scholarly journals Seasonal dynamics and entomophthoralean infection of the pea aphid, Acyrthosiphon pisum Harris

2001 ◽  
Vol 37 (No. 1) ◽  
pp. 17-24 ◽  
Author(s):  
Ľ. Cagáň ◽  
M. Barta
Keyword(s):  
Entomopathogenic Fungi ◽  
Seasonal Dynamics ◽  
Positive Relationship ◽  
Acyrthosiphon Pisum ◽  
Correlation Coefficients ◽  
Pea Aphid ◽  
Infestation Level ◽  
Erynia Neoaphidis ◽  
Growing Seasons ◽  
Aphid Populations

The seasonal dynamics of the pea aphid, Acyrthosiphon pisum Harris, and entomopathogenic fungi from the order Entomophthorales attacking the aphid were analysed in alfalfa and field pea crops during the growing seasons of 1998 and 1999 at Nitra-Malanta. In both years, pea aphid populations on pea showed a pattern with one peak, culminated at flowering and pod formation. The infestation level on alfalfa was low in both years. Entomopathogenic fungi attacking the pea aphid were identified as Erynia neoaphidis Remaudičre and Hennebert and Conidiobolus obscurus (Hall and Dunn) Remaudičre and Keller. Both pathogens infected the aphid on pea, but only E. neoaphidis was found in the alfalfa plots. Infected aphids were not found on alfalfa during 1999. The maximum levels of infected aphids on pea were 10.30% and 48.39% in 1998 and 1999, respectively. During both years alate aphids were more frequently attacked than apteral ones. Correlation coefficients indicated a positive relationship between the number of infected aphids and precipitation, but this relationship was weak or moderately strong. A strong correlation was found between the number of dead aphids and number of alate aphids counted 5 to 10 days earlier.

scholarly journals THE PHENOLOGY AND DISTRIBUTION OF APHIDS IN CALIFORNIA ALFALFA AS MODIFIED BY LADYBIRD BEETLE PREDATION (COLEOPTERA: COCCINELLIDAE)

1980 ◽  
Vol 112 (5) ◽  
pp. 489-495 ◽  
Author(s):  
A. P. Gutierrez ◽  
C. G. Summers ◽  
J. Baumgaertner
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Hippodamia Convergens ◽  
Ladybird Beetle ◽  
Distribution Parameters ◽  
Aphid Populations

AbstractThe phenologies and distributions of pea aphid (Acyrthosiphon pisum (Harris)), blue alfalfa aphid (A. kondoi (Shinji)), and spotted alfalfa aphid (Therioaphis maculata (Buckton)) were intensively studied in California alfalfa. The results showed, as expected, that aphid populations across all densities were aggregated; but that ladybird beetle (Hippodamia convergens (G.-M.)) predation increased the degree of aggregation. The distribution parameters of the aphids were estimated using methods developed by Iwao and Kuno (1971).

MULTITROPHIC MODELS OF PREDATOR–PREY ENERGETICS: III. A CASE STUDY IN AN ALFALFA ECOSYSTEM

1984 ◽  
Vol 116 (7) ◽  
pp. 950-963 ◽  
Author(s):  
A. P. Gutierrez ◽  
J. U. Baumgaertner ◽  
C. G. Summers
Keyword(s):  
Population Dynamics ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Predator Prey ◽  
Pool Model ◽  
Metabolic Pool ◽  
Species Specific ◽  
Hypera Brunneipennis ◽  
Aphid Populations

