Showing papers on "Myzus persicae published in 1977"

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

Abstract: 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.

Effects of Mineral Oil on Probing Behavior and Transmission of Stylet-borne Viruses by Myzus persicae

Abstract: Electronic monitoring of probing, salivation, and feeding of Myzus persicae (Sulzer) adults on pepper leaves, Capsicum annum L., variety ‘California Wonder,’ after treatment with an 0.75% emulsion of Sunoco 7E oil revealed significant increases in preprobing time over aphids on untreated leaves, little effect on salivation, and fewer aphids ingested sap after contacting oil coated leaves. The antitransmission activity of oil was associated with oil located over the anticlinal walls of epidermal cells. This activity could be removed by absorptive dusts applied to oil treated leaves. Studies on the influence of temperature or expansion of leaf surfaces on persistence of activity of oil showed that rate of loss of activity is greater at 32° than at 24° and 16°C, and expansion of leaf areas up to 150% does not significantly reduce the effectiveness of the oil over a 6-day period following application. Young leaves treated with oil were more susceptible to infection with potato virus (PVY) than were mature leaves. Oil affected aphid transmission of a normally vectorless strain of tobacco etch virus much the same as it did an efficiently vectored strain of PVY. Previous work on effects of oil against both acquisition and inoculation of virus by aphids was verified. Protection of a leaf was limited to the surface on which oil was applied. Momentary contact between an aphid’s labium and an oil treated leaf sufficed to reduce transmission. The anti-transmission effect also resulted from a momentary contact between the labium and a surface impermeable to stylet penetration. Oil can be removed from the aphid’s labium by absorption on cellulose.

Investigations of carnation viruses

Abstract: SUMMARY Carnation vein mottle virus (CarVMV) is rare in glasshouse carnations in Britain, although locally common in Dianthus barbatus in private gardens. In Sim carnations free from other viruses, CarVMV caused slight diffuse chlorotic mottling in the younger leaves, decreased flower yield by c. 22%, and caused flower breaking in cvs William Sim and Dusty. In non-Sim cultivars Pink Shibiuya, Orchid Beauty and Vesta, leaf symptoms and flower breaking were more pronounced. In mixed infections with carnation mottle virus, symptoms were much more severe. CarVMV was not eliminated from carnation or D. barbatus plants grown for 4 wk at 37oC, and only rarely from cuttings then taken from them, but it was readily eliminated by meristem-tip culture. Myzus persicae adults or nymphs acquired and transmitted the virus within a total time of 4 min, and remained infective for 30–60 min if feeding, or for 75 min if starved. The carnation aphid, M. persicae f. dianthi, transmitted the virus much less efficiently. The virus was not transmitted by dodder (Cuscuta campestris), or through seed of D. barbatus or Chenopodium quinoa. The maximum infective dilution in sap of D. barbatus, carnation and C. quinoa ranged from 10-2 to 10-5. The virus withstood 10 min at 60 but not 65oC, up to 9 days at c. 18oC or 3–4 wk at c. 2oC. CarVMV infected twenty-two of 107 plant species in six of thirty-seven families; suscepts were confined to the Chenopodiaceae, Caryophyllaceae and closely allied families. C. quinoa was the best local lesion assay host. Seedling clones of D. barbatus, selected as resistant to carnation mottle virus, proved the best indicator and propagation species. Up to 50 mg virus/kg tissue were obtained by butanol clarification followed by differential and density gradient centrifugation. The preparations contained a single sedimenting component, s20w= 144S, and had flexuous filamentous particles, c. 790 times 12 run; the particles contained a single polypeptide, mol. wt 34800, and 5% of a single-stranded ribonucleic acid (RNA) with nucleotide base ratios of G21: A25: C25: U29. Serologically CarVMV was related distantly to turnip mosaic (cabbage black ring strain), pea mosaic, watermelon mosaic (Strain 2) and bean yellow mosaic viruses, more closely to pepper veinal mottle virus, but unrelated to twelve other potyviruses. CarVMV is not at present a danger to carnation crops in Britain, but the recent trend of sending carnation plants to overwinter outdoors in warmer countries involves potential risks of more rapid spread by effective vector races of M. persicae.

