scholarly journals Influence of Plant Diversity on the Numerical Response ofEriopis connexa(Coleoptera: Coccinellidae) to Changes in Cereal Aphid Density in Wheat Crops

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
María C. Tulli ◽  
Dora M. Carmona ◽  
Ana M. Vincini
Keyword(s):  
Plant Diversity ◽  
Aphid Species ◽  
Linear Increase ◽  
Numerical Response ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Higher Plant ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Eriopis Connexa

Cereal aphids cause economic injury to wheat crops. In Argentina,Eriopis connexais an indigenous ladybird. In the present study, the numerical response ofE. connexato changes in aphid density on wheat crops with high and low plant diversity was investigated. The study was carried out in Balcarce, Buenos Aires, Argentina, from September to December 2007 and 2008, on two wheat crops with either a higher plant diversity (HPD) with refuge strips or a lower plant diversity (LPD) without refuge strips. Crops were sampled every week and the abundance of aphids andE. connexawas recorded. The dominant aphid species wereSchizaphis graminum, Metopolophium dirhodum,andSitobion avenae.Eriopis connexashowed a linear increase in the numerical response to an increase in aphid density, which varied in space and time. The abundance ofE. connexaincreased in relation to the crop development and aphid population and was higher in the HPD than in the LPD system. This predator increased its reproductive numerical response only in 2008, with a significant liner response in the HPD system. This suggests that the potential ofE. connexaas a predator of cereal aphids also increases directly in proportion to landscape vegetal diversity.

scholarly journals Comparison of Field Population Growths of Three Cereal Aphid Species on Winter Wheat

2011 ◽  
Vol 39 (No. 2) ◽  
pp. 61-64 ◽  
Author(s):  
V. Jarošík ◽  
A. Honěk ◽  
A. Tichopád
Keyword(s):  
Winter Wheat ◽  
Rhopalosiphum Padi ◽  
Intrinsic Rate ◽  
Aphid Species ◽  
Population Increase ◽  
Intrinsic Rate Of Increase ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Rate Of Increase

Population growths of three aphid species colonising winter wheat stands, Metopolophium dirhodum, Rhopalosiphum padi and Sitobion avenae, were analysed by regression method. The calculations were based on counts in 268 winter wheat plots at 3 or 7 day intervals over 10 (leaves) or 6 (ears) years. The population dynamics of a particular species differed widely between years. Density independent exponential growth of the population was most common, but its rate differed significantly between species, and for S. avenae also between populations on leaves and ears, on which the populations grew fastest. Field estimates of the intrinsic rate of increase derived from the exponential growths ranged between 0.010–0.026 in M. dirhodum, 0.0071–0.011 in R. padi, and between 0.00078–0.0061 and 0.0015–0.13 in S. avenae on leaves and ears, respectively. In the populations with the most vigorous population growth, S. avenae on ears and M. dirhodum on leaves, the rate of population increase significantly decreased with increasing aphid density.  

Comparing growth patterns among field populations of cereal aphids reveals factors limiting their maximum abundance

2006 ◽  
Vol 96 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Honek ◽  
V. Jarosik ◽  
A.F.G. Dixon
Keyword(s):  
Exponential Growth ◽  
Rhopalosiphum Padi ◽  
Growth Patterns ◽  
Aphid Population ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Density Dependent ◽  
Maximum Abundance ◽  
Aphid Density

AbstractCereal stands in central Europe are commonly infested with three species of aphids that may become serious pests. With increasing abundance, the proportion of a particular species in the total aphid population may remain constant, suggesting a density-independent exponential growth, or the proportion can change, suggesting density-dependent constraints on growth. The constraints that affect particular species, and thus their relative abundance, were studied. The proportionality between maximum abundances of the cereal aphids was studied using a 10-year census of the numbers of aphids infesting 268 winter wheat plots. For two species their abundance on leaves and ears was compared. With increasing aphid density the maximum abundance of Rhopalosiphum padi (Linnaeus) remained proportional, but not that of Sitobion avenae (Fabricius), which was constrained by the smaller surface area of ears compared to leaves. There was no evidence of inter-specific competition. Maximum abundance of R. padi and Metopolophium dirhodum (Walker) on leaves did not change proportionally as the proportion of M. dirhodum decreased with increasing overall aphid density. This decrease was probably caused by the restricted distribution of M. dirhodum, which is confined to leaves, where space is limiting. No change in proportion between populations was detected when the average densities were below 0.54 aphids per leaf or ear. Non-proportional relationships between aphid populations appeared to be due to spatial constraints, acting upon the more abundant population. Detecting the limitation of population growth can help with the assessment of when density-independent exponential growth is limited by density-dependent factors. This information may help in the development of models of cereal aphid population dynamics.

