Flight patterns of Russian wheat aphid,Diuraphis noxia (Kurdj.) during its expansion to Central Europe (Hom., Aphididae)

Flight patterns of migrant alate Russian wheat aphids (=RWA),Diuraphis noxia (Kurdj.) during its expansion from the south-east to Central Europe were determined. Samples were taken by Rothamsted-type suction air traps in Hungary (one location, 1990–1997) and in the Czech Republic (5 locations, 1994–1998). The results document a progressive expansion of RWA, and population variation in the individual years and periods of the season. A comparison of the evidence on RWA in the individual years since its detection in Hungary and in the Czech Republic supports the presumption on the occurrence of an expansion route from the south-east (Turkey) to Central Europe. This expansion is classified as an adventive route of the over-all expansion that has covered the whole West-Mediterranean (South Europe, North Africa).     

Within-field refugiums of Russian wheat aphid, Diuraphis noxia (Kurdj.) in cereals (Hom., Aphididae)

An analysis of the Russian wheat aphid (RWA) (Diuraphis noxia Kurdj.), overpopulated due to extraordinary weather conditions (2000) in the Czech Republic, enabled the identification of several within-field situations ouside of the routine approach. This group, classified as within-field refugium, includes variation due to field relief, some injuries caused by the use of machinery, the unharvested field margins and, last but not least, the volunteer plants. Differences between the RWA populations in these situations and the normal grove are presented and recommended to be taken into consideration in the research on RWA population dynamics and movement.     

Russian wheat aphid, Diuraphis noxia (Kurdj.) under adverse weather conditions (2001) (Hom., Aphididae)

Cool and wet weather in some periods of the season generally supressed the RWA (Diuraphis noxia Kurdj.) populations in the Czech republic in 2001. However, some sites manifested population levels ranging out of the population mean stated per area, and these sites were also apparently responsible for respective peaks of alate aphids sampled by suction traps. An analysis of these sites determined them to be attributed to some poor quality barley fields in a warmer area of the state. RWA is known to vary in all-over populations in different years, and the year 2001 illustrated its capability of its surviving even unfavourable periods and seasons, remaining well-established in the area.     

Increase of Russian wheat aphid, Diuraphis noxia (Kurdj.) in hot and dry weather (2000) (Hom., Aphididae)

Two hot and dry weather periods during mid-spring and early summer caused severe drought-stress to barley groves in many districts of the Czech Republic in 2000. Although not generally taken into consideration as an injury-increasing factor, the Russian wheat aphid (=?RWA), Diuraphis noxia (Kurdj.), was discovered to contribute significantly to injury in the ripening stage of spring barley as well as to the substantial decrease of yield (up to 30?–?40?% of the calculated mean, in some districts). RWA increased considerably not only in the lowland banker areas but also in the higher altitudes, values in the latter case then manifesting those found in the lowland banker areas in the previous years.     

On-going expansion of Russian wheat aphid, Diuraphis noxia (Kurdj.) in central Europe (Horn.: Aphididae)

A supplementary research on Russian wheat aphid (= RVA), Diuraphis noxia (Kurdj.) between 1998-99 documented the pest distribution all over the Czech republic already. RVA abundance was proved to be significantly area-dependent within the state. The banker areas are in southern Moravia (district Znojmo, the frontier area near Austria) up to central Moravia. The determined RWA distribution area is much broader than presumed on grounds of climatic characteristics.The abundance of RVA generally decreases from the SE to the NW and N direction, as well as with the increasing altitude within the area.The highest altitude a.s.l. of RWA occurrence in the crop was 762 in. The re-classified main expansion route was determined to follow two directions (sourcing from Hungary and Austria) to southern-central-northem Moravia, and to southern Bohemia and further on to the central Bohemian lowland. The field information indicated the development of preference of RWA for barley.     

