Feromônio sexual do bicho-mineiro do café, Leucoptera coffeella: avaliação para uso em programas de manejo integrado
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Data
2001
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Universidade Federal de Viçosa
Resumo
O componente principal do feromônio sexual de Leucoptera coffeella, 5,9-dimetilpentadecano, possui quatro formas enantioméricas e estudos com outros insetos têm demonstrado que a quiralidade pode ser responsável, em grande parte, pela determinação da resposta comportamental de atração a uma mistura particular de um atraente sexual. Objetivou-se neste trabalho determinar a importância relativa de cada isômero desta molécula. Avaliou-se os isômeros puros com eletroantenografia, túnel-de-vento e em armadilhas no campo. Os testes realizados com eletreoantenografia e túnel-de-vento indicaram uma pequena resposta do isômero 5S,9S-dimetilpentadecano (SS). No entanto nenhum dos estereoisômeros puros do 5,9 -dimetilpentadecano foi capaz de atrair um número significante de machos para armadilhas no campo quando comparados com a mistura racêmica. Por serem muito pequenos, a observação direta do comportamento de chamamento em fêmeas se torna muito difícil e imprecisa. Foi feito um estudo determinar o padrão de produção do feromônio sexual em fêmeas virgens como uma medida indireta do comportamento de chamamento. O componente principal, biologicamente ativo, (5,9 -dimetilpentadecano) foi extraído para ser usado em dois experimentos. O primeiro investigou a produção de feromônio ao longo do tempo (horas) em fêmeas virgens. Para isto, extratos de 10 fêmeas de dois dias de idade foram extraídos de fêmeas a cada 2 h durante o período de 24 h (12:12 D:L). O outro experimento avaliou o efeito da idade das fêmeas na produção de feromônio. Com as idades variando de 1 a 5 dias, 10 fêmeas de cada idade foram usadas. Os extratos foram feitos e analisados em um cromatógrafo a gás. As fêmeas produziram as maiores quantidades de feromônio nas quatro últimas horas da escotofase e nas duas primeiras horas da fotofase seguinte. As quantidades de feromônio foram baixas em todos os outros períodos avaliados. Fêmeas de um dia de idade tiveram as maiores quantidades de feromônio na glândula. Após o segundo dia de emergência, os títulos de feromônio diminuíram significativamente e permaneceram baixos e nos mesmos níveis até os 5 dias de idade. Foram conduzidos experimentos de campo para determinar a eficiência de armadilhas de feromônio considerando a dose aplicada no liberador, a vida útil do liberador e a altura da armadilha para captura de machos. Diferentes modelos de armadilhas foram preparadas com 300µg de feromônio sexual e colocadas em plantações de café. Todos os experimentos foram feitos em Minas Gerais, MG. No primeiro estudo a dose de 300µg e 3000µg coletaram mais mariposas que em doses inferiores. Entretanto, quando se levou em consideração a vida útil do liberador a dose de 300µg foi insuficiente para coletar machos depois de 15 dias e a dose de 3000µg repeliu os machos das armadilhas nos primeiros 15 dias. Em outro estudo concluiu-se que a melhor dose a ser aplicada nas armadilhas foi a de 900µg. No estudo com os diferentes modelos comparou-se armadilhas Delta® nas cores branca e verde, Tubular com cartão de cola no interior e a armadilha Cica®. Os resultados mostraram não haver diferenças entre as armadilhas Delta® e Cica. No entanto, a armadilha cilíndrica coletou significativamente menos insetos que as demais testadas. Por razões de economia e praticidade recomenda-se a Delta® para o monitoramento deste inseto. A avaliação da altura da armadilha determina que estas sejam colocadas no solo entre as linhas de plantio.
