Showing papers on "Aphididae published in 1987"

A study of feeding by polyphagous predators on cereal aphids using ELISA and gut dissection.

Abstract: (1) Enzyme-linked immunosorbent assay (ELISA) was used to detect aphid consumption by predators collected from three fields of winter wheat. (2) A total of 7781 predators belonging to 105 species was tested and 81 species were found to have eaten aphids at some time during the study. (3) An unexpectedly high percentage of many species had eaten aphids when aphid density was low, early in the season. (4) The relative efficiencies of ELISA and gut dissection for detecting prey remains varied according to the species of predator tested, and secondary predation was a potential problem, especially in the former technique. (5) In general, staphylinid beetles and beetle larvae digested their aphid meal much more rapidly than carabid beetles and spiders. (6) Field data on percentage of predators positive in ELISA and on predator density were combined with laboratory data on digestion rates to give predation indices which enabled comparison of species in terms of some aspects of their probable value as aphid predators. Spiders usually had the highest predation indices, but mites and adult and larval beetles were also of significance as aphid predators. It is concluded that aphid control by polyphagous predators is likely to be widely based.

Chemical basis of host-plant resistance to aphids

Abstract: The importance of host-plant resistance of crop plants in the biological control of aphids and the formation of aphid biotypes is discussed. The rapid response of plant breeders to the formation of new aphid biotypes requires detailed knowledge on the mechanism of host-plant resistance. Current knowledge on the chemical basis of host-plant resistance to aphids is summarized. Of central importance to this relationship is the aphid-pectinase plant-pectin interdependence. Parallels between the mechanism of aphid-plant and pathogen-plant attack are pointed out and how aphid bacterial endo-symbiotes play a central role in host-plant selection.

Morphological discrimination of a tobacco-feeding form from Myzus persicae (Sulzer) (Hemiptera: Aphididae), and a key to New World Myzus (Nectarosiphon) species

Abstract: Multivariate techniques, principally the method of canonical variates, were used to investigate morphological variation within and between populations of the group of Myzus persicae (Sulzer) from North and South America, Europe, Africa and Asia. The scores on the first canonical variate of samples from tobacco in North America, the Mediterranean region, the Middle East, Africa and Sri Lanka all grouped consistently when compared with samples from other host-plants, even after aphids from tobacco had been reared for up to seven years on a non-tobacco host. Thus there is a widely-distributed tobacco-adapted form, closely related to M. persicae but with its own characteristic morphology. Morphological discriminants are given for the recognition of apterous and alate viviparae of this tobacco form, which is given the name M. nicotianae sp. n. Both M. persicae and M. nicotianae have 2n = 12, and both are frequently heterozygous for apparently the same autosomal translocation, which they must have acquired independently. M. nicotianae is presumably isolated from M. persicae by being permanently parthenogenetic. In Japan and Central Asia, however, aphids of the M. persicae group on tobacco can produce sexual morphs; the taxonomic status of these latter populations is still unclear. Multivariate comparison of European and North American populations of dark green aphids of the M. persicae group with 13 or 14 chromosomes in somatic cell nuclei instead of the normal 12, led to the conclusion that these all belong to one morphologically variable taxon, M. antirrhinii (Macchiati). Keys are provided to the apterous and alate virginoparae of the species of the M. persicae group in America.

Information on and identification of Diuraphis noxia (Homoptera: Aphididae) and other aphid species colonizing leaves of wheat and barley in the United States

Abstract: In the United States, Diuraphis noxia (Mordvilko), variously called the “Russian wheat aphid,” the “Russian grain aphid,” and the “barley aphid,” was first collected and identified in March 1986, near Muleshoe, Bailey County, Tex. By the end of 1986, D. noxia had been collected in Colorado, Kansas, Nebraska, New Mexico, Oklahoma, Texas, and Wyoming on wheat, barley, oats, rye, triticale, and several grasses. Damage to wheat and barley during 1986 was extensive in some fields in Texas, New Mexico, and Colorado; crop losses were heavy in these areas. In addition to D. noxia , 12 other aphid species are known to colonize leaves of wheat, barley, and other small grains and some related grasses in the United States. A brief summary of taxonomic characteristics, usual hosts, and known distribution within the United States is given here for each species along with a couplet key and pictorial plates. This information should prove very useful to county, state, and federal personnel involved with surveys of grain aphids, particularly those surveys for D. noxia as it spreads into other grain-growing areas of the United States.

