bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the most effective method for field establishment of biocontrol agents of the genus chilocorus (Coleoptera: Coccinellidae)
Authors: Hattingh Vaughan , Samways Michael J.
Published: July 2009

The coccinellid biocontrol agent Chilocorus nigritus (Fabricius) can be established on the non-target scale Asterolecanium sp. (Hemiptera: Asterolecaniidae) on giant bamboo Dendrocalamus giganteus. When these sites are adjacent to citrus orchards, the coccinellid readily moves across to reduce population levels of the target prey, red scale Aonidiella aurantii (Maskell) (Hemiptera: Diaspididae). C. bipustulatus (Linnaeus) and C. infernalis Mulsant are potential new biocontrol agents against A. aurantii in South Africa. Each life stage of C. nigritus, C. bipustulatus and C. infernalis has advantages and disadvantages for field introductions. This paper investigates different methods of introduction of the different life stages for field establishment. A number of synthetic materials were tested as egg pads for C. infernalis without success. Introduction of eggs adhering to stiff paper cards was unsuccessful and impractical for all species. Eggs, young larvae (first and second instars), older larvae (third and fourth instars) and adult C. nigritus were introduced into stands of bamboo. The adult was the most suitable life stage for establishment followed by older larvae, then younger larvae, with the least suitable being the egg stage. Adults of the three species were released on to scale-infested bamboo at two sites to evaluate the viability of such introductions and to compare their persistence at these sites. C. nigritus and C. infernalis persisted at one release site through the winter and the hottest period of the summer.
Sampling Mononychellus tanajoa (Acari: Tetranychidae) on cassava in Africa
Authors: Yaninek J.S. , Baumgaertner J. , Gutierrez A.P.
Published: July 2009

Density-specific sampling plans were developed under African conditions for the exotic spider mite, Mononychellus tanajoa (Bondar), a serious pest of cassava, Manihot esculenta. The within-plant distribution of Mononychellus tanajoa was found to favour new foliage, regardless of time of planting or plant age. Consequently, the first developed leaf near the top of the foliage was selected as the sampling unit and related to whole plant populations of M. tanajoa. The relationship between the mite population's variance and mean as measured by Taylor's Power Law proved to be stable over a range of planting dates, seasons and locations. Two binomial sampling plans, one based on Taylor's dispersion parameters and another based on direct field observations, were developed and compared. Binomial sampling, appropriate only for densities below 30 mites per leaf, was replaced by an enumerative procedure based on a ‘quick count’ protocol at higher mite densities.
Inheritance of metabolic resistance to the synthetic pyrethroids in Australian Helicoverpa armigera(Lepidoptera: Noctuidae)
Authors: Daly Joanne C. , Fisk Jennifer H.
Published: July 2009

Two strains of Helicoverpa armigera (Hübner), resistant to synthetic pyrethroids, were isolated from field populations collected in the irrigated cotton growing areas of northern New South Wales: an isofemale strain, Mfo, and a composite field strain, Field. A series of crosses were undertaken between the Mfo and susceptible strains to determine the genetic basis of the resistance. Dose-responses were obtained by bioassay using topical application of fenvalerate in acetone. Considerable variation in tolerance was observed in both resistant and susceptible strains. In the Mfo strain, the major shift in resistance phenotype (33-fold resistance) was due to a single major gene with incomplete dominance. The resistance phenotype was not diluted by 23 generations of backcrossing. The major resistance phenotype could be eliminated almost completely by the addition of piperonyl butoxide which affects oxidative breakdown of the pyrethroids by mixed function oxidase (mfo) enzymes. Similar results were observed in the Field strain. Monitoring for resistance in field populations will be imprecise because a true discriminating dose does not exist for susceptible and heterozygous resistant individuals.
The effect of permethrin-impregnated bednets on house entry by mosquitoes (Diptera: Culicidae) in The Gambia
Authors: Lindsay S.W. , Adiamah J.H. , Armstrong J.R.M.
Published: July 2009

A trial was carried out using experimental huts to determine whether mosquitoes deterred from entering a building where a person slept under a permethrin-impregnated bednet would enter neighbouring dwellings where people used untreated nets. In each of the six experimental huts a man slept under a bednet for six weeks during the dry season in The Gambia. One bednet was impregnated with permethrin, the other five nets were untreated. The design of the trial was based on a series of Latin squares, so that both men and nets were rotated between huts on different nights. At the end of the trial each man had slept under each net in each hut. Mosquitoes collected from the huts each morning were used to estimate the total number of mosquitoes which had entered each hut during the night. Fewer Anopheles gambiae Giles (sensu lato), A. pharoensis Theobald and Mansonia spp. entered a hut with an impregnated bednet than those with untreated nets. However, there was no evidence that mosquitoes deterred from entering a hut with a treated net entered neighbouring huts with untreated nets. Thus it appears unlikely that people using untreated bednets in a community where most use impregnated nets would receive more bites than if everyone had an untreated net. However, the responses of mosquitoes to permethrin-impregnated bednets were found to depend both upon their species and nutritional condition since A. rufipes Gough, banded Culex spp. and non-human bloodfed A. gambiae (sensu lato) freely entered huts with a treated net.
Legume-feeding psyllids of the genus Heteropsylla (Homoptera: Psylloidea)
Authors: Muddiman S.B. , Hodkinson I.D. , Hollis David
Published: July 2009

