Acephate and methamidophos residues in greenhouse and in field grown tomatoes
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Data
2005-03-01
Autores
Trevizan, Luiz Roberto P.
Baptista, Gilberto C. de
Papa, Geraldo [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Associação Brasileira de Horticultura
Resumo
O aumento da produção hortícola em cultivo protegido necessita de estudos mais detalhados acerca da ocorrência de resíduos de agrotóxicos, devido às condições ambientais peculiares nesse sistema, no qual pragas de pouca importância no campo assumem relevância. Avaliou-se os resíduos dos inseticidas acefato e de seu metabólito metamidofós em tomate sob cultivo protegido e em campo. Os tratamentos aplicados foram: (a) testemunha; (b) uma aplicação de 75 g i.a. acefato.100 L-1 de água; (c) uma aplicação com 150 g i.a.100 L-1 de água; (d) quatro aplicações na dosagem de 75 g i.a.100 L-1 de água. As amostras foram tomadas a (-1), zero, 1, 3, 7, 14 e 21 dias após a última ou única aplicação. A determinação quantitativa foi feita por técnica de cromatografia em fase gasosa, usando-se detector fotométrico de chama. Os resíduos de acefato e de metamidofós nos frutos de cultivo protegido e de campo, sempre estiveram abaixo dos respectivos limites máximos de resíduos (LMRs) em todo o período de colheita das amostras. Ainda, o metabolismo de acefato a metamidofós foi muito baixo nos frutos, particularmente importante nas folhas, mas não foi bem caracterizado no solo. Os resíduos de acefato foram maiores no cultivo protegido do que no campo, especialmente em folhas e no solo, sendo também estáveis e persistentes, em geral até a amostragem de 7 dias após a aplicação.
Increasing horticultural production under protected cultivation requires more detailed studies about the occurence of pesticide residues, due to the special and peculiar environment under controlled conditions, in which some pests, that are of little concern in the field, become important. The insecticide acephate and its methamidophos metabolite residues were evaluated in greenhouse-grown tomatoes and compared to an open-field tomato crop. The treatments: (a) check; (b) one application of 75 g a.i. acephate.100 L-1 water; (c) one application of 150 g a.i.100 L-1 water; (d) four applications of 75 g a.i.100 L-1 water were evaluated. Fruit, leaf and soil samples were taken at (-1), zero, 1, 3, 7, 14, 21 days after the last or only application. The quantitative determinations were done by gas chromatography, using flame-photometric detector. The acephate and methamidophos residues in fruits harvested in the greenhouse and in the field were always below their respective maximum residue levels (MRL) during the whole sampling period. The metabolism of acephate into methamidophos was very low in fruits, especially important in leaves, but not well characterized in soil. Acephate residues were higher in the greenhouse than in the field, especially in leaves and soil, showing stability and persistence up to the 7-day-sampling after application.
Increasing horticultural production under protected cultivation requires more detailed studies about the occurence of pesticide residues, due to the special and peculiar environment under controlled conditions, in which some pests, that are of little concern in the field, become important. The insecticide acephate and its methamidophos metabolite residues were evaluated in greenhouse-grown tomatoes and compared to an open-field tomato crop. The treatments: (a) check; (b) one application of 75 g a.i. acephate.100 L-1 water; (c) one application of 150 g a.i.100 L-1 water; (d) four applications of 75 g a.i.100 L-1 water were evaluated. Fruit, leaf and soil samples were taken at (-1), zero, 1, 3, 7, 14, 21 days after the last or only application. The quantitative determinations were done by gas chromatography, using flame-photometric detector. The acephate and methamidophos residues in fruits harvested in the greenhouse and in the field were always below their respective maximum residue levels (MRL) during the whole sampling period. The metabolism of acephate into methamidophos was very low in fruits, especially important in leaves, but not well characterized in soil. Acephate residues were higher in the greenhouse than in the field, especially in leaves and soil, showing stability and persistence up to the 7-day-sampling after application.
Descrição
Palavras-chave
Lycopersicon esculentum, resíduos de pesticidas, metabolismo, cultivo protegido, Lycopersicon esculentum, pesticide residues, metabolism, greenhouse
Como citar
Horticultura Brasileira. Associação Brasileira de Horticultura, v. 23, n. 1, p. 38-43, 2005.