Detection and characterization of new genotypes of Myzus antirrhinii (Hemiptera: Aphididae) in Japan, with evidence for their production of sexual morphs

Two forms of Myzus persicae (Sulzer), F-15 and R306N', resembling M. antirrhinii (Macchiati) in esterase profile have been found in Japan. To determine the genetic relationship of F-15 and R306N' with M. antirrhinii, clonal lineages of F-15, R306N' and those of 14 other forms of M. persicae collected in Japan were analysed for 17 polymorphic microsatellite DNA loci. Two microsatellite multi-locus (MS) genotypes of M. persicae and two MS genotypes, Ma3 and Ma4, of M. antirrhinii from Australia were used as references. The 16 Japanese forms were represented by different MS genotypes. F-15 and R306N' had, respectively, 44.1% and 35.3% of their alleles at the 17 loci in common with Ma3 and Ma4, and some of the common alleles were peculiar in size. F-15 and R306N' shared 22.6% and 29.6%, respectively, of their alleles with the other 16 MS genotypes of M. persicae. The corresponding values for Ma3 and Ma4 were both 27.4%. F-15 and R306N' were grouped reliably with the two Australian MS genotypes of M. antirrhinii both by neighbour-joining method based on shared allele distance and by a Bayesian method with Markov Chain Monte Carlo algorithm. These results suggest that F-15 and R306N' are genetically closely related to M. antirrhinii and isolated from the gene pool of M. persicae despite their ability to produce sexual morphs. It is therefore proposed that F-15 and R306N' should be classified as M. antirrhinii.     

Microsatellite isolation, linkage group identification and determination of recombination frequency in the peach-potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Fifteen polymorphic microsatellite markers were used to establish linkage groups and relative rates of recombination in male and female Myzus persicae (Sulzer) (Hemiptera: Aphididae) (peach-potato aphid). We cloned nine markers from M. persicae and for these we report primer sequences and levels of allelic diversity and heterozygosity in four Australian M. persicae populations. Of the remaining six loci, four loci, also cloned from M. persicae, were obtained from G. Malarky (Natural History Museum, London) and two loci from Sitobion miscanthi were used. Additionally, the primer sequences of locus M77, a locus monomorphic in M. persicae but polymorphic in the closely related Myzus antirrhinii, are presented. Eleven of the 15 polymorphic markers were autosomal and four were X-linked. A linkage analysis was performed on a European pedigree of aphids containing five families with between seven and 11 offspring each. There was no linkage between any loci in females. In males, several pairwise comparisons yielded no recombinant offspring. With the exception of locus M40, these observations were supported in a linkage analysis performed on larger families produced from Australian M. persicae crosses. Locus M40 showed segregation consistent with involvement in a translocation between autosomes 1 and 3 in European samples but not in the Australian samples. From the Australian crosses we report an absence of recombination in males but high recombination rates in females. One X chromosome and four autosomal linkage groups were identified and tentatively assigned to chromosomes. The relevance of achiasmate meiosis to the evolution of sex is discussed.     

The shallot aphis,Myzus ascalonicus Doncaster,and its behaviour as a vector of plant viruses

A new species of aphis, Myzus ascalonicus Doncaster, is briefly described, and compared with Myzus persicae Sulz., which it resembles superficially. It has been found on shallots in storage and on onions and other species of plants both in glasshouses and in the open between October and June. Its summer habits and hosts are unknown. In comparative virus transmission tests with M. persicae it was found that Myzus ascalonicus transmits dandelion yellow mosaic virus, which is not transmitted by Myzus persicae ; and also cucumber virus I, Hyoscyamus virus III and sugar-beet yellows virus, all of which are transmitted by M. persicae. Myzus ascalonicus does not transmit the viruses of potato Y severe etch, lettuce mosaic and sugar-beet mosaic which are transmitted by Myzus persicae.     

