Genetic diversity and insecticide resistance during the growing season in the green peach aphid (Hemiptera: Aphididae) on primary and secondary hosts: a farm-scale study in Central Chile

Abstract

The seasonal dynamics of neutral genetic diversity and the insecticide resistance mechanisms of insect pests at the farm scale are still poorly documented. Here this was addressed in the green peach aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) in Central Chile. Samples were collected from an insecticide sprayed peach (Prunus persica L.) orchard (primary host), and a sweet-pepper (Capsicum annum var. grossum L.) field (secondary host). In addition, aphids from weeds (secondary hosts) growing among these crops were also sampled. Many unique multilocus genotypes were found on peach trees, while secondary hosts were colonized mostly by the six most common genotypes, which were predominantly sensitive to insecticides. In both fields, a small but significant genetic differentiation was found between aphids on the crops vs. their weeds. Within-season comparisons showed genetic differentiation between early and late season samples from peach, as well as for weeds in the peach orchard. The knock-down resistance (kdr) mutation was detected mostly in the heterozygote state, often associated with modified acetylcholinesterase throughout the season for both crops. This mutation was found in high frequency, mainly in the peach orchard. The super-kdr mutation was found in very low frequencies in both crops. This study provides farm-scale evidence that the aphid M. persicae can be composed of slightly different genetic groups between contiguous populations of primary and secondary hosts exhibiting different dynamics of insecticide resistance through the growing season.

Temporal and spatial distribution of insecticide‐resistance mutations in the green peach aphid Myzus persicae (Hemiptera: Aphididae) on primary and secondary host plants in central Chile

“…Regarding the MACE mutation, a high frequency of the SS genotype was detected (SS > RS > RR) in our study. A similar situation has been detected in the UK 27 and Chile, although in samples collected with suction traps (regional scale) and from peach trees and sweet‐pepper hosts (farm scale), respectively. Studies from the UK 19 and Tunisia have reported a wide range in the frequency of SS genotypes (ranging between 15 and 100% in samples collected from peach trees, potato, brassica, and tobacco).…”

“…Regarding super ‐kdr , this mutation exhibited a very low frequency of RR and RS genotypes, with the following frequency order: SS > RS > RR (Table ). In our study, we report for the first time in Chile the presence of a resistant homozygote genotype . This genotype was detected in the spring of the last year studied (2012), mainly in the TM and VH orchards.…”

“…In addition, other comparisons among individuals of M. persicae from insecticide‐treated fields, including peach orchards and sweet‐pepper plantations with weeds, indicated that frequencies of the R allele for the kdr and MACE mutations were higher in peach trees > sweet‐pepper > weeds . In the same study, the authors proposed that the variation of insecticide resistance may be affected by the arrival on peach trees of migrant individuals that carry the S allele and that have been inhabiting surrounding weeds, thus maintaining a high frequency of RS during the spring and autumn seasons . However, Fuentes‐Contreras et al .…”

Diversity, frequency, and geographic distribution of facultative bacterial endosymbionts in introduced aphid pests

“…To date 135 aphid species have been reported, 104 of them introduced, and most constitute economically important pests (Zepeda-Paulo et al, 2010). Overall, little is known about their biology, and even less about the factors determining their introduction process and underlying causes of success, although some research has been done in the case of the grain aphid Sitobion avenae, the pea aphid A. pisum and the tobacco aphid, M. persicae nicotianae (Figueroa et al, 2005;Peccoud et al, 2008;Zepeda-Paulo et al, 2010;Rubiano-Rodriguez et al, 2014). Populations of those species are characterized in Chile by a few common genotypes, usually predominant and time-persistent, usually referred as "superclones" (Vorburger et al, 2003).…”

The Distribution and Host Shifts of Cotton-Melon Aphids in Northern China

“…The species is considered to be anholocyclic in other areas [ 1 , 14 ]. Similarly, green peach aphid populations are also genetically more diverse in areas where sexual reproduction occurs than in areas where asexual reproduction predominates [ 23 ]. Pairwise F ST values indicated there were moderate levels of genetic differentiation among geographic and Anyang populations.…”