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

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.

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
María C. Tulli ◽  
Dora M. Carmona ◽  
Ana M. Vincini

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.


2006 ◽  
Vol 96 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Honek ◽  
V. Jarosik ◽  
A.F.G. Dixon

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.


1999 ◽  
Vol 35 (No. 2) ◽  
pp. 67-70
Author(s):  
H. Havlíčková ◽  
V. Holubec

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.


2004 ◽  
Vol 94 (1) ◽  
pp. 19-26 ◽  
Author(s):  
A. Honek ◽  
Z. Martinkova

AbstractThe sudden decline following the peak in population abundance of aphids on crops of small grain cereals is attributed to the joint effect of natural enemies and plant senescence. To distinguish between these causes, a four year experiment was established in which the numbers of Metopolophium dirhodum (Walker) infesting spring wheat plots sown from April to June at c. 14 day intervals were determined. Aphid abundance in replicates sown at successive dates peaked within a period of 5–9 days (106–171 day degrees above a base temperature of 0°C) although their sowing dates varied by 62–97 days (727–1106 day degrees). At the time of the aphid population peaks, plants in the different sowings differed in age (11–99 days), developmental stage (stage 15–65 on the Zadoks scale), leaf nitrogen content and shoot mass. Maximum abundance of M. dirhodum decreased with sowing date because the time available for its population increase was shorter on late than early sowings. The abundance of M. dirhodum on spring wheat was similar to its abundance on winter wheat. After reaching peak abundance, aphids declined in numbers within 3–7 days. The effect of host plant ageing on the M. dirhodumdecline thus appeared small. Natural enemies (largely mycoses), and timing of alata production may have contributed to the aphid decline.


1983 ◽  
Vol 73 (4) ◽  
pp. 645-657 ◽  
Author(s):  
H. D. Loxdale ◽  
P. Castañera ◽  
C. P. Brookes

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.


2018 ◽  
Vol 73 (3) ◽  
pp. 29-36
Author(s):  
ROBERT KRZYŻANOWSKI ◽  
IZABELA BEDNARCZYK ◽  
JOLANTA CUDZIŁO-ABRAMCZUK

Chlorophenoxyacetic herbicides such as 4-chloro-2-methylphenoxyacetic acid (MCPA) and 2,4-dichlorophenoxyacetic acid (2,4-D) are used for cereal protection. However, some of them penetrate the tissues of protected plants and also get in contact with cereal pathogens. The up-to-date studies concerned their effectiveness in combating the weeds without paying attention to the herbivores occurring in cereal agrocenoses. Therefore, the aim of the present study was to determine the effect of chlorophenoxyacetic herbicides on the probing behavior of grain aphid, Sitobion avenae (F.), bird cherry-oat aphid, Rhopalosiphum padi (L.) and rose-grain aphid, Metopolophium dirhodum (Walk.). The experiment was carried out on wingless females feeding on winter wheat seedlings of Tonacja cv. using the electronic penetration graph (EPG) method. Tested herbicide preparations exerted an influence on the probing behavior of all aphids examined. The inhibitory effect of MCPA and 2,4-D on the uptake of phloem juice was found. It has been shown that chlorophenoxyacetic herbicides are not only effective in combating the weeds of cereal crops, but can also have positive side-effects in the form of limiting the cereal aphids population.


1987 ◽  
Vol 77 (4) ◽  
pp. 555-568 ◽  
Author(s):  
V. T. Vorley ◽  
S. D. Wratten

AbstractThe dynamics of migration of the parasitoids Aphidius spp. between grassland and cereal fields of varying sowing dates was investigated in southern England in 1980 and 1981. Using baffled water traps, direct evidence of migration of A. rhopalosiphi De Stefani Perez females from grassland to winter wheat was obtained in June 1980, suggesting that the early-maturing grassland aphid Metopolophium festucae (Theobald) can act as a reservoir of cereal aphid parasitoids. In 1981, estimates of parasitoid production in cereal fields containing the aphids Sitobion avenae (F.), M. dirhodum (Walker) and Rhopalosiphum padi (L.) were compared with actual numbers to calculate net immigration and emigration. Barley and early-sown wheat (drilled before 14 October) proved to be significant sources of Aphidius spp., with one wheat field generating sufficient parasitoids in May to account for immigration into about 25 late-sown fields. Parasitoid migration as larvae inside aphid alatae was apparently of considerably less significance than that by adults, which were predominantly female. The advantages of early drilling of cereals to form ‘semi perennial’ reservoirs of beneficial insects is discussed and weighed against the corresponding disadvantages, especially an increased risk of barley yellow dwarf virus (BYDV).


ENTOMON ◽  
2020 ◽  
Vol 45 (3) ◽  
pp. 237-238
Author(s):  
J. Nayanathara ◽  
R. Narayana
Keyword(s):  
New Host ◽  

Anthene lycaenina lycaenina (R. Felder, 1868) is reported on mango for the first time.


10.1649/732 ◽  
2004 ◽  
Vol 58 (4) ◽  
pp. 578-579 ◽  
Author(s):  
Juan Rodrigo Salazar ◽  
Carlos Céspedes Acuña ◽  
Felipe A. Noguera
Keyword(s):  
New Host ◽  

2016 ◽  
Vol 70 (3) ◽  
pp. 566-568
Author(s):  
Anderson Melo Rosa ◽  
Alexandre Dos Santos ◽  
Rosane Segalla ◽  
Jerffersoney Garcia ◽  
Vagner Aniceto Teixeira
Keyword(s):  

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