Host plant preference of Diuraphis noxia (Kurdj.) (Hom., Aphididae)

Host plant preference of the Russian wheat aphid Diuraphis noxia (Kurdj.) was studied on 11 cultivars of 9 plant species: winter barley, spring barley, winter wheat, spring wheat, rye, oat, Triticale, canary grass, red millet yellow millet and maize. Seeds of the host plants were sown in a circle near the edge of pots. The host plant choice was evaluated 24 hours after releasing 55 Diuraphis noxia female adults in the middle of each pot. The suitability of different hosts for aphid development was evaluated 2, 7 and 14 days after infestation based on the mean number of Russian wheat aphid individuals per plant. Red millet, yellow millet and maize were chosen by significantly fewer aphids than grain crops. Winter and spring barley were chosen as hosts most frequently, and the progeny production was also the highest on these plants. The growth rate of D. noxia was significantly affected by the host plants and the date of assessment and their interaction.     

Distribution and Ecology of the Russian Wheat Aphid,Diuraphis noxia (Kurdj.), expanded to Central Europe (Hom.: Aphididae)

A part of the territory of the Czech Republic represents the up-dated northern limit of distribution (status 1997) which the Russian wheat aphid (=RWA),Diuraphis noxia (Kurdj.) has reached during its expansion from the southeast to central Europe. The newly defined area is classified as one of the adventive routes which may be derived from the main expansion of RWA from its native home (central-western Asia) into the broader Mediterranean area. Distribution and its history, and ecology (life-cycle, host plants, seasonal history, both native and introduced natural enemies) of RWA are presented on ground of field evidence and trials obtained in 1995–1997 in the Czech Republic. The origin of RWA, its distribution and establishment in the target area, as well as prognosis of its further expansion, are reviewed and discussed. Steps and approaches to RWA detection in the crop, as well as some notes on its management, are added.     

The expansive Russian wheat aphid,Diuraphis noxia (Mordw.) detected in the Czech Republic

The Russian wheat aphid,Diuraphis noxia (Mordw.) has been detected in southern Moravia, the Czech Republic in June, 1995. Its location is related to its incidence in central Hungary. The further predicted area of distribution covers the grain-maize growing districts of southern Moravia (Czeck Republic), neigh-bouring parts of Austria, southern and south-eastern parts of the Slovak Republic. The aphid is classified as a species expanding to the north from its mediaterranean area of distribution, apart of extensive areas (North to South Americas, S. Africa, expected in Australia) which it has covered thorugh accidental introductions and further spread over the world.     

Adaptation of native syrphid flies to new exotic plant (Impatiens spp.)-aphidant associations in Central Europe (Dipt., Syrphidae; Hom., Aphididae; Hym., Formicidae)

Impatiens parviflora andI. glandulifera, two invasive touchme-not species of exotic origin were found to be associated with two aphid groups in Central Europe: a) Exotic species subsequently following their invasive plant hosts (Impatientinum asiaticum Nevsky), b) native species secondarily adapted to the new exotic hosts (Aphis fabae cirsiiacanthoidis Scop.). The species number (listed) of associated syrphid flies in the newly developed guilds was rather high, consisting of broadly oligophagous species. The plant phenology and adaptation of the aphids have resulted in associations which apparently represent seasonally significant sources of prey, their importance apparently increasing with the decreasing season. Antattendance was determined in both aphid species, and no adverse interference with the preying syrphid larvae was observed. In spite of an overall classification of the target plants as expansive weeds, they are classified positively as contributing to the enhancement of syrphid fly populations in the biocorridors in the cultivated landscape.     

Über das Auftreten der Getreideblattlausarten (Hom., Aphididae) in norddeutschen Weizenanbaugebieten (1974/75)

The ocurrence of the different cereal aphids (Hom., Aphididae) in Northern German wheat growing areas 1974 and 1975 In July, 1974 and 1975,Macrosiphum avenae (F.) was the most common aphid on cereal fields in Northern German wheat growing areas.Rhopalosiphum padi (L.) was less abundant, whileMetopolophium dirhodum (Wlk.) was found very seldom.R. padi infested field edges only in most cases, while this was not true for all fields infested byM. avenae.     