The biology and biogeography of the economically important species of Heteropsylla Crawford, including H. cubana Crawford, are discussed. Heteropsylla comprises a group of legume-feeding neotropical psyllids within the subfamily Ciriacreminae. Taxonomic characteristics previously used to diagnose Heteropsylla and related genera are discussed and a new generic diagnosis is made using both adult and larval characters. Thirty-nine species of Heteropsylla are now recognized and each is described and illustrated. Of these, 21 are new to science. One species, H. boquetensis (Brown & Hodkinson), is transferred from Limbopsylla Brown & Hodkinson. Final instar larvae of 22 species are described and illustrated. Host-plants are recorded for 35 species, showing that Heteropsylla species are generally found on legumes belonging to the Mimosoideae. Three exceptions occur in the Caesalpinioideae. A checklist of species and keys to the identification of adult males, adult females and final instar larvae are provided.
Selection for resistance to phosphine or methyl bromide in Tribolium castaneum (Coleoptera: Tenebrionidae)
Authors: Rajendran S.
Published: July 2009

The build-up of resistance to phosphine and methyl bromide in the developmental stages of Tribolium castaneum (Herbst) after six selections in successive generations was investigated in the laboratory at 25 ± 1°C. Responses of the life stages of the fumigant-selected insects were compared with those of untreated controls with a 24 h exposure and mortality was assessed after 14 days. Phosphine induced the development of resistance irrespective of the life stage chosen for selection. The onset of phosphine resistance was noted after the first selection but the levels of resistance attained in the different stages varied depending on the stage tested, and in each case the degree of expression was different in the four stages of T. castaneum. After selection, phosphine resistance was highest in the pupae followed by eggs, adults and larvae. Resistance to methyl bromide in the methyl bromide treated insects increased only slightly (less than × 2.0). Adults derived from egg, larva, pupa and adult-selected methyl bromide lines showed cross-resistance to phosphine (× 1.8 to 11.5 at LD95), while cross-resistance of adults to methyl bromide was noted only in adult-selected phosphine-resistant insects (× 1.5 at LD95).
Interaction betweenChrysomya rufifaciesandCochliomyia macellaria(Diptera: Calliphoridae): the possible consequences of an invasion
Authors: Wells Jeffrey D. , Greenberg Bernard
Published: July 2009

Four Old World blow flies (Diptera: Calliphoridae),Chrysomya albiceps(Wiedemann), C.putoriaWiedemann, C.megacephala(Fabricius), and C.rufifacies(Macquart), have recently invaded the New World. The interaction ofChrysomya rufifacies(Macquart) with native carrion flies in Texas, USA, was investigated by reducing oviposition by the invader on rabbit carcasses outdoors. These carcasses produced significantly moreCochliomyia macellaria(Fabricius) adults compared to carcasses on which the invader was not reduced. The results suggest that C.macellariapopulations will decline where the two species co-occur. They also support the hypothesis that the carrion community is saturated with species, and provide a mechanism for the possible elimination ofLucilia caesar(Linnaeus) in Madeira and the reduction of C.macellariain South America byChrysomya albiceps(Wiedemann).
Use of the random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) to detect DNA polymorphisms in aphids (Homoptera: Aphididae)
Authors: Black William C. , DuTeau Nancy M. , Puterka Gary J. , Nechols James R. , Pettorini Jennifer M.
Published: July 2009

We have used a new technique to identify discrete genetic markers in aphids, a family in which biochemical and morphological genetic polymorphisms are rare. The new technique uses the polymerase chain reaction (PCR) to amplify random regions of aphid genomes (random amplified polymorphic DNA) and has been termed RAPD-PCR. We demonstrate the use of the technique in revealing genetic variation in four aphid species, the greenbug (Schizaphis graminum (Rondani)), the Russian wheat aphid (Diuraphis noxia (Mordvilko)), the pea aphid (Acyrthosiphon pisum (Harris)), and the brown ambrosia aphid (Uroleucon ambrosiae (Thomas)). In contrast with allozyme surveys, RAPD-PCR revealed large amounts of genetic variation among individuals in each of these species. Variation was detected among biotypes, populations, colour morphs and even individuals on a single plant. We also explored the utility of RAPD-PCR in the detection and identification within aphid bodies of two endoparasitic wasps, Diaeretiella rapae (McIntosh) and Lysiphlebus testaceipes (Cresson). The use of RAPD-PCR in species diagnostics, parasitoid detection, and population studies is discussed.
Electrophoretic distinction between the peach-potato aphid, Myzus persicae, and the tobacco aphid, M. nicotianae(Homoptera: Aphididae)
Authors: Blackman Roger L. , Spence Jennifer M.
Published: July 2009

