As soqueiras de cana-de-açúcar (Saccharum spp.) são colhidas anualmente, momento em que são expostas a uma grande interferência negativa interespecífica das plantas daninhas, sendo essencial o manejo destas plantas para obtenção de uma produtivade economicamente rentável da cultura. Comumente este controle é feito com a aplicação de herbicidas residuais em condições de pré ou pós-plantio através da recomendação de acordo com a infestação local. Apesar da existência de várias opções de controle químico de plantas daninhas em pré-emergência na cultura da cana-de-açúcar, novas opções de formulaçõoes de herbicidas são necessárias. Sendo assim, esta pesquisa teve o objetivo de estudar uma nova associação de moléculas, imazapic e imazapyr, para o controle das plantas daninhas em cana-de-açúcar, através da avaliação da influência de parâmetros de solo e culturais, na eficácia de controle de plantas daninhas e seletividade para a cultura. Para este propóstito foram conduzidos experimentos em condições de campo e casa de vegetação. Em condições de campo, em agosto de 2012 foram instalados experimentos em áreas de solos arenoso e argiloso com e sem palhada, para avaliação da eficácia da associação de imazapic e imazapyr no controle de plantas daninhas e da seletividade à cultura, no qual as menores doses testadas de (imazapic + imazapyr), em todas as situações continuaram eficientes no controle da comunidade infestante até 120 dias após a aplicação, equiparando estatisticamente aos tratamentos com maiores doses, aos tratamentos associados ao tebuthiuron e aos padrões, com a ausência de sintomas fitotóxicos nas variedades. Para avaliação da fitotoxidade foram instalados três experimentos durante o mês de novembro de 2012 sobre soqueira de 2º corte, nos quais foram feitas aplicações do (imazapic + imazapyr) isolado e associados a outros herbicidas nos estádios de pré-emergência total, pós-inicial e pós-tardia da cultura, sendo possível observar a seletividade quando aplicada a dose (80,25 + 26,25 g imazapic + imazapyr ha-1) na modalidade de pré-emergência, como também quando associada ao tebuthiuron, metribuzin e clomazone. Foram realizados estudos em casa de vegetação para avaliação de características do herbicida quanto à capacidade de lixiviação pela palha em relação à precipitação, quanto ao período residual durante época seca, quanto à lixiviação do herbicida da superfície às diferentes camadas de solo, e quanto ao controle de espécies daninhas em diferentes texturas de solo. Volumes de 10 e 20 mm de água foram suficientes para promover a transposição do herbicida sobre a camada de palha em solo argiloso e médio-arenoso, respectivamente, apresentando atividade do (imazapic + imazapyr) no controle do bioindicador mesmo após 120 dias sem irrigação após a aplicação do herbicida, quando aplicado sobre a palha ou sobre o solo. A presença do herbicida foi observada até a camada 10-20 cm de profundidade, pelos índices de controle do bioindicador resultantes da lixiviação, e do efeito residual em solo arenoso e argiloso aos 75 e 90 dias após a aplicação, sendo de um modo geral as associações (imazapic + imazapyr) + clomazone e (imazapic + imazapyr) + tebuthiuron foram as mais eficientes no controle das espécies daninhas estudadas. / The weed management is essential in sugarcane crop. After the harvest, sugarcane ratoons are exposed to interspecific weed competition, and its control usually is done with residual herbicides in pre or post-planting according to the local infestation. Although there are several options for weed chemical control inn sugar cane, new options of formulations are needed. Thus, this research aimed to study the imazapic and imazapyr association through the evaluation of soil parameters influence, the efficacy of weed control and selectivity for the sugar cane. For this purpose field and greenhouse experiments were conducted. In August 2012, field experiments were conducted in sandy and clay soils areas, with and without crop residues to evaluate the effectiveness of imazapic + imazapyr on weed control and selectivity to sugarcane, in which the lower doses tested of imazapic + imazapyr were enough to control the weeds until 120 day after application equating to higher doses in association to tebuthiuron and standard treatments, without phytotoxic symptons in the studied varieties. To evaluate the phytotoxicity, three experiments were installed in november 2012 on second ratoon, Imazapic + imazapyr was selective when applied at 80.25 + 26.25 g ha-1 in pre-emergence, as well as associated with tebuthiuron, metribuzin and clomazone. In early post-emergence, selectivity was noted when applied at 80.25 + 26.25 g imazapic + imazapyr ha-1, as