Co-existence of different host-adapted forms of the Myzus persicae group (Hemiptera: Aphididae) in southern Italy

Multivariate morphometric analysis (method of canonical variates) was used to compare 38 parthenogenetic lineages and three field collections of aphids of the Myzus persicae (Sulzer) group sampled on peach and tobacco in the Caserta region of southern Italy. Comparisons were also made with the morphology of lineages collected on peach in Lehonia, in central eastern Greece away from tobacco-growing regions, and on tobacco in Naphplion, in southern Greece. The lineages were measured after parthenogenetic rearing for one to three generations on the same host (potato) under constant conditions. As in previous work, the multivariate morphometric approach separated the aphids from peach from those feeding on tobacco. The life cycle category of the lineages was also examined. Almost all the lineages from peach in Caserta were holocyclic, yet the lineages from tobacco in the same region were unable to produce sexual morphs. The results suggest that tobacco-adapted and non-tobacco-adapted forms co-exist in the same region in southern Italy, not only because they colonize different host plants, but also because they have different life cycles. This is in complete contrast to the situation in peach-growing areas of northern Greece, and shows that the ecology and population structure of M. persicae is different in neighbouring counties of the Mediterranean area, even where climatic conditions and cultivated crops are similar.     

The attack of the clones: tracking the movement of insecticide-resistant peach-potato aphids Myzus persicae (Hemiptera: Aphididae)

Myzus persicae (Sulzer) collected in Scotland were characterized for four microsatellite loci, intergenic spacer fingerprints and the resistance mechanisms modified acetylcholinesterase (MACE), overproduced carboxylesterase and knockdown resistance (kdr). Microsatellite polymorphisms were used to define a limited number of clones that were either fully susceptible to insecticides or possessed characteristic combinations of resistance mechanisms. Within these clones, intergenic spacer fingerprints could either be very consistent or variable, with the latter indicating ongoing evolution within lineages, most likely derived from the same zygote. Two clones (termed A and B) possessed all three resistance mechanisms and predominated at sites treated with insecticides. Their appearance on seed potatoes and oilseed rape in Scotland in 2001 coincided with extensive insecticide use and severe control failures. Clones C, I and J, with no or fewer resistance mechanisms, were found in samples from 1995 and were dominant at untreated sites in 2001. A comparison of Scottish collections with those from other UK and non-UK sites provides insight into the likely origins, distribution and dynamics of M. persicae clones in a region where asexual (anholocyclic) reproduction predominates, but is vulnerable to migration by novel genotypes from areas of Europe where sexual (holocyclic) reproduction occurs.     

Host quality of different aphid species for rearing Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae)

This study aimed to evaluate the quality of the aphid Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach) and Brevicoryne brassicae (L.) as hosts for the parasitoid Diaeretiella rapae (McIntosh). Parasitization by D. rapae was higher on M. persicae than on L. erysimi and B. brassicae. The time of development of D. rapae from egg to mummy or egg to adult male or female were shorter on M. persicae than on L. erysimi and B. brassicae. Moreover, D. rapae showed no significant differences in the emergence rate, sex ratio and longevity when reared on the three aphid species. Myzus persicae was the largest aphid host, with B. brassicae and L. erysimi being of intermediate and of small size, respectively. Diaeretiella rapae reared on M. persicae was larger than when reared on L. erysimi and B. brassicae, and females of D. rapae were significantly larger than males on M. persicae, but males of D. rapae were larger than females when reared on L. erysimi. No difference in size was detected between males and females in parasitoids reared on B. brassicae. Among the aphid species studied, M. persicae was found to be the most suitable to D. rapae.     

Genetic diversity and insecticide resistance of Myzus persicae (Hemiptera: Aphididae) populations from tobacco in Chile: evidence for the existence of a single predominant clone

The tobacco-feeding race of Myzus persicae (Sulzer), formerly known as M. nicotianae Blackman, was introduced into Chile during the last decade. In order to evaluate the genetic diversity and insecticide resistance status of Chilean tobacco aphid populations, a field survey was conducted in 35 tobacco fields covering a 300 km latitudinal survey. The populations sampled were characterized using microsatellite markers and morphometric multivariate analysis. Insecticide resistance levels were assessed through a microplate esterase assay and the mutation status of the kdr gene. All samples collected corresponded to the same anholocyclic aphid genotype, and showed morphological variation within the range expected for the tobacco-feeding race of M. persicae. Esterase activity showed the level and variability expected for an R1 clone lacking mutations in the sodium channels (susceptible kdr), thus corresponding to a type slightly resistant to organophosphate and carbamate, and susceptible to pyrethroid insecticides.     