The electrophoretic mobility of the enzyme glutamate oxaloacetate transaminase (GOT) on cellulose acetate plates was compared among sibling species of the Myzus persicae (Sulzer) group (M. persicae, M. nicotianae Blackman, M. antirrhinii (Macchiati)). M. persicae itself is monomorphic for GOT-1 (genotype ff), whereas European populations of M. nicotianae are polymorphic for this enzyme, with two forms of slightly different mobility (alleles s, f). In the samples of M. nicotianae examined, M. persicae-likeff genotypes were rare and heterozygotes (sf) were in large excess, even in samples from Greece where M. nicotianae has a regular holocycle (i.e., annual sexual reproduction). In North America, where M. nicotianae is probably entirely anholocyclic, samples of both red and green colour morphs of this species were found to be heterozygous for GOT-1. The enzyme difference can thus provide a means of distinguishing most individual specimens, including trapped alatae, of M. persicae and M. nicotianae. The anholocyclic taxon M. antirrhinii appears to be a fixed heterozygote for GOT-1 and thus resembles most M. nicotianae, but can be distinguished electrophoretically from both M. persicae and M. nicotianae by its distinctive pattern of esterases.
Factors affecting seasonal dispersal of the tsetse flies Glossina pallidipes and G. longipennis (Diptera: Glossinidae) at Nguruman, south-west Kenya
Authors: Brightwell R. , Dransfield R.D. , Williams B.G.
Published: July 2009

Seasonal changes in the distribution of the tsetse flies, Glossina pallidipes Austen and G. longipennis Corti, along a transect from riverine thickets out into open plains were monitored along with tsetse density, climatic factors, vegetation and host abundance. Dispersal of tsetse into open country was quantified using the mean spread. During and after the rains both species extended their distribution out into open country up to at least 3.5 km from riverine thicket areas. The mean spread of G. longipennis was greater than that of G. pallidipes. The spread of males and females was very similar, as was the spread of different age categories of parous females, but nulliparous flies and females carrying second instar larvae were under-represented in samples from open areas. This seasonal dispersal can be accounted for by random diffusion with an average root mean square displacement of about 175 m per day. Observed degrees of spread were best correlated with humidity conditions prior to sampling, but multiple regression models suggested that host abundance, vegetation as measured by Normalised Difference Vegetation Indices (NDVI), and, in the case of G. longipennis, tsetse density, were also factors in determining the degree of spread. The significance of these findings in relation to tsetse control is discussed.
The pugnacious ant, Anoplolepis custodiens (Hymenoptera: Formicidae), and its beneficial effect on coconut production in Tanzania
Authors: Löhr B.
Published: July 2009

In a field of six hectares, the number of palms foraged by Anoplolepis custodiens (Smith) increased from January to December 1988 from 32 to 85% and the ant activity scores (0–3 system) from 0.5 to 2.0. During the same time, the population of the coconut bug, Pseudotheraptus wayi Brown (Heteroptera: Coreidae) as well as the damage it caused, decreased significantly. A significant relationship between low percentages of damaged nutlets and high ant scores of the palms could be established. The nut set of ant foraged palms was 2–3 times higher than that of comparable palms in an immediately adjacent field free of A. custodiens. Palms with high A. custodiens scores had invariably high scores of the coconut aphid, Cerataphis variabilis Hille Ris Lambers (Homoptera: Aphididae). The performance of the palms was not visibly affected by the aphids.
Determining the ages of adult females of different members of the Simulium damnosum complex (Diptera: Simuliidae) by the pteridine accumulation method
Authors: Millest A.L. , Cheke R.A. , Howe M.A. , Lehane M.J. , Garms R.
Published: July 2009

A significant relationship between pteridine content of the head, fly age and fly size, which was independent of temperature, was found for adult females of Simulium sirbanum Vajime & Dunbar using flies maintained at different constant temperatures after eclosion. Similar relationships for flies maintained at varying temperatures within the species' natural ranges were obtained in experiments with the Beffa form of S. soubrense Vajime & Dunbar (sensu Post, 1986), S. sanctipauli Vajime & Dunbar (= S. soubrense sensu Post, 1986), S. squamosum (Enderlein), S. yahense Vajime & Dunbar and S. damnosum sensu stricto. Common slopes for the effects of age and size could be fitted to all these species. Relations between pteridine concentration in the head, fly size and age, with the common slopes but with species-specific intercepts, were used to estimate the age structure of wild-caught populations of the Beffa form of S. soubrense, S. squamosum and S. yahense. A dry season sample of S. squamosum was estimated to be older than a wet season sample. The mean age of the S. soubrense population, sampled one week after its presumptive breeding sites were treated with larvicides, was estimated to be 13.5 days. The maximum was 30.9 days and a frequency distribution of the estimates had distinct peaks, at three day intervals between 8 and 21 days. The significance of the results is discussed in relation to fly longevity and gonotrophic cycle lengths.
Nocturnal observations on the emergence and flight behaviour of Helicoverpa armigera (Lepidoptera: Noctuidae) in the post-rainy season in central India
Authors: Riley J.R. , Armes N.J. , Reynolds D.R. , Smith A.D.
Published: July 2009

A range of techniques was used to quantify the nocturnal flight behaviour of Helicoverpa armigera (Hübner) in pigeon pea (Cajanus cajan) crops near Hyderabad, in central India. These included visual observations in the field, the use of field cages and a vehicle-mounted net, optical and video imaging in the infra-red, and radar. Moth emergence from the soil was observed to start at dusk and recruitment continued steadily throughout the first half of the night. Little activity was observed in moths on the night of emergence, except for weak flying or crawling to daytime refuges. Flight activity of one-day old moths started about 20 min after sunset, peaked 15 min later and within about an hour of sunset had declined to a low level which persisted for the rest of the night. Flight of reproductively mature moths was most frequent about 1 h after sunset and at this time mainly comprised females searching for oviposition sites and nectar sources. By about 2 h after sunset, flight had decreased markedly, but there was a slight increase in activity in the second half of the night caused by males undertaking mate-finding flights. Under the conditions studied, the majority of H. armigera dispersed below 10 m, and there were no mass ascents to higher altitudes like those observed at outbreak sites of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae). The contrasting migratory strategies of H. armigera and S. exempta are briefly discussed.
Esterase activity in populations of the whitefly,Bemisia tabaci(Homoptera: Aleyrodidae): heritability and associated organophosphorus insecticide resistance
Authors: Bloch Guy , Wool David
Published: July 2009