by the association of this rate with the herbicides clomazone and isoxaflutole. However, the application in late post-emergence proved to be non-selective for any use of the association of the herbicides imazapic + imazapyr. Other studies were conducted in a greenhouse to evaluate the the herbicide association ability to leach the straw in relation to rainfall volume, the residual period during the dry season, the herbicide leaching from the surface into different layers of soil as the weed species control in different soil textures. Simulated rainfall volumes from 10 to 20 mm were sufficient to promote herbicide transposition through the straw to clay and mediumsandy soil, respectively. Imazapic + imazapyr effects on bio-indicator showed that even after 120 days of drought conditions after application, when applied on straw or to the soil. Imazapic + imazapyr were able to leach in the sandy and clay soils up to 10-20 cm deep layer, and residual effect at 75 and 90 days after application in sandy and clay soil. Generally, better weed control levels were obtained by the association of imazapic, imazapyr and clomazone, and imazapic, imazapyr and tebuthiuron.

Os benefícios advindos da tecnologia Roundup Ready são expressivos, e a aceitação desta tecnologia pelos produtores rurais é inegável, dando suporte para o rápido crescimento das áreas da soja RR. Mas ao mesmo tempo resultados de pesquisas recentes indicam que o glyphosate aplicado em pós-emergência, em soja RR, pode em algumas situações, além de gerar efeitos fitotóxicos, influenciar o balanço nutricional, afetar a fotossíntese, a rizosfera, o acúmulo de biomassa, a síntese de aminoácidos e compostos secundários, a eficiência no uso da água, e ainda a qualidade das sementes produzidas. Porém, persistem muitas especulações e dúvidas que precisam ser melhores elucidadas, no âmbito científico e técnico, envolvendo a questão da soja transgênica (RR). Em virtude deste fato faz-se necessária a busca de informações que permitam diagnosticar as reais consequências do uso do glyphosate. Deste modo, o presente trabalho teve por objetivo avaliar o impacto da aplicação de diferentes doses, manejos e formulações de glyphosate, na soja RR, em distintos ambientes de produção. Para isso foram conduzidos dois experimentos principais, em duas safras, em diferentes locais, e alguns experimentos complementares. Foi utilizado, na maioria dos experimentos, arranjo fatorial 2X2X5 (formulações X manejos X doses), totalizando 20 tratamentos. Nestes ensaios foram avaliadas diversas variáveis relacionadas ao desempenho agronômico. Os resultados alcançados permitiram caracterizar alguns problemas referentes ao uso de glyphosate em pós-emergência, na cultura da soja RR, identificando que altas doses são nocivas ao desempenho das plantas e produtividade. A partir dos resultados obtidos, espera-se fomentar um posicionamento mais seguro e sustentável desta tecnologia, possibilitando a diminuição de possíveis efeitos deletérios do glyphosate sobre a cultura da soja RR. / The benefits of the Roundup Ready technology are expressive and the acceptance of this technology by farmers is undeniable, giving support to the rapid growth of RR soybean crops. Recent studies indicate, however, that glyphosate applied in post-emergence in RR soybean can eventually cause phytotoxic effects, as well as influence the plant nutritional balance, affecting photosynthesis, the rhizosphere, biomass accumulation, amino acid synthesis and secondary compounds, water use efficiency, and the quality of seeds produced. Therefore, there are many speculations and questions that need to be clarified in the scientific and technical context, involving the issue of RR soybeans regarding the use of glyphosate. Thus, it is necessary the search for information allowing to diagnose the real consequences of its use. This study evaluated the impact of the application of different doses, management procedures and formulations of glyphosate, in RR soybean, in different production environments. For that purposes, were conducted two major experiments, in different harvests, in different locations, and some additional experiments. Were used a factorial design 2X2X5 (formulations X management X doses) totaling 20 treatments. Were evaluated several variables related to the agronomic performance. The results allowed to characterize some problems regarding the glyphosate use in post-emergence in RR soybeans, identifying that high doses are harmful to the plant performance and productivity. The results allow a better understanding and a more secure positioning of this technology, enabling the reduction of possible deleterious effects of glyphosate on RR soybeans.

