Aphis Fabae Scop Research Articles

The Distribution and Abundance of the Spindle Tree, Euonymus europaeus, in Southern England with Particular Reference to Forecasting Infestations of the Black Bean Aphid, Aphis fabae

SUMMARY (1) A method is discussed for determining distribution and abundance of the spindle tree, Euonymus europaeus L. This could be used for other hedgerow species. (2) The work forms part of a study on forecasting of crop infestations of the black bean aphid, Aphisfabae Scop. based on overwintering populations on spindle for which corrections need to be made for the varying abundance of this winter host. (3) In southern England, spindle occurs in hedgerows, scrubland and woodland and is generally associated with calcareous soils where it is sometimes 'Common' (126-625 bushes/10 kM2) or locally 'Abundant' (>625/10 kM2) except on open downland where hedgerows are scarce or where the chalk and limestone are overlain by acidic soils. Elsewhere spindle is widely distributed, often at densities of about 6-25 bushes/10 km2 though it is 'Absent' or 'Very Rare' (<5 bushes/10 kM2) in some large areas such as the Fenland and much of the Midlands. It is, however, 'Occasional' to 'Common' (26-625 bushes/10 kM2) in some non-calcareous areas notably over parts of the Old Red Sandstone in Herefordshire and S. Shropshire and over Weald Clay. (4) The data were used to make adjustments to forecasts in sixteen areas in southern England. This notably improved forecasts in areas of high spindle density in contrast to areas of low density. The correction factors will therefore be applied only in high density areas.

Relative toxicities of phorate and some of its metabolites to Aphis fubae Scop

AbstractAn aqueous solution of bromine was used to oxidise 14C‐labelled phorate to its metabolites. A substantial amount of [14C]phorate sulphone (O,O‐diethyl S‐ethylsulphonyl[14C]methyl phosphorodithioate) with minute quantities of [14C]phorate sulphoxide (O,O‐diethyl S‐ethylsulphinyl[14C]methyl phosphorodithioate) and [14C]phoratoxon sulphoxide (O,O‐diethyl S‐ethylsulphinyl[14C]methyl phosphorothioate) were recovered using this method. Various concentrations of [14C]phorate and these toxic metabolites were individually incorporated in an artificial diet and fed to Aphis fabae Scop. Mortality was recorded after 48 h. The toxic fractions of the compounds were extracted from the diet and their radioactivity was measured to determine the dose unit. The aphids feeding on diet containing high concentrations of [14C]phorate sulphoxide and [14C]phoratoxon sulphoxide were seen wandering restlessly, which suggested that the acceptability of the diet had been changed by the presence of these metabolites. Phorate appeared to be the most toxic to the aphids, followed by phorate sulphone, phorate sulphoxide and phoratoxon sulphoxide in that order; the reasons for this are discussed.

The effect of juvenile hormone on host‐plant preference in the black bean aphid, Aphis fabae

ABSTRACT. When offered the choice between a germinating tick bean (summer host) and a detached spindle leaf (winter host) adult gynoparae of Aphis fabae Scop. showed a distinct preference for spindle, as judged by site of larviposition. However, when offered the same alternatives, all four larval instars showed a settling preference for bean. A switch in host preference therefore occurs at or shortly after final (fourth) moult. Fifth instar, supernumerary larvae induced by juvenile hormone (JH I) treatment also preferred bean, indicating that the host preference switch at the fourth moult had been inhibited. Larval/adult intermediate forms produced by JH I treatment, but which were capable of parturition, showed a significant increase in the acceptability of bean as a larviposition site. Acceptability was proportional to the degree of juvenilization. Thus, although larviposition is an adult prerogative, JH I can influence the preferred site. This may, however, be an indirect effect which reflects a juvenilized settling preference.

EFFECTS OF CONTACT DURATION OF 0.5% THIOTEPA ON THE ADULT VIVIPARAE AND SUBSEQUENT GENERATIONS OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE)

The compound tris (1-aziridinyl) phosphine sulphide, known by the trivial name thiotepa, has been tested against few aphids. Considerable reduction in fecundity occurred due to thiotepa treatment of the cabbage aphid, Brevicoryne brassicae (L.) (Bonnemaison 1966). In 0.3% thiotepa-treated Aphis fabae Scop. a 90% decrease in reproductive capacity was observed by Steffan and Stüben (1976). Sharma and Thériault (1980) tested 0.5% thiotepa on various nymphal instars of the pea aphid, Acyrthosiphon pisum (Harris), and observed up to 83% decrease in fecundity of those treated in first and second instars. The third and fourth instar aphids were much less influenced by thiotepa. The effects of thiotepa on the adult viviparae of the pea aphid are unknown and nothing has been recorded on the transmissibility of thiotepa-caused sterility to progeny. Further to the results of Sharma and Thériault (1980) this paper describes the effects of two contact periods with 0.5% thiotepa on the adult viviparae of A. pisum and delayed effects on subsequent generations.

