Insecticide toxicity to three strains of green peach aphid (Myzus persicae Sulzer) reared on resistant and susceptible potato cultivars

Three green peach aphid (GPA) strains, Myzus persicae (Sulzer) (Homoptera: Aphididae) obtained from New York, Puerto Rico and Minnesota, were reared on resistant potato hybrid D888-4 and a susceptible cv. Red Pontiac. No significant differences in GPA mortality were observed when aphids were reared on either the resistant or susceptible potato cultivars and later exposed to methamidophos 4EC, pirimicarb 50 WP, azinphos-methyl 2EC or permethrin 2EC. The interaction between the four insecticides × three GPA strains was significant. Of the three aphid strains, those from Minnesota had the lowest susceptibility to permethrin, pirimicarb and azinophos-methyl. No mortality was observed in this GPA strain when tested with azinphosmethyl.     

Monitoring for MACE resistance in the tobacco-adapted form of the green peach aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae) in the eastern United States

Organophosphate and carbamate insecticides exert their neurotoxic effects by inhibiting acetylcholinesterase (AChE), thereby, prolonging the action of acetylcholine at cholinergic synapses, resulting in neuronal hyperexcitation. Mutations at the AChE target site confer modified acetylcholinesterase (MACE) phenotypes. Target-site insensitivity of AChE was characterized in field-collected, tobacco-adapted forms of the green peach aphid, Myzus persicae (Sulzer), from nine different states in the eastern United States from 2004 to 2007. The specific activity of the AChE among the 65 aphid colonies screened by Ellman's assay ranged from 0.017–0.259 U/min/mg protein. Eight colonies, with a wide range of specific activities were chosen to study the inhibition of AChE in the presence of two carbamate insecticides, methomyl and pirimicarb. IC₅₀ values for methomyl ranged from 0.35 to 2.4 μM, while six out of eight colonies had lower values that ranged from 0.16 to 0.30 μM for pirimicarb. Two colonies that were inhibited by methomyl had very high IC₅₀ values for pirimicarb, 40.4 and 98.6 μM respectively. The target-site insensitivity in these two colonies that are resistant to pirimicarb could be due to an ace2 gene mutation. This is the first instance where MACE phenotypes in M. persicae from the United States were studied and confirmed. The results indicate that the possible insensitivity due to MACE resistance in some colonies may render selected carbamate insecticides ineffective. Concerns of MACE resistance in managing the tobacco-adapted form of the green peach aphid on tobacco in the United States are discussed.     

Characterization of Solanum chomatophilum resistance to 2 aphid potato pests, Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer)

The aphids Macrosiphum euphorbiae (Thomas) and Myzus persicae (Sulzer) (Hemiptera: Aphididae) are responsible for yield reduction in potato (Solanum tuberosum) production by direct phloem feeding and by spreading viruses. Breeding resistant traits from Solanum chomatophilum into the potato germplasm provides alternative means to control aphid infestations. Integrated pest management strategy, using plant resistance, benefits from the characterization of the resistance and of its impact on aphid biology. Our objective was to characterize the resistance of S. chomatophilum by assessing the effects of accessions, plant parts on aphid performance, and by assessing the impact of the resistance factors on different aphid developmental stages and on alate morph production. Detailed aphid performance was obtained by measuring fecundity, survival, percentage of nymphs that reached adult moult, and population growth using whole plant and clip cage experimental designs. Accession and plant physiological age, but not aphid developmental stage, influenced all life-history parameters, except for alate morph production which was not induced on the resistant accessions. Plant part influence was independent of plant species and accession. Both experimental designs resulted in congruent resistance levels at the accession level for each of the two aphid species, supporting the use of any of them in S. chomatophilum resistance screening. PI243340 was resistant to both aphid species, while PI365324 and PI310990 were also resistant to M. euphorbiae and M. persicae, respectively.     

Aspects of insecticide resistance and reproductive biology ofAphis gossypii glover on seed potatoes

Summary For several years the aphid population patterns and the incidence of the main potato virus diseases have been monitored in Italian potato-growing areas. Starting from 1992, an increase inAphis gossypii, as compared toMyzus persicae, Macrosiphum euphorbiae andAphis fabae, was observed on seed potato fields in the north of Italy. Laboratory tests revealed thatA. gossypii was insensitive to the pesticide pirimicarb, even at the maximum dose tested (2400 μg/ml). Moreover, in the presence of pirimicarb the reproductive capacity increased up to 30% as compared with the control, and the new-born aphids began to appear 2 days earlier in the treated group. By contrast,M. persicae was controlled at a lower dose (300 μg/ml). Lambda-cyhalothrin and imidacloprid were very effective against both aphids.     