Made available in DSpace on 2016-01-26T18:56:17Z (GMT). No. of bitstreams: 1 dissertacao_rodrigo.pdf: 152775 bytes, checksum: f2338214da0780d951520c726ab5576c (MD5) Previous issue date: 2008-11-17 / The sugarcane is one of most important cultures in Brazil, and is very important social and economically. The simultaneous use of nematicides with herbicides in sugarcane are growing every season, due to the positive along with productivities with the aim of these products. That coned responses in be explained due to high infestation of ectoparasitic nematode and weed in monoculture, when the application of these products is not accomplished. Some studies detected an interaction and a negative effect among the nematicides carbamates class, when they are associated to herbicides classified as substituted ureas. The objective this work was to study the biometricals and physiologicals parameters in cultivar RB72-454 in combined application with nematicide (Carbofuran) and herbicide (Tebuthiuron) with Al2(SO4)3 addition. The experiment was canned in pots of 20 L in greenhouse campus II - UNOESTE. In each recipients two stem were planted, with 20 cm of length. The treatments were the following: T1 - test; T2 - nematicide application carbofuran, at 2,975 kg a.i. for hectare; T3 - herbicide application (tebuthiuron), at 1 kg of a.i. for hectare; T4 nematicide application the carbofuran base, of 2,975 kg a.i. for hectare with application herbicide (tebuthiuron), at 1 kg of a.i. for hectare; T5 - nematicide application (carbofuran), at 2,975 kg a.i. for hectare with herbicide application (tebuthiuron), at 1 kg of a.i. for hectare, with more the addition of 27 mg Al for per kg of sail. In treatments of 600 kg was used by hectare of the formulation 8-28-16 as feeder. The work didn t show an interaction between Tebuthiuron and Carbofuran. A phytotoxic Tebuthiuron´s effect of was just detected with high sensibility equipments, and no Carbofuran´s phytotoxic effect was detected. / A cana-de-açúcar é uma das principais culturas do país, e assume um importante papel no cenário econômico e social brasileiro. O uso de nematicidas e herbicidas em cana de açúcar, principalmente em cana planta, tem aumentado significativamente, devido às boas respostas de produtividades quando de suas aplicações, estes aumentos de produtividades podem ser explicados devido a maior incidência de fitonematóides ectoparasitos e plantas invasoras em áreas com monocultura, quando não ocorre a utilização de nematicidas e herbicidas. O objetivo deste trabalho foi estudar os parâmetros biométricos de crescimento e os parâmetros fisiológicos da cultivar RB72-454 em situações de aplicação combinada de nematicida com herbicida e da adição Al2(SO4)3. O experimento foi conduzido em vasos de 20 L em ambiente controlado (casa de vegetação do campus II UNOESTE), sendo que em cada unidade experimental foram plantados com 2 toletes de 20 cm. Os tratamentos foram os seguintes: T1 testemunha; T2 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare; T3 Aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T4 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação do herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T5 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare, mais a adição de 27 mg Al por kg de terra; Em todos os tratamentos utilizou-se a adubação de 600 kg ha-1 da formulação 8-28-16. O trabalho mostrou que não ocorreu interação entre Tebuthiuron e Carbofuran, e que existe um efeito fitotóxico do Tebuthiuron detectado apenas com equipamentos de alta sensibilidade, e não foi detectado nenhum efeito fitotóxico do Carbofuran.