Field collections of Aphis fabae scopoli S. lat. (Homoptera: Aphididae) studied by starch gel electrophoresis andisoelectric focusing

1. 1. Electrophoresis separations of two enzyme systems and isoelectric focusing of soluble proteins of black bean aphids ( Aphis fabae Scop.) have been examined. 2. 2. Results from the two systems in general supported each other and were reproducible within each single parent stock. 3. 3. Correlations were found between separation patterns and host plants and between patterns and aphids collected from different localitities. 4. 4. Single parent colonies which survived the winter oviparously did not show pattern differences the following year.

Coccinellid Beetles on Sugar Beet in Eastern England, 1961–75

SUMMARYThe times of flight and the annual fluctuations in the numbers of coccinellid beetles on sugar beet crops in eastern England from 1961 to 1975 were determined using yellow, cylindrical sticky traps and by examining plants in plots which had not been treated with insecticide. Adalia bipunctata (L.) was the coccinellid most often trapped and it formed 33 per cent of the total catch. Propylea 14‐punctata (L.) formed 25 per cent of the total catch. Coccinella septempunctata L. was less often caught, forming only nine per cent of the total catch on traps, and it was uncommon on sugar beet except when the plants were heavily infested with Aphis fabae Scop, in August. The ‘plagues’ of C. septempunctata occasionally recorded on the East Anglian coast occurred only in years when aphids had been common on cereal crops.Although coccinellids are one of the causes of the rapid decline of aphid populations on sugar beet in August, no evidence was found that they play an important part in controlling the spread of yellowing viruses. However, they may prevent a crop from becoming heavily infested with aphids which are potential vectors in the spring and they may destroy aphids overwintering on virus‐infected weeds and other sources of infection.

The Incidence of Aphis fabae Scop. on Spring‐sown Field Beans in South‐east England and the Efficiency of Control Measures

SUMMARYSurveys of crops of spring‐sown field beans from 1966 to 1974 in the counties of Hampshire, Berkshire, Buckinghamshire and Oxfordshire showed that the incidence of Aphis fabae Scop, infestation varied from season to season and often between counties in the same year. The heaviest infestations occurred in 1967, 1972 and 1973 and the lightest infestation was in 1968 vvhen few winged aphids colonized headland plants. Estimates for 1972 and 1973 showed that treatment was economically worth while on most fields in these years. Phorate was the most frequently used insecticide and gave good control, although it was less effective in years in which there was a dry spring. Disulfoton and sprays of demeton‐S‐methyl and menazon also gave good control, although menazon was less effective as an eradicant spray after colonies of aphids had become established.

Use of Forecasting in Chemical Control of Black Bean Aphid, Aphis fabae Scop., on Spring‐sown Field Beans, Vicia faba L.

SUMMARYCounts of Aphis fabae Scop, eggs in winter and of the active stages in May on the spindle bush, Euonymus europaeus L., are used to predict the need for chemical control of the black bean aphid on spring‐sown field beans, Vicia faba L. For the purposes of forecasting, most of England south of the Humber is divided into 18 areas for which separate forecasts are made. A level of 5 per cent of plants colonized on the SW. headlands of fields in early to mid‐June is used as an economic threshold above which control measures are justified.From 1970 to 1975, area forecasts of the probability of attack were successful. According to the sampled fields there was considerable annual variation in the size of infestations, ranging from widespread, potentially damaging populations in 1973 and 1974 to very small populations in 1975. There was also considerable variation between areas: for example, in East Anglia and the East Midlands treatment was justified only in 1973 and 1974, whereas in Hampshire and Worcestershire/Herefordshire treatment was justified in all years except 1975. It was estimated that, from 1970 to 1975, control based on forecasting would have led to a gain of £11·4/ha over no treatment, and £3·8/ha over correctly timed routine preventive treatment applied annually irrespective of the aphid situation.

