Development of tomato fruits in paper bags (Lycopersicon esculentum Mill.) for pest control and pesticide reduction

Visando o controle das pragas Neoleucinodes elegantalis (Guenée, 1854), Helicoverpa zea (Boddie, 1850) e Tuta absoluta (Meyrick, 1917) e a redução de resíduos de inseticidas, pencas de tomates, Lycopersicon esculentum Mill., foram ensacadas com papel-manteiga. Além do efeito do ensacamento, foram testados dois repelentes de insetos, pastilhas desodorizantes e dentes de alho, colados no interior dos saquinhos, com tamanhos de aproximadamente 90 mm3. Foram realizados cinco tratamentos: saquinhos contendo pastilha desodorizante (A), saquinhos contendo dente de alho (B), saquinhos sem repelente (C), testemunha (D) e controle químico com o inseticida Metamidofós (E). A eficiência do ensacamento e dos repelentes no controle das pragas estudadas foi verificada através do número médio de lagartas vivas encontradas. A quantidade de resíduo de Metamidofós encontrada nos frutos ensacados e nos frutos expostos diretamente à pulverização foi comparada ao limite máximo permitido por lei. Verificou-se, também, a qualidade dos frutos produzidos pelo método do ensacamento através de análises de coloração, firmeza, acidez titulável, sólidos solúveis, relação sólidos solúveis/acidez titulável e pH. Os custos do método do ensacamento foram comparados aos do método químico de controle das pragas. Os resultados demonstraram que o ensacamento, associado ou não aos repelentes de insetos, reduz o ataque das lagartas N. elegantalis e H. zea aos frutos. Para o controle de T. absoluta é necessária a integração com controle químico nas épocas de maior infestação. A análise de resíduos demonstrou que os frutos não ensacados possuíam quantidade de Metamidofós seis vezes superiores ao máximo tolerado por lei e os frutos ensacados quantidade três vezes inferiores a este limite. Verificou-se que o ensacamento das pencas de tomates não modificou os parâmetros físico-químicos dos frutos produzidos. Quanto aos custos, o método do ensacamento requer maior investimento econômico, porém esse investimento poderá ser recuperado na venda do produto, que poderá alcançar um preço superior aos tomates produzidos pelo método químico de controle das pragas. Os resultados deste trabalho servem de incentivo para que o agricultor procure obter selos de certificação para seus produtos, diferenciando-os para um mercado moderno e exigente em tomates mais saudáveis.Experiments were carried out to reduce the application of insecticides during the cultivation of tomatoes, Lycopersicon esculentum Mill., by the use of bags for protection of the fruits. Efficiency of the use of paper bags was evaluated in bunches of tomatoes harvested in combination wise insect repellents which control the pest agents Neoleucinodes elegantalis (Guenée, 1854), Helicoverpa zea (Boddie, 1850) and Tuta absoluta (Meyrick, 1917). Bags were made from wax paper due to its specific characteristics of resistance, permeability, flexibility, availability in the market and low cost. The repellents used in combination with the paper bags were of two types, deodorant tablets and garlic cloves, which were cut in approximately 90 mm3 pieces. Five treatments were designed: (A) paper bags carrying deodorant tablets, (B) paper bags with garlic cloves, (C) paper bags containing no repellent at all, (D) control without repellent and (E) standard or chemical control with the insecticide Methamidophos. Efficiency of the use of paper bags and the repellents used for control of pests under study was verified by the number of caterpillars found on the fruits. Fruits protected in wax-paper bags and the ones exposed directly to Methamidophos during application were compared with the maximum tolerable residue amount allowed by federal laws. Another aspect considered was fruit quality which was evaluated by fruit characteristics of colour, firmness, pH, titratable acidity, soluble solids and the relation between soluble solids/titratable acidity. ln addition, the costs of the method in use here with wax-paper bags were evaluated in comparison to the conventional chemical control. Results obtained revealed that the use of paper bags reduced the number of caterpillars of N. elegantalis and H. zea per fruit. Residue analysis carried out during application showed that the fruits out of bags presented six times higher levels than the maximum tolerable ones; while the fruits in paper bags showed three times lower levels than the maximum. It was found that the use of paper bags for tomato fruits protection does not alter the characteristics analysed in the fruits. Considering the costs, the method of tomato fruits kept in paper bags during cultivation required more financial investment in the beginning. However, it tends to be recovered by the sale in the market since the product will be of greater value for consumers. Results presented here may encourage the increment of the production of tomatoes cultivated under conditions which will guarantee the approval by official agricultural inspection organisations responsible for controlling crop quality