scholarly journals Abundance of cereal aphids (Hemiptera: Aphididae) within wild Triticum and Aegi­lops spp., and cultivated wheat

1999 ◽  
Vol 35 (No. 2) ◽  
pp. 67-70
Author(s):  
H. Havlíčková ◽  
V. Holubec
Keyword(s):  
Rhopalosiphum Padi ◽  
Significant Negative Correlation ◽  
Aphid Species ◽  
Gene Bank ◽  
Cereal Aphids ◽  
Aegilops Species ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Triticum Species ◽  
The Individual

Accessions of the wild Triticum species: T. boeticum, T. dicoccoides, T. urartu, and the Aegilops species:  Ae. columnaris, Ae. geniculata, Ae. markgrafii, Ae. neglecta and Ae. triuncialis in the collection of the Gene Bank of RICP Prague-Ruzyně, with T.  aestivum cv. Sandra as control, were evaluated for cereal aphid occurrence in the open during 1995–1998 period. The cereal aphid species Rhopalosiphum  padi (RP), Metopolophium dirhodum (MD) and Sitobion avenae (SA) were predominant on the plants. Variations in the abundance of individual aphid species in each year were found. The results from 1997, the optimal year for aphid occurrence, showed differences between both aphid and plant species. RP significantly dominated in Triticum species, while SA preferred Aegilops accessions. A significant negative correlation was found between RP and MD densities in the Triti­ cum spp., while MD and SA occurrence showed a negative relation to that of RP and SA in the Aegilops accessions. The individual aphid species showed a similar pattern of infestation in several genomically close accessions.

Electrophoretic study of enzymes from cereal aphid populations. I. Electrophoretic techniques and staining systems for characterising isoenzymes from six species of cereal aphids (Hemiptera: Aphididae)

1983 ◽  
Vol 73 (4) ◽  
pp. 645-657 ◽  
Author(s):  
H. D. Loxdale ◽  
P. Castañera ◽  
C. P. Brookes
Keyword(s):  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Individual Species ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Electrophoretic Study ◽  
Banding Patterns ◽  
Glycerophosphate Dehydrogenase ◽  
Electrophoretic Techniques

AbstractOne–dimensional slab polyacrylamide gel electrophoretic techniques, staining systems and isoenzyme banding patterns for 14 soluble enzymes separated from crude homogenates of individuals of six species of cereal aphids (Sitobion avenae (F.), S. fragariae (Wlk.), Metopolophium dirhodum (Wlk.), M. festucae (Theo.), Rhopalosiphum padi (L.) and R. maidis (Fitch)) are described. The value of the techniques and banding patterns to taxonomic and population genetic studies of these and other aphid species are briefly discussed. With the six species, it was possible to separate the different genera as well as individual species within genera. The enzymes found to be most useful for inter–generic and/or -specific separations were adenylate kinase (AK), esterase (EST), glucose-6-phosphate dehydrogenase (G-6-PDH), hexokinase (HK), malate dehydrogenase (MDH), peptidase (PEP), phosphatase (PHOS), phosphoglucomutase (PMG), 6-phosphogluconate dehydrogenase (6-PGD) and sorbitol dehydrogenase (SORDH), whilst glutamate oxaloacetate transaminase (GOT), α-glycerophosphate dehydrogenase (α-GPD), malic enzyme (ME) and peroxidase (POD) were of relatively little taxonomic use. There were no banding pattern differences between the various morphs of S. avenae (first to fourth-instar nymphs, apterous and alate adults using the 14 enzymes.