Observations on the Colonization and Egg‐layiiig Behaviour of Aphis fabae Scop, on Various Species of Euonymus

Observations on the Colonization and Egg‐layiiig Behaviour of Aphis fabae Scop, on Various Species of Euonymus

Reproductive capacity of the bean aphid, Aphis fabae Scop. (Homoptera: Aphididae) as affected by Metepa

AbstractThe second nymphal instar of Aphis fabae Scop, was reared on leaves of the broad bean plant dipped in different water‐metepa solutions for 24 hrs. After this time, the nymphs were transferred to fresh plants and studied for their biological activities. It was found that two concentrations, 0.005 and 0.0005%, were equivalent to the control in respect to their toxicity. However, metepa solution proved to be a sterilant for the aphids. As the concentration increased, the number of nymphs born per apterous adult female was decreased. Longevity was also affected by the sterilant. At 0.005% level, the adults lived 14.02 days compared to 20.63 days for the untreated adults. On the other hand, the average number of nymphs given by F1 was significantly reduced by metepa treatment.ZusammenfassungZur Wirkung von Metepa auf die Reproduktion der Bohnenlaus Aphis fabae Scop. (Homopt.: Aphididae)Die Zweitlarven von Aphis fabae wurden auf Blättern von Vicia faba aufgezogen, die zuvor 24 Stunden lang in verschieden konzentrierte Wasser‐Metepa‐Lösungen getaucht waren. Danach wurden die Versuchstiere auf frische unbehandelte Pflanzen gesetzt und ihre biologische Aktivität untersucht. Es zeigte sich, daβ die 2 Konzentrationen 0,005% und 0,0005% im Vergleich zur Kontrolle die gleiche Toxizität hatten. Jedoch erwies sich die Metepa‐Lösung als Chemosterilant. In dem Maβe, wie die Konzentration anstieg, sank die Zahl der Nachkommen pro Weibchen. Auch die Lebensdauer wurde durch das Sterilant beeinfluβt. Nach Einwirkung von 0,005% Metepa lebten die Adulten 14,0 Tage, verglichen mit 20,6 Tagen der unbehandelten Läuse. Andererseits wurde die Produktion von F1‐Nachkommen durch Metepa gehemmt.

Longevity, Fecundity and Size; Control of Reproductive Potential in a Polymorphic Migrant, Aphis fabae Scop.

Longevity, Fecundity and Size; Control of Reproductive Potential in a Polymorphic Migrant, Aphis fabae Scop.

The Flight Activity and Movements of Myzus persicae (Sulzer) and Brevicoryne brassicae (L.) in a Field Cage

Previous work on the behavioural and ecological aspects of aphid migration has not provided a completely satisfactory account of the number and duration of aphid flights (C. G. Johnson 1969; Kring 1972). Myzus persicae Sulz. is an extremely restless aphid, staying on a host long enough to deposit one or two larvae and then moving on (Broadbent & Martini 1959; Kennedy, Booth & Kershaw 1959; van Emden et al. 1969). B. Johnson (1958) suggested that this behaviour might be typical of aphids with wide host ranges since they would frequently land on many plants, on which they could feed, and perhaps deposit a few larvae without being stimulated sufficiently to settle permanently. Kennedy et al. (1959) suggested that 'repeated alighting, brief probing and re-take-off from hosts and non-hosts is a common pattern among migrant Aphididae'. Conversely, other evidence suggests that aphids that have made long migratory first flights would be unlikely to fly again. Although alate Aphisfabae Scop. have been induced to fly again after being flown, tethered on pins, to apparent exhaustion (Cockbain 1961), all the A. fabae tested in other experiments settled permanently on beans, with autolysis of the flight muscles, after tethered flights of 1 h (Cockbain, Gibbs & Heathcote 1963). As Kring (1972) suggests, the flight duration of aphids in the field may be far less than their potential flight duration determined in the laboratory. The close relationship in time between the density of aphids at crop level and the integrated total number of aphids in the air, suggested that flight is rather limited in duration and that most of the aphids caught in traps were making their first flight (C. G. Johnson 1956). This view was supported by the observation that most A. fabae caught in the suction trap at Rothamsted seemed to be young (Taylor 1957). A possible solution to these two conflicting views of the significance of subsequent flights lies in the duration of the first flight. Aphids seen to take off shortly after landing may have been flying only a few minutes (Taylor 1965), but little is known about the extent to which they move after the initial flight in spite of the fact that it is this behaviour that makes alate aphids well suited for spreading viruses in the field (Kennedy 1960). The aim of this paper is to determine the importance of subsequent flights in aphids which had either made long initial flights or been stimulated to settle by long periods of starvation.