Plant-derived synergists of alarm pheromone from turnip aphid,Lipaphis (Hyadaphis) erysimi (Homoptera, Aphididae).

Abstract: The turnip aphid,Lipaphis (Hyadaphis) erysimi, responds weakly to (E)-β-farnesene, the main component of the alarm pheromone, but the response is substantially increased by incorporating plant-derived isothiocyanates, identified in aphid volatiles by coupled gas chromatography-single-cell recording.

Migration of parasitoids (Hymenoptera: Braconidae) of cereal aphids (Hemiptera: Aphididae) between grassland, early-sown cereals and late-sown cereals in southern England.

Abstract: The 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).

Oviposition and niche partitioning in aphidophagous insects on maize

Abstract: Principal components analysis was used to assess niche partitioning between four aphid predators on the basis of oviposition strategies. The study was conducted by sampling abundance and position of the eggs of these predators in corn monocultures in two locations of southern Quebec. The results indicated that the chrysopid Chrysopa occulata Say laid its eggs on corn leaves usually without aphid colonies, and late in the season. All other predators reacted to aphid concentrations. The syrphid Sphaerophoria philanthus (Mg.) oviposited close to the ground, early in the season, and among colonies of the aphid Rhopalosiphum padi (L.). The two coccinellids laid their eggs during July and August with a maximum during tasseling for Coleomegilla maculata lengi (Timberlake) and after pollination for Hippodamia tredecimpunctata tibialis Say. Of these two species, the latter one selected sites at higher levels on the plant, and was more abundant at the edges of the field. It is suggested that the observed niche partitioning cannot be the result of interspecific competition in variable environments such as maize monocultures.

Development rate, fecundity and lifespan of apterae of the Russian wheat aphid, Diuraphis noxia (Mordvilko) (Hemiptera: Aphididae), under controlled conditions

Abstract: The rate of development, fecundity and lifespan of apterae of Diuraphis noxia (Mordvilko) were determined at five sets of temperature and daylength conditions. The time required to complete pre-imaginal growth at mean daily temperatures of 10, 13, 14, 17·25 and 20°C was 19·70, 12·09, 11·25, 9·88 and 8·17 days, respectively. The threshold for development was estimated to be 0·54°C and the number of day-degrees C required to complete development was 158·73.

Aphid Feeding Behavior: Relationship to Barley Yellow Dwarf Virus Resistance in Agropyron Species

Abstract: Shukle, R. H .• Lampe, D. J ., Lister, R. M .• and Foster, J. E. 1987. Aphid feeding behavior: Relationship to barley yellow dwarf vi rus resistance in Agropyron species. Phytopathology 77: 725-729. The infectibility of various Agropyron species (wheatgrasses) was examined with respect to thl\"« isotates of barley yellow dwarf virus (BYDV) by infl:$ting them with appropriate vector aphids, followed by testing by enzyme-linked immunosorbent assay. Feeding behavior of the VCi:tors Rhopalosiphum padi and SilObion avenoe was also electronically monitored to determine their abi lity to inoculate phloem. The results indicated that resistance to BYDV infection occurs in several Agrop>'n}n species. For most species tested. resistance seemed due to failure in virus increase. but in $Orne species a major constraint on infection \\\\'as the inability ofvcctors 10 locate phloem. Two potential approaches to breeding for reduced BYDV in wheat by crossing with Agropyron species may thus be: incorporating facto rs reducing or preventing virus production and incorporating factors reducing the ability of \"ectors to inoculate plants successfully. Addirlonal kry words: 8 YDV-resistant germ plasm.luteoviru.ses, wheat improvement. The term barley yellow dwarf virus (BYDV) includes at least five variously interrelated types of luteovirusts (9. 18) that are appa rently res t ricted to gramineou5 plants. They cause yellowdwarf diseases in cereals that affect the su pply of whcat, oats, and barley throughout the world (6, 18). Like the other luteovirusts, Th. publlc'!ion COlt. of !ht •• nlcle wer. def,.yed In p.,t by p.~ chl'g. p.yment This .,Uct. mu\" lI,or.r.,..o be horoby mlrked \" • .,.. ... ,; ..... .\",In _,,.nco wllh t8 U.S.C. t 11304 s

