk and it is more toxic for P. mesopotamicus (3.72 mg/L), followed by H. eques. L. minor can be used as a bioindicator for florfenicol toxicity, P. canaliculata for enrofloxacine and H. eques for TH and TOL, emphasizing that enrofloxacine and thiamethoxan cause high environmental risk. Key words: Environmental monitoring, disease, environmental impact, chemotherapeutic products, aquaculture drugs.

Made available in DSpace on 2015-10-22T07:22:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01. Added 1 bitstream(s) on 2015-10-22T09:45:58Z : No. of bitstreams: 1 S0100-83582015000100103.pdf: 244227 bytes, checksum: 523bcde80a37ddff0dbdda7fa3838f90 (MD5) O objetivo deste estudo foi determinar a eficácia do imazapyr no controle de macrófitas flutuantes e a ecotoxicidade para organismos não alvos. Para os ensaios de eficácia de controle das macrófitas flutuantes, foram utilizadas as doses de 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 e 4,0 L ha-1 e um controle com 10 réplicas. A toxicidade aguda para organismos não alvos foi estimada pela concentração letal de 50% (CL50 e CE50). A eficácia de controle para as macrófitas flutuantes foi acima de 90%. O imazapyr foi classificado como moderadamente tóxico para os bioindicadores L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata e P.mesopotamicus e ligeiramente tóxico para A. caroliniana. Assim, o herbicida imazapyr é uma ferramenta com grande potencial para ser usada no controle de macrófitas flutuantes (E. crassipes, P. stratiotes e S. molesta) no Brasil, e a sua utilização pode ser avaliada por meio de bioindicadores de aplicação. the aims of this study were to determine imazapyr efficacy for floating macrophyte control and ecotoxicology for non-target organisms. For the floating macrophyte control efficacy tests were used the doses of 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 and 4,0 L ha(-1) and a control with 10 replicates. The acute toxicology for non-target organisms was estimated by lethal concentration 50% (LC50 and EC50). The floating macrophyte control efficacy was over 90%. Imazapyr was classified as moderately toxic for the following biomarkers: L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata, and P. mesopotamicus and lightly toxic for A. caroliniana. Thus, imazapyr herbicide is a tool with great potential to be used on floating macrophyte control (E. crassipes, P. stratiotes e S. molesta) in Brazil and this practice can be evaluated by the use of application biomarkers. Ctr Univ Fundacao Educ Barretos, Barretos, SP, Brazil UNESP, Nucl Estudos &Pesquisas Ambientais Matol, Jaboticabal, SP, Brazil Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias de Jaboticabal, Nucl Estudos &Pesquisas Ambientais Matol, Jaboticabal, SP, Brazil

The goal of this study was to evaluate the effectiveness of diquat, both isolated and associated with copper sources (oxychloride and hydroxide) in controling the H. verticillata submerged macrophyte and the A. gracilis microalgae. For this purpose, 10.0 cm H. verticillata young branches and 300 mL of A. gracilis culture were used. The experiments were performed in laboratory and the tested diquat concentrations were: 0.1; 0.2; 0.4; 0.8; 1.2; and 1.8 mg L-1, either isolated or added with 1.0% copper oxychlorideand hydroxide, as well as a control sample. On day 3, 7, 11, 21 and 30 after application, phytotoxicity signs were evaluated and on day 60 after application, green and dry biomass production and plant length were measured. To obtain dry mass, plants remained in a greenhouse with forced air circulation at 65.0 oC, until constant weight. On day 1, 7, 15, 21, 30, 45 and 60 after application, the concentration of chlorophyll a in the water was assessed. The herbicide diquat used alone or in combination with sources copper oxychloride and hydroxide was effective in the control of H. verticillata and microalgae A. gracilis. RESUMO O objetivo deste estudo foi avaliar a eficácia do diquat isolado e em mistura com fontes de cobre (hidróxido e oxicloreto) para o controle da macrófita submersa Hydrilla verticillata e da microalga A. gracilis. Para isso, foram utilizados ponteiros com 10,0 cm de H. verticillata e 300 mL de cultura de A. gracilis. Os experimentos foram conduzidos em laboratório, e as concentrações de diquat testadas foram: 0,1; 0,2; 0,4; 0,8; 1,2; e 1,8 mg L-1 isoladas ou acrescidas de 1,0% de oxicloreto de cobre e de hidróxido de cobre, além de um controle. Aos 3, 7, 11, 21 e 30 dias após aplicação foram avaliados os sinais visuais de fitotoxicidade, e aos 60 dias após aplicação foi mensurada a produção de biomassa fresca e seca e o comprimento das plantas. Aos 1, 7, 15, 21, 30, 45 e 60 dias após aplicação foi avaliada a concentração de clorofila a presente na água. O herbicida diquat utilizado de forma isolada ou em mistura com as fontes de cobre oxicloreto e hidróxido foi efetivo no controle de H. verticillata e da microalga A. gracilis.