The main compound of Leucoptera coffeella sex pheromone, 5,9-dimethylpentadecane, has four possible pure stereoisomers and studies with other insects have been demonstrated that this optical isomer may carries biological activity. The objective of the present work was to study whether only one or more of the pure stereoisomers were needed for biological activity. The evaluation of the pure stereoisomers was made using electroantennography, wind tunnel and pheromone trap in the field. The eletroantenography and wind tunnel experiments indicated a small response from the 5S,9S-dimethylpentadecane (SS) isomer. However no stereoisomer alone was able to trap significant number of moths when compared to the racemic mixture of 5,9 -dimethylpentadecane. Due to the small size direct observation of the calling behavior in females is very difficult and inaccurate. A study was undertaken to access the pattern of sex pheromone production in glands of virgin females as an indirect measure of the calling behavior. The major compound, biologically active, (5,9-dimethylpentadecane) was extracted to be used in two experiments. The first one investigated the effect of the pheromone production time by females. Extracts of 10 females with age of two days were carried out at 2-hour intervals during 24 hours (12:12 D:L). The other experiment evaluated the effect of female age on pheromone production. Age ranged from 1 to 5 days after emergence and 10 females of each age class were used. Extracts were analyzed by GC. Females had the highest amount of pheromone at the last four hours in the dark and the two first hours in the light period. Amounts of pheromone were lower in all other periods. One-day old females produced the highest amount of pheromone in the glands. After two days of emergence the titers of pheromone dropped significantly and remained low until females were 5 days old. Field experiments were conducted to determine the effectiveness of doses, the lifetime of the releaser, and the height of pheromone-baited traps to capture of coffee leaf miner, L. coffeella, males. Also traps of different design were baited with 300µg of sex pheromone and were placed in coffee field. All experiments were done at Minas Gerais State - Brazil. In one study, the dose of 300µg and 3000µg in Delta traps collected more moths than the inferior doses. However, the considering the lifetime of the releaser the dose of 300µg was inefficient to trap moths more than 15 days and the 3000µg dose was a repellent in the first 15 days. In another study was concluded that the best dose to be applied in the traps 900µg. In the study of trap design the capture was compared among white delta, green delta, a tubular glued cardboard and the Cica® trap. Results showed that there were no differences in capture among traps with different colors. However, a circular glued cardboard trap trapped a significant less males than any other trap tested. For economic reasons the best option for monitoring purposes is recommended the Delta trap. The height of trap study determines that the trap should be positioned on the soil between the row of plants.
The main compound of Leucoptera coffeella sex pheromone, 5,9-dimethylpentadecane, has four possible pure stereoisomers and studies with other insects have been demonstrated that this optical isomer may carries biological activity. The objective of the present work was to study whether only one or more of the pure stereoisomers were needed for biological activity. The evaluation of the pure stereoisomers was made using electroantennography, wind tunnel and pheromone trap in the field. The eletroantenography and wind tunnel experiments indicated a small response from the 5S,9S-dimethylpentadecane (SS) isomer. However no stereoisomer alone was able to trap significant number of moths when compared to the racemic mixture of 5,9 -dimethylpentadecane. Due to the small size direct observation of the calling behavior in females is very difficult and inaccurate. A study was undertaken to access the pattern of sex pheromone production in glands of virgin females as an indirect measure of the calling behavior. The major compound, biologically active, (5,9-dimethylpentadecane) was extracted to be used in two experiments. The first one investigated the effect of the pheromone production time by females. Extracts of 10 females with age of two days were carried out at 2-hour intervals during 24 hours (12:12 D:L). The other experiment evaluated the effect of female age on pheromone production. Age ranged from 1 to 5 days after emergence and 10 females of each age class were used. Extracts were analyzed by GC. Females had the highest amount of pheromone at the last four hours in the dark and the two first hours in the light period. Amounts of pheromone were lower in all other periods. One-day old females produced the highest amount of pheromone in the glands. After two days of emergence the titers of pheromone dropped significantly and remained low until females were 5 days old. Field experiments were conducted to determine the effectiveness of doses, the lifetime of the releaser, and the height of pheromone-baited traps to capture of coffee leaf miner, L. coffeella, males. Also traps of different design were baited with 300µg of sex pheromone and were placed in coffee field. All experiments were done at Minas Gerais State - Brazil. In one study, the dose of 300µg and 3000µg in Delta traps collected more moths than the inferior doses. However, the considering the lifetime of the releaser the dose of 300µg was inefficient to trap moths more than 15 days and the 3000µg dose was a repellent in the first 15 days. In another study was concluded that the best dose to be applied in the traps 900µg. In the study of trap design the capture was compared among white delta, green delta, a tubular glued cardboard and the Cica® trap. Results showed that there were no differences in capture among traps with different colors. However, a circular glued cardboard trap trapped a significant less males than any other trap tested. For economic reasons the best option for monitoring purposes is recommended the Delta trap. The height of trap study determines that the trap should be positioned on the soil between the row of plants.
Descrição
Tese de Doutorado defendida na Universidade Federal de Viçosa
Palavras-chave
Bicho mineiro do cafeeiro Comportamento Manejo integrado Armadilha com feromônio Dinâmica do feromônio Controle biológico Leucoptera coffeella, Coffee leaf miner Behavior Integrated manegement programs Pheromone traps Pheromone biodynamics Biological control Leucoptera coffeella
Citação
Lima, Eraldo Rodrigues de. Feromônio sexual do bicho-mineiro do café, Leucoptera coffeella: avaliação para uso em programas de manejo integrado. Viçosa : UFV, 2001. 71p. : il. (Tese - Doutorado em Entomologia) Orientador: Evaldo Ferreira Vilela. T 595.7810418 L732f 2001