bluuebunny/crossref_metadata_2025_split huggingface dataset:
Encarsiaparasitoids ofBemisia tabaci(Hymenoptera: Aphelinidae, Homoptera: Aleyrodidae): a preliminary guide to identification
Authors: Polaszek A. , Evans G.A. , Bennett F.D. 
Published: July 2009

AbstractA key is provided for the recognition of previously describedEncarsiaspecies which are known to attack the tobacco whitefly,Bemisia tabaci(Genna-dius). 28 nominal species are included, of which type material has been examined for 22. Eight new synonymies are proposed:Encarsia aleyrodis(Mercet) andE. partenopeaMasi are both synonymized withE. inaron(Walker); E.bemi-siae(Ishii) is synonymized withE. transvena(Timberlake);E. citri(Ishii) is synonymized withE. strenua(Silvestri),E. angelicaHoward andE. desertiRivnay & Gerling are both synonymized withE. luteolaHoward;E. perspicuipennis(Girault) is synonymized withE. quaintancei(Howard);E. tabacivoraViggiani is synonymized withE. pergandiellaHoward.E. hispidaDe Santis is removed from synonymy withE. meritoriaGahan. A lectotype is designated forE. porteri(Mercet). The known distributions and alternative hosts ofEncarsiaspecies attackingB. tabaciare provided as well as references to biology and notes on their use in biological control.
Evaluation of resistance, cross-resistance and synergism of abamectin and teflubenzuron in a multi-resistant field population of Plutella xylostella (Lepidoptera: Plutellidae)
Authors: Iqbal M. , Wright D.J. 
Published: July 2009

AbstractThe efficacy of abamectin (AgrimecR) and teflubenzuron (NomoltR) was assessed by leaf-dip bioassay against larvae of the diamondback moth, Plutella xylostella Linnaeus from a population (SERD3) collected originally in lowland Malaysia in December 1994. Evidence for resistance to both abamectin and teflubenzuron was found in the F7 generation (LC50 ratio of 60 and 24 respectively compared with a laboratory, insecticide-susceptible strain). Selection of sub-populations of SERD3 (F7–F9) with abamectin and teflubenzuron increased the LC50 ratio to 220 and 360 respectively and estimates of realized heritability [h2] were high (c. 0.8 and 0.9) for both compounds. There was no cross-resistance between these compounds in the abamectin and teflubenzuron-selected sub-populations but some indication of negatively-correlated resistance. Topical application of the synergists piperonyl butoxide, S,S,S-tributylphosphorotrithioate and maleic acid diethyl ester to the laboratory strain had no significant effect on the toxicity of abamectin or teflubenzuron in subsequent leaf-dip assays. In contrast, pre-treatment with piperonyl butoxide and S,S,S-tributylphosphorotrithioate significantly increased the toxicity of abamectin (c. 4- and 3-fold) and teflubenzuron (c. 7- and 19-fold) in the abamectin and teflubenzuron-selected sub-populations of SERD3, suggesting that microsomal monoxygenases and/or esterases may be involved in resistance. Pre-treatment with maleic acid diethyl ester only increased the toxicity of abamectin by c. 2-fold and had no significant effect on the toxicity of teflubenzuron, providing limited evidence for the involvement of glutathione-S-transferases in resistance to the former compound alone.
Geographic variation in host selection behaviour and reproductive success in the stemborer parasitoidCotesia flavipes(Hymenoptera: Braconidae)
Authors: Potting R.P.J. , Vet L.E.M , Overholt W.A 
Published: July 2009

AbstractLocal parasitoid populations may be adapted to their sympatric major plant host complex. Parasitoid strains may thus differ in their propensity to search for a particular micro-habitat or host or they may differ in their physiological compatibility with particular plant or host species.Cotesia flavipesCameron, a larval parasitoid used worldwide in biological control against tropical stemborers, has a wide host range in diverse habitats. The existence of plant and/or host specific strains inC. flavipeshas been postulated. To provide insight into the existence of strains inC. flavipes, we compared the plant/host complex selection behaviour, and physiological compatibility with different stemborers, of six different geographic strains ofC. flavipesthat differed in the plant/host complex they were obtained from. The results of the host selection experiments indicate that there is no intraspecific variation in host selection behaviour amongC. flavipesstrains. However, our comparative experiments show variation in reproductive success among strains. The most significant result was that the strain with the longest period of co-existence with the new hostDiatraea saccharalisFabricius had the highest reproductive success on this host species. We argue that the reported existence ofC. flavipesstrains is based not on differences in host selection behaviour, but on differences in physiological compatibility between local parasitoid and host population.
Canopy knockdown of arthropods in exotic plantations and natural forest in Sabah, north-east Borneo, using insecticidal mist-blowing
Authors: Chey V.K. , Holloway J.D. , Hambler C. , Speight M.R. 
Published: July 2009