Made available in DSpace on 2016-01-26T18:56:18Z (GMT). No. of bitstreams: 1 DISSERTACAO COMPLETA.pdf: 152778 bytes, checksum: 583e8e29727e70694447a04afa042274 (MD5) Previous issue date: 2008-11-17 / The sugarcane is one of most important cultures in Brazil, and is very important social and economically. The simultaneous use of nematicides with herbicides in sugarcane are growing every season, due to the positive along with productivities with the aim of these products. That coned responses in be explained due to high infestation of ectoparasitic nematode and weed in monoculture, when the application of these products is not accomplished. Some studies detected an interaction and a negative effect among the nematicides carbamates class, when they are associated to herbicides classified as substituted ureas. The objective this work was to study the biometricals and physiologicals parameters in cultivar RB72-454 in combined application with nematicide (Carbofuran) and herbicide (Tebuthiuron) with Al2(SO4)3 addition. The experiment was canned in pots of 20 L in greenhouse campus II - UNOESTE. In each recipients two stem were planted, with 20 cm of length. The treatments were the following: T1 - test; T2 - nematicide application carbofuran, at 2,975 kg a.i. for hectare; T3 - herbicide application (tebuthiuron), at 1 kg of a.i. for hectare; T4 nematicide application the carbofuran base, of 2,975 kg a.i. for hectare with application herbicide (tebuthiuron), at 1 kg of a.i. for hectare; T5 - nematicide application (carbofuran), at 2,975 kg a.i. for hectare with herbicide application (tebuthiuron), at 1 kg of a.i. for hectare, with more the addition of 27 mg Al for per kg of sail. In treatments of 600 kg was used by hectare of the formulation 8-28-16 as feeder. The work didn t show an interaction between Tebuthiuron and Carbofuran. A phytotoxic Tebuthiuron´s effect of was just detected with high sensibility equipments, and no Carbofuran´s phytotoxic effect was detected. / A cana-de-açúcar é uma das principais culturas do país, e assume um importante papel no cenário econômico e social brasileiro. O uso de nematicidas e herbicidas em cana de açúcar, principalmente em cana planta, tem aumentado significativamente, devido às boas respostas de produtividades quando de suas aplicações, estes aumentos de produtividades podem ser explicados devido a maior incidência de fitonematóides ectoparasitos e plantas invasoras em áreas com monocultura, quando não ocorre a utilização de nematicidas e herbicidas. O objetivo deste trabalho foi estudar os parâmetros biométricos de crescimento e os parâmetros fisiológicos da cultivar RB72-454 em situações de aplicação combinada de nematicida com herbicida e da adição Al2(SO4)3. O experimento foi conduzido em vasos de 20 L em ambiente controlado (casa de vegetação do campus II UNOESTE), sendo que em cada unidade experimental foram plantados com 2 toletes de 20 cm. Os tratamentos foram os seguintes: T1 testemunha; T2 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare; T3 Aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T4 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação do herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T5 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare, mais a adição de 27 mg Al por kg de terra; Em todos os tratamentos utilizou-se a adubação de 600 kg ha-1 da formulação 8-28-16. O trabalho mostrou que não ocorreu interação entre Tebuthiuron e Carbofuran, e que existe um efeito fitotóxico do Tebuthiuron detectado apenas com equipamentos de alta sensibilidade, e não foi detectado nenhum efeito fitotóxico do Carbofuran.