Over-wintering of aphids,especially Myzus persicae,Sulzer, in root clamps

Mangold clamps in many districts of the British Isles were found to provide overwintering sites for Myzus persicae (Sulz.), Hyperomyzns staphyleae (Koch) and Aulacorthum solani (Kalt.). After a severe winter, when other means of overwintering are few, clamps may be the most important source of Myzus persicae. Only Myzus ascalonicus Doncaster was found in swede clamps.
Factors affecting the infestation of clamped mangolds by M. persicae were the number of aphids on the crop when lifted, the methods of topping and clamping the roots, and the temperature in the clamp. M. persicae was introduced on the leaves, and close topping was often an efficient means of control. Close topping did not control Hyperomyzus staphyleae; normally, this aphid does not seem to be a root-feeding species, but with artificially colonized mangolds it fed on both exposed roots and foliage. It is not known how this species enters the clamps. The temperature in clamps was influenced by that of the outside air and the type of cover, but changes were long-term and did not reflect diurnal variations in external air temperature. Straw, covered with soil, was the best form of cover.
In addition to harbouring Myzus persicae , mangold clamps are also important sources of sugar-beet yellows virus.     

七星瓢虫成虫对烟蚜的捕食作用

对七星瓢虫CoccinellaseptempunctataL .成虫对烟蚜Myzuspersicae的捕食作用进行了定量研究。七星瓢虫成虫对烟蚜的功能反应属HollingⅡ型反应 ,拟合的圆盘方程为Na =1 .1 5 76Nt ( 1 +0 .0 0 3 48Nt) ,χ2 检验表明圆盘方程理论值与实测值相符。捕食选择试验表明在烟蚜、烟青虫Helicoverpaassaut(Guenee)卵和 1龄幼虫 3种猎物中 ,七星瓢虫成虫最喜好烟蚜。七星瓢虫成虫对自身密度的功能反应用Watt模型拟合为A =2 90 .0 3P-0 .7584,其捕食作用率与个体间相互干扰作用的关系用Hassell模型拟合为E =0 .8783 7P-0 .1 0 0 94。文中进一步就烟田中七星瓢虫的保护利用进行了讨论。     

Identification of indole glucosinolate breakdown products with antifeedant effects on Myzus persicae (green peach aphid)

The cleavage of glucosinolates by myrosinase to produce toxic breakdown products is a characteristic insect defense of cruciferous plants. Although green peach aphids ( Myzus persicae ) are able to avoid most contact with myrosinase when feeding from the phloem of Arabidopsis thaliana , indole glucosinolates are nevertheless degraded during passage through the insects. A defensive role for indole glucosinolates is suggested by the observation that atr1D mutant plants, which overproduce indole glucosinolates, are more resistant to M. persicae , whereas cyp79B2 cyp79B3 double mutants, which lack indole glucosinolates, succumb to M. persicae more rapidly. Indole glucosinolate breakdown products, including conjugates formed with ascorbate, glutathione and amino acids, are elevated in the honeydew of M. persicae feeding from atr1D mutant plants, but are absent when the aphids are feeding on cyp79B2 cyp79B3 double mutants. M. persicae feeding from wild-type plants and myrosinase-deficient tgg1 tgg2 double mutants excrete a similar profile of indole glucosinolate-derived metabolites, indicating that the breakdown is independent of these foliar myrosinases. Artificial diet experiments show that the reaction of indole-3-carbinol, a breakdown product of indol-3-ylmethylglucosinolate, with ascorbate, glutathione and cysteine produces diindolylmethylcysteines and other conjugates that have antifeedant effects on M. persicae . Therefore, the post-ingestive breakdown of indole glucosinolates provides a defense against herbivores such as aphids that can avoid glucosinolate activation by plant myrosinases.     