Observations on the flight periods of aphids in a Sitka spruce plantation in north-eastern Scotland

Flight activity of aphids during 1969–71 in a Sitka spruce plantation in north-eastern Scotland was recorded by means of sticky traps. Two flight periods occurred, June–August and September–October. Fewer aphids were caught at 120 and 180 cm than at 60 cm above ground during June–August, while fewer were caught at 60 cm in September–October. After accounting for differences in wind speed at these heights, it was shown that aerial density was consistently higher at 60 cm. The first flight which comprised mostly Elatobium abietinum (Wlk.) was three weeks early in 1971; this was associated with the rapid increase in aphid population on spruce shoots, due to the preceding mild winter. Reinfestation by this species after spraying could follow under similar circumstances. Adelges laricis Vail. and A. viridis (Ratz.) sexuparae were caught in the first flight, and A. cooleyi (Gill.) gallicolae in the second; all galls on Sitka were by gallicolae of A. cooleyi. Aphis fabae Scop, was the most common species in the second flight.

A Study of Blackfly (Aphis fabae Scop.) on Broad Bean Plants, and of Insects Associated Directly or Indirectly with the Colony

A Study of Blackfly (<i>Aphis fabae Scop.</i>) on Broad Bean Plants, and of Insects Associated Directly or Indirectly with the Colony

Synergism of terramycin to inhibit the reproductivity of aphis fabae scop.

Nachweis, dass Piperonylbutoxid (0,2%) in Kombination mit Terramycin (0,2%) und dem Emulgator NP10 (0,1%) die Larvalentwicklung verlangsamt und sowohl das Gewicht wie die Reproduktionsfähigkeit der resultierenden Adulten vonAphis fabae reduziert. Durch Zugabe des allein unwirksamen Piperonylbutoxyds werden diese Effekte gesteigert.

The effect of the transmission of the beet mosaic virus on the variability of its incubation period

The variability of the incubation period of the beet mosaic virus [Beta virus 2(Lind) Smith] was investigated in a three year experiment. The virus was transmitted by the black bean aphid (Aphis fabae Scop.) or by a mechanical inoculation onAmaranthus caudatus L. Variability characterized by the standard deviation indicates a closer distribution of measurements when the virus was transmitted by mechanical inoculation. The differences in variability of the incubation period between the two methods of virus tramission are statistically significant; dispersion and standard deviation are lower after mechanical inoculation. The average length of the incubation period after virus transmission by aphids and by mechanical inoculation was 10.8 and 7.7 days, respectively. The difference was found statistically significant and may be explained by the higher number of viral particles transmitted by mechanical inoculation which may accelerate the process of infection. A significant correlation between the temperature of the environment and the length of the incubation period was also found in some experiments.

Laboratory studies on aggregation, size and fecundity in the black bean aphid, Aphis fabae Scop.

Adults of Aphis fabae Scop. can weigh from as little as 200 μg to as much as 1 800 μg (Way &amp; Banks, 1967), a remarkable range in size for a single species. An extensive range in size also occurs among the adults in other species of aphid (Murdie, 1969a, b; Dixon, 1970). Small individuals result when aphids develop either under crowded conditions or on a mature host-plant; large aphids result when the nymphs are reared in isolation or on young or senescent host-plants (Way &amp; Banks, 1967; Murdie, 1969a, b; Dixon, 1970). A small adult produces fewer nymphs and also smaller nymphs than average (Murdie, 1969b; Dixon, 1970). When aphids are overcrowded or feed on host-plants of poor quality, many aphids reach maturity that might otherwise fail to mature because of the ability of the species to produce viable adults of a great variety of size, including very small adults (Way &amp; Banks, 1967).

Control of Aphis fabae on broad beans (Vicia faba) by the systemic action of gamma‐bhc, thionazin and aldicarb