Trophic interactions between three species of cereal aphid (Hemiptera: Aphididae) and spring wheat (Poaceae): implications for pest management

2007 ◽  
Vol 139 (6) ◽  
pp. 850-863 ◽  
Author(s):  
Samuel M. Migui ◽  
Robert J. Lamb
Keyword(s):  
Spring Wheat ◽  
Trophic Interactions ◽  
Plant Biomass ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Economic Damage ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Economic Thresholds ◽  
Specific Impact

AbstractThe susceptibilities of genetically diverse Canadian spring wheats, Triticum aestivum L. and Triticum durum Desf., to three aphid species, Rhopalosiphum padi (L.), Sitobion avenae (Fabricius), and Schizaphis graminum (Rondani), were investigated. Trophic interactions measured as changes in biomass of aphids and wheat plants were used to quantify levels of resistance, components of resistance, and impact of aphids on yield. Plants in field cages were infested with small numbers of aphids for 21 days at heading. These plants were usually more suitable for the development of S. avenae and S. graminum than of R. padi. Partial resistance, measured as seed production by infested plants as a proportion of that by a control, varied from 11% to 59% for different aphid species and wheat classes when all wheat plants were infested at the same stage. Cultivars within wheat classes responded similarly to each of the aphid species. None of the wheat cultivars showed agriculturally effective levels of antibiosis. The specific impact of each aphid species and wheat class varied from 5 to 15 mg of plant biomass lost for each milligram of biomass gained by the aphids. Canadian Western Red Spring wheat had a lower specific impact and therefore was more tolerant to aphids than the other two classes, but not tolerant enough to avoid economic damage at the aphid densities observed. Plants did not compensate for feeding damage after aphid feeding ceased, based on the higher specific impacts observed for mature plants than for plants that were heading. The interactions between aphids and plants show that current economic thresholds probably underestimate the damage caused by cereal aphids to Canadian spring wheat.

scholarly journals Pathogenicity of the fungus Lecanicillium longisporum against Sipha maydis and Metopolophium dirhodum in laboratory conditions

2014 ◽  
Vol 54 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Safoora Fadayivata ◽  
Gholamhossein Moravvej ◽  
Javad Karimi
Keyword(s):  
Field Tests ◽  
Control Program ◽  
Aphid Species ◽  
Cereal Aphids ◽  
Conidial Suspension ◽  
Metopolophium Dirhodum ◽  
Whole Plant ◽  
Conidial Concentration ◽  
Lecanicillium Longisporum ◽  
Aphid Populations

Abstract This study aimed to evaluate the susceptibility of two cereal aphids, Sipha maydis (Passerini) and Metopolophium dirhodum (Walker), to the entomopathogenic fungus, Lecanicillium longisporum (Zimm.) Zare and Gams strain LRC 190, under controlled conditions. The conidial suspension of the fungus was administered using a sprayer on the whole plant over apterous adult aphids. The results indicated that both aphid species were susceptible to L. longisporum and that aphid populations were significantly reduced, compared to the control. Nine days after treatment, the LC50 value of the fungus was obtained as 5.9 × 105 and 3.2 × 106 conidia/ml for S. maydis and M. dirhodum, respectively. The LT50 value of the fungus at a concentration of 108 conidia/ml was obtained as 2.9 and 4.4 days for S. maydis and M. dirhodum, respectively. The results demonstrated that there was a varying susceptibility to the fungus between aphid species. The estimated LC50 and LT50 indicated that L. longisporum was more virulent to S. maydis than to M. dirhodum. The LT50 and R0 decreased as the conidial concentration increased. This is the first study to demonstrate the susceptibility of S. maydis to the entomopathogenic fungi. The present study suggests that L. longisporum has high virulence against the aphids S. maydis and M. dirhodum. Further research with an emphasis on greenhouse and field tests are required, however, before making any decision about using the fungus in a control program

A GENERAL METHOD FOR ESTIMATING CEREAL APHID POPULATIONS IN SMALL GRAIN FIELDS BASED ON FREQUENCY OF OCCURRENCE

1995 ◽  
Vol 127 (1) ◽  
pp. 59-63 ◽  
Author(s):  
G.L. Hein ◽  
N.C. Elliott ◽  
G.J. Michels ◽  
R.W. Kieckhefer
Keyword(s):  
Weighted Average ◽  
Aphid Species ◽  
Parameter Estimates ◽  
Single Model ◽  
Cereal Aphid ◽  
Grain Aphid ◽  
Aphid Density ◽  
Single Set ◽  
General Method ◽  
Aphid Populations