AbstractThe field population dynamics of pea aphid (Acyrthosiphon pisum) and blue alfalfa aphid (A. kondoi) in alfalfa (Medicago sativa), as influenced by weather, competitors (Egyptian alfalfa weevil = EAW, Hypera brunneipennis), predation from coccinellids (Hippodamia convergens) and harvesting practices, are examined with a stochastic multitrophic level simulation model. The model incorporates a demand-driven functional-response model to estimate prey consumption, and a metabolic pool model to determine the rates and priorities of food allocation to respiration, growth, reproduction, and egestion.The model results compare favorably with field data, and are used to examine the effects of removal of each of the above factors on the dynamics of the aphids. The model shows that the observed density of EAW did not affect the aphid dynamics, but did reduce the standing crop of alfalfa. The predator H. convergens had a significant effect on the population dynamics of the aphids and the plant. Harvesting greatly affected the aphid population dynamics, as well as the dynamics of plant growth and reserve accumulation. However, high temperatures mediated through species-specific respiration costs and possibly a fungal pathogen were responsible for the observed dominance of blue aphid populations in the cool parts of the year and pea aphid populations during warmer parts of the year.

POPULATION GROWTH OF THE PEA APHID, ACYRTHOSIPHON PISUM (HARRIS) (HOMOPTERA: APHIDIDAE), AND PLANT RESPONSE TO APHID NUMBERS IN COMMERCIALLY GROWN FIELD PEAS IN MANITOBA

1990 ◽  
Vol 122 (6) ◽  
pp. 1201-1210 ◽  
Author(s):  
J.J. Soroka ◽  
P.A. Mackay
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Economic Thresholds ◽  
Field Peas ◽  
Aphid Control ◽  
Pea Aphids ◽  
Significant Yield ◽  
Unsprayed Plot ◽  
Plant Stem ◽  
Aphid Populations

AbstractPea aphids, Acyrthosiphon pisum (Harris), were sampled weekly or biweekly over the summers of 1985 and 1986 in a total of 15 commercial plantings of Century, Trapper, or Triumph field peas across Manitoba. Pea aphid populations rose more quickly in fields of Trapper than in Century or Triumph fields. The owners of all Trapper fields sampled initiated aerial application of insecticide for pea aphid control; at the time of spraying in 1985, plants in Trapper fields had significantly greater numbers of aphids in sweep samples than such samples from Century or Triumph fields. In 1986, Triumph plants supported greater numbers of aphids than Century or Trapper plants. Triumph plants remained green longer than plants of the other cultivais; in 1985 pea aphid numbers on this cultivar were highest on the last date sampled.Yield components were measured in sprayed and unsprayed plots within the commercial fields. When data were averaged for each cultivar, there were no significant differences in yield per area or in 1000 seed weight between sprayed and unsprayed plots. Data indicated that existing economic thresholds are too low for Trapper peas. However, one of the fields of Trapper peas that we sampled had significantly reduced numbers of pods per plant, yield per square metre, and weight of 1000 seeds in the unsprayed plot; this field had the largest population of pea aphids of any field sampled, with aphid numbers peaking at 48.5 ± 9.2 (SE) per plant lip during pod formation and filling. Significant yield losses also occurred in unsprayed plots of a Triumph field, which had a peak aphid population of 4.8 ± 1.6 per plant stem at pod maturation.

Aphid (Homoptera: Aphididae) Management in Alfalfa by Spring Grazing with Cattle

1997 ◽  
Vol 32 (3) ◽  
pp. 332-341 ◽  
Author(s):  
G. D. Buntin ◽  
J. H. Bouton
Keyword(s):  
Acyrthosiphon Pisum ◽  
Harmonia Axyridis ◽  
Coccinella Septempunctata ◽  
Growth Cycle ◽  
Pea Aphid ◽  
Early Application ◽  
Large Plot ◽  
Small Plot ◽  
Harmonia Axyridis Pallas ◽  
Aphid Populations

