Susceptibility of the bird cherry‐oat aphid, <scp><i>Rhopalosiphum padi</i></scp> (Hemiptera: Aphididae), to four insecticides

Umina, Paul A; Reidy‐Crofts, Jenny; Babineau, Marielle; Maino, James L.; Edwards, Owain

doi:10.1111/aen.12490

Cited by 12 publications

(22 citation statements)

References 41 publications

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“…4 While farmers currently have effective control strategies for R. padi, these strategies are over-reliant on insecticide treatments. 6 In turn, R. padi populations, as in the case of many pest species, have encountered intense selection that has favored the rapid evolution of resistance to insecticides. [7][8][9][10][11] To mitigate the risk of R. padi evolving further resistance, a diverse suite of R. padi management approaches is required to ensure farmers rely less on commonly used insecticides and reduce selection for resistance.…”

Section: Introductionmentioning

confidence: 99%

Fungicides have transgenerational effects on Rhopalosiphum padi but not their endosymbionts

Chirgwin¹,

Yang

Umina

et al. 2022

Pest Management Science

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BACKGROUND: While several agricultural fungicides are known to directly affect invertebrate pests, including aphids, the mechanisms involved are often unknown. One hypothesis is that fungicides with antibacterial activity suppress bacterial endosymbionts present in aphids which are important for aphid survival. Endosymbiont-related effects are expected to be transgenerational, given that these bacteria are maternally inherited. Here, we test for these associations using three fungicides (chlorothalonil, pyraclostrobin and trifloxystrobin) against the bird cherry-oat aphid, Rhopalosiphum padi, using a microinjected strain that carried both the primary endosymbiont Buchnera and the secondary endosymbiont Rickettsiella. RESULTS:We show that the fungicide chlorothalonil did not cause an immediate effect on aphid survival, whereas both strobilurin fungicides (pyraclostrobin and trifloxystrobin) decreased survival after 48 h exposure. However, chlorothalonil substantially reduced the lifespan and fecundity of the F1 generation. Trifloxystrobin also reduced the lifespan and fecundity of F1 offspring, however, pyraclostrobin did not affect these traits. None of the fungicides consistently altered the density of Buchnera or Rickettsiella in whole aphids. CONCLUSIONS: Our results suggest fungicides have sublethal impacts on R. padi that are not fully realized until the generation after exposure, and these sublethal impacts are not associated with the density of endosymbionts harbored by R. padi. However, we cannot rule out other effects of fungicides on endosymbionts that might influence fitness, like changes in their tissue distribution. We discuss these results within the context of fungicidal effects on aphid suppression across generations and point to potential field applications.

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Section: Introductionmentioning

confidence: 99%

Fungicides have transgenerational effects on Rhopalosiphum padi but not their endosymbionts

Chirgwin¹,

Yang

Umina

et al. 2022

Pest Management Science

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“…It can decrease crop yield directly by feeding on plants and indirectly by transmitting the barley yellow dwarf virus (Smyrnioudis et al, 2007). Additionally, R. padi adapted to the long-term use of insecticides and developed insecticide resistance, making it difficult to control (Zuo et al, 2016;Zhang et al, 2017;Gong et al, 2020;Umina et al, 2020). The need for environmentally friendly pest control methods to ensure the sustainable production of agriculturally and economically important crops has compelled researchers to investigate insect pests at the ecological, physiological, and molecular levels over the past few decades.…”

Section: Introductionmentioning

confidence: 99%

Selection and Validation of Reference Genes For qRT-PCR Analysis of Rhopalosiphum padi (Hemiptera: Aphididae)

Wang

et al. 2021

Front. Physiol.