不同地理种群烟蚜形态特征差异分析

烟蚜Myzus persicae是一种世界性的重要农业害虫。为探讨我国不同地理种群烟蚜形态特征变异情况, 本研究测量了我国18个地理种群烟蚜的体长、 体宽、 头宽、 各足腿节长、 各足胫节长等18个形态性状度量特征和Q值, 并进行方差分析和基于欧氏距离与地理距离和海拔差距的Mantel Test, 利用各形态特征与体长的比值构成的比例特征进行系统聚类和主成分分析。结果表明： 部分地理种群烟蚜的形态性状差异显著。系统聚类和主成分分析表明, 18个烟蚜地理种群中贵州贞丰种群（ZF-GZ）与其他种群相比差异最大, 陕西南泥湾（NNW-SX）、 湖南慈利（CL-HN）、 安徽谯城（QC-AH）和重庆武隆（WL-CQ）种群差异最小, 其他种群间的差异程度介于这两者之间。Mantel Test显示欧氏距离与地理距离、 海拔高度差距都不具有相关性。烟蚜种群的形态分化不符合地理隔离模式, 地理气候条件对种群形态有一定影响, 种群形态差异的形成是多种因素综合作用的结果, 但具体作用机制尚不明确。     

Effect of mixed viral infections (potato virus Y-potato leafroll virus) on biology and preference of vectors Myzus persicae and Macrosiphum euphorbiae (Hemiptera: Aphididae)

Mixed viral infections of heterologous viruses such as Potato virus Y (family Potyviridae, genus Potyvirus, PVY) and Potato leafroll virus (family Luteoviridae, genus Polerovirus, PLRV) are a regular occurrence in Idaho's potato, Solanum tuberosum (L.), cropping systems. An increased number of plant samples from Idaho's potato fields over the past 2 yr has serologically tested positive for both PVY and PLRV via double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) and exhibited more severe symptoms than singly-infected plants (PVY or PLRV). Several studies have extensively examined the mixed infection phenomenon but to the best of our knowledge, none have examined the effect of such infections on vector biology and preference. Laboratory studies were conducted to examine the effect of mixed viral (PVY-PLRV) infection on the fecundity and preference of two of the most efficient PVY and PLRV vectors, the green peach aphid, Myzus persicae (Sulzer), and the potato aphid, Macrosiphum euphorbiae (Thomas) (Hemiptera: Aphididae). M. persicae and M. euphorbiae adults were clip-caged (one adult per cage) to leaflets of PVY, PLRV, PVY-PLRV-infected, and noninfected potato plants. The number of nymphs produced in all four treatments was recorded after 96 h. M. persicae and M. euphorbiae fecundity was significantly higher on mixed infected plants than on singly infected plants or noninfected plants. Preference of alatae and apterae of M. persicae and M. euphorbiae was determined with the use of settling bioassays. Both alatae and apterae of M. persicae and M. euphorbiae preferentially settled on PVY-PLRV-infected plants than on singly infected plants (PVY or PLRV) or noninfected plants.     

Segregation of autosomes during spermatogenesis in the peach-potato aphid (Myzus persicae) (Sulzer) (Hemiptera: Aphididae)