The effect of continuous, intensive grazing by cattle on aphid populations was examined in the first growth cycle of ‘Alfagraze’ and ‘Apollo’ alfalfa which are tolerant and not tolerant to grazing, respectively. Populations were almost entirely pea aphid, Acyrthosiphon pisum (Harris). The effect of grazing on aphid populations was examined in small plot exclusion studies in 1991 and 1992, and the effects of grazing and use of an early insecticide application with ≤7 day grazing restriction were examined in large plot exclusion trials in 1993 and 1994. Grazing reduced aphid populations by 66% to 90% when numbers exceeded ~1 aphid per stem. Populations were not significantly reduced by grazing when numbers did not exceed 1 per stem. Permethrin reduced aphid numbers for up to 7 wks and was more effective than carbofuran. Effects of grazing were similar regardless of insecticide usage. Coccinellid beetle populations in 1993 and 1994 were composed of Coccinella septempunctata L., Harmonia axyridis (Pallas), and Coleomegilla maculata DeGeer. Coccinellid numbers were much lower in grazed than ungrazed plots when aphid numbers were reduced by grazing in 1993, but were not greatly affected by grazing in 1994 when aphid numbers were low. Coccinellid numbers paralleled trends in aphid numbers. Continuous, intensive grazing or the early application of an insecticide at a low rate followed by grazing were effective approaches for suppressing pea aphid in alfalfa.

scholarly journals Seasonal dynamics of: the pea aphid, Acyrthosiphon pisum (Harris), its natural enemies the seven spotted lady beetle Coccinella septempunctata Linnaeus and variegated lady beetle Hippodamia variegata Goeze, and their parasitoid Dinocampus coccinellae (Schrank)

2015 ◽  
Vol 55 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Safura Soleimani ◽  
Hossein Madadi
Keyword(s):  
Acyrthosiphon Pisum ◽  
Coccinella Septempunctata ◽  
Aphid Species ◽  
Lady Beetle ◽  
Pea Aphid ◽  
Beetle Species ◽  
Dinocampus Coccinellae ◽  
Parasitism Rates ◽  
Hippodamia Variegata ◽  
Aphid Populations

Abstract Two important lady beetle species commonly found in alfalfa fields in Iran are the variegated lady beetle Hippodamia variegata Goeze and the seven spotted lady beetle Coccinella septempunctata (Linnaeus, 1758) (Coleoptera: Coccinellidae). These two species attack many aphid species including the pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). In this study, the seasonal population changes of A. pisum, H. variegata, C. septempunctata and the parasitoid, Dinocampus coccinellae (Schrank) (Hymenoptera: Braconidae) were studied in alfalfa fields in the 2012 and 2013 seasonal periods. The highest ladybird densities were noted on July 5, 2012 and on September 6, 2013 (17.2±2.8 and 13.4±1.6) individuals per 20 sweeps, respectively. Parasitism rates by D. coccinellae ranged from approximately 3 to 6% in two subsequent years, respectively. Parasitism was higher early in the growing season. Most parasitised ladybirds were females. There was no significant relationship between the temperature and relative humidity with pea aphid populations, although the aphid populations declined during the hot summer period. In contrast, the relationship between temperature and the H. variegata population was significant and positive in both years of the study. It has been shown that these lady beetle species have a major role in reducing the pea aphid populations in alfalfa fields. Due to the relatively low percentage of field parasitism by D. coccinellae, this parasite might not reduce the biocontrol efficiency of lady beetle species.

scholarly journals Trehalose and glucose levels regulate feeding behavior of the phloem-feeding insect, the pea aphid Acyrthosiphon pisum Harris

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Guang Wang ◽  
Jing-Jiang Zhou ◽  
Yan Li ◽  
Yuping Gou ◽  
Peter Quandahor ◽  
...  
Keyword(s):  
Feeding Behavior ◽  
Growth And Development ◽  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Feeding Time ◽  
Electrical Penetration Graph ◽  
Glucose Content ◽  
Glucose Levels ◽  
Phloem Feeding ◽  
Trehalose Content