AbstractThe in‐row application of aldicarb granules at 2 lb active ingredient (a.i.)/acre (2·24 kg/ha) at sowing gave complete control of Aphis fabae Scop. on broad beans (Vicia faba L. cv. Seville) up to 7 days before harvest and resulted in a three‐fold increase in yield compared with a similar thionazin treatment. Bean plants grown from seeds which were soaked in a gamma‐BHC solution at 20 ppm for 24 h prior to planting were protected from this aphid for most of the growing season almost as effectively as with the thionazin treatment.A thin‐layer chromatography method was developed for the determination in plants and soil of aldicarb and its two major toxic metabolites, the sulphoxide and sulphone. Gas‐liquid chromatography was used to monitor the declining levels of gamma‐BHC and thionazin, and simultaneous bioassays were made with Aphis fabae on excised leaf discs from the crop. Analysis of the bean seeds and pods at harvest 90 days after sowing indicated no detectable gamma‐BHC, less than 0·01 ppm of thionazin and approximately 0·09 ppm total residue of aldicarb sulphone and sulphoxide. Approximately 22% and 13% of the applied aldicarb, in the form of sulphone and sulphoxide but not the parent compound, remained in the top 6 in (152 mm) of soil at the end of 2 and 4 months respectively.Toxicity studies with Aphis fabae, Acyrthosiphon pisum Harris, and Megoura viciae Buck showed an increasing sensitivity in that order to gamma‐BHC at 1 ppm in bean plants. Acute toxicity investigations with feeding Aphis fabae indicated an increasing sensitivity in the order of gamma‐BHC &lt; aldicarb sulphone &lt; aldicarb sulphoxide &lt; thionazin &lt; aldicarb. Despite the high acute toxicity of thionazin to Aphis fabae it gave low protection against aphids, possibly owing to its relatively short persistence in both plants and soil when compared with aldicarb.

Effect of Plant Spacing and Time of Sowing of Sugar Beet on Aphid Infestation and Spread of Virus Yellows

SUMMARYAphid infestation and incidence of plants with virus yellows in sugar‐beet crops at Broom's Barn Experimental Station from 1964 to 1968 differed greatly with changes in densities of stand ranging from 8,000 to 68,000 plants per acre (0.4047 ha), and with changes in sowing date. The numbers of Myzus persicae (Sulz.) and of Aphis fabae Scop, infesting beet during June and July, the numbers of virus‐itifected plants per unit area, and the percentages of plants with yellows, usually decreased as the plant population increased but usually increased with delay in sowing from mid‐March to early May.

Studies on the biology and control of pests of seed beans (Phaseolus vulgaris) in northern Tanzania

Light-trap catches of Heliothis armigera (Hb.) reach peaks during the wet seasons, April and November–January. Initial infestation of seed beans by H. armigera occurs in April–May at the time of flowering of the early-sown crop, the adults probably originating from an earlier generation on maize. Two generations are completed during the main seed bean season, the first on early-sown beans and the second on later beans, and the dry period July–October may be passed in pupal diapause. Damage, caused by the older larvae eating the seeds in the pod, is prevented by spraying the young larvae with DDT (25% e.c. at 3 pt/2 gal spray/acre) (the standard treatment) or endosulfan (35% e.c. at 1½ pt/2 gal spray/acre) at about six weeks after the beans emerge.Adults of the Pentatomid Nezara viridula (L.) invade bean fields from alternative host-plants at the same time as H. armigera. This species, even in small numbers, causes the loss of young pods and also damages or kills the developing seed. It is not controlled by the standard DDT treatment for H. armigera, but the following insecticides were found to be effective: γBHC 20% e.c. (1¼ pt), dieldrin 18% e.c. (2 pt) and endosulfan 35% e.c. (1½ pt) in 2 gal spray/acre. Where N. viridula and H. armigera are found together, the standard recommendation is endosulfan 35% e.c. (1½ pt/2 gal spray/acre).The Coreids Acanthomia horrida (Germ.) and A. tomentosicollis (Stål) cause damage similar to that of N. viridula, but are serious only when infestations are heavy. They were found to be controlled by DDT, dieldrin or endosulfan at the rates given above.Alatae of the bean aphis Aphis fabae Scop, invade bean fields mainly during the first two weeks of the crop, producing apterae which concentrate on the tip of the plants. Damage (stunting, and loss of flowers and pods) is serious only when large populations of apterae are produced on a high proportion of the young plants. The early infestation demands control measures separate from those for the other pests, the most effective being methyl-demeton 50% e.c. (½ pt/2 gal spray/acre) applied 3–4 weeks after emergence. Endosulfan, although promising and far less toxic than methyl-demeton to larvae of the predator Cheilomenes lunata (F.), was discarded on grounds of cost, as was dimethoate. Aphid populations reached a peak during July and August and decreased with the warmer weather in September. A large number of alternative host-plants is listed, but the source of the primary flight into beans is not known.Melanagromyza phaseoli (Tryon), the life-cycle of which is completed in 23 days, is unimportant on seed beans as it is least abundant during the growing period of the main crop, but may damage plants suffering from water stress. Tunnelling in stems by larvae was controlled by seed dressings of aldrin or heptachlor (both 40% wettable powders mixed with seed at 1:200 w/w).