AbstractSimilarities in population parameters among aphid species led us to investigate the potential for a single set of parameters that can be used to develop a ‘generic’ sampling plan for multiple small grain aphid species. A weighted average for the slope and intercept used to relate the proportion of infested tillers to the number of aphids per tiller was determined from the data in 15 published reports. These average parameter estimates were used to predict the number of aphids per tiller in 48 wheat fields sampled for four aphid species. The predicted estimates were regressed on the observed estimates with neither slopes nor intercepts differing significantly from one or zero, respectively. Therefore, it appears the single model is adequate for predicting aphid density for the aphid species tested.

Assessment of methods for estimating the numbers of aphids (Hemiptera: Aphididae) in Cereals

1982 ◽  
Vol 72 (4) ◽  
pp. 675-685 ◽  
Author(s):  
Alan M. Dewar ◽  
Godfrey J. Dean ◽  
Ray Cannon
Keyword(s):  
Field Studies ◽  
Accurate Method ◽  
Sitobion Avenae ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
Aphid Density ◽  
Very High ◽  
Vacuum Sampling

AbstractVisual counting was found to be the most accurate method of estimating cereal aphid numbers in field studies in England. Vacuum sampling decreased in efficiency as aphid density increased, but could be a useful alternative to visual counts at very low aphid densities when the latter became too time-consuming. Cutting tillers for later washing in the laboratory was less efficient than visual counting as aphids, especially Metopolophium dirhodum (Wlk.), fell off the plants during sampling, but this method was useful in determining the proportion of different morphs of Sitobion avenae (F.) present at very high densities.

Antioxidant defense mechanisms of cereal aphids based on ascorbate and ascorbate peroxidase

Biologia ◽  
2009 ◽  
Vol 64 (5) ◽  
Author(s):  
Iwona Łukasik ◽  
Sylwia Goławska ◽  
Agnieszka Wójcicka
Keyword(s):  
Caffeic Acid ◽  
Ascorbate Peroxidase ◽  
Defense Mechanisms ◽  
Antioxidant Defense ◽  
Rhopalosiphum Padi ◽  
Aphid Species ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Antioxidant Responses ◽  
Grain Aphid

AbstractEffects of plant o-dihydroxyphenols on ascorbate (ASA) content and ascorbate peroxidase (APOX) activity in the tissues of the grain aphid Sitobion avenae and the bird cherry-oat aphid Rhopalosiphum padi were studied. Among the aphid morphs, the highest ASA content and APOX activity were noted for larvae and the lowest for wingless apterae. When exposed to o-dihydroxyphenols, aphids of both species contained significantly lower concentrations of ASA and higher APOX activity than the controls. Among the studied compounds, caffeic acid had the strongest effect on ASA-based antioxidant responses in that caffeic acid caused a 5-fold decrease of ASA in aphid tissues. The influences of the plant o-dihydroxyphenols on antioxidant defense mechanisms within the cereal aphid species are discussed.

Toxares deltiger (Haliday) (Hymenoptera: Aphidiidae) parasiting the cereal aphid, Metopolophium dirhodum (Walker) (Hemiptera: Aphididae), in southern England: a new host-parasitoid record

1980 ◽  
Vol 70 (3) ◽  
pp. 407-409 ◽  
Author(s):  
W. Powell
Keyword(s):  
Host Plant ◽  
Cereal Aphids ◽  
Cereal Aphid ◽  
Metopolophium Dirhodum ◽  
New Host ◽  
Southern England ◽  
Field Laboratory

AbstractSixty-seven per cent of parasitoid mummies which developed from Metopolophium dirhodum (Wlk.) collected in wheat fields at Rothamsted, southern England, in 1979 were of Toxares deltiger (Hal.), a species previously unrecorded from cereal aphids. T. deltiger formed only 1% of samples when parasitoid mummies were collected directly from cereals in the field. Laboratory observations of the parasitoid indicate that affected aphids probably leave the host-plant prior to death and mummy formation.

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