The association of esterase (EST) activity with resistance to the organophosphorus (OP) insecticide methidathion was investigated in field-collected populations of whitefly (Bemisia tabaci(Gennadius)) in Israel. The inheritance of EST activity was studied by controlled crosses in the laboratory. Among-family variance of EST activity was highly significant although all families were maintained in the same rearing room. This indicates that genetic or common environmental effects due to rearing each family on a different caged plant must have been important. Heritability estimated from son-mother regression was h2=0.98, but this estimate seems to be unrealistically high. Daughter-mother and daughter-mid-parent regressions produced lower heritability estimates (as expected). None of the regression coefficients of daughters on mother, however, were significantly different from zero and the regression on parent explained only very small amounts of the activity variation in the offspring. Estimates obtained from intraclass correlations among offspring were higher and outside the acceptable range, reflecting the variance component due to the common environment. The predictive value of the heritability estimates appears to be very low. The frequency distribution of activity among individuals sampled from one insecticide treated site (AM) was skewed to the right, as previously reported. But samples from another site (TZ) showed a symmetrical distribution, unlike the previous pattern. When field collected individuals from AM were released on clean plants in the laboratory, samples taken from the plants one or more days later showed symmetrical EST distribution. Electro-phoretic paterns of field and laboratory samples were the same, but band intensity was stronger in samples from laboratory populations. Differences in mean EST activity between populations and sampling years were unrelated to methidathion resistance.
The effects of triflumuron, a chitin synthesis inhibitor, on the housefly,Musca domestica(Diptera: Muscidae)
Authors: Howard Julia , Wall Richard
Published: July 2009

The effects of the chitin synthesis inhibitor triflumuron, 2-chloro-N-[[[4-(trifluoromethoxy)phenyl]amino]carbonyl]benzamide, on the housefly,Musca domesticaLinnaeus were examined in the laboratory. A dose of 1 μg of triflumuron applied topically to adult females ofM. domesticaresulted in egg hatch inhibition greater than 95%. At doses below 1 μg applied topically to adult females, subsequent hatched larvae were also highly sensitive to triflumuron; 0.5 μg applied topically produced 25% inhibition of egg hatch, but of the larvae that eclosed, only 20% survived to pupation. Hence, a dose of 0.5 μg applied to adults gave a total mortality of 85%. The effects of a single topical application of triflumuron declined over time in a dose dependent manner. After a dose of 1 μg, <5% of the first egg batch hatched, however, after 14 days egg hatch had risen to >90%. Topically applied triflumuron was most effective in inhibiting egg hatch when applied to females less than 3 days old. After 60 min tarsal contact with 20% triflumuron suspension concentrate on poly cotton cloth, 100% egg hatch inhibition was maintained for up to 1 week. Lower contact times, or triflumuron concentrations, gave lower percentage mortalities. The results suggest that triflumuron has considerable potential as a control agent for incorporation into autosterilizing devices for housefly control. However, further work is required to develop delivery systems capable of transferring an effective dose to females under field conditions.
Estimates of mortalities of larvae and pupae of theAedes simpsoni(Theobald)(Diptera: Culicidae) complex in Uganda
Authors: Lutwama J.J. , Mukwaya L.G.
Published: July 2009

Studies were carried out to estimate and compare mortalities of larvae and pupae ofAedes (Stegomyia) simpsoni sensu latobreeding in axils ofColocasia esculenta, Xanthosoma sagittifolium(Araceae) andMusaspp. (Musaceae) in different locations in Uganda and also to ascertain whether there are any differences in their dynamics that could be used to separate the species. The probability of larvae surviving from one day to the next (40·5 – 99·8%), and the proportions dying in each instar (0·97 – 77·3%) and dying daily in all the four instars (3·9 – 46·3%) varied between seasons at each site and between sites and species of plants. Estimates of larval and pupal mortality were generally highest for fourth instar [52·4 ± 6·0% (mean ± SE)] and lowest for the second instar larvae (16·0 ± 2·6%). There was higher larval instar mortality in axils ofX. sagittifolium(96·9%) andMusaspp. (82·2 – 96·5%) than inC. esculenta(47·1 – 88·4%).
Spatial dispersion patterns of larval Aedes cantans (Diptera: Culicidae) in temporary woodland pools
Authors: Renshaw M. , Silver J.B. , Service M.W. , Birley M.H.
Published: July 2009