Made available in DSpace on 2016-07-18T17:51:03Z (GMT). No. of bitstreams: 1 dissertacao_rodrigo.pdf: 152775 bytes, checksum: f2338214da0780d951520c726ab5576c (MD5) Previous issue date: 2008-11-17 / The sugarcane is one of most important cultures in Brazil, and is very important social and economically. The simultaneous use of nematicides with herbicides in sugarcane are growing every season, due to the positive along with productivities with the aim of these products. That coned responses in be explained due to high infestation of ectoparasitic nematode and weed in monoculture, when the application of these products is not accomplished. Some studies detected an interaction and a negative effect among the nematicides carbamates class, when they are associated to herbicides classified as substituted ureas. The objective this work was to study the biometricals and physiologicals parameters in cultivar RB72-454 in combined application with nematicide (Carbofuran) and herbicide (Tebuthiuron) with Al2(SO4)3 addition. The experiment was canned in pots of 20 L in greenhouse campus II - UNOESTE. In each recipients two stem were planted, with 20 cm of length. The treatments were the following: T1 - test; T2 - nematicide application carbofuran, at 2,975 kg a.i. for hectare; T3 - herbicide application (tebuthiuron), at 1 kg of a.i. for hectare; T4 nematicide application the carbofuran base, of 2,975 kg a.i. for hectare with application herbicide (tebuthiuron), at 1 kg of a.i. for hectare; T5 - nematicide application (carbofuran), at 2,975 kg a.i. for hectare with herbicide application (tebuthiuron), at 1 kg of a.i. for hectare, with more the addition of 27 mg Al for per kg of sail. In treatments of 600 kg was used by hectare of the formulation 8-28-16 as feeder. The work didn t show an interaction between Tebuthiuron and Carbofuran. A phytotoxic Tebuthiuron´s effect of was just detected with high sensibility equipments, and no Carbofuran´s phytotoxic effect was detected. / A cana-de-açúcar é uma das principais culturas do país, e assume um importante papel no cenário econômico e social brasileiro. O uso de nematicidas e herbicidas em cana de açúcar, principalmente em cana planta, tem aumentado significativamente, devido às boas respostas de produtividades quando de suas aplicações, estes aumentos de produtividades podem ser explicados devido a maior incidência de fitonematóides ectoparasitos e plantas invasoras em áreas com monocultura, quando não ocorre a utilização de nematicidas e herbicidas. O objetivo deste trabalho foi estudar os parâmetros biométricos de crescimento e os parâmetros fisiológicos da cultivar RB72-454 em situações de aplicação combinada de nematicida com herbicida e da adição Al2(SO4)3. O experimento foi conduzido em vasos de 20 L em ambiente controlado (casa de vegetação do campus II UNOESTE), sendo que em cada unidade experimental foram plantados com 2 toletes de 20 cm. Os tratamentos foram os seguintes: T1 testemunha; T2 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare; T3 Aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T4 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação do herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T5 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare, mais a adição de 27 mg Al por kg de terra; Em todos os tratamentos utilizou-se a adubação de 600 kg ha-1 da formulação 8-28-16. O trabalho mostrou que não ocorreu interação entre Tebuthiuron e Carbofuran, e que existe um efeito fitotóxico do Tebuthiuron detectado apenas com equipamentos de alta sensibilidade, e não foi detectado nenhum efeito fitotóxico do Carbofuran.