Biological control of the spotted alfalfa aphid, Therioaphis trifolii F. maculata, on lucerne crops in Australia, by the introduced parasitic hymenopteran Trioxys complanatus

Abstract: SUMMARY satisfactorily account for it. The capacity of the aphid to infest and increase on susceptible lucerne remains unchanged. The drought, which developed concurrently with the decline and may have reduced source populations on non-irrigated lucerne plants thus lowering immigration rates into irrigated crops, broke in 1983 with no indication of aphid resurgence since. Insecticide use, although high at first, decreased rapidly with the reduction in infestations. Relative to the rate of decline, the replacement of aphid- susceptible lucerne with aphid-resistant varieties proceeded slowly to reach only 10%/o in 1981 and 26%/o in 1984. The majority of lucerne grown in Australia is still susceptible to the aphid. Although native predatory insects became numerous in aphid-infested crops, they did not reduce aphid numbers sufficiently consistently to account for the decline. (4) Of the hymenopterous parasites, only one, Trioxys cornplanatus, became generally widespread and numerous throughout the lucerne-growing areas of Australia. (5) Parasitization by T. complanatus increased from one lucerne growth cycle to the next and higher levels were associated with aphid infestations that did not increase to damaging levels. (6) Observed reductions in the proportion of apterous adult female aphids in field populations were consistent with estimates of parasitization by T. complanatus. (7) When the properties of the aphid and parasite, as measured in the laboratory, were assembled into a simulation model of their interacting life systems on irrigated lucerne crops, outputs from the model closely matched the observed field data. Furthermore, the simulated population at harvest from initial lucerne growth cycles, when used as input for other runs of the model, resulted in good simulations of aphid and parasite populations in subsequent cycles in the same season. (8) It is concluded that Therioaphis trifolii on irrigated lucerne crops was biologically controlled by the introduced hymenopterous parasite Trioxys complanatus. (9) The short-term (say 5-year) value of the biological control, in terms of the reduction in the cost of insecticide applications needed to prevent loss and spoilage of the N.S.W. lucerne-hay crop, has probably been of the order of 1 million dollars a year. In terms of reduced urgency for replanting with aphid-resistant varieties, the value was similar. Over the whole of Australia, the value would be proportionally greater. (10) Although T. complanatus was known to be less effective at high summer temperatures, this did not prevent an overall reduction in immigration rates, although some alates still infest many crops.

The effect of previously infested spruce needles on the growth of the green spruce aphid, Elatobium abietinum, and the effect of the aphid on the amino acid balance of the host plant

Abstract: SUMMARY The effect of chlorosis induced in needles of Sitka and Norway spruce by the green spruce aphid on growth of the aphid is investigated, and the effect of infestation of the aphid on amino acid levels in Sitka spruce foliage is reported. On both Sitka and Norway spruce green spruce aphids were heavier when reared on chlorotic (previously infested) needles than when reared on green (previously uninfested) needles. The effect was more pronounced on Sitka than on Norway spruce. Infestation of the aphid altered the amino acid balance of Sitka spruce foliage but not the concentration of total amino acids. Possible causes of chlorosis, the influence of individual amino acids on aphid growth, the potential effect of chlorosis on outbreaks of the aphid and the differences in susceptibility of Sitka and Norway spruce to damage by the aphid are discussed.