AbstractCanopy knockdown of arthropods using mist-blowing was carried out in Brumas, Sabah (north-east Borneo), in plantations of exotic (non-indigenous) tree species (Acacia mangium, Eucalyptus deglupta, Gmelina arborea, Paraserianthes[=Albizia]falcataria, andPinus caribaea), plus secondary natural forest and dense understorey withinE. degluptastands. Each habitat had three 1 m2samples taken four times in one year. The average arthropod species richness within the stands of the exotic tree species ranged from 27 inE. deglupta, to 68 in natural, secondary forest. The total number of individuals caught ranged from 137 in G.arboreato 1628 in secondary forest. The dense and plant-species rich understorey withinE. degluptastands yielded both higher numbers of species and individuals than the eucalypt trees themselves, indicating the importance of allowing the development of a luxuriant understorey for the enhancement of conservation and biodiversity. Though arthropod biodiversity is reduced by the conversion of tropical forests to plantations, abundance and richness are still substantial in the latter habitats.
Biological control ofBemisia argentifolii(Hemiptera: Aleyrodidae) on poinsettia with inundative releases ofEretmocerus eremicus(Hymenoptera: Aphelinidae): do release rates affect parasitism?
Authors: Hoddle M.S. , Van Driesche R.G. , Sanderson J.P. , Minkenberg O.P.J.M. 
Published: July 2009

AbstractThe effectiveness of inundative releases of the parasitoidEretmocerus eremicusn. sp. Rose & Zolnerowich for control ofBemisia argentifoliiBellows & Perring on poinsettia in replicated experimental greenhouses was determined. We evaluated two release rates ofE. eremicus:a low release rate (one female per plant per week, released in two greenhouses, in spring 1995) and a high release rate (three females per plant per week, released in two greenhouses, in spring 1994), each over a 14 week growing season. Each release trial had either one (1995) or two (1994) control greenhouses in whichB. argentifoliideveloped on poinsettia in the absence ofE. eremicus. Life-tables were constructed forB. argentifoliiin the presence and absence ofE. eremicusby using a photographic technique to follow cohorts of whiteflies on poinsettia leaves. Weekly population counts of whiteflies were also made. In the absence ofE. eremicus, egg to adult survivorship ofB. argentifoliion poinsettia was 75–81%. At the low release rate, egg to adult survivorship ofB. argentifoliiwas 12% and parasitism was 34%. At the high release rate, egg to adult survivorship ofB. argentifoliiwas 0.9% and parasitism was 10%. The average net reproductive rates (Ro) for populations ofB. argentifoliiin the absence ofE. eremicusranged from 20.5 to 26.1, indicating a rapidly increasing population density. Net reproductive rates for whitefly populations subject to parasitoid releases were 3.7 in the low release rate greenhouses, and 0.25 in the high release rate greenhouses, indicating substantially reducedB. argentifoliipopulation growth. At week 14 of the trial, densities of immature whiteflies were lower in greenhouses at the low release rate when compared to the high release rate greenhouses. This was attributed to high levels of in-house reproduction by parasitoids at the low release rate.
Population density, development and behaviour of Diopsis longicornis and D. apicalis (Diptera: Diopsidae) on rice in the Republic of Guinée
Authors: Chiasson H. , Hill S.B. 
Published: July 2009