Aphid Alarm Pheromones: Dispersion of Hyadaphis erysimi and Myzus persicae,

Abstract: Clusters of the turnip aphid, Hyadaphis erysimi (Kaltenbach), and green peach aphid, Myzus persicae (Sulzer), feeding on turnip leaves, were exposed to alarm pheromone from cornicle droplets. Aphids dispersed by walking or falling, both responses occurring about equally. The proportion of aphids dispersing by falling decreased with increase in distance of the pheromone source. Aphids that responded to pheromone by walking usually resettled on the same leaf. Redistribution of aphids to other leaves on the plant was attributable almost entirely to the return of aphids which had fallen off the host plant. No preference was exhibited by returning aphids for or against the leaf on which the cluster was originally located.

Assessment of the potential for and development of organophosphorus resistance in field populations of Myzus persicae

Abstract: SUMMARY A survey of esterases in field populations of the peach-potato aphid, Myzus persicae was made during the spring of 1975. Assay was by electrophoresis of single aphid homogenates, and the known association between the activity of an esterase and resistance to organophosphorus insecticide (OP) was used to infer resistance in field populations. The resistant variant replaced the susceptible in populations which had been treated with OP and another variant with threefold (approximately) more esterase activity appeared to be replacing the resistant variant in populations which have been treated twice with OP. The significance of this for control of M. persicae is discussed. Differences in resistance between aphids in different parts of the same field, and the widespread association of these esterase variants in favoured combinations with two electrophoretic variants at another locus have also been investigated.

The inheritance of natural chromosomal polymorphisms in the aphid Myzus persicae (Sulzer)

Abstract: Two types of chromosomal abnormality have been found in natural populations of Myzus persicae in Japan. One type is apparently due to an autosome 3 dissociation, giving a 2n=13 karyotype. The other is interpreted as a translocation between autosomes 1 and 3, resulting in a 2n=12 complement with marked structural heterozygosity. In laboratory crosses, both types of abnormality were inherited through the sexual phase. The proportions of each type in the F1 agreed well with expectations, except that no forms homozygous for the translocation were obtained from crosses between translocation heterozygotes, and no karyotypes with both the translocation and the dissociation were obtained when translocated and dissociated forms were crossed. In the F1 of one cross a triploid clone with the autosomal 1,3 translocation was obtained.

Pepper veinal mottle virus associated with a streak diseaseof tomato in Nigeria

Abstract: SUMMARY A destructive streak disease of tomato (Lycopersicon esculentum) was observed on the University of Ife farm. The disease killed many plants and greatly diminished the quantity and quality of fruit produced by the other plants. A virus that is readily transmitted by mechanical inoculation, by the green peach aphid (Myzus persicae) and by grafting was isolated consistently from diseased plants. The virus was propagated in Nicotiana occidentalis and assayed in Physalis angulata. It was infective after dilution to io-3 but not io-4; after iomin at 55 but not 60oC; or after 5 days but not 7 days at 20–26oC. Electron microscope examination of sap from infected N. occidentalis leaves revealed flexuous rods with a modal length of about 780 nm. Based on the host range and symptomatology, particle morphology and size, properties in vitro and serology, the virus is shown to be related to, and possibly indistinguishable from, pepper veinal mottle virus.

Anatomy of an aphid vector: myzus persicae

Abstract: Publisher Summary This chapter discusses the anatomy of an aphid vector. Anatomical study on aphids reported that the reproductive system of the aphids contains many embryos in various stages of development, that honey-dew does not drop from heaven but is excreted by the aphid from the anus, that aphids possess two chronicles on the posterior dorsal end of the abdomen out of which comes a drop of clear liquid, and that aphids molt four times. The most anterior part of the alimentary tract of an aphid is the food canal of the maxillary stylets. Each half of the salivary gland system of an aphid is composed of the accessory and principal gland. The ducts from both glands join to a single one that runs further to form, together with the contralateral duct, a common salivary duct.. In Myzus persicae, the mesodermal tissue forms a continuous sheet situated in the body cavity against the body wall. It shows three distinct types of cells. Most numerous are the fat cells, characterized by a strong vacuolization of their cytoplasm. The second type of cells are even dispersed individually among the fat cells. They are called basophilic mesodermal cells by their homogeneous basophilic cytoplasm. Mainly distributed along the surface of the mesodermal tissue are the much smaller connective tissue cells.

Peach-potato Aphid, Myzus persicae (Sulz.), Resistant to Organophosphorus and Carbamate Insecticides on Potatoes in Scotland

Abstract: SUMMARY Peach-potato apbids, Myzus persicae (Sulz.), collected from six potato fields in western and central Scotland in 1976 were tested for aphicide resistance biochemically and by bioassay. Most aphids were resistant to organophosphorus insecticides. At five of the sites, some aphids were both highly resistant to organophosphorus compounds and moderately resistant to pirimicarb.