Made available in DSpace on 2016-07-18T17:51:03Z (GMT). No. of bitstreams: 1 DISSERTACAO COMPLETA.pdf: 152778 bytes, checksum: 583e8e29727e70694447a04afa042274 (MD5) Previous issue date: 2008-11-17 / The sugarcane is one of most important cultures in Brazil, and is very important social and economically. The simultaneous use of nematicides with herbicides in sugarcane are growing every season, due to the positive along with productivities with the aim of these products. That coned responses in be explained due to high infestation of ectoparasitic nematode and weed in monoculture, when the application of these products is not accomplished. Some studies detected an interaction and a negative effect among the nematicides carbamates class, when they are associated to herbicides classified as substituted ureas. The objective this work was to study the biometricals and physiologicals parameters in cultivar RB72-454 in combined application with nematicide (Carbofuran) and herbicide (Tebuthiuron) with Al2(SO4)3 addition. The experiment was canned in pots of 20 L in greenhouse campus II - UNOESTE. In each recipients two stem were planted, with 20 cm of length. The treatments were the following: T1 - test; T2 - nematicide application carbofuran, at 2,975 kg a.i. for hectare; T3 - herbicide application (tebuthiuron), at 1 kg of a.i. for hectare; T4 nematicide application the carbofuran base, of 2,975 kg a.i. for hectare with application herbicide (tebuthiuron), at 1 kg of a.i. for hectare; T5 - nematicide application (carbofuran), at 2,975 kg a.i. for hectare with herbicide application (tebuthiuron), at 1 kg of a.i. for hectare, with more the addition of 27 mg Al for per kg of sail. In treatments of 600 kg was used by hectare of the formulation 8-28-16 as feeder. The work didn t show an interaction between Tebuthiuron and Carbofuran. A phytotoxic Tebuthiuron´s effect of was just detected with high sensibility equipments, and no Carbofuran´s phytotoxic effect was detected. / A cana-de-açúcar é uma das principais culturas do país, e assume um importante papel no cenário econômico e social brasileiro. O uso de nematicidas e herbicidas em cana de açúcar, principalmente em cana planta, tem aumentado significativamente, devido às boas respostas de produtividades quando de suas aplicações, estes aumentos de produtividades podem ser explicados devido a maior incidência de fitonematóides ectoparasitos e plantas invasoras em áreas com monocultura, quando não ocorre a utilização de nematicidas e herbicidas. O objetivo deste trabalho foi estudar os parâmetros biométricos de crescimento e os parâmetros fisiológicos da cultivar RB72-454 em situações de aplicação combinada de nematicida com herbicida e da adição Al2(SO4)3. O experimento foi conduzido em vasos de 20 L em ambiente controlado (casa de vegetação do campus II UNOESTE), sendo que em cada unidade experimental foram plantados com 2 toletes de 20 cm. Os tratamentos foram os seguintes: T1 testemunha; T2 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare; T3 Aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T4 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação do herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare; T5 Aplicação de nematicida a base de carbofuran, na dose de 2,975 kg i.a. por hectare com a aplicação de herbicida a base de tebuthiuron, na dose de 1 kg do i.a. por hectare, mais a adição de 27 mg Al por kg de terra; Em todos os tratamentos utilizou-se a adubação de 600 kg ha-1 da formulação 8-28-16. O trabalho mostrou que não ocorreu interação entre Tebuthiuron e Carbofuran, e que existe um efeito fitotóxico do Tebuthiuron detectado apenas com equipamentos de alta sensibilidade, e não foi detectado nenhum efeito fitotóxico do Carbofuran.

Environmental effects of selected monomers, eventually aditives of polymers, will be evaluated by ecotoxicity tests. For this purpose two alternative tests of toxicity: Thamnotoxkit F TM on testing organism Thamnocephalus platyurus and Daphnotoxkit F TM on testing organism Daphnia magna will be used. Two phytotoxicity tests will be also used: Sinapis alba root growth inhibition toxicity test and Allium cepa L root growth inhibition toxicity test. Obtained results enable calculation of value LC50, EC50 and IC50 for tested substances.

Polymers or their modifiers may become parts of a wide range of products. After the end of life cycle useful parts of the products are recycled but significant parts still become household waste. It´s therefore desirable not only by law on chemicals and chemical products, but also according to the requirements of European directive REACH, to assess the impact not only chemical but also the additives of all products or products themselves in terms of their impact on the environment. For these purposes it serves ecotoxicity tests, which allow prediction of the influence test compounds in the environment. In this diploma thesis were evaluated polypropylene modifiers, which are commercially produced. Use of ecotoxicity tests were evaluated maleic anhydride and itaconic anhydride effects on the environment. Alternative tests have been used for toxicity and namely Thamnotoxkit FTM the organism Thamnocephalus platyurus and Daphnotokit FTM the organism Daphnia magna. The phytotoxicity test groups were selected toxicity tests: Sinapis alba root growth inhibition toxicity test, Allium cepa L root growth inhibition toxicity test and Semi-chronic toxicity test on Lemna minor L. From marine toxicity tests was performed Acute inhibition test of brine shrimps Artemia salina.