Os objetivos deste estudo foram determinar a eficácia de controle dos herbicidas imazamox e saflufenacil, isolados e em mistura com hidróxido de cobre (fonte de íon cobre) no controle da macrófita (Ceratophyllum demersum) e determinar a eficácia de controle de alga unicelular (Ankistrodesmus gracilis) e filamentosa (Pitophora kewensis) das misturas imazamox + 0,1% de cobre e saflufenacil + 0,1% de cobre, em condição de laboratório. Para o controle de C. demersum, os experimentos foram instalados com as concentrações de 0,01; 0,1; 1,0; 2,5; 5,0; e 10,0 mg L-1 imazamox e saflufenacil isolados ou acrescido de 0,1% de fonte cobre. Para os experimentos com alga unicelular (70 mL da água coletada) e alga filamentosa (1,0g) foi utilizado a concentrações 0,01; 0,1; 1,0; 2,5; 5,0; e 10,0 mg L-1 imazamox e saflufenacil acrescidos de 0,1% de cobre. Após o término do experimento foi determinado à concentração de clorofila a e feofitina a presentes nas amostras. Com a utilização de imazamox + 0,1% de cobre ocorreu redução de 100% do peso e do comprimento da macrófita a partir de 2,5 mg L-1. Com o saflufenacil + 0,1% de cobre ocorreu 100% de mortalidade das plantas em 1,0 mg L-1. As misturas testadas também foram eficazes na redução da atividade fotossintética de algas unicelulares e filamentosas. A aplicação dos herbicidas imazamox e saflufenacil acrescidos de 0,1% de hidróxido de cobre apresenta sinergismo no controle de macrófitas submersas e pode apresentar efeito secundário algicida.

Successful disease treatment depends on molecular studies under indoor conditions with experimental infection protocols that facilitate understanding the disease and the drug`s efficacy. The internal transcribed spacer (ITS) region was sequenced from three isolates, which were identified as Saprolegnia aenigmatica . Subsequently, healthy fish were immunosuppressed with dexamethasone (1.2 mg kg -1 ) and descaled to the skin using a sharp scalpel. These individuals were isolated in individual aquariums maintained at 22°C. Individuals in one group were subcutaneously inoculated with 9,000 zoospores (DDZ treatment), a second group was exposed to oomycetes in water with three colonized baits (DDB), a third group was maintained in water without zoospores (DD), and a control group (C) consisted of healthy animals. After 48 and 96 hours, two animals from each group were euthanized for fungal re-isolation. The fish from groups DD and C did not show clinical signs, and no oomycetes were isolated. The animals from the DDZ and DDB groups showed cotton-wool-like masses on the skin, and S . aenigmatica was re-isolated. Thus, for infection using zoospores or baits parasitized by S. aenigmatica , an immunosuppressor (dexamethasone) and a sharp scalpel can be used effectively to establish an experimental infection in P. mesopotamicus.

Made available in DSpace on 2018-11-26T16:19:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-04-02 ABSTARCTThe aims of this research were to evaluate the efficacy of copper oxychloride (CuCl2.3Cu(OH)(2)), copper hydroxide (Cu(OH)(2)) and diquat (1.1-ethylene-2.2-bipyridyldiylium dibromide), isolated and in association with 0.1% of both copper sources, in the control of the unicellular algae Ankistrodesmus gracilis and the filamentous algae Pithophora kewesis, and to determine the acute toxicity of the tested chemicals in Hyphressobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana. The efficacy was estimated by the methods of chlorophyll a and pheophytin a readings, changed into growth inhibition percentage. Both algae were exposed to the following concentrations: 0.2; 0.4; 0.8; 1.2mg L-1 of diquat and its association with the copper sources; and 0.1; 0.3; 0.5; 0.7; 1.0 and 1.5mg L-1 in the isolated applications of copper hydroxide and copper oxychloride. An untreated control was kept. The acute toxicity was estimatedby 50% lethal concentration (LC50). The copper sources were effective for A. gracilis control, at rates as high as 0.1mg L-1 (>95% efficacy). Isolated diquat and its association with copper hydroxide were both effective at rates as high as 0.4mg L-1, with 95 and 88% control efficacy, respectively. The copper oxychloride was effective at 0.2mg L-1, with 93% efficacy. None of the tested chemicals and associations was effective on P. kewesis control. The most sensitive non target organism to the tested chemicals was L. minor; the less sensitive was H. eques. Sao Paulo State Univ, Coll Agr & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil Barretos Educ Fdn, Univ Ctr, Barretos, SP, Brazil Fisheries Inst Sao Paulo, Sao Paulo, Brazil Sao Paulo State Univ, Ctr Coll Agr & Vet Sci, Weed Sci Environm Res Studies, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Dept Appl Biol, Coll Agr & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Coll Agr & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Ctr Coll Agr & Vet Sci, Weed Sci Environm Res Studies, BR-14884900 Jaboticabal, SP, Brazil Sao Paulo State Univ, Dept Appl Biol, Coll Agr & Vet Sci, BR-14884900 Jaboticabal, SP, Brazil