The spatial dispersion patterns of larvae of the Palaearctic mosquito Aedes cantans (Meigen) were studied in two temporary woodland pools in England, between 1988 and 1990. Variance to mean ratios indicated that all larval instars were aggregated, but the degree of aggregation differed between ponds and between years, depending on the population density. The negative binomial model was found to fit the majority of the data, and the values for the parameter k varied between 0.05 and 0.96. Taylor's power law gave a good fit to the data with values of b, an index of aggregation, varying between 1.42 and 1.91. Iwao's patchiness regression yielded values for α between –1.63 and 6.92, and β from 1.49 to 3.25. These values indicate that the population is aggregated due to habitat heterogeneity, and younger instars may demonstrate a propensity to congregate with one another. A relationship between water temperature and mean number of larvae sampled at each transect point was observed in Pond One in 1989, suggesting that larvae aggregate where water temperatures are higher.
Responses of tsetse flies (Diptera: Glossinidae) to natural and synthetic ox odours
Authors: Torr S.J. , Hall D.R. , Smith J.L.
Published: July 2009

In Zimbabwe, studies were made of the levels of known tsetse attractants present in natural ox odour. Typically an ox (400 kg) produced phenol (0.1 mg/h), 3-methylphenol (0.09 mg/h), 4-methylphenol (0.7 mg/h), 3-ethylphenol (0.01 mg/h), 4-ethylphenol (0.02 mg/h), 3- and 4-n-propylphenol (0.02 mg/h), l-octen-3-ol (0.01 mg/h), carbon dioxide (140 l/h), acetone (5 mg/h) and butanone (0.3 mg/h). Of these, only phenol, 4- and 3-methylphenol and carbon dioxide were always detected in ox odour. Studies were made of the numbers of Glossina pallidipes Austen and G. morsitans morsitans Westwood attracted to natural ox odour and synthetic odour, the latter consisting of blends of identified attractants dispensed at the doses naturally present in ox odour. Natural ox odour caught twice (P < 0.05) as many G. pallidipes and 1.5 (P < 0.05) times as many G. m. morsitans as the synthetic blend suggesting the presence of an unidentified attractant in ox odour. Passing ox odour through filters indicated that all attractants can be trapped on a combination of charcoal and sodalime filters but the unidentified attractant(s) may pass through a sodalime filter, and break through a charcoal filter used for more than 6 h. Increasing the dose of ketones in the synthetic odour from 2 to 100 mg/h doubled the catches at the source. Increases in ketone levels in hosts, induced by starvation or possibly trypanosomiasis, may increase attraction of tsetse to such animals.
A biologically-active compound from pupae of the sandfly Lutzomyia longipalpis (Diptera: Psychodidae) and its possible role in defence
Authors: Dougherty M.J. , Hamilton J.G.C.
Published: July 2009

Gas chromatography analysis of Lutzomyia longipalpis (Lutz & Neiva) pupae and fourth instar larvae revealed a compound which was not present in other larval stages. Squashed pupae were repellent to conspecific larvae and ants (Lasius niger (Linnaeus) (Hymenoptera: Formicidae)), whereas second and third instars were not. Hexane extracts of pupae were repellent to conspecific larvae and L. niger, but extracts of second and third instars were not. The biologically active chemical was isolated from pupae and fourth instars and was found to be repellent to conspecific larvae and L. niger. The possibility that pupae and fourth instars may use a combined chemical and mechanical defensive strategy to avoid predation and cannibalism is discussed.
Comparative survival of insecticide-susceptible and resistant peach-potato aphids, Myzus persicae (Sulzer) (Hemiptera: Aphididae), in low temperature field trials
Authors: Foster S.P. , Harrington R. , Devonshire A.L. , Denholm I. , Devine G.J. , Kenward M.G. , Bale J.S.
Published: July 2009

The survival of Myzus persicae (Sulzer) clones, representing the full range of the recognized levels of insecticide resistance, was measured after 3–4 week exposure to the winter climate in the field. Ten separate trials were carried out using known numbers of first/second instar nymphs on unsprayed oilseed rape and groundsel. These predominantly showed a negative association between resistance level and the proportion of aphids recovered alive after exposure. The strength of the relationship correlated closely with three meteorological variables: the length of time that aphids spent below 2°C, mean rainfall and mean windspeed. We conclude that selection for resistance to insecticides is subject to counteracting selection by cold, wet and windy conditions in the UK winter. Revertant clones, that had spontaneously lost extreme resistance to insecticides despite retaining resistance genes, survived no better than aphids that had kept their high resistance, indicating that overproduction of esterase was not the reason for poor survival.
The effects of exposing eggs of four cotton insect pests to volatiles of Allium sativum (Liliaceae)
Authors: Gurusubramanian G. , Krishna S.S.
Published: July 2009

Exposure of freshly laid eggs (<24 h old) of Earias vittella Fabricius (Lepidoptera: Noctuidae) and Dysdercus koenigii (Fabricius) (Hemiptera: Pyrrhocoridae) to volatiles from bulbs of Allium sativum significantly reduced their hatchability. Eggs of Spodoptera litura (Fabricius) (Noctuidae) treated likewise, failed to hatch. Eggs of Helicoverpa armigera (Hübner) (Noctuidae) were more tolerant and showed only a slight decrease in mortality. None of the immature stages of D. koenigii and H. armigera and only 30% of those of E. vittella that hatched from treated eggs managed to complete their metamorphosis. A few larvae of H. armigera developed to the pupal stage but their pupal weights were markedly low. These findings are interpreted as the chronic effects of volatiles affecting larvae/nymphs following developmental defects sustained during embryonic development. The known chief constituents such as allicin, 2-propene sulfenic acid, 2-propene thiol, propylene, thioacrolein and ajoene present in the volatiles were presumed to be responsible for the adverse consequences reported here.
Factors affecting host preference of Lutzomyia evansi (Diptera: Psychodidae), a vector of visceral leishmaniasis in Colombia
Authors: Montoya-Lerma James , Lane Richard P.
Published: July 2009