Die Parasitoide der Blutlaus (Eriosoma lanigerum Hausmann) (Hom., Aphididae) und ihre Verbreitung in der Pfalz

Zusammenfassung Die Blutlaus kam zwischen September 1986 und Oktober 1987 in allen Apfelangebieten der Pflaz vor. Von insgesamt 50 untersuchten Orten mit Apfelvorkommen trat der Schädling in 22 von 28 bewirtschafteten Apfelanlagen, dagegen nur an 2 von 24 Orten mit wildwachsenden oder extensiv bewirtschafteten Apfelbäumen auf. Außer in der Westpfalz konnte überall auch gleichzeitig der einzige spezifische Parasitoid, die BlutlauszehrwespeAphelinus mali Hald. gefunden werden.NebenA. mali wurden aus mumifizierten Blutläusen 4 weitere Species aus der Überfamilie Chalcidoidea gezogen, wobei es sich um Hyperparasitoide der ArtenAsaphes vulgaris Walk.,Asaphes suspensus Nees undPachyneuron solitarium Htg. (Pteromalidae) sowie umAphidencyrtus aphidivorus Mayr (Encyrtidae) handelte.Um die Bedeutung der Zehrwespe bei der biologischen Bekämpfung der Blutlaus festzustellen, wurden in verschieden bewirtschafteten Apfelanlagen während einer Vegetationsperiode die Stärke des Blutlausbefalls über die Koloniezahlen und der Parasitierungsgrad durchA. mali über Präparationen von mehr als 63 000 Läusen ermittelt. Die Auswirkungen der zu dieser Zeit eingesetzten Pflanzenschutzmittel wurden berücksichtigt.Die Ergebnisse zeigen, daß in der Pflaz die biologische Bekämpfung vonEriosoma lanigerum mitA. mali in integriert bewirtschafteten Anlagen möglich ist, wobei der termingerechte Einsatz selektiver Präparate die Wirkung der Zehrwespe sinnvoll unterstützen kann. Die konventionell bewirtschafteten Anlagen waren dagegen besonders nach Einstellen der Insektizidbehandlungen viel stärker befallen und zeigten auch aufgrund vorangegangener Schädigungen der Wespe durch breitenwirksame Präparate deutlich geringere Parasitierungsraten.Eine Empfehlung an die Praxis wird gegeben.

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The parasitoids of the Woolly Apple Aphid (Eriosoma lanigerum Hausm.) Hom., Aphididae) and their distribution in the Palatinate, FRG

The Wooly Apple Aphid (Eriosoma lanigerum Hausm.) appeared during September 1986 and October 1987 in all greater areas with apple orchards in the Palatinate. From a total of 50 investigated places the parasite had been found in 22 of 28 treated orchards. On not or only extensive cultivated apple-trees it could have been only found in 2 of 24 places. With exception of the Western Palatinate, the only monophagous parasite ofE. lanigerum, Aphelinus mali Hald. appeared always sametimes.BesideA. mali, 4 other species of Chalcidoidea emerged from mummified aphids. These hyperparasites referred toAsaphes vulgaris Walker,Asaphes suspensus Nees,Pachyneuron solitarium Hartig (Pteromalidae) andAphidencyrtus aphidivorus Mayr (Encyrtidae).To determine the importance ofA. mali for biological control of woolly aphid, the infestation in different treated apple orchards has been investigated by counting the colonies during the season. The course of parasitism has been determined by dissecting altogether more than 63.000 aphids of all larval stages. The effects of pesticide treatments have been discussed.The results show, that in the Palatinate the biological control ofE. lanigerum by the parasitic waspA. mali is possible in apple orchards with selective treatment. In regular sprayed orchards the infestation by woolly aphid had especially after cessation of insecticide treatment been evidently higher, with lower rates of parasitism.A recommendation to the practice is given.