AbstractTrehalose serves multifarious roles in growth and development of insects. In this study, we demonstrated that the high trehalose diet increased the glucose content, and high glucose diet increased the glucose content but decreased the trehalose content of Acyrthosiphon pisum. RNA interference (RNAi) of trehalose-6-phosphate synthase gene (ApTPS) decreased while RNAi of trehalase gene (ApTRE) increased the trehalose and glucose contents. In the electrical penetration graph experiment, RNAi of ApTPS increased the percentage of E2 waveform and decreased the percentage of F and G waveforms. The high trehalose and glucose diets increased the percentage of E2 waveform of A. pisum red biotype. The correlation between feeding behavior and sugar contents indicated that the percentage of E1 and E2 waveforms were increased but np, C, F and G waveforms were decreased in low trehalose and glucose contents. The percentage of np, E1 and E2 waveforms were reduced but C, F and G waveforms were elevated in high trehalose and glucose contents. The results suggest that the A. pisum with high trehalose and glucose contents spent less feeding time during non-probing phase and phloem feeding phase, but had an increased feeding time during probing phase, stylet work phase and xylem feeding phase.

CORNICLE LENGTH AS A CRITERION FOR SEPARATING FIELD-COLLECTED NYMPHAL INSTARS OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE)

1983 ◽  
Vol 115 (12) ◽  
pp. 1615-1619 ◽  
Author(s):  
William D. Hutchison ◽  
David B. Hogg
Keyword(s):  
Acyrthosiphon Pisum ◽  
Pea Aphid ◽  
Field Sample ◽  
Rearing Temperature ◽  
Multimodal Analysis

AbstractCornicle length measuremetns of Acyrthosiphon pisum (Harris) nymphs reared in the laboratory were instar-specific and unaffected by rearing temperature. A multimodal analysis of cornicle lengths of field-collected aphids clearly detected four distribution peaks (i.e., instars) in five different field populations, and there was generaaly little overlap between successive instar distributions. However, third and fourth instars in the spring field sample could not be separated accurately due to the shorter cornicle length of nymphs that developed from overwintered eggs. Cornicle length proved to be a useful criterion for separating virginoparous A. pisum instars in samples collected in southern Wisconsin.

scholarly journals The Phytopathogen Dickeya dadantii (Erwinia chrysanthemi 3937) Is a Pathogen of the Pea Aphid

2006 ◽  
Vol 72 (3) ◽  
pp. 1956-1965 ◽  
Author(s):  
Anne-Marie Grenier ◽  
Gabrielle Duport ◽  
Sylvie Pagès ◽  
Guy Condemine ◽  
Yvan Rahbé
Keyword(s):  
Acyrthosiphon Pisum ◽  
Ecological Impact ◽  
Sitophilus Oryzae ◽  
Pea Aphid ◽  
Erwinia Chrysanthemi ◽  
Future Research ◽  
Close Relative ◽  
Bacterial Cells ◽  
Dickeya Dadantii ◽  
Phytopathogenic Bacterium

ABSTRACT Dickeya dadantii (Erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. The sequencing of its genome identified four genes encoding homologues of the Cyt family of insecticidal toxins from Bacillus thuringiensis, which are not present in the close relative Pectobacterium carotovorum subsp. atrosepticum. The pathogenicity of D. dadantii was tested on the pea aphid Acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either by septic injury or by oral infection. The lethal inoculum dose was calculated to be as low as 10 ingested bacterial cells. A D. dadantii mutant with the four cytotoxin genes deleted showed a reduced per os virulence for A. pisum, highlighting the potential role of at least one of these genes in pathogenicity. Since only one bacterial pathogen of aphids has been previously described (Erwinia aphidicola), other species from the same bacterial group were tested. The pathogenic trait for aphids was shown to be widespread, albeit variable, within the phytopathogens, with no link to phylogenetic positioning in the Enterobacteriaceae. Previously characterized gut symbionts from thrips (Erwinia/Pantoea group) were also highly pathogenic to the aphid, whereas the potent entomopathogen Photorhabdus luminescens was not. D. dadantii is not a generalist insect pathogen, since it has low pathogenicity for three other insect species (Drosophila melanogaster, Sitophilus oryzae, and Spodoptera littoralis). D. dadantii was one of the most virulent aphid pathogens in our screening, and it was active on most aphid instars, except for the first one, probably due to anatomical filtering. The observed difference in virulence toward apterous and winged aphids may have an ecological impact, and this deserves specific attention in future research.

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