Previous studies have shown the sandfly Lutzomyia evansi to be the vector of Leishmania chagasi in northern Colombia. A longitudinal survey during seven months on the host preference of Lutzomyia evansi was conducted in the visceral leishmaniasis focus of San Andrés de Sotavento, Colombia. Host preference was determined by presenting sandflies with a choice of three baits (human, and the reservoirs dog and opossum) and a blank control in specially designed cone traps. A rotational experimental design involved 56 trap nights in which the effect of bait, proximity to forest and season could be distinguished from the potentially confounding factors of site and day to day variation. From a total of 598 sandflies caught during all experiments, females and males of Lutzomyia evansi accounted for 93.8% of the captures in the baited traps. Overall, human attracted the greatest number of sand flies, followed by the other two baits. Attraction and feeding success showed significant differences (P < 0.0001) between baits.
On the coexistence of the cassava mealybug parasitoidsApoanagyrus diversicornisandA. lopezi(Hymenoptera: Encyrtidae) in their native South America
Authors: Pijls Janine W.A.M. , van Alphen Jacques J.M.
Published: July 2009

The encyrtid parasitoidApoanagyrus diversicornis(Howard) (formerly known asEpidinocarsis diversicornis) failed to establish itself in Africa where it was introduced, in addition toA. lopeziDe Santis for the biological control of the cassava mealybug,Phenacoccus manihotiMatile-Ferrero.Apoanagyrus lopeziis a better competitor and available evidence suggests that competition prevents the coexistence. Yet, both parasitoid species were reared fromP. manihotiin the same locality in their native South America. Competition should prevent coexistence onP. manihotiin South America as well as in Africa. We investigated howA. diversicornispersists in South America. The use of alternative hosts could explain its persistence. We aimed at finding possible alternative hosts forA. diversicornisthat can serve as a refuge from competition withA. lopezi. The existing information on the distribution ofA. lopeziandA. diversicornisand their known hosts in South America is reviewed. Candidate alternative hosts forA. diversicorniswere selected and tested. Alternative hosts should at least be suitable for development ofA. diversicornisand unsuitable for development ofA. lopezi. OnlyPhenacoccus herreniCox & Williams met these requirements.Phenacoccus madeirensisGreen,P. solaniFerris andFerrisia virgata(Cockerell) were unsuitable hosts for both species. In cages with continuous parasitoid populations under strong interspecific competition,A. diversicornisdid significantly better if half the population ofP. manihotiwas replaced byP. herreni. This supports the hypothesis thatP. herrenican serve as an alternative host forA. diversicornisin South America and that its presence enhances coexistence ofA. diversicornisandA. lopezi.Phenacoccus herreniis absent in Africa.
Circadian flight activity of Arabian sandflies (Diptera: Psychodidae) using a vehicle-mounted net
Authors: Roberts D.M.
Published: July 2009

A vehicle-mounted net was used on 15 nights during June 1990 and 1991 in northern Oman to collect sandflies in order to identify potential vectors of visceral and cutaneous leishmaniasis. A total of 2216 sandflies was collected comprising four species of Phlebotomus and three of Sergentomyia. Catches were made every 30 minutes between 17.00 h (2 hours before sunset) and 07.00 h (1.5 hours after sunrise). Very few flies were caught before sunset. Most flies were caught at light intensities < 0.1 lux (between 20.00 and 0.500 h), but some flight activity, particularly of males and unfed females, continued even up to 07.00 h (50,000 lux, 1.25 hours after sunrise). Females of the two most abundant species, Phlebotomus alexandri Sinton and Sergentomyia clydei Sinton were significantly more active during the first half of the night (19.00-01.00 h), but males were not. Males of S. clydei showed no clear activity pattern, while males of P. alexandri had two peaks with a decline in activity around 01.00 h. Sergentomyia tiberiadis Adler & Theodor and S. fallax Parrot similarly showed different activity patterns for the two sexes. The circadian activity of females of P. alexandri and S. clydei changed during their gonotrophic cycles. Thus unfed and gravid P. alexandri had two activity peaks during the night, but the blood-fed females were most active during the first half of the night. S. clydei activity was similar, except that the gravid flies, like the blood-fed, had an early peak of activity. Too few parous females were collected to show any clear difference in activity from the nullipars.
Effect of the ratios ofListronotus bonariensisandSitona discoideus(Coleoptera: Curculionidae) to their respective parasitoidsMicroctonus hyperodaeandM. aethiopoides(Hymenoptera: Braconidae), on parasitism, host oviposition and feeding in the laboratory
Authors: Barratt B.I.P. , Evans A.A. , Johnstone P.D.
Published: July 2009