The acquisition of a caulimovirus by different aphid species: comparison with a potyvirus

Abstract: SUMMARY The acquisition and transmission of cauliflower mosaic virus (CaMV) by six aphid species and three clones of aphids was studied and compared with that of turnip mosaic virus (TuMV) with Myzus persicae. Two clones of Aphis fabae were unable to transmit CaMV, but the other species, Acyrthosiphon pisum, Brevicoryne brassicae, Megoura viciae, M. persicae and Rhopalosiphum padi transmitted in a bior multi-phasic manner. There was no statistical evidence of a bimodal transmission pattern. R. padi is recorded as a vector of CaMV for the first time. The transmission efficiency of CaMV varied with time of acquisition and suggested that accumulation of the virus occurred with two peaks of efficiency within the anterior region of the insect gut. The time at which these two peaks occurred varied between the species, but the basic pattern was common to all transmitting aphid species in this study. This pattern contrasted with that of TuMV. The transmission data are discussed in terms of bimodal transmission, the influence of feeding behaviour, the role of a helper protein associated with both TuMV and CaMV and the evidence for site specific attachment of CaMV.

Energy acquisition and allocation in plants and insects: a hypothesis for the possible role of hormones in insect feeding patterns

Abstract: A distributed delay age structure model is presented for plants and insects that describes the dynamics of per capita energy (dry matter) acquisition and allocation patterns, and the within-organism subunit (e.g. leaves, fruit, ova) number dynamics that occur during growth, reproduction, and development. Four species of plants (common bean, cassava, cotton, and tomato) and two species of insects (pea aphid and a ladybird beetle) are modeled. A common acquisition (i.e. functional response) submodel is used to estimate the daily photosynthetic rates in plants and consumption rates in pea aphid and the ladybird beetle. The focus of this work is to capture the essence of the common attributes between trophic levels across this wide range of taxa. The models are compared with field or laboratory data. A hypothesis is proposed for the observed patterns of reproduction in pea aphid and in a ladybird beetle.

Economic injury levels and economic thresholds for cereal aphids (Homoptera: Aphididae) on spring-planted wheat

Abstract: Foliar insecticide treatments were applied at various stages of plant growth to control natural infestations of two cereal aphids, the English grain aphid, Sitobion avenae (F.), and the rose-grass aphid, Metopolophium dirhodum (Walker), in field plots of spring wheat. Yield increases of 2.7 t/ha (36.5%) and 1.2 t/ha (29.3%) were obtained when sprays were applied at flowering in 1984 and 1985, respectively. Lower but significant yield increases were also obtained when sprays were applied at the milky ripe and early dough stages. Depending on the cost of chemical treatment and price received per kilogram of wheat, the economic injury level was calculated to be 15 and 10 aphids per tiller in 1984 and 1985, respectively. Based on the plant growth stage and the rate of aphid population growth, economic thresholds were calculated to be 2–4 aphids per tiller at flowering, 6–10 aphids per tiller up to the milky ripe stage, and 10 or more aphids per tiller from the milky ripe to medium-dough stage. After the medium-dough stage, treatment cannot be justified.

Screening for resistance against Rhopalosiphum padi (L.). 2. Hordeum species and interspecific hybrids

Abstract: Twenty-seven accessions of Hordeum species and interspecific hybrids were screened in a growth chamber for resistance against the aphid Rhopalosiphum padi. Resistance measurement was based on the aphids' population growth during a 16-day period. The mean number of nymphs produced per female was only about 14% of that on the control cv. Tellus. H. bogdani was the most resistant accession. As a group, interspecific F1-hybrids with common barley (H. vulgare × H. sp.) held an intermediate position. Differences in resistance between hybrids as well as between species (H. jubatum and H. lechleri) were observed. The most resistant species were all diploids. No effects of the host plant on formation of alatae or on the within-plant distribution of aphids were found.