Most aphids are cyclic parthenogens, so are ideal models in studies of the mechanisms and consequences of sex and recombination. However, owing to a shortage of physical and genetic markers, there have been few studies of the most fundamental genetic processes in these organisms. For example, it is not known whether autosomal segregation during male spermatogenesis is in Mendelian proportions: we address that question here. The aphid Myzus persicae has a typical karyotype of 2n = 12 in females (XX), while males are XO (2n = 11). During male meiosis, only the spermatocytes with an X chromosome are viable. We hypothesized that assortment of autosomes might be non-random because chromosomal imprinting leading to elimination of the paternal autosomes is seen in the closely related coccoids. In other aphid models, we have observed segregation distortions at single microsatellite loci (Wilson, 2000). Such distortions may have nothing to do with 'selfish' behaviour, but may be caused by mutation accumulation causing fitness differentials. Thus single-locus distortions might be predicted to be more likely to be detected via the male lines of clones that have lost the ability to reproduce sexually (male-producing obligate parthenogenesis (androcyclic)). Using microsatellites we show that genetic imprinting or selfish autosome behaviour does not occur in male M. persicae. Generally, loci segregated in Mendelian proportions in both sexes of cyclically parthenogenetic (holocyclic) clones. However, in androcyclic clones, segregation distortions consistently involved the same two autosomes. This is consistent with linkage of markers to deleterious mutations associated with a loss of sexual reproduction.     

Relative feeding rates of Brevicoryne brassicae and Myzus persicae on Brussels sprout plants in relation to their susceptibility to systemic insecticides

Brevicoryne brassicae and Myzus persicae removed similar quantities of ³²P-labelled material from Brussels sprout leaves whether they fed for 24 or 48 h periods. They also removed similar quantities from untreated leaf disks as from leaf disks treated with a sub-lethal dose of menazon. When a lethal dose was used, the uptake of ³²P by B. brassicae was significantly less than by M. persicae. M. persicae excreted a greater proportion of ³²P label in the honeydew than B. brassicae and a greater proportion of the amount absorbed was lost in the progeny of this aphid than in B. brassicae.
B. brassicae was 6.2 times more susceptible than M. persicae to dimethoate acting systemically. When it was applied topically the aphids were equally susceptible.
Considerable variation in uptake of ³²P occurred between replicates and the factors that could influence this are discussed.     

Continuous occurrence of intra-individual chromosome rearrangements in the peach potato aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Analysis of the holocentric mitotic chromosomes of the peach-potato aphid, Myzus persicae (Sulzer), from clones labelled 50, 51 and 70 revealed different chromosome numbers, ranging from 12 to 14, even within each embryo, in contrast to the standard karyotype of this species (2n?=?12). Chromosome length measurements, combined with fluorescent in situ hybridization experiments, showed that the observed chromosomal mosaicisms are due to recurrent fragmentations of chromosomes X, 1 and 3. Contrary to what has generally been reported in the literature, X chromosomes were frequently involved in recurrent fragmentations, in particular at their telomeric ends opposite to the nucleolar organizer region. Supernumerary B chromosomes have been also observed in clones 50 and 51. The three aphid clones showed recurrent fissions of the same chromosomes in the same regions, thereby suggesting that the M. persicae genome has fragile sites that are at the basis of the observed changes in chromosome number. Experiments to induce males also revealed that M. persicae clones 50, 51 and 70 are obligately parthenogenetic, arguing that the reproduction by apomictic parthenogenesis favoured the stabilization and inheritance of the observed chromosomal fragments.     

桃蚜、萝卜蚜的种内密度和种间竞争效应

在温室内不同密度条件下,研究了桃蚜和萝卜蚜在甘蓝上的种内密度效应和种间竞争作用。结果表明：单独饲养时,在5头／株和10头／株密度下,两种蚜虫种内密度效应均较弱;而在15头／株时,桃蚜和萝卜蚜的寿命和产蚜量都随之显降低,说明当两种蚜虫达到一定的拥挤程度时,种内密度对种群均产生一定的负效应。两种蚜虫共存时,单头产蚜量均比单独饲养时显下降,种问竞争作用明显。在10、15头／株密度下,桃蚜的竞争作用大于萝卜蚜,萝卜蚜的寿命和单头产蚜量都极显低于桃蚜。     

Resistance of potato cultivars to Myzus persicae (Sulz.) (Hemiptera: Aphididae)