Cowpea, Vigna unguiculata (L.) Walp. is an important edible legume crop gaining recognition in the world generally and in Africa particular. The seed is a very good source of vegetable protein for millions of people living in sub-Saharan Africa. Cowpea seed are susceptible to global post-harvest losses caused by insect damage, microbial deterioration and other factors especially when stored at high ambient temperatures and relative humidities. The detection of Fusarium species and fumonisins associated with cowpea seed was primarily investigated in this study. Secondly, the antifungal activity of extracts from three Rubiaceae plant species was evaluated against five Fusarium species. Column chromatography was used in an attempt to isolate potential compounds from the plant extracts. Cowpea seed samples were obtained from a local market of a rural community in Mpumalanga Province, South Africa and were analysed for seed mycoflora and various fungal genera including, Aspergillus spp., Fusarium spp. (Fusarium oxysporum. F. solani, F. subglutinans, F. verticillioides and F. proliferatum), Penicillium spp., Chaetomium spp., Chrysonilia spp., Cladosporium spp., Monascus spp., Phoma spp., Mucor spp., Alternaria alternata, Epicoccum spp. and Lasiodiplodia theobromae were isolated from the seed samples. Some Fusarium species including F. oxysporum, F. verticillioides, F. subglutinans, F. solani and F. proliferatum were cultured on maize patty media and analysed for fumonisin production. Fumonisin detection was conducted using the VICAM Affinity method. Only Fusarium subglutinans and F. oxysporum produced fumonisin B analogues ranging between 1.1 - 4.3 ìg/g and 3.47 - 31.66 μg/g, respectively. Neither Fusarium verticillioides, F. solani nor F. proliferatum revealed any production of fumonisin B. Fumonisin B analogues were found to be present in all the cowpea seed samples with levels ranging between 6.2 - 59 μg/g. Purified fumonisin B1 was used to investigate the phytotoxic effects of the toxin in vitro and in vivo on cowpea seedling growth and emergence and also on the ultrastructure of the seed tissue. Surface-disinfected seeds were imbibed in sterile distilled water amended with FB1 at various concentrations (10, 25, 50 and 100 μg/ml) and dry seeds and seeds imbibed in sterile distilled water served as the controls. Percentage germination was determined in vitro and in vivo according to the International Seed Testing Association (ISTA) rules. Root and shoot length was measured after 8 days. Compared to the controls all the concentrations significantly decreased seed germination and the highest concentrations of FB1 (50 and 100 μg/ml) inhibited root and shoot elongation. Transmission electron microscopy (TEM) was used to study sections of the cotyledon and embryonic tissue of cowpea seed. Samples were treated with different concentrations of FB1. Compared to the controls, the degree of damage to the vacuoles, cell walls and lipid bodies of cowpea seed tissue was directly proportional to the concentrations. The efficacy of crude extracts from Morinda citrifolia, Gardenia brighamii, and Psychotria capensis was investigated against various Fusarium species by two methods. The microtitre plate doubling dilution method and bioautography method were used to test methanol, acetone, and dichloromethane extracts of the leaves for their antifungal activity. Psychotria capensis acetone extracts showed the best inhibition against F. proliferatum and F. verticillioides with an MIC of 1.5 mg/ml and an MFC of 1.5 mg/ml. The dichloromethane extracts exhibited no activity against the Fusarium species tested. Column chromatographic purification of methanolic extracts of the leaves of P. capensis led to the isolation and identification of two compounds namely β-sitosterol and a carotenoid derivative. / Dissertation (MSc)--University of Pretoria, 2010. / Plant Science / unrestricted

