Interactions between acaricide and insecticides isolated or combined in Brevipalpus yothersi and Brevipalpus californicus (Acari: Tenuipalpidae): a study of biological and biochemical effects

Author(s)

Jaqueline Franciosi Della Vechia

• Document type: Doctoral Thesis
• Press: Jaboticabal. 2021-08-04.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal
• Defense date: 2021-07-07
• Advisor: Daniel Júnior de Andrade; Guilherme Duarte Rossi

Abstract

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. (AU)

• FAPESP's process: 18/06174-4 - Determination of enzymatic activity and biological and behavioral changes induced by the combination of acaricides with insecticides in Brevipalpus yothersi (Acari: Tenuipalpidae)
• Grantee: Jaqueline Franciosi Della Vechia
• Support Opportunities: Scholarships in Brazil - Doctorate