Interação entre acaricida e inseticidas isolados ou combinados em Brevipalpus yothersi e Brevipalpus californicus (Acari: Tenuipalpidae): estudo dos efeitos biológicos e bioquímicos
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Data
2021-07-07
Autores
Vechia, Jaqueline Franciosi Della [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A intensa pulverização de agrotóxicos para o controle de artrópodes pragas em citros tem afetado negativamente o manejo de ácaros vetores de vírus (Brevipalpus yothersi e Brevipalpus californicus) que causam a leprose dos citros. Além dos casos de resistência de ácaros a acaricidas, falhas de controle de populações do ácaro da leprose suscetíveis a acaricidas têm sido associadas a exposição desses organismos a inseticidas utilizados para o manejo de insetos pragas dos citros. Alguns desses inseticidas não apresentam toxicidade significativa ao ácaro da leprose, mas, quando aplicados em mistura com acaricidas, podem reduzir a toxicidade de acaricidas. Detalhes sobre os efeitos que exposições combinadas de inseticidas com acaricidas podem exercer sobre ácaros do gênero Brevipalpus não são detalhadamente conhecidos. Diante disso, o objetivo principal da tese foi estudar os efeitos biológicos e bioquímicos do acaricida espirodiclofeno e inseticidas isolados ou combinados sobre os ácaros B. yothersi e B. californicus em condições de laboratório e campo. A atividade de enzimas de detoxificação foi caracterizada nesses ácaros, e o efeito de inibidores de enzima de detoxificação foi estudado em B. californicus. Verificou-se que o espirodiclofeno e os inseticidas cipermetrina, fosmete e imidacloprido alteraram parâmetros biológicos e demográficos importantes de B. yothersi. A combinação do espirodiclofeno com os inseticidas reduziram, substancialmente, a eficiência do acaricida sobre ovos e adultos de B. yothersi. Nos experimentos realizados a campo, a adição dos inseticidas à calda de espirodiclofeno reduziu o período de reinfestação de B. yothersi comparado ao acaricida aplicado isoladamente. Contudo, o teor de espirodiclofeno não foi alterado quando inseticidas foram adicionados à calda. A indução ou a inibição da atividade de enzimas de detoxificação em B. yothersi foi dependente do inseticida ou da mistura realizada, bem como do tempo de exposição aos inseticidas. Para os experimentos com B. californicus, a combinação do inseticida imidacloprido em mistura com espirodiclofeno resultou em efeito antagônico para controle, e os ácaros expostos a essa mistura apresentaram aumento na atividade de P450s, esterases e glutationa-S-transferases (GST). A adição de PBO (um inibidor da mono-oxigenase P450) à mistura de espirodiclofeno e imidacloprido resultou em efeito sinérgico sobre a mortalidade de B. californicus, mas a adição de DEM (um inibidor de GST) resultou em efeito antagônico. As consequências das misturas de espirodiclofeno com os inseticidas avaliados sobre o manejo dos ácaros Brevipalpus sp. e formas para minimizar os prejuízos das misturas antagônicas são discutidas.
The intense spraying of pesticides for the citrus pest control has negatively affected the management of virus vector mites (Brevipalpus yothersi and Brevipalpus californicus) that cause citrus leprosis. In addition to cases of mite resistance to acaricides, failure to control leprosis mite populations susceptible to acaricides has been associated with the exposure of these organisms to insecticides used for the management of citrus pest insects. Some of these insecticides are not toxic to leprosis mite, but when sprayed in a mixture with acaricides, they can reduce the toxicity of acaricides. Details on the effects that combined exposures of insecticides with acaricides on mites of the genus Brevipalpus are not known in detail. Therefore, the main objective of the thesis was to study the biological and biochemical effects of acaricide spirodiclofen and insecticides isolated or combined on B. yothersi and B. californicus mites in laboratory and field conditions. The detoxification enzyme activity was characterized in these mites and the effect of detoxification enzyme inhibitors was studied in B. californicus. It was found that spirodiclofen and the insecticides cypermethrin, phosmet, and imidacloprid altered important biological and demographic parameters of B. yothersi. The combination of spirodiclofen with insecticides substantially reduced the efficiency of the acaricide on eggs and adults of B. yothersi. In experiments carried out in the field, the addition of insecticides to the spirodiclofen solution reduced the period of reinfestation of B. yothersi compared to the acaricide sprayed alone. However, the spirodiclofen concentration was not changed when insecticides were added to the spray solution. The induction or inhibition of the detoxification enzyme activity in B. yothersi was dependent on the insecticide or the mixture, as well as on the time of exposure to the insecticides. For the experiments with B. californicus, the combination of the imidacloprid in a mixture with spirodiclofen resulted in an antagonistic effect for mite control and the mites exposed to this mixture showed an increase in the activity of P450s, esterases, and glutathione-S-transferases (GST). The addition of PBO (a P450 monooxygenase inhibitor) to the mixture of spirodiclofen and imidacloprid resulted in a synergistic effect on the B. californicus mortality, but the addition of DEM (a GST inhibitor) resulted in an antagonistic effect. The consequences of mixtures of spirodiclofen with the insecticides evaluated on the management of Brevipalpus sp. mites and ways to minimize the damage from antagonistic mixtures are discussed.
The intense spraying of pesticides for the citrus pest control has negatively affected the management of virus vector mites (Brevipalpus yothersi and Brevipalpus californicus) that cause citrus leprosis. In addition to cases of mite resistance to acaricides, failure to control leprosis mite populations susceptible to acaricides has been associated with the exposure of these organisms to insecticides used for the management of citrus pest insects. Some of these insecticides are not toxic to leprosis mite, but when sprayed in a mixture with acaricides, they can reduce the toxicity of acaricides. Details on the effects that combined exposures of insecticides with acaricides on mites of the genus Brevipalpus are not known in detail. Therefore, the main objective of the thesis was to study the biological and biochemical effects of acaricide spirodiclofen and insecticides isolated or combined on B. yothersi and B. californicus mites in laboratory and field conditions. The detoxification enzyme activity was characterized in these mites and the effect of detoxification enzyme inhibitors was studied in B. californicus. It was found that spirodiclofen and the insecticides cypermethrin, phosmet, and imidacloprid altered important biological and demographic parameters of B. yothersi. The combination of spirodiclofen with insecticides substantially reduced the efficiency of the acaricide on eggs and adults of B. yothersi. In experiments carried out in the field, the addition of insecticides to the spirodiclofen solution reduced the period of reinfestation of B. yothersi compared to the acaricide sprayed alone. However, the spirodiclofen concentration was not changed when insecticides were added to the spray solution. The induction or inhibition of the detoxification enzyme activity in B. yothersi was dependent on the insecticide or the mixture, as well as on the time of exposure to the insecticides. For the experiments with B. californicus, the combination of the imidacloprid in a mixture with spirodiclofen resulted in an antagonistic effect for mite control and the mites exposed to this mixture showed an increase in the activity of P450s, esterases, and glutathione-S-transferases (GST). The addition of PBO (a P450 monooxygenase inhibitor) to the mixture of spirodiclofen and imidacloprid resulted in a synergistic effect on the B. californicus mortality, but the addition of DEM (a GST inhibitor) resulted in an antagonistic effect. The consequences of mixtures of spirodiclofen with the insecticides evaluated on the management of Brevipalpus sp. mites and ways to minimize the damage from antagonistic mixtures are discussed.
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Ácaro de plantas, Enzimas Indução, Inseticidas, Pragas Controle