Identification of the Population Structure of Myzus persicae (Hemiptera: Aphididae) on Peach Trees in China Using Microsatellites

In this study, we characterized the genetic structure of Myzus persicae (Sulzer) (Hemiptera: Aphididae) populations in China using microsatellites. We expected that these data will reveal the genetic relationships among various populations of M. persicae and will be of value in the development of better methods for pest control. Four hundred sixty individuals from 23 areas over 13 provinces were collected in the early spring of 2010, all from their primary host, Prunus persicae. The markers analyzed were highly polymorphic, as demonstrated by the expected heterozygosity value (H_e = 0.861) and the Polymorphism Information Content (PIC = 0.847), which indicated that M. persicae maintains a high level of genetic diversity. Analysis of molecular variance revealed an intermediate level of population differentiation among M. persicae populations (F_ST = 0.1215). Geographic isolation existed among these populations, and, consequently, the genetic structure of the populations was split into a southern group and a northern group divided by the Yangtse River.     

Domyzus (nectarosiphon) species other thanm persicae pose a threat to the idaho potato crop?

Green peach aphids (Myzus persicae (Sulzer) ) pose a threat to the Idaho potato (Solanum tuberosum L.) crop primarily because they transmit potato leafroll virus (PLRV). Only colonizing vectors are epidemiologically significant because PLRV is persistently transmitted. Additionally, Idaho winters are severe enough that most permanently anholocyclic aphid species do not establish. It is now accepted that the taxon that has been known asMyzus (Nectarosiphon)persicae (Sulzer) is in fact at least three species (M. persicae, Myzus nicotianae Blackman andMyzus antirrhinii (Macchiati) ). It was not known whether the newly designated species had the potential to damage the Idaho potato crop. The objectives of our research were to determine whetherMyzus (Nectarosiphon) spp. other thanM. persicae occurred naturally in Idaho, whether they could colonize potato and transmit PLRV, and whether they were potentially holocyclic. NoMyzus (Nectarosiphon) spp. other thanM. persicae were found in Idaho in trap nurseries; howeverMyzus ascalonicus Doncaster recently has been found on stored bulbs and in suction trap collections in north Idaho. Laboratory bioassays for PLRV vector potential usingPhysalis floridana Rydb. indicator plants show thatM. nicotianae can transmit PLRV as efficiently asM. persicae. Similarly,M. nicotianae colonized potato as well asM. persicae in a replicated laboratory experiment comparing two clones ofM. nicotianae and one clone ofM. persicae. Our observations indicate that North AmericanM. nicotianae may be capable of a limited facultative holocycle. Thus, in laboratory experiments,M. nicotianae is as damaging asM. persicae with respect to PLRV vector potential; however,M. nicotianae may not occur naturally in areas like Idaho that have no tobacco production. A summary of allMyzus (Nectarosiphon) spp. with respect to PLRV epidemiology is provided.     

Monitoring of inflights of green peach aphids,Myzus persicae (Sulzer), in New Brunswick potato fields by yellow pans from 1974 to 1983: Results and degree-day simulation

Based on 10 years of trapping with yellow pan traps it was determined that on the average inflights of green peach aphids,Myzus persicae (Sulzer), start July 26 and cumulative catches of more than five aphids August 8. The lack of significant differences in the timing of first and cumulative catches of aphids between the northern and the southern section of the potato production area is additional evidence thatM. persicae does not usually overwinter in New Brunswick. Important yearly variations in the timing of the first cumulative catch of more than 5 aphids can be simulated by the thermal summation of 1188 DD and forecasted by regression on the timing of first inflights. The use of these results to improve the extension program is discussed.     

Population Growth of Myzus persicae on Potato Plants Infected with Different Strains and Variants of Potato virus Y

Potato virus Y (PVY) is one of the most economically important viruses affecting the potato crop. Several strains of the virus, including PVY^O, PVY^N, recombinant isolates; PVY^N:O (PVY ^N-Wi) and PVY^NTN and several variants of PVY^O have been reported from North American potato-production areas. The green peach aphid, Myzus persicae Sulzer, is a colonizer of potatoes and is considered the most important vector of PVY. The objective of this study was to measure the population growth of M. persicae on potato plants infected with different strains and genetic variants of PVY. The initial population of ten winged adults of M. persicae was allowed to develop on a potted plant for 12 days. Results clearly indicated that infections by different strains and genetic variants of PVY did not influence the population growth of M. persicae on potato plants during this period.     