The role of predators and parasites in the natural regulation of lucerne aphids in Eastern Australia

Abstract: (1) The impact of invertebrate predators on lucerne aphids (Acyrthosiphon kondoi (Shinji), Therioaphis trifolii (Monell) and Acyrthosiphon pisum (Harris) was studied in the Hunter Valley, New South Wales, Australia, using a selective insecticide to suppress predators. Aphid and predator numbers were monitored weekly over 2 years in unsprayed and carbaryl-treated plots. (2) The major predator groups were hemerobiids (Micromus sp.), coccinellids (Coccinella repanda Thunberg), predatory mites (Bdellidae) and syrphid larvae. (3) In 1980-81, predators had a significant effect on aphid numbers in late spring, summer and early autumn but not in late autumn. (4) There was no build-up of aphids in spring or summer of the second year (1981-82). When aphid numbers did increase, in autumn 1982, no significant impact of predators was demonstrated. (5) Parasitism by the braconid parasite Aphidius ervi Haliday became an increasingly important mortality factor for A. kondoi during the 2-year period. The high incidence of parasitism in the winter and spring in 1981 and 1982 was significant in preventing the spring build-up that had characterized populations of A. kondoi since its arrival in the Hunter Valley. (6) A. kondoi appeared to be sensitive to the stage of growth of the host plant, alate production increasing as the plant approached maturity, even when there were few aphids. (7) It was concluded that predators and parasites are capable of making a significant contribution to lucerne aphid control in a pest management programme.

Functional Responses and Switching of Tetragnatha laboriosa Hentz (Araneae: Tetragnathidae) and Clubiona pikei Gertsh (Araneae: Clubionidae) for the Aphids Rhopalosiphum maidis (Fitch) and Rhopalosiphum padi (L.) (Homoptera: Aphididae)

Abstract: Laboratory experiments were performed to determine the functional responses and switching behavior of the two dominant spider species of southern Quebec (Canada) corn crops, Tetragnatha laboriosa Hentz and Clubiona pikei Gertsh, and for the two dominant aphid species, Rhopalosiphum maidis (Fitch) and Rhopalosiphum padi (L.). Each spider species was tested with one, and then with the two aphid species at increasing prey density. Switching tests were done by offering the spiders two different ratios of aphid species (4:1 and 1:4). Both spider species showed sigmoid, complex, domed-shaped and, sometimes, linear functional responses in both the monospecific and bispecific tests. Complex functional responses were observed only with C. pikei . Hence, the capture rates were often density-dependent, although inverse density-dependent capture rates were obtained at high prey densities. Both spider species consumed disproportionally more R. maidis than R. padi , whatever the ratio. A greater exploration rate of the experimental spaces by R. maidis could explain the predators' preference. These results suggest that these spiders have some potential for being effective biological control agents.

Seasonal abundance of the crapemyrtle aphid,Sarucallis kahawaluokalani, in relation to the pecan aphids,Monellia caryella andMonelliopsis pecanis and their common predators

Abstract: The seasonal abundance of the crapemyrtle aphid,Sarucallis kahawaluokalani (Kirkaldy), and the majority of its predators that are common with the yellow pecan aphid,Monelliopsis pecanis Bissel, and the blackmargined aphid,Monellia caryella (Fitch), were determined in norh Florida.S. kahawaluokalani populations were tri — and bimodal in the 2 years studied and peak populations ofS. kahawaluokalani preceeded those of the pecan aphid complex. Peaks in predator populations consisting of Coccinellidae, Syrphidae, Chrysopidae and Anthocoridae, either coincided with or occurred just afterS. kahawaluokalani peaks. The implications of the findings with respect to use ofS. kahawaluokalani as an alternate host of predators of pecan aphids and the potential for manipulation of the system to enhance biological control in pecan are discussed. The use of this system is advocated for augmentation and manipulation of generalist predators in other crop systems.

The relationship between the ash bolete (Boletinellus merulioides) and an aphid parasitic on ash tree roots

Abstract: A new and apparently mutualistic association between the ash-tree bolete mushroom Boletinellus merulioides and an aphid parasitic on ash roots has been discovered. When feeding on roots, the aphid (Meliarhizophagus fraxinifolii), a specific parasite of ash leaves and roots, is enclosed by hollow storage structures (sclerotia) of the fungus. We suggest that in exchange for housing the aphid, the fungus receives nutrients excreted by the aphid in its honeydew. This relationship could explain the specific occurrence of Boletinellus under ash trees. An older hypothesis, that B. merulioides is an ectomycorrhizal symbiont of ash trees, should now be rejected.