Aphids are the most important vectors of viruses infecting potato (Solanum tuberosum). We focused on the response of the aphid vector Myzus persicae (Sulzer) to five commercial potatocultivars: ágata, Jaette Bintje, Mondial, Monalisa and Santè, by traditional antibiosis and antixenosis tests and by the EPG (Electrical Penetration Graph) technique, as a step forward to the design of effective management practices. Our aim was to identify plant factors involved in resistance of these cultivars against M. persicae, both at the surface and in deeper plant tissues. Results from the antixenosis test confirmed a strong preference of M. persicae for the Mondial cultivar. The antibiosis study indicated a lower population development of the aphid in 'Monalisa' when compared to 'ágata' and 'Jaette Bintje'. EPG assays indicated that 'Santè' inhibited the initial feeding process of M. persicae, whereas 'Monalisa' showed a physical-type of resistance as demonstrated by a very high number of short probes. The cultivar Mondial showed average values for all EPG variables analyzed. The behavior in 'Jaette Bintje' indicated this cultivar was an ideal host for aphid feeding and reproduction. Together, the EPG data revealed the existence of pre and post-phloematics factors in the cultivars under study, which have important implications on the efficiency of transmission and spread of virus in potato by M. persicae.     

Genetic, biochemical, and behavioral uniformity among populations of Myzus nicotianae and Myzus persicae

Prior to designation as distinct species, an appellation presently in question, the tobacco aphid, Myzus nicotianae Blackman (Homoptera: Aphididae), was classified as a tobacco-feeding form of the green peach aphid, Myzus persicae (Sulzer). In this study, RAPD polymorphisms distinguished members of the Myzus persicae complex (M. persicae and M. nicotianae) from three outgroup Myzus species (M. cerasi (F.), M. hemerocallis Takahashi, and M. varians Davidson). Polymorphisms within the complex did not separate populations on the basis of host association (tobacco versus other host plants) or geographic origin (collections from the United States, Europe, and Japan). Similarly, while GC-MS analysis of cuticular hydrocarbon profiles revealed both developmental and inter-populational differences within the M. persicae complex, it did not separate populations of tobacco feeding aphids from those collected off non-tobacco hosts. Finally, with the exception of their responses to a choice between lettuce and collards, the host preference behavior of a green peach aphid population, a red tobacco aphid population, and a green tobacco aphid population was indistinguishable in host preference experiments. These results add to a growing body of evidence suggesting M. nicotianae and M. persicae are conspecific.     

Effects of kaolin particle film on Myzus persicae (Hemiptera: Aphididae) behaviour and performance

The emergence of resistance mechanisms to, and revocation of, many insecticides used in the control of the polyphagus aphid pest, Myzus persicae (Sulzer), has increased the pressure to develop novel approaches for the control of the pest in many crops. Kaolin-based particle films provide a physical barrier against insect pests and show considerable potential for controlling M. persicae. We conducted a series of laboratory experiments to investigate the mode of action of kaolin against aphids. The material appeared to have no direct effect on M. persicae; spraying adult aphids with aqueous kaolin suspension had no significant impact on their subsequent survival or reproduction on untreated plants. Similarly, when aphids were placed on kaolin-treated host-plants (Brassica oleracea), their performance (survival, growth rate and reproduction) was not significantly different from aphids on untreated plants. However, when M. persicae were given a choice between kaolin-treated and untreated (or water solvent-treated) leaf areas, both adults and nymphs exhibited a significant preference for non-kaolin-treated host-plant material. Rejection of kaolin-treated plant material occurred very rapidly (within 20 min) and this behavioural effect may be related to the efficacy of kaolin in controlling aphids under field conditions.     

云南主要烟区烟蚜抗药性的监测

采用浸叶法测定了云南省红河弥勒、楚雄东华、昆明寻甸、丽江七河及昭通昭阳共5个烟区的烟蚜Myzuspersicae(Sulzer)种群对7种常用杀虫剂的抗性水平。结果表明,5个烟区烟蚜对甲胺磷均产生了中等或中等程度以上抗性。红河弥勒和昭通昭阳两烟区烟蚜对氧化乐果产生了中等或中等程度以上抗性;楚雄东华、红河弥勒、昭通昭阳和丽江七河烟区烟蚜对硫丹产生了中等或中等程度以上抗性。对其余杀虫剂尚处于低抗以下水平。