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Mit 7 Abbildungen und 2 Tabellen     

Expansion of the aphid Myzocallis (Lineomyzocallis) walshii (Monell) on the red oak Quercus rubra, and adaptation of local parasitoids in the northeastern Iberian Peninsula (Hom., Aphididae, Calaphidinae; Hym., Braconidae, Aphidiinae)

An ongoing expansion of Myzocallis (L.) walshii (Monell) in the NE Iberian Peninsula was detected. The aphid species was recorded in Catalonia, Andorra and Navarra. Adaptation of local native parasitoids (at least Trioxys pallidus Haliday and T. tenuicaudus Stary) to the new immigrant was documented, together with background information on their host range in the native environments. The detection of parasitoids of M. walshii is the first published evidence in Europe. The new evidence for M. walshii in the NE Iberian Peninsula also supports the warning of the expansion of the aphid as a pest of Quercus rubra over Europe.     

Zur Taxonomie,Biologie und Ausbreitung der Tannentrieblaus Dreyfusia nordmannianae (Eckst.) (Hom., Adelgidae) in Tirol

Studies made in the inquirydistrict of Kufstein/Wörgl, Tyrol, showedDreyfusia normannianae (Eckst.) being the sole species of genusAdelges living on the firs. Observations on the phaenology of the generations at five different localities showed among other things that there was no summer-sistens-generation. The winter-mortality of the aphid on twigs and stems amounted to 7 till 9%. The rates of progrediens- and sistensgeneration as well as the number of eggs laid by sistens female were determined. At last experiments were made on the spreading. Within some weeks the youngA. nordmannianae progredientes and sistentes had a maximal migration distance of about three meters.     

Spring aphid-parasitoid (Hom., Aphididae,Hym., Braconidae) associations and interactions in a Mediterranean arable crop ecosystem,including <Emphasis Type="Italic">Bt</Emphasis> maize

Conspecific and heterospecific associations of aphid parasitoids (Hymenoptera, Braconidae, Aphidiinae) were used to determine the interactions between crops forming the main arable crop ecosystem (wheat, alfalfa, isogenic and [Bt Bacillus thuringiensis] transgenic maize) in an irrigated area in Catalonia, Spain. Species composition and instars of parasitized aphids (mummies) were used to detect the parasitoid population movements between the crops and proved interactions (alternation) between the crops, including transgenic maize. Parasitoid interactions were species-dependent, appearing in the movements between alfalfa-wheat-maize in the individual species. Aphidius ervi Hal., A. rhopalosiphi DeSt.-Perez, A. uzbekistanicus Luzh., Lysiphlebus testaceipes (Cress.) and Praon volucre (Hal.) were classified as key-stone species in the target agroecosystems in the area. No differences were found in aphid-parasitoid associations on Bt transgenic maize and isogenic maize for aphid species composition and associated parasitoid guild.     

Die Reaktion von Getreideblattläusen (Hom., Aphididae) bei holozyklischer Überwinterung auf die Aussaatzeit von Weizen. Mit Beobachtungen zum Einfluß heftiger Niederschläge

On plots (25 m²) sown at different dates it was tested from 1982 to 1984 near Kiel (FRG) whether the sowing date would result in different levels of infestation of wheat by holocyclic cereal aphid populations. Aphids were too scarce to obtain results in 1982, and in the subsequent yearsSitobion avenae F. was the only species being abundant. In winter wheat (var. “Diplomat”), holocyclicS. avenae did not respont numerically to the sowing date. The maximum of attack, being equal in all sowing dates, occurred in growth stage 75. Small differences between sowing dates could be explained by the different abundance of natural enemies. In spring wheat (var. “Kolibri”) significant differences between sowing dates were observed, the earliest sown plots being attacked most heavily byS. avenae. The maximum of attack occurred in growth stage 71, mostly. Heavy precipitations proved to diminish significantly the numbers ofS. avenae per head at milky ripeness (GS 75), but not at GS 71. Numbers ofRhopalosiphum padi (L.) were not influenced significantly by the amount of precipitations falling during the observations. But precipitations and 8 other factors considered failed to explain the differences between sowing dates of spring wheat concerning the attack byS. avenae. It is assumed, therefore, that the physiological conditions of the wheat plant were gouverning the aphids' reproduction. The differences concerning the attack of winter wheat, apparently existing between holocyclic and prevailingly anholocyclic populations ofS. avenae, are stressed.     