Inheritance of resistance to the cowpea aphid in cowpea

Abstract: Inheritance of resistance to cowpea aphid, Aphis craccivora Koch, in three resistant cultivars of cowpea, Vigna unguiculata (L.) Walp, was studied. The parents, F1 and F2 population were grown in an insect-proof screenhouse. Each 3-day-old seedling was infested with 10 apterous adult aphids. Seedling reaction was recorded when the susceptible check was killed. The segregation data revealed that the resistance of ICV11 and TVU310 is governed by single dominant genes. All the F2 seedlings of the cross ICV10xTVU310 were resistant, indicating that they have the same gene for resistance. However, the F2 populations from the crosses ICV10xICV11 and ICV11xTVU310 segregated in a ratio of 15∶1, indicating that the dominant genes in ICV11 and TVU310 are non-allelic and independent of each other. The resistance gene of ICV10 and TVU310 is designated as Ac1 and that of ICV11 as Ac2.

Cucurbit potyvirus transmission by alate aphids (Homoptera: Aphididae) trapped alive.

Abstract: In a 3-year field study in cucurbits infected with potyviruses, alate aphids trapped alive on a vertical screen or in horizontal suction or yellow-pan traps were tested individually on virus-susceptible plants for virus (natural) infectivity. Trap types differed in effectiveness for trapping some aphid species. Of 40 species of aphids tested for natural infectivity, 4 transmitted virus: Aphis citricola Van der Goot, A. middletonii (Thomas), A. illinoisensis Shimer, and Myzus persicae (Sulzer). Of these, 92.0% of all infective aphids were either A. citricola (52.0%) or A. middletonii (40.0%). In another study, 7 of 23 species of aphids trapped alive where there were no infected cucurbits, and fed on sources of watermelon mosaic virus 2 (WMV-2) or zucchini yellow mosaic virus (ZYMV) in the laboratory, transmitted the virus. Of these transmissions, 93.1% were by three species: A. citricola (48.3%), A. middletonii (27.6%), or M. persicae (17.2%). Their efficiency rates were 18.3, 30.8, and 23.8%, respectively. Average rate of transmission of WMV-2 was 9.7% and of ZYMV was 21.4%.

Release rates for control of green peach aphid (Homoptera: Aphidae) by the predatory midge Aphidoletes aphidimyza (Diptera: Cecidomyiidae) under winter greenhouse conditions.

Abstract: Control of green peach aphid, Myzus persicae , (Sulzer), on green pepper plants by the predatory midge Aphidoletes aphidimyza (Rondani), was investigated under winter greenhouse conditions (21°C daytime maximum, 15°C night minimum). Four release rates (1 predator: 3 aphids, 1:10, 1:50, 1:100) were compared in a randomized complete block design cage experiment from mid-November to mid-January. Best control was achieved with the 1:10 rate. There was significant effect due to location along the temperature gradient on the bench; differences between 1:3 and 1:10 rates appeared to have been due more to location than to initial predator/prey ratio. Aphids were not controlled in a subsequent experiment using the 1:10 rate in late February when daytime temperatures were 23–26°C.

The effect of short-term aphid feeding on the partitioning of 14CO2 photoassimilate in three legume species

Abstract: The short-term effects of the feeding of cowpea aphids (Aphis craccivora Koch) and pea aphids (Acyrthosiphon pisum (Harris)), both Homoptera: Aphididae, on 14C translocation and plant growth of broadbean (Vicia faba L. cv. Aquadulce), cowpea (Vigna unguiculata (L.) Walp. cv. Caloona), and garden pea (Pisum sativum L. cv. Victory Freezer) seedlings were investigated, but not all plant–aphid combinations were utilized. Within 10 days of infestation, aphid feeding reduced the flux of translocate to the roots, changed the assimilate partitioning pattern in affected shoots, and apparently induced assimilate sources to become assimilate sinks. Cowpea aphid feeding also caused more lateral branches to be formed in broadbean. Some of these effects may be related to the imbibing of translocate by aphids, while other effects may result from a series of interactions involving substances in the saliva of aphids, plant hormones, and the assimilate ratio of sources–sinks. The amount of radioactivity found per unit weig...