The parasitoidsMicroctonus hyperodaeLoan andM. aethiopoidesLoan have been introduced into New Zealand to control the forage pestsListronotus bonariensis(Kuschel) andSitona discoideusGyllenhal, respectively. Laboratory experiments were carried out to investigate the effect of host–parasitoid ratio, and exposure time on host survival, parasitism, oviposition and feeding. Cages of 20 field collected weevils were exposed to 0, 1, 3 or 6 parasitoids for 0, 1, 12 or 48 hours, maintained until parasitoid pupal emergence, and surviving weevils dissected. Over the ranges studied, increasing parasite number, and to a greater extent, period of exposure of parasitoids to their hosts increased parasitism levels.Microctonus aethiopoidesachieved higher levels of parasitism inS. discoideusat the lower parasitoid contact treatments than didM. hyperodaeinL. bonariensis. Fecundity in unparasitized weevils was progressively reduced in bothL. bonariensisandS. discoideusin relation to increasing exposure to parasitoids. Feeding was reduced by about 40% inL. bonariensisfor at least four days after parasitoids were removed, and inS. discoideusfor the duration of the experiment, averaging 15%. Results were discussed in relation to possible mechanisms of indirect effects of parasitoids on unparasitized hosts.
Relationship between bioassay data and the simulated field performance of insecticides against susceptible and resistant adult Bemisia tabaci (Homoptera: Aleyrodidae)
Authors: Cahill Matthew , Denholm Ian , Ross Gavin , Gorman Kevin , Johnston Diana
Published: July 2009

Adults from seven strains of Bemisia tabaci (Gennadius) were tested with nine insecticides or combinations in both leaf-dip bioassays and the Rothamsted field simulators. A statistical model was used to describe the survival of the insects in the field simulators and comparisons made to the resistance factors from leaf-dip assays. Strains of B. tabaci shown to be susceptible in bioassays were well controlled by field rates of the insecticides in the field simulators. For each insecticide or combination, the degree of adult survival in field simulators after insecticide treatment was positively related to the resistance factor. However, similar resistance factors for different insecticides gave quite different adult field simulator survival. In populations with high resistance factors, adult mortality in the field simulators after insecticide application was not different to untreated controls. These data provide information about the implications of B. tabaci resistance on the field performance of insecticides.
Resolution of baseline responses and documentation of resistance to buprofezin in Bemisia tabaci (Homoptera: Aleyrodidae)
Authors: Cahill Matthew , Jarvis Wayne , Gorman Kevin , Denholm Ian
Published: July 2009

The insect growth regulator buprofezin was tested using a leaf-dip assay on immatures of Bemisia tabaci (Gennadius). The method was robust and repeatable, and baseline data were calculated for a laboratory strain and a number of field collections from Pakistan where the insecticide has not been used. A baseline LC50 of 0.53 ppm buprofezin was defined and compared to other field collections. Populations known or suspected to have been intensively selected with buprofezin showed substantial tolerance to the insecticide at both the LC50 and at specific diagnostic doses, with the highest resistance factor of 47 fold in a population from the Netherlands. Reasons for the variation between populations, biotypes and geographical areas are discussed and the dangers of human-assisted movement of resistance genes are highlighted.
Winter moth (Operophtera brumata(Lepidoptera: Geometridae)) outbreaks on Scottish heather moorlands: effects of host plant and parasitoids on larval survival and development
Authors: Kerslake J.E. , Kruuk L.E.B. , Hartley S.E. , Woodin S.J.
Published: July 2009

Outbreaks of the winter moth,Operophtera brumataLinnaeus (Lepidoptera: Geometridae), have recently become widespread on heather moorlands in northeast Scotland. These outbreaks represent remarkable phenomena given the poor nutritional quality of the dominant moorland host plantCalluna vulgaris(Linnaeus) Hull (Ericaceae). Winter moth performance onC. vulgariswas compared with that on the other available moorland host plant,Vaccinium myrtillus(Linnaeus) (Ericaceae), and parasitism levels were measured in two moorland outbreak populations. Larval densities in the field were generally higher onCallunathan onVaccinium. However, larvae showed better survival, more rapid development and greater pupal weights onVacciniumthan onCalluna. Feeding trials indicated thatVacciniumwas more digestible thanCalluna. No evidence of parasitism was found in a high-altitude moorland winter moth outbreak population from mainland Scotland, but the parasitoidPhobocampe neglecta(Holmgren) (Hymenoptera: Ichneumonidae) was present in 27% of larvae from a lower-altitude moorland outbreak on Orkney. The results indicate that the presence ofVacciniumand the opportunity to escape from parasitism may facilitateO. brumataoutbreak formation in high-altitude moorland sites. However, neither factor can provide a full explanation for the present phenomenon.
Susceptibility of larvae of the sandflyPhlebotomus papatasi(Diptera: Psychodidae) toBacillus sphaericus
Authors: Pener H. , Wilamowski A.
Published: July 2009

Laboratory experiments were conducted to measure the susceptibility of larvae of the sandflyPhlebotomus papatasiScopoli to the insect pathogenBacillus sphaericusapplied to the larval breeding medium.B. sphaericushad no effect on larvae aged 30 ± 2 days old, but larvae aged 13 ± 2 and 20 ± 2 days were highly susceptible and a clear dose response effect was detected. WhenB. sphaericuswas left in the rearing medium for 18 days there was a significant increase in larval mortality, indicating persistence and possibly recycling. The results support the feasibility of employingB. sphaericusin the integrated control of sandflies.
Population status of the bush fly, Musca vetustissima (Diptera: Muscidae), and native dung beetles (Coleoptera: Scarabaeinae) in south-eastern Australia in relation to establishment of exotic dung beetles
Authors: Tyndale-Biscoe Marina , Vogt W.G.
Published: July 2009