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Rhopalosiphum padi (L.) (Hemiptera: Aphididae) is an important cosmopolitan pest in cereal crops. Reference genes can significantly affect qRT-PCR results. Therefore, selecting appropriate reference genes is a key prerequisite for qRT-PCR analyses. This study was conducted to identify suitable qRT-PCR reference genes in R. padi. We systematically analyzed the expression profiles of 11 commonly used reference genes. The ΔCt method, the BestKeeper, NormFinder, geNorm algorithms, and the RefFinder online tool were used to evaluate the suitability of these genes under diverse experimental conditions. The data indicated that the most appropriate sets of reference genes were β-actin and GAPDH (for developmental stages), AK and TATA (for populations), RPS18 and RPL13 (for tissues), TATA and GAPDH (for wing dimorphism), EF-1α and RPS6 (for antibiotic treatments), GAPDH and β-actin (for insecticide treatments), GAPDH, TATA, RPS18 (for starvation-induced stress), TATA, RPS6, and AK (for temperatures), and TATA and GAPDH (for all conditions). Our study findings, which revealed the reference genes suitable for various experimental conditions, will facilitate the standardization of qRT-PCR programs, while also improving the accuracy of qRT-PCR analyses, with implications for future research on R. padi gene functions.

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“…One caveat of our study was our lack of a characterised kdr -SS homozygous pyrethroid susceptible reference clone. A susceptible clone can be used as a reference baseline in order to calculate resistance ratios for each tested population and to act as an internal reference (Walsh et al ., 2020a; Wang et al ., 2020), although this is not included in every survey (Umina et al ., 2020; Gong et al ., 2021). The calculated EC 50 values for our most highly sensitive aphid population for each species, R. padi (0.44 mg a.i.…”

Section: Discussionmentioning

confidence: 99%

“…The insecticide sensitivity assays broadly followed the IRAC leaf-dip method (IRAC, 2016) and the method deployed by (Umina et al ., 2020). Briefly, c .…”

Section: Methodsmentioning

confidence: 99%

Common facultative endosymbionts do not influence sensitivity of cereal aphids to pyrethroids

Leybourne

Melloh

Martin

2022

Preprint

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Cereal aphids, including the bird cherry-oat aphid, Rhopalosiphum padi, and the grain aphid, Sitobion avenae, can transmit viruses that significantly reduce crop yields. To mitigate against yield losses, insecticides are routinely used to manage aphid populations. Aphids can form relationships with endosymbionts that confer fitness benefits or consequences to the aphid. Recent artificial inoculation experiments indicate that endosymbionts could increase aphid susceptibility to insecticides, but this has not been explored using aphid populations naturally infected with endosymbionts. Here, we sampled aphids from an important cereal production region in Lower Saxony, Germany. We characterised the endosymbiont profile of these aphid populations and conducted pyrethroid dose-response assays to test the hypothesis that facultative endosymbionts increase aphid susceptibility to insecticides. We find that the level of insecticide susceptibility is highly variable in S. avenae and we identify populations that are sensitive and tolerant to pyrethroids, including populations collected from the same field. For R. padi, we find evidence for decreased sensitivity to pyrethroids, representing the first report of reduced sensitivity to pyrethroids in R. padi sampled from Central Europe. We detected high endosymbiont infection frequencies in the aphid populations. 84% of aphids carry one facultative endosymbiont and 9% of aphids carry two facultative endosymbionts. We detected associations with Regiella insecticola, Fukatsia symbiotica, and Hamiltonella defensa. However, we do not identify a link between endosymbiont infection and insecticide susceptibility, indicating that other factors may govern the development of insecticide resistance and the need for alternative management strategies.

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Susceptibility of the bird cherry‐oat aphid, Rhopalosiphum padi (Hemiptera: Aphididae), to four insecticides

Cited by 12 publications

References 41 publications

Fungicides have transgenerational effects on Rhopalosiphum padi but not their endosymbionts

Fungicides have transgenerational effects on Rhopalosiphum padi but not their endosymbionts

Selection and Validation of Reference Genes For qRT-PCR Analysis of Rhopalosiphum padi (Hemiptera: Aphididae)

Common facultative endosymbionts do not influence sensitivity of cereal aphids to pyrethroids

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