Isolation, purification, and properties of tamarillo mosaic virus, a member of the potato virus Y group

Abstract: Tamarillo (Cyphomandra betacea Sendt.) in the Auckland, Kerikeri, and Tauranga-Te Puke areas were commonly found to be infected with a virus causing severe vein-banding and blister-mottle foliage symptoms, and blemished fruit. This virus, proposed name tamarillo mosaic virus (TaMV), has a narrow host range, being mechanically transmissible only to several members of the Solanaceae. With acquisition feeding periods of between 2 and 5 min, the aphid Myzus persicae (Sulz.) readily transmitted the virus. The molecular weight of viral coat protein was calculated to be c. 30 000 daltons and could not be distinguished by polyacrylamide-gel electrophoresis from the molecular weight of coat protein of potato virus Y. Cytoplasmic pinwheel inclusions were readily observed in thin sections of infected Nicotiana clevelandii A. Gray leaf tissue. The mean particle length (745 nm), the ability to induce cytoplasmic pinwheel inclusions, and other properties of TaMV place this virus in the potato virus Y group.

Aldicarb and Thiofanox: Effect on the Feeding Activity of Green Peach Aphids

Abstract: Aldicarb killed 26% and thiofanox killed 64% of Myzus Persicae (Sulzer) exposed once to potato plants treated with these systemic insecticides Six serial exposures to aldicarb and 3 to thiofanox were required to achieve 98% mortality From the information obtained when using an electronic system to record the probing and feeding of the aphids, neither insecticide can be expected to prevent a mature viruliferous green peach aphid from transmitting potato leaf roll virus to at least one plant, even though both materials will prevent reproduction and virus spread during the early part of the growing season

Infection of karaka (Corynocarpus laevigatus J. R. & G. Forst.) by cucumber mosaic virus

Abstract: A virus isolated from karaka (Corynocarpus laevigatus) showing line-pattern and mottle symptoms was shown to be cucumber mosaic virus. The virus was transmitted from infected to healthy karaka by the aphid Myzus persicae in a non-persistent manner.

Failure of the aphid, Myzus persicae, to compensate for poor diet during early growth

Abstract: . Compensation in mean relative growth rate of M. persicae occurred when aphids normally kept on susceptible brussels sprout plants were starved for only 2 h daily or kept on ‘resistant’ plants (given low nitrogen:high potassium fertilization) for 48 h. More adverse conditions, e.g. 4 or 8 h daily starvation, 48 h on leaf discs or 60 h on 20% sucrose, resulted in a low aphid growth rate being maintained on transfer to susceptible plants. The low overall growth rate could not be explained in terms of a weight loss by the aphid at any stage and is assumed to be a behavioural phenomenon. It is concluded that it is unwise, in the study of aphid—plant relationships, to rely on pre-conditioning aphids in poor conditions with the hope that this might magnify differences in subsequent aphid response.

The potential of the fungus, Verticillium lecanii, as a microbial control agent of glasshouse aphid pests

Abstract: The ecology of the fungus, Vertlciilium lecanii, and its potential as a microbiological insect cide against the aphids, MyzuS persicae, Macrosiphoniella sanborni and Brachycaudus helichrysz, on glasshouse chrysanthemums have been examined. To achieve reproducibility, a single-spore isolate of V. lecanii, C-3, was used and designated as standard. It produced conidiospores on solid media and, more abundantly and readily, blastospores in liquid media. In nutritional studies, submerged production of conidiospores was not achieved. In aqueous suspension, conidiospores survived longer than blastospores. Conidiospores exposed below 80% relative humidity soon died, the speed of death depending on the spore microenvironment. A bioassay technique was developed and is believed to be the first statistically reliable method of quantifying fungal spore pathogenicity towards insects. With M. sanborni.the semi-weighted mean lethal concentration 50% of 28 assays was 1.83 x 10"' spore /ml suspension (fiducial limits, 1.45 and 2.31). All but one of 15 V„ lecanii strains, some pathogens of other insects and some probable hynerparasxtes of rust fungi, were similar in pathogenicity to C-3, Five other strains, all from rust or mildew fungi, were apathogenxc. B ..astospores of C—3 were approximately twice as pathogenic as conidiosporeso With single- and multi-spore isolates, repeated passage through apaids or subcu, ture on agars scarcely altered pathogenicity, but subculture greatly chanced colonial morphology. In glasshouses, blastospores and conidiospores produced similar levels of aphid control. Spore sprays established excellent control of My. persicae within 2-3 weeks, maintaining control for up to 8 weeks. Also, B. helichrysi was controlled in vegetative plant tips but not on tightly closed flower buds. Control of M. sanborni was usually unsatisfactory. In laboratory bioassays, all 3 aphid species were equally susceptible to V. lecariii suggesting that behavioural and ecological factors explain differences in glasshouses. V. lecanii could be used advantageously in integrated control systems on chrysanthemums.