AbstractThe behaviour and pest status of the rice stem borers Diopsis longicornis Macquart and D. apicalis Dalman were investigated in the Republic of Guinée, particularly during the dry season. The variables were direct seeded and transplanted rice, and three (1988, 1989) and four (1987) planting dates. Transplanted rice was damaged nearly three times more than direct seeded rice in the dry season, but no significant difference was detected during the wet season. As previously observed in other West African countries, D.apicalis only occasionally damages rice in Guinée. Contrary to findings elsewhere, D. longicornis was not an important pest of Guinean rice, infesting only 5% and 3% of stems over the three dry and the two wet seasons, respectively. However, year round rice production could promote build up of the diopsid population if dry season planting is not sufficiently delayed (45 days) after the last rains of the wet season.
Interference by ants in biological control of the cassava mealybug Phenacoccus manihoti (Hemiptera: Pseudococcidae) in Ghana
Authors: Cudjoe A. R. , Neuenschwander P. , Copland M. J. W. 
Published: July 2009

AbstractIn surveys of cassava fields in the coastal savanna and rain forest zones of Ghana, eight species of ants, mostly in the genera Camponotus, Crematogaster and Pheidole (Hymenoptera: Formicidae), were found attending cassava mealybug, Phenacoccus manihoti Matile-Ferrero. Ant densities were much higher in the rain forest than in the savanna and, in most zones, positively correlated to mealybug population densities. Pheidole megacephala (Fabricius) was the only species more abundant in the interior of fields, whereas the other species preferred the edges of fields or, like Camponotus spp., did not respond to edge effects. Weediness of the fields did not clearly influence the presence of ants. Crematogaster sp. and P. megacephala spent most of the time on cassava tips, where they built carton tents. Ants of the three genera reduced parasitism rates by the exotic Epidinocarsis lopezi (De Santis) (Hymenoptera: Encyrtidae) to half, compared to the rates observed on mealybug colonies of equal size that were not attended. Hyperparasitism by Prochiloneurus insolitus (Alam) (Hymenoptera: Encyrtidae) and Chartocerus hyalipennis Hayat (Hymenoptera: Signiphoridae) and predation by the indigenous Exochomus troberti Mulsant (Coleoptera: Coccinellidae) were similarly reduced. Where ants were excluded experimentally by insectcide barriers, parasitism was 32%, compared to only 10% in the control, and predator densities were reduced three-fold. In a 24 h experiment, Pheidole megacephala was observed to remove about half the E. troberti larvae; Crematogaster sp. and Camponotus spp. were less efficient. The results show the locally strong interference of ants with biological control of the cassava mealybug. Despite this interference, mealybug populations in the rain forest were judged to be below damaging levels.
Expression of pyrethroid resistance in adult Helicoverpa armigera (Lepidoptera: Noctuidae) and selective mortality in field populations
Authors: Daly Joanne C. , Fisk Jennifer H. 
Published: July 2009

AbstractPyrethroid resistance was examined in adult Helicoverpa armigera (Hübner) in both laboratory and field selected strains. A series of F1 and backcrosses was made between a susceptible and an isofemale resistant strain. Dose-responses were obtained using contact with a treated surface inside a scintillation vial. Inheritance of resistance was consistent with an incompletely dominant major gene and resistance factors were greater than 100-fold. Piperonyl butoxide synergized the effects of the synthetic pyrethroid, fenvalerate, 1000-fold and eliminated resistance entirely. Field trials examined the mortality of resistant and susceptible adults exposed to commercial application rates of synthetic pyrethroids. Adults were immobilized and placed in cotton fields prior to aerial applications of insecticide. Survival of resistant adults was significantly greater than susceptible ones in both trials. It was concluded that selective mortality in the adult life-stage contributes to the evolution of pyrethroid resistance.
An optical method for automatic classification and recording of a suction trap catch
Authors: Hobbs S.E. , Hodges G. 
Published: July 2009

AbstractA simple optical method for automatic recording and classification of a suction trap catch is described. The insects are illuminated against a dark background as they pass through a detection volume, and the amount of scattered light is used to measure insect size. The design centres on the detection volume, which is a volume through which the insects are made to pass, and within which they may be detected. The design is approached in four stages: 1. Delivery of insects to the detection volume. 2. Illumination of the detection volume. 3. Collection and detection of scattered light. 4. Signal analysis. The analysis could also be applied to related techniques. Results with a prototype demonstrate that classification into broad size categories is straight-forward (e.g. approximately three classes spanning body lengths of 2–7 mm), despite uncertainties of insect reflectivity, aspect and trajectory. Applications of the method are discussed, along with a brief mention of alternative techniques.
Effects of ivermectin treatment on the attraction of dung beetles (Coleoptera: Scarabaeidae and Hydrophilidae) to cow pats
Authors: Holter P. , Sommer C. , Grønvold J. , Madsen M. 
Published: July 2009