The objective of this study was to evaluate the consumption potential, food preference and use of snail Pomacea canaliculata as a biocontrol agent of four submerged aquatic macrophytes (Ceratophyllumdemersum, Egeriadensa, Egerianajas and Hydrilla verticillata). Two experiments were performed. In the first experiment, the introduction of a snail took place and 10 grams of each macrophyte in plastic containers with 1 liter of water. The assessments of consumption by the snail were performed at each 48 hours, during 12 days. The second experiment was performed in 600 liters microcosms containing five snails in each experimental unit. Fifty grams of each macrophyte were offered the snails at the same time, adding the same amounts after seven, 14, 21 and 30 days. On both trials, the most consumed macrophyte by the P.canaliculata was H.verticillata (7.64 ± 1.0 g 48 h and 50 ± 0.18 g) respectively, significantly differing from the others. However, in the absence of H.verticilata, E.najas and E.densa were consumed. The preference of P.canaliculata for H.verticillata is very interesting, because this plant is exotic and problematic in Brazil, and the snail is one more tool for biological management of submerged aquatic macrophyte H.verticillata. RESUMOO objetivo deste estudo foi avaliar o potencial de consumo, a preferência alimentar e o uso do caramujo Pomacea canaliculata como agente de biocontrole de quatro macrófitas aquáticas submersas (Ceratophyllum demersum, Egeria densa, Egeria najas e Hydrilla verticillata). Para isso, dois experimentos foram realizados. No primeiro, foi feita a introdução de um caramujo e 10 gramas de cada macrófita em recipientes plásticos contendo 1 litro de água. A cada 48 horas foram realizadas avaliações do consumo do caramujo, no total de seis avaliações. O segundo experimento foi feito em microcosmos com capacidade para 600 litros de água, contendo cinco caramujos em cada unidade experimental. Cinquenta gramas de cada uma das macrófitas foram oferecidos aos caramujos ao mesmo tempo, acondicionando-se as mesmas quantidades após 7, 14, 21 e 30 dias. Tanto no primeiro quanto no segundo ensaio, a macrófita mais consumida por P. canaliculata foi H. verticillata (7,64 ± 1,0 g 48 h), diferindo significativamente das demais. H. verticillata (50 ± 0,18 g) foi a planta preferida pelo caramujo no segundo experimento, em relação às demais macrófitas, porém, na ausência de H. verticillata, E. najas e C. demersum foram consumidas. A preferência de P. canaliculata por H. verticillata é muito interessante, por esta planta ser exótica e problemática no Brasil, sendo o caramujo mais uma ferramenta para uso no manejo biológico da macrófita aquática submersa H. verticillata.

A gramínea B. decumbens é a mais cultivada em formação de pastagens no Brasil, em áreas são utilizadas para outros cultivos torna-se uma das plantas daninhas mais indesejadas, devido o seu difícil controle e rusticidade. Assim, o objetivo deste estudo foi determinar a emergência das plântulas de B. decumbens em profundidades de semeadura. Os ensaios foram realizados em casa de vegetação com as seguintes profundidades de semeadura (0,0; 0,5; 1,0; 1,5; 2,0; 2,5; 3,0; 4,0; 5,0; 6,0; 7,0; 8,0; 9,0 e 10,0 cm). A partir de 7,0 cm de profundidade ocorreu redução significativa no índice de velocidade de emergência (IVE) e na porcentagem de emergência das plântulas (%E) de B. decumbens. A emergência de plântulas de B. decumbens é afetada pela profundidade das sementes no perfil do solo.