Myzus persicae (Sulzer) in diffuse light and dark rustic storages and resultant PLRV transmission

Population levels ofMyzus persicae (Sulzer) were studied on potato tubers in diffuse light and dark rustic storage houses in Peru. No differences in numbers of aphids/sprouted eye on potatoes infested naturally during storage in diffuse light or darkness were observed. Significantly more alate aphids were observed on tubers stored in darkness than in diffuse light storage houses. Viral transmission was occurring during the storage period. The incidence of viral transmission was not significantly influenced by storing tubers in diffuse light or dark storages. There were significantly more plants infected with virus from tubers that had not been sprayed for aphid control than from tubers that had been sprayed     

Improved control of potato virus Y by mineral oil plus the pyrethroid cypermethrin applied electrostatically

Field potato plants sprayed with a mixture of a pyrethroid (cypermethrin at 40 g a.i./ha) and a paraffinic oil (Sunoco Sunspray 7E at 7 $\text{l}$/ha) were colonized by fewer aphids and were less frequently diseased by potato virus Y (PVY) than unsprayed plants or plants sprayed with either cypermethrin or the oil alone; aphids given access to leaves of PVY-infected field plants sprayed with the mixture were also less likely to transmit PVY to laboratory test plants than aphids given access to leaves of plants sprayed with either chemical alone, or to untreated leaves. When alate aphids were confined above virus-infected and healthy plants, combined oil and cypermethrin treatment also gave greater protection against virus inoculation than either chemical alone. Electrostatic charging of spray droplets increased chemical deposits on field plants, especially when the plants were small and on upper leaves. These greater deposits improved control of PVY by the oil and the cypermethrin, individually or in combination, and enhanced the aphicidal action of the cypermethrin.     

Potassium phosphate induces tolerance against the Russian wheat aphid (Diuraphis noxia,Homoptera: Aphididae) in wheat

Diuraphis noxia Kurdjumov is an aphid pest that hampers the global production of wheat (Triticum aestivum L.). Infestation of wheat by D. noxia reduces crop yield and sometimes leads to the death of susceptible cultivars. To date resistant cultivars have been used to control infestations. However, the development of resistance-breaking aphid biotypes is complicating this management strategy. This study aimed to ascertain the effect that 25 mM potassium phosphate (K₃PO₄) treatment has on inducing resistance in wheat against D. noxia. The effects of potassium phosphate on induced resistance against D. noxia were determined using gene regulation and enzymatic levels of lipoxygenase (EC 1.13.11) and phenylalanine ammonia lyase (EC 4.3.1.24). The results indicated that the treatment of both susceptible (Scheepers) and resistant (Tugela DN) wheat cultivars with potassium phosphate induces genes differentially. A phenotypic study showed delayed development and less severity of symptoms with decreased numbers of aphids feeding on plants treated with potassium phosphate in comparison with untreated plants for both resistant and susceptible cultivars. The results from the gene expression and enzyme activity studies indicated that both of the induced systemic resistance-linked genes were similarly regulated after potassium phosphate treatment. The data strongly support treatment of wheat with potassium phosphate to induce tolerance against D. noxia.     

Transmission Efficiency of <Emphasis Type="Italic">Potato Leafroll Virus</Emphasis> by Four Potato Colonizing Aphid Species in Tunisian Potato Fields

This study investigated the transmission efficiency of Potato leafroll virus (PLRV) by four potato colonizing aphid species, Myzus persicae, Macrosiphum euphorbiae, Aphis gossypii and Aphis fabae, reported from leaves and yellow water trap. Physalis floridana was used as a test plant for virus transmission. DAS-ELISA was used for virus screening of samples as well as virus detection on the test plant after transmission experiment. A 2-h period was sufficient for the tested aphids to acquire PLRV virions. However, a difference in the transmission potential occurred according to the aphid species. The highest potential was recorded for M. persicae and M. euphorbiae, at 90 and 80%, respectively. For the first time, the study revealed the PLRV transmission efficiency of A. fabae, estimated at 50%. The lowest potential rate of 30% was recorded for A. gossypii. This study highlights the PLRV transmission capacities of four potato colonizing aphids suspected to play a key role in the spread of PLRV in potato seed production sites.     