Thesis (M.Sc. Agriculture (Horticulture)) -- University of Limpopo, 2017 / Phytonematicides, mainly due to their allelopathic nature, might be highly phytotoxic to crops protected against nematode damage. Phytotoxicity issues are compounded by the fact that the efficacy of plant extracts on nematode suppression depended much on their concentration and duration of exposure to the nematodes. Phytotoxicity could result in low crop yield and/or even in the eventual death of the protected crops. Concentrations that were suppressive to nematode numbers, but phytotoxic to the tested crop would not be useful when applied as a post-planting phytonematicides. The Mean Concentration Stimulation Point (MCSP) values were developed from the Curve fitting Allelochemical Response Dosage (CARD)computer based model to ensure that a non-phytotoxic concentration was applied for each crop. The objective of this study was to determine whether a series of Nemarioc-AL and Nemafric-BL phytonematicide concentrations would provide the MCSP for beetroot (Beta vulgaris) under greenhouse, microplot and field conditions. The greenhouse treatments included 0, 2, 4, 8, 16 and 32% for each phytonematicide. The microplot treatments were 0, 0.8, 1.6, 3.2, 6.4 and 12.8% concentrations, whereas in the field trial treatments were 0, 2.4, 4.8, 9.6, 19.2 and 38.4%. Under each condition, treatments of Nemarioc-AL and Nemafric-BL phytonematicides were, in separate experiments arranged in a randomised complete block design, with the greenhouse, microplot and field trials having 15, 10 and 9 replications, respectively. In the greenhouse, seedlings were raised in 20cm diameter plastic pots, containing pasteurised river sand and commercial seedling growing medium Hygromix® at 3:1 (v/v) ratio. Each seeding was inoculated with 5000 eggs and second-stage juveniles (J2) of Meloidogyne incognita. Seedlings were irrigated with chlorine free tapwater every other day using 250 ml/plant, with irrigation substituted by the treatment once weekly. On the microplot, the procedures were as in the greenhouse except that they growing mixture comprised pasteurised soil collected from the site. In the field, seedlings were directly transplanted into the soil. At 56 days after inoculation, in the greenhouse trial, the effects of Nemarioc-AL and Nemafric-BL phytonematicides were highly significant (P ≤ 0.01) on root galls, contributing 77 and 72% in total treatment variation (TTV) of root galls, respectively. Relative to untreated control, the respective products reduced root galls by 28-72% and 43-67%. Nemarioc-AL and Nemafric-BL phytonematicides had MCSP values on beetroot of 18.1 and 6.4%, respectively, with overall sensitivity values of 0 and 1, respectively.There was no treatment effect on nematode since there was absence of nematode in untreated control.Under microplottrials,Nemafric-BL phytonematicide had significant (P≤ 0.05) effects on fresh root mass, dry root mass and root galls, contributing 20, 19 and 57% in TTV of the three variables, with relative increases for fresh root mass and dry root mass of 65-159% and 63-143%, respectively, whereas root galls were reduced by 82-100%. Nemafric-BL phytonematicide had MCSP value on beetroot of 10.2%, with overall sensitivity value of 4 units. There was no treatment effect on nematode since there was absence of nematode in untreated control. In microplots, Nemarioc-AL phytonematicide did not have significant effects on all plant variables. Under field conditions, the treatments did not have significant effects on plant variables. In conclusion, results of the current study suggested that under greenhouse and microplot conditions the MCSP values of the phytonematicides ranged from 6.4 to 18.1%, with a wide range of overall sensitivities of phytonematicides to the test of beetroot cultivar / National Research Foundation (NRF) and Land Bank Chair of Agriculture - University of Limpopo and the Agricultural Research Council Universities Collaboration Centre