The ups and downs of insecticide resistance in peach-potato aphids (Myzus persicae) in the UK

cDNA clones for the esterase (E4) responsible for broad insecticide resistance in peach-potato aphids (Myzus persicae Sulz.) were isolated and used to study the molecular basis of resistance. Increased esterase synthesis by resistant aphids was found to be associated with amplification of the structural gene for the esterase (E4 or its closely related variant, FE4), the degree of amplification being correlated with the activity of the esterase and the level of resistance. Hybridization of the cDNA clones to genomic Southern blots showed that only some of the esterase-related restriction fragments are amplified. Qualitative differences between restriction patterns in different clones of resistant aphids correlated with the presence or absence of a specific chromosome translocation and with production of E4 or FE4.

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Intensification of insecticide resistance in UK field populations of the peach-potato aphid, Myzus persicae (Hemiptera: Aphididae) in 1996

Bulletin of Entomological Research ◽

10.1017/s0007485300025694 ◽

1998 ◽

Vol 88 (2) ◽

pp. 127-130 ◽

Cited By ~ 47

Author(s):

S.P. Foster ◽

I. Denholm ◽

Z.K. Harling ◽

G.D. Moores ◽

A.L. Devonshire

Keyword(s):

Insecticide Resistance ◽

Myzus Persicae ◽

Resistance Mechanism ◽

The Novel ◽

Potato Aphid ◽

Aphid Control ◽

Target Site Resistance ◽

The Uk ◽

First Time ◽

Peach Potato Aphid

AbstractThe well-established carboxylesterase-based resistance to insecticides in Myzus persicae Sulzer has recently been accentuated by the appearance of aphids with a modified acetylcholinesterase (MACE) insensitive to pirimicarb and the novel aphicide, triazamate. This target site resistance mechanism was found in M. persicae from crops in the UK for the first time in 1996, together with especially large proportions of aphids with R2 and R3 levels of carboxylesterases, a combination that was associated with serious insecticide failures. This paper describes the incidence of both mechanisms and discusses the implications for future recommendations for aphid control in the UK.

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Clonal turnover of MACE-carrying peach-potato aphids (Myzus persicae (Sulzer), Homoptera: Aphididae) colonizing Scotland

Bulletin of Entomological Research ◽

10.1017/s0007485307005445 ◽

2007 ◽

Vol 98 (2) ◽

pp. 115-124 ◽

Cited By ~ 17

Author(s):

L. Kasprowicz ◽

G. Malloch ◽

S. Foster ◽

J. Pickup ◽

J. Zhan ◽

...

Keyword(s):

Insecticide Resistance ◽

Myzus Persicae ◽

Negative Selection ◽

Resistance Mechanism ◽

Resistance Mechanisms ◽

The Other ◽

Fitness Costs ◽

Field Samples ◽

Sexual Recombination ◽

Potato Aphids

AbstractPeach-potato aphids, Myzus persicae (Sulzer), collected in Scotland in the years 1995 and 2002–2004 were characterized using four microsatellite loci and three insecticide resistance mechanisms. From 868 samples, 14 multilocus genotypes were defined (designated clones A–N). Five of these (denoted A, B, H, M and N) carried modified acetylcholinesterase (MACE) resistance, the most recent resistance mechanism to have evolved in M. persicae. The current paper shows that the continued presence of MACE aphids is due to turnover, as clones A and B were replaced in field samples by clones H, M and N in later seasons. Thus, insecticide-resistant populations in Scotland can be attributed to multiple waves of rapid clone colonisations and not to the continued presence of stable resistant clones or mutation or sexual recombination in local populations. The MACE clones carried varying levels of the other insecticide resistance mechanisms, kdr and esterase. The presence of these mechanisms could alter the clones success in the field depending on insecticide spraying (positive selection) and resistance fitness costs (negative selection).

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The properties of a carboxylesterase from the peach-potato aphid, Myzus persicae (Sulz.), and its role in conferring insecticide resistance

Biochemical Journal ◽

10.1042/bj1670675 ◽

1977 ◽

Vol 167 (3) ◽

pp. 675-683 ◽

Cited By ~ 135

Author(s):

Alan L. Devonshire

Keyword(s):

Insecticide Resistance ◽

Myzus Persicae ◽

Order Rate Constant ◽

Preliminary Evidence ◽

Exchange Chromatography ◽

Potato Aphid ◽

First Order ◽

Different Strains ◽

Hydrolysis Of ◽

Peach Potato Aphid

Carboxylesterases from different strains of Myzus persicae were examined to try to understand their contribution to insecticide resistance. Preliminary evidence that they are involved comes from the good correlation between the degree of resistance and the carboxylesterase and paraoxon-degrading activity in aphid homogenates. Furthermore the carboxylesterase associated with resistance could not be separated from the insecticide-degrading enzyme by electrophoresis or ion-exchange chromatography. Homogenates of resistant aphids hydrolysed paraoxon 60 times faster than did those of susceptible aphids, yet the purified enzymes from both sources had identical catalytic-centre activities towards this substrate and also towards naphth-1-yl acetate, the latter being hydrolysed by both 2×106 times faster than paraoxon. These observations provide evidence that the enzyme from both sources is identical, and that one enzyme hydrolyses both substrates. This was confirmed by relating the rate of paraoxon hydrolysis to the rate at which paraoxon-inhibited carboxylesterase re-activated. Both had the same first-order rate constant (0.01min−1), showing clearly that the hydrolysis of both substrates is brought about by the same enzyme. Its Km for naphth-1-yl acetate was 0.131mm, and for paraoxon 75pm. The latter very small value could not be measured directly, but was calculated from substrate-competition studies coupled with measurements of re-activation of the diethyl phosphorylated enzyme. Since the purified enzymes from resistant and susceptible aphids had the same catalytic-centre activity, the 60-fold difference between strains must be caused by different amounts of the same enzyme resulting from mutations of the regulator gene(s) rather than of the structural gene.

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