Spraying potatoes to prevent leaf roll spread by the green peach aphid

Studies were made at Presque Isle, Maine, 1962–1966, to determine the suppressive effects of several materials against spread of the potato leaf roll cirus,Corium solani Holmes, transmitted by the green peach aphid,Myzus persicae (Sulzer), when applied as foliar sprays to Kennebec, Green Mountain, or Chippewa potatoes in field cages or in field plots. The early cage tests showed that spray mixtures containing 1% of the systemic plant growth regulant chlorocholine chloride (2-chloroethyltri-methylammonium chloride) or 1% of mineral oil were more effective than the insect antifeeding compound AC-24,055^® (=ENT-25,651), the aphid-repellent compounds ENT 20,430 or ENT 21,178, or the surfactants Sarkosyl-O^® (bis (2-ethylhexyl) sodium sulfosuccinate) or Aerosol-OT^® (CH₃ (CH₂)_n CON (CH₃) CH₂ COOH). Field tests disclosed that chlorocholine chloride at 5.2 lb or 2.6 lb/a/a was more effective when healthy green peach aphids were placed on infector plants in the plots soon after the plants were sprayed, 1 week later, or soon after the 2nd of 2 weekly applications than when the aphids were introduced before spraying. The difference in leaf roll suppression at these two dosages was not significant at the 5% level; as high as 90% control of leaf-roll spread was obtained. When only natural infestations of aphids were involved and field spread of the virus was light, the 86% control of leaf roll spread that was obtained from 4 weekly applications made in late June and in July was not significantly different (P=0.05) from the 79% control obtained from 2 biweekly applications made during the same period of time. The potato plants soon recovered from the slight chlorosis resulting from the spray treatment and there was no reduction in weight of US 1 tubers at harvest. Aphid population trends in treated plots were not affected.     

Advances in the identification and agrochemical importance of sesquiterpenoids from Bulnesia sarmientoi essential oil

Bulnesia sarmientoi Lorentz ex Griseb volatile oil was characterized by GC × GC-TOF-MS analysis. Major components were guaiol and bulnesol, followed by hanamyol. The enhanced sensitivity and superior resolution of GC × GC resulted in the identification of thus-far unreported oil constituents as β-guaiene, guaioxide, elemol, germacrene-B, eudesm-5-en-11-ol, γ-eudesmol, α-eudesmol and (−)-hanamyol. The insecticidal effect of B. sarmientoi oil and its main constituents (guaiol, bulnesol and hanamyol) on Spodoptera littoralis, Rhopalosiphum padi and Myzus persicae was studied. Guaiol affected the aphids in a dose-response fashion, showing low efficiency, while bulnesol and hanamyol were inactive. Both the oil and its constituents were also assayed for antifungal action against Fusarium spp. and phytotoxicity to Lactuca sativa. Among the pure compounds tested, bulnesol had a low-moderate effect on Fusarium moniliforme while hanamyol had a strong effect on Fusarium solani. Neither the oil nor the tested compounds affected L. sativa germination or radicle length, indicating that B. sarmientoi is not phytotoxic.     

Multi-generational Effects of Different Resistant Wheat Varieties on Fitness of Sitobion avenae (Hemiptera: Aphididae)

Crop resistance plays a role in preventing aphid damage, benefiting food production industries, but its effects are limited due to aphid adaptation and phenotypic plasticity. Therefore, furthering understanding of aphid–crop interactions will improve our ability to protect crops from aphids. To determine how aphids adapt to resistant varieties of wheat, Triticum aestivum L. over time, we performed a laboratory experiment to assess the multi-generational effects of three wheat varieties, Batis, Ww2730, and Xiaoyan22, with different resistance levels on the fitness of Sitobion avenae (Fab.) (Hemiptera: Aphididae). The results showed that Ww2730 and Xiaoyan22 were more resistant than Batis to S. avenae, regardless of whether the aphids were newly introduced or had been acclimated before being introduced to the three wheat varieties. However, the effect of resistance on aphid life-history traits was time dependent. Aphid weigh gain increased and they development faster of the acclimated generation compared to the newly introduced generation on all three varieties. And the fecundity on the three varieties and net reproduction rates on Batis and Xiaoyan22 significantly decreased. Aphid fitness in terms of individual life-history parameters improved, whereas aphid fitness in terms of reproductive decreased, and a convergence effect, the difference gaps and standard errors of all life-history traits among the three acclimated populations had narrowed and were less than those in the three first-generation populations, was observed during the 3-mo experimental period. We suggested that S. avenae could rapidly respond to wheat resistance through life-history plasticity.     