We compare the pest status and age structure of bush fly,Musca vetustissima Walker, populations, and the abundance of native dung beetles at Uriarra, ACT, for five fly seasons before (1976–81) and three seasons after (1990–93) the exotic dung beetles Euoniticellus fulvus (Goeze) and Onthophagus taurus (Schreber) became established in the area during the late 1980s. Fly populations in all post-introduction seasons of 1990–93 were much older than in the pre-introduction seasons, indicating reduced levels of local fly breeding and higher proportions of immigrants. During the pre-introduction period, the fly annoyance index exceeded the ‘minimum discomfort’ threshold of 10.0 in parts of all seasons. The mean index was 11.3, and this did not differ significantly between seasons. The total dry weight of dung beetles at the time of the first influx of bush flies each year was consistently below 3 g/dung pad which was apparently too low to depress bush fly breeding below their replacement level of 3%. The mean annoyance index of 3.1 for the 1990–91 season was significantly lower than for the pre-introduction period and the total dry weight of beetles during November-December exceeded 3 g/dung pad on all sampling occasions. In the 1991–92 and 1992–93 seasons fly annoyance indices reverted to pre-introduction levels (seasonal means of 13.7 and 7.8 respectively) and total dry weight of beetles was again below 3 g/dung pad when the bush flies first appeared. Survival of immature bush flies in local dung pads remained below the replacement level of 3% during 1990–91, but exceeded 3% on two occasions during 1991–92. Apart from 1976–77, when mean catches of native dung beetles (O. australis and O. granulatus) were exceptionally high, mean catches of native dung beetles during pre- and post-introduction years were very similar, but the mean dung beetle biomass increased following the establishment of exotic species.
Effect of pirimicarb on the foraging behaviour of Diaeretiella rapae (Hymenoptera: Braconidae) on host-free and infested oilseed rape plants
Authors: Umoru P.A. , Powell W. , Clark S.J.
Published: July 2009

The effects of the aphicide pirimicarb on the foraging behaviour of the aphid parasitoid Diaeretiella rapae were investigated in the laboratory, using aphid-infested and uninfested, young oilseed rape plants. Female parasitoids spent significantly less time foraging on plants sprayed with pirimicarb within the previous 24 h than on untreated plants, regardless of the presence of aphid hosts. Whilst foraging on sprayed plants, parasitoids spent relatively more time walking than they did when foraging on untreated plants. On sprayed plants foraging parasitoids tended to avoid leaf surfaces, thereby reducing the chances of encountering aphid hosts whilst on the plant. These sublethal effects of the aphicide on foraging parasitoids would considerably reduce their impact on aphid populations which survived in a crop after spraying. This has important implications for the control of aphids, such as Myzus persicae, which have developed pesticide resistant strains.
Multitrophic interactions and management of the diamondback moth: a review
Authors: Verkerk Robert H.J. , Wright Denis J.
Published: July 2009

The diamondback moth,Plutella xylostellaLinnaeus (Yponomeutidae), remains one of the most serious pests of crucifers in many parts of the world, particularly in South East Asia. This paper reviews the wide array of strategies which have been used in attempts to controlP. xylostellaover the last 40 years and consolidates the fragmented and sometimes hard-to-access literature on two and three level trophic interactions (e.g. host plant—herbivore, herbivore—natural enemy and host plant-herbivore—natural enemy interactions) involving the pest. Special reference is made to studies and examples from South East Asia, and in particular Malaysia, whereP. xylostellaand its primary parasitoids have been well studied owing to the great economic significance of the pest in this region. It is suggested that a multitrophic approach to research may assist in the development of more sustainable methods for the management ofP. xylostellaand overcome some of the problems inherent with insecticide-intensive methods.
Age composition of the filarial vector Culex quinquefasciatus (Diptera: Culicidae) in Calcutta, India
Authors: Chandra G. , Seal B. , Hati A.K.
Published: July 2009

Age composition of the filarial vector mosquito Culex quinquefasciatus (Say) was determined by examining the number of ovariolar dilatations of 1200 adult females from Calcutta. Average duration of the gonotrophic cycle was 4.5 days. The proportion parous, the daily survival rate and daily mortality rates of the natural population were 0.53, 0.87 and 13%, respectively. The oldest mosquito sampled in the study area passed eight gonotrophic cycles in its lifetime.
Ecological and geographical variations in the siphonal index of Culex pipiens larvae (Diptera: Culicidae)
Authors: Vinogradova E.B. , Reznik S.Ya. , Kuprijanova E.S.
Published: July 2009

Culex pipiens Linnaeus is represented by two forms: the form molestus which is autogenous, stenagamous and has no reproductive diapause, and the form pipiens which is anautogenous, eurygamous and diapauses. The ecological, physiological and geographical variations in the larval siphonal index of C. pipiens (the ratio of the length of the siphon to its width at the base) was investigated using both original measurements and previously published data. In all, data were used from 259 collections from open water bodies (marshes, ditches, holes, barrels, etc.) and underground waters (house basements) in areas of Europe, Asia and part of Africa. Autogeny was studied in some cases by dissection of females. In C. pipiens the mean siphonal index was strongly correlated with ecology (water body type) and adult physiology (autogeny). In spite of high geographical and individual variation, which makes the identification of individual larvae difficult, the mean siphonal index can be used with certainty for the differentiation of populations of the two forms of C. pipiens.