Relationship of Insecticide Tolerance to Esterase Enzyme Activity in <I>Aphis pomi</I> and <I>Aphis spiraecola</I> (Hemiptera: Aphididae)

Abstract

Green apple aphid, Aphis pomi De Geer, and Aphis spiraecola Patch (both Hemiptera: Aphididae), are sympatric aphid species that are pests of apples (Malus spp.) and other crops. A. spiraecola has been shown to be significantly more tolerant to several insecticides compared with A. pomi. To establish the mechanisms contributing to this difference in insecticide response, clones of both species were collected from British Columbia, Canada, and Washington state. Dose-response bioassays were conducted to determine relative tolerances to the insecticides pirimicarb, dimethoate, and imidacloprid; these results have been reported previously. Samples of adult aphids from each clone were assayed for the activity of esterase enzymes often involved in the detoxification of insecticides. A. spiraecola had higher esterase activity compared with A. pomi; this was apparent for two model substrates, alpha-naphthyl acetate (alpha-NA) and alpha-naphthyl butyrate (alpha-NB). Aphid clones of both species collected from Washington had higher esterase activity than clones collected from British Columbia. Clones from both species and locations hydrolyzed alpha-NA to a greater extent than alpha-NB. Esterase activity measured with both substrates was significantly positively correlated with the relative response to pirimicarb and dimethoate; a significant positive correlation also was found for hydrolysis of alpha-NB and imidacloprid. The apparent involvement of esterases in the differential response of A. pomi and A. spiraecola to insecticides indicated that the choice of control chemicals for A. spiraecola should not involve chemistries that are metabolized predominantly by esterases.

Aphis pomi and Aphis spiraecola (Hemiptera: Sternorrhyncha: Aphididae) in Europe - new information on their distribution, molecular and morphological peculiarities

“…Namely, authors reporting winged males of the apple aphid (Davletshina, 1963;Karczewska, 1965) might actually refer to the spirea aphid. Competitive displacement of apple aphid by spirea aphid is reported as mediated by human activities in North America (Hogmire et al, 1992;Brown et al, 1995;Lowery et al, 2006;Smirle et al, 2010), making host plant based discrimination of both species even more complicated. Recently, a resolution of this discrimination problem was proposed using molecular taxonomy (Lushai et al, 2004;Foottit et al, 2009;Naaum et al, 2012).…”

Orchard aphids (Hemiptera: Sternorrhyncha, Aphidoidea) of Lithuania: a century of research

“…The coexistence between these two Aphis LINNAEUS, 1758 species is challenging for pest aphid management practice, because both species are similar in their morphology but differ in their ecological features and resistance to pesticides. Therefore, competitive displacement of A. pomi by A. spiraecola is reported as mediated by human activities in North America (SMIRLE et al 2010). The life cycle and host specificity of the Lithuanian populations of Dysaphis plantaginea appeared to be similar to those described by BLACKMAN & EASTOP (2000).…”

Esterase in Imported Fire Ants, Solenopsis invicta and S. richteri (Hymenoptera: Formicidae): Activity, Kinetics and Variation

“…As a critical component in insect's detoxification process, esterase has been intensively investigated in the context of insecticide resistance. Elevated esterase activities are associated with decreased insecticide susceptibility in numerous insects1617181920212223242526. The detoxifying enzymes are important not only in tolerance and resistance of insects to both synthetic and natural toxins, but also in defense against microbial infection.…”

“…Esterase isozymes in insects, particularly those in Drosophila and mosquitoes, are classified according to their preferential hydrolysis of the isomeric artificial substrates, α-naphthyl acetate (α-NA) and β-naphthyl acetate (β-NA)15. Although the classification has little value as a predictor of enzyme function, esterase activities measured using those substrates have often been proven to be associated with insecticide tolerance and resistance1617181920212223242526. In this study, we tested a hypothesis that S. invicta has higher esterase activity than S. richteri .…”