AbstractThe effect of ivermectin treatment of cattle on the rate of dung beetle colonization of cow pats was assessed by pitfall trapping in Denmark, Tanzania and Zimbabwe. Ivermectin was injected subcutaneously into heifers at the recommended dose of 0.2 mg/kg body weight, and dung to be used as bait in pitfalls was collected at intervals after treatment. In one experiment in Denmark, species of the scarab beetle Aphodius and the hydrophilids Sphaeridium and Cercyon, preferred control dung from untreated cattle; no preference was found in two other experiments, involving some of the same species. In the Tanzanian trials, the overall tendency for scarabaeid beetles was to prefer control dung. In Zimbabwe, two scarabaeid species (Euoniticellus intermedius (Reiche) and Liatongus militaris (Castelnau), both belonging to Oniticellini) were particularly attracted to dung from treated cattle; two other scarabaeids showed no preference. It is concluded: 1. That ivermectin therapy can affect the rate of dung colonization by attracting or repelling beetles. 2. That the responses are probably not caused by ivermectin per se, but by some side effect, the nature of which is obscure and unpredictable with our present knowledge.
A multiple basis for insecticide resistance in a strain ofCulex quinquefasciatus(Diptera: Culicidae) from Muheza, Tanzania, studied as resistance declined
Authors: Khayrandish A. , Wood R.J. 
Published: July 2009

AbstractEvidence from observing resistance in decline in fourth instar larvae of the multiple resistant MUHEZA strain ofCulex quinquefasciatusSay from Tanzania (MUHEZA), showed that the major mechanisms for chlorpyrifos and propoxur resistance were different. Resistance to chlorpyrifos declined more than 400-fold (from an initial resistance ratio (RR) of 14285) while resistance to propoxur remained stable for at least 30 generations of laboratory culture. Significant synergism was found between propoxur and piperonyl butoxide (PB), propoxur and s,s,s-tributyl trithiophosphate (DEF), and permethrin and PB, but antagonism occurred between chlorpyrifos and PB, and no synergism between chlorpyrifos and DEF. Nine esterase isozymes active against naphthyl acetates on polyacrylamide gel electrophoresis (PAGE), were identified, four (A2, A3, B2, B3) showing polymorphism in activity, with very intense expression at one or other position in more than 32% of larvae, and null expression in less than 30%. The frequency of intense bands and of nulls both declined as resistance declined. A selected substrain (MUHEZA-fb), breeding true for A2, A3, B2 and B3 at the standard level of activity, showed almost stable chlorpyrifos resistance (RR=1428–1785) for approximately 35 generations. In mass larval assays ofin vitrosensitivity of acetylcholinesterase (AChE) to propoxur, the I50in MUHEZA was 950-fold greater than in a reverted resistant strain (RANGOON). Single larval assays indicated an AChE resistance allele (AceR) at frequency 0.43. PAGE of AChE revealed nine isozymes in MUHEZA and five in RANGOON, three of which were in common. It is concluded that propoxur resistance was due principally toAceRwith a minor influence from oxidases and non-specific esterases, while chlorpyrifos resistance was due to an interaction betweenAceRand non-specific esterases, the latter exerting the dominant effect.
An insect sorting device to be used in conjunction with insect suction samplers
Authors: Moore R. , Clarke R.T. , Creer S. 
Published: July 2009

AbstractA new field-based method for sorting insects collected in suction samplers is proposed. Test sampling on grassland showed that for most taxonomic groups it was over 80% efficient. The efficiency of sorting for certain insect groups was influenced by the amount of debris in the sample. However, it was possible to determine a relationship between these two variables which enabled a correction factor to be calculated and used to compensate for this. It is suggested that popular use of this technique would radically increase the amount of research performed in the field.
Field and laboratory trials using a locally produced neem insecticide against the Sahelian grasshopper, Kraussaria angulifera (Orthoptera: Acrididae), on millet in Mali
Authors: Passerini J. , Hill S. B. 
Published: July 2009