Studies on the life history of green peach aphid, Myzus persicae Sulzer (Homoptera)

Abstract: The green peach aphid Myzus persicae(Sulzer), is known as the most important vector of potato leaf-roll virus and PVY. Yield of potato plants infested with these viruses are remarkably lower than non-infested plants. A study was conducted to investigate the life history of the green peach aphid at Suweon, Korea (Lat. 'N., Long. 'E). The following were obtained: 1. Overwintering eggs hatched from late March to early April, with a hatching rate averaging ninety-five percent. 2. The fundatrigeniae leave the primary host(Punus persica) in early to mid May and migrate to the secondary hosts. 3. From mid to late Oct., the gymnoparae migrate from the secondary hosts to the primary hosts. 4. From early to mid Nov., gymnoparae lay fertilized eggs around buds, in bark crevices, or between bifurcated twigs of the primary hosts. 5. The early-born progeny have 23 generations and the late-born progeny have 9 generations on peach trees, potatoes and raddish from Apr. to Oct. 6. The average length of life was about 28.5 days, with a developmental period of approximate 10.8 days and a reproductive period of 15.8 days. 7. The average number of nymphs produced by a female was fifty, with a maximum number of 118. 8. The average number of nymphs produced by a female per day was about 3.2, with a maximum number of 13.

Resistance in the Peach‐potato Aphid (Myzus persicae (Sulz.)) to Organophosphorus Insecticides in Yorkshire and Lancashire

Abstract: SUMMARY Field populations of Myzus persicae (Sulz.) collected from 30 sites in Yorkshire and Lancashire were tested by total esterase or bioassay techniques for resistance to Organophosphorus insecticides. All the populations examined included some resistant aphids and some populations contained individuals with esterase activity characteristic of very resistant aphids.

The effect of genotype, environment, age and morph on morphological variation in alate Myzus persicae (Sulzer) (Hemiptera: Aphididae)

Abstract: Six morphological variates were examined in fundatrigeniae and alienicolae of Myzus persicae (Sulz.) from four clones. In all clones, fundatrigeniae had significantly more abdominal tubercles, a relatively larger tubercle on segment 4, and relatively shorter cornicles than did alienicolae. Alienicolae reared on Chinese cabbage had significantly shorter hind femurs than those reared on potato, but otherwise there were no consistent differences between the two types. Mature fundatrigeniae did not differ consistently from young ones. The total number of abdominal tubercles was the most reliable character for distinguishing alate fundatrigeniae from alienicolae.

The development on potatoes of a glasshouse strain of Myzus persicae resistant to organophosphorous insecticides

Abstract: SUMMARY When potato tubers infested with a strain of Myzus persicae resistant to organophosphorus insecticides were planted, the tops became heavily colonized despite a furrow-application of disulfoton granules. The observation showed a more feasible way for resistant aphids of glasshouse origin to establish themselves in the field than by direct migration by alates.

Studies on the Aphid Transmission of Some Cruciferous Viruses

Abstract: This is the fist report on detailed aphid transnsmission studies of cruciferous virus in Korea, and experiments aimed to get basic informations for control of vectors Aphid transmission of turnip mosaic virus prevalent on radish in the field was studied Results obtained were as follows: 1 Myzus persicae, Lipaphis erysimi, Aphis gossypii and Aphis craccivora were found to transmit turnip mosaic virus 2 The proper time for turnip mosaic virus transmission by Myzus persicae was 1 hour of fasting, 3 minutes for acquisition, and 1 minute for inoculation: Lipaphis erysimi was 2 hours for fasting, 5 minutes for acquisition, and 3 miuutes for inoculation: while Aphis gossypii needed 1hour for fasting, and 3 minutes for each of the acquisition and inoculation periods 3 There was Po great difference in probing patterns between nonfasted and fasted aphids for 2 hours All the fasted aphids began feeding after 4 minutes, 4 When Myzus persicae were transferred artificially at 1-2 minute intervals, the number of probes with aphids fasted for 2 hours was much greater than that of nonfasted aphids Aphids fasted for 2 hours mainly transmitted the virus before 4 minutes, with an acquisition feeing period of less than 3 minutes