Aphicidal Activity of an Ageraphorone Extract From Eupatorium adenophorum Against Pseudoregma bambucicola (Homoptera: Aphididae,Takahashi)

The bamboo aphid, Pseudoregma bambucicola, is an important insect pest of bamboo that affects normal bamboo growth and induces sooty molds. The control of P. bambucicola involves the application of chemicals, such as imidacloprid, to which many species are resistant. In this study, we isolate a novel botanical pesticide (9-oxo-10,11-dehydro-ageraphorone) from an Eupatorium adenophorum(Asteraceae: Compositae) petroleum ether extract and test the aphicidal activity of this compound against P. bambucicola in laboratory bioassay and field-based experiments. This ageraphorone compound at a concentration of 2 mg/ml caused 73.33% mortality (corrected mortality [Subtracted the mortality of the negative control]: 70%) of P. bambucicola by laboratory bioassay within 6 h. Even at lower concentrations, this compound caused greater 33% mortality (corrected mortality: 30%) of aphids. Field experiments with naturally infested bamboo plants showed that two applications of 2 mg/ml ageraphorone to infested plants completely cleared infestations within 30 d. These effects were similar to those of the positive control (imidacloprid). These results reveal that 9-oxo-10,11-dehydro-ageraphorone exhibits significant aphicidal activity against bamboo aphids. We suggest that future research be directed at developing this ageraphorone compound from E. adenophorum as an aphicidal agent for biocontrol.     

Populations of aphids on named varieties of Irish potatoes

Populations of the green peach aphid,Myzus persicae (Sulzer), and the potato aphid,Macrosiphum euphorbiae (Thomas), were observed on 27 named varieties of Irish potatoes in the Yakima Valley of Washington intermittently from 1947 through 1968. The Epicure, Great Scot, and B5141-6 varieties produced relatively fewer green peach aphids than other varieties tested; Bliss Triumph and Red Pontiac produced relatively fewer potato aphids. Except for Doebay Red, the red-skinned varieties, Bliss Triumph, Red McLure, Norland, and Earnly Rose, were extremely to moderately productive of the green peach aphid. No correlation was apparent between abundance of aphids and the specific gravity or yield of tubers.     

Resistance of potato clones to the green peach aphid and potato leafroll virus

During 1980 and 1981 potato cultivars and breeding selections, including cultivated species and their hybrid derivatives, were evaluated for resistance to the green peach aphid (GPA),Myzus persicae (Sulzer), and to potato leafroll virus (PLRV). Criteria used were the number of aphids which colonized the clones in free choice field experiments and the number of plants derived from these experiments which showed symptoms of PLRV infection. Generally, greater resistance to GPA was found inSolarium tuberosum gp.andigena selections and hybrids than in gp.tuberosum cultivars. There were approximately fourfold differences in season-mean GPA levels among the clones tested each year. Forty-two families, representing a cross-section of the USDA breeding populations at the University of Idaho Research and Extension Center, Aberdeen, showed a similar range in colonization levels. Resistance to GPA colonization appeared to be more prevalent in gp.andigena, gp.phureja, and gp.stenotonum derivatives. There was a weak positive correlation (r² = .34, P = .01) between foliar total glycoalkaloids and season-mean GPA colonization levels for six clones representing the range of observed resistance to GPA. Resistance to GPA colonization was apparently not directly related to resistance to PLRV infection. Katahdin, for example, was relatively susceptible to GPA colonization but very resistant to PLRV infection whereas selection A69657-4 (gp.andigena) was among the most resistant to GPA colonization but among the more susceptible to PLRV infection. Breeding for resistance to GPA colonization therefore may not be as promising for PLRV control as developing PLRV resistant cultivars.     

Methamidophos,Salithion, phenthoate,and R&H 0994 for control ofMyzus persicae(Sulzer) on tubers in Peru

The efficacy of methamidophos, Salithion, phenthoate, and R&H 0994 for control ofMyzus persicae (Sulzer) on stored tubers was determined. In Huancayo, Peru, which is in the Sierra, R&H 0994 proved to be most efficacious and protected tubers for 45 days. Phenthoate, at the rate tested, was not effective. In San Ramon, Peru, which is tropical in climate, methamidophos was most efficacious and protected tubers for 22 days. In both locationsM. persicae populations developed very rapidly on unsprayed tubers in rustic store.