Effectiveness of different types of pheromone traps used against Ips typographus (L.) (Col., Scolytidae) in Sweden

No effects of different surface textures on cylinder traps were found, except for traps with a very smooth surface which caught fewer beetles. The addition of a large exterior funnel, collecting beetles falling down on the outside of the cylinders, resulted in a doubling of trap catches. Two types of barrier traps, which turn with the wind, are described. The best of these traps had a catch efficiency approaching that of the most efficient cylinder traps.     

Insect growth regulators as agents to control the Florida wax scale,Ceroplastes floridensis Comst. (Hom., Coccidae)

The effect of 5 insect growth regulators (IGRs): 3 juvenile hormone analogues (JHAs), fenoxycarb, CGA 29-170 and Pro-Drone and two moult inhibiting compunds, Dawco 439 and R-20458 in addition to the organophosphate isoxathion was evaluated on the Florida wax scale. Treatment with 100 ppm induced good reduction in the population when the compounds were applied to the first generation. The effect extended to the following generation up to 8 months posttreatment and the juvenile hormone analogues showed superior effect over the moult inhibiting compounds and also the organophosphate. The influence of the IGRs on the oviposition was clearly obvious with both the JHA, fenoxycarb and the IGR, Dawco 439 since they completly prevented the scale maturity and oviposition.     

Comparison of seasonal responses ofHylobius abietis (L.) (Col., Curculionidae) to chemical and natural lures in baited pitfall traps

Differences in catches ofHylobius abietis (L.) adults in baited pitfall traps with chemical (alpha-pinene, ethanol, water) and natural (spruce billets, water) lures were found not in the over-all number of trapped adult weevils, but in the per cent occurrence and number of old and young beetles in individual periods of the season.     

Control ofAgrotis ypsilon (Hufn.) (Lep., Noctuidae) on some vegetable crops in Egypt using the microbial agentBacillus thuringiensis

The effective threshold rate of application of Dipel 2X was 250g/f. Incorporation of some chemical additives such as calcium sulphate (CaSO₄) or calcium oxide (CaO) significantly potentiated the effectiveness of Dipel 2X on larval population. The addition of calcium carbonate (CaCO₃) and zinc sulphate (ZnSO₄) to Dipel 2X greatly reduced the larval population and led to a significant increase in the yield of some vegetable crops. Dipel 2X baits at 250g/f were almost as effective as the chemical insecticide Hostathion when used at 1.5l/f in controllingA. ypsilon larvae attacking vegetable crops. Control of the greasy cutwormAgrotis ypsilon population was better achieved when the biological control agent Dipel 2X was used as baits.     

MonitoringHylobius abietis (L.) (Col., curculionidae) by baited pitfall traps in relation to planting and treatment of seedlings in a re-forested area

The method of standardized baited pitfall, traps for monitoring population ofHylobius abietis (L.) was experimentally included into the routine planting and control schedule (model area) in the Czech Republic. It is recommended to determine characteristics of the area on the basis of long-term monitoring. A short-term prognosis per site must be drawn from monitoring done from the earliest beginning of the season. However, it seems advisable to treat all the individual seedlings immediately after theyhave been planted in the area where the over-all characteristics (ascertained by monitoring) indicate generally high population levels. To base a decision for treatment on the percentage of seedlings attacked (feeding scars) per site is considered unadvisable in comparison with data obtained bymonitoring using baited pitfall traps. Insecticides for the treatment of newly planted seedlings need to be applied to two-thirds of the trunk of a seedling (including the root collar), their action should be fast enough to paralyse (kill) the weevils before they reach xylem by feeding and, furthermore, the residues should be effective up to the end of the season.With one figure and 3 tables