AbstractField and laboratory trials were undertaken to determine effects and efficacy of neem extracts on the Sahelian grasshopper, Kraussaria angulifera (Krauss). Formulations of aqueous extracts were sprayed in field experiments. Concentrations of 0.5% and 1% were effective in reducing grasshopper feeding. Neem kernel powder applied systematically, partially protected millet against K. angulifera. The residual activity of the botanical insecticide was at least seven days. Analysis of plant selection behaviour showed that neem is primarily an antifeedant rather than a repellent for this insect. On first to third instar nymphs, growth regulating activity, expressed as difficulty in moulting or an incompleteness of sclerotization, may occur.
Characterization and inheritance of elevated esterases in organophosphorus and carbamate insecticide resistant Culex quinquefasciatus (Diptera: Culicidae) from Sri Lanka
Authors: Peiris H.T.R. , Hemingway J. 
Published: July 2009

AbstractCulex quinquefasciatus Say from Peliyagoda, Sri Lanka, has elevated esterases A2 and B2. In vitro insecticide metabolism studies on the temephos-selected Sri Lankan Cutex quinquefasciatus strain, Pel RR, showed that fenitrothion was hydrolysed more rapidly than malathion. A significantly larger amount of fenitrothion was metabolized in Pel RR compared to the insecticide susceptible Pel SS strain, but the amount of malathion metabolized in the two strains was not significantly different. There was more esterase hydrolysis of fenitrothion than oxidase or glutathione S-transferase metabolism in Pel RR, which suggests that the elevated esterases in this strain have both metabolic and sequestering functions and that the relative importance of the two roles depends on the insecticide used. Genetic crosses of the temephos resistant and susceptible strains, showed that both resistance and elevated esterase activity were inherited as semi-dominant multi-genic characters. Hydrolysis of 2-naphthyl acetate was highest in the Pel RR strain, lowest in the Pel SS and intermediate in the F1 cross of the two strains. A minor maternal effect on resistance occurred with backcrosses involving resistant (F1) females, which gave consistently and significantly lower mortalities than those involving resistant (F1) males.
Comparison of permethrin treatments for bednets in The Gambia
Authors: Pleass R.J. , Armstrong J.R.M. , Curtis C.F. , Jawara M. , Lindsay S.W. 
Published: July 2009

AbstractAn experimental hut trial of bednets was undertaken in The Gambia to compare six different permethrin treatments, including a wash-resistant formulation, and to test the effect of thorough hand washing of the nets. The wash-resistant formulation on nylon and cotton nets deterred Anopheles gambiae Giles (sensu lato) from house entry. All treated bednets killed a significantly higher number of A. gambiae (sensu lato) than untreated nets. The ability to kill mosquitoes was not diminished with the wash-resistant and Wellcome formulations after washing unlike the normal ICI formulation, this result being consistent with the permethrin residues found by gas liquid chromatographic (GLC) analyses to persist on the nets after washing. The mortality on treated cotton nets was significantly less than on treated nylon nets. Of the unwashed nets only the cotton net was significantly repellent. Both washed and unwashed treated nets significantly reduced the proportion of human bloodfed mosquitoes that survived and were potentially able to transmit malaria. Although the wash-resistant formulation might prove more efficient at killing mosquitoes with time, as compared to the other treatments, in The Gambia, where women wash their nets frequently, we suggest that the cheapest and most readily available formulation is used on nylon nets where possible.
Host preference in African ticks (Acari: Ixodida): a quantitative data set
Authors: Cumming G.S. 
Published: July 2009

AbstractDespite the large number of collection rocords available, there has recently been some debate concerning how host-specific ticks are. A quantitative data set is presented for the host preferences of African ticks. The results are based on 43,615 individual collection records from published sources covering most countries in mainland Africa. Out of 223 ticks species, 112 have been collected 20 times or more; 14 of these are generalists and at least 39 are potential specialists. Further collections are needed for greater clarity in many cases. It is important that people working on problems that relate to tick-host interactions are aware of the context in which these occur, lest they make false a prior hypotheses about the importance of hosts or parasites in the system.