bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of the Residual Toxicity of DDT Solutions by the addition of Coumarone Resin
Authors: Van Tiel N.
Published: July 2009

An investigation was made into means of increasing the effectiveness of the usual DDT-containing residual sprays with a kerosene base.

The common house-fly, Musca domestica, was used as biological material.

It was found that there exists a distinct relationship between crystal size and residual toxicity. Finely crystalline residues from DDT solutions in volatile solvents, such as xylene, proved to be considerably more toxic than coarsely crystalline residues from DDT solutions in less volatile solvents, such as kerosene. Addition of small quantities of coumarone resin to a DDT solution in kerosene was found to reduce the size of the DDT crystals and to increase the toxicity considerably.
On the Distribution of Leucoptera Daricella (Meyr.) with the Description of a New Leaf-Miner from Coffee
Authors: Washbourn Roger
Published: July 2009

1. An examination has been made of all specimens labelled Leucoptera daricella (Meyr.), standing in the collections of the British Museum and of the late E. Meyrick.

2. Crobylophora staterias, Meyr., and Crobylophora onychotis, Meyr., two species previously regarded as synonymous with Leucoptera daricella, are thought to be good species. The specimens of the former, which were bred from Plumbago, have been received from India and Ceylon ; the latter is an Indian species.

3. A new African species, Leucoptera caffeina, Washbn., is described, which causes damage to coffee trees.

4. Records of Leucoptera daricella have been investigated, and, as a result, the writer is of the opinion that this species has not yet been recorded outside Australia, and that records from Africa, India and Burma, prove unsubstantiated.

5. Lectotypes are cited of the species Leucoptera daricella (Meyr.), Crobylophora staterias, Meyr., Crobylophora onychotis, Meyr., and these are in the British Museum (Natural History), London.
Three Sawflies attacking Guava in Brazil (Hymenoptera Symphyta)
Authors: Benson Robert B.
Published: July 2009

Representatives of three species of sawfiies attacking guava (Psidium guajava, L.)in Brazil, were recently sent for determination by Dr. Louis Pyenson, formerly head of the Entomology Section of the Instituta de Pesquisas Agronomicas, Pernambuco, Brazil.
Further Notes on the Ecology and Control of Pine Beetles in Great Britain
Authors: Hanson H. S.
Published: July 2009

The following is an account of the continuation of experiments and observations carried out in connexion with an investigation into the ecology and control of pine beetles, with special reference toMyelophilus piniperdaandM. minor.
Notes on the Distribution ofCephus Pygmaeus, Linn., and of its Parasite,Collyria calcitrator, Gray
Authors: Walker Marjory G.
Published: July 2009

The wheat crops in certain districts of England are attacked every year by the wheat-stem sawfly, which in its turn acts as host to various species of parasitic insects. The aim of the present investigation is to try to discover from an analysis of records if any sort of simple numerical relations exist within the complex including the wheat field, the sawflies which infest the wheat-stalks, and the parasites which attack the sawflies. The results of this work lead to a discussion of the peculiar difficulties involved in the application of mathematics to the study of animals and plants in their natural environments.
Determination of parous rates in Phlebotomine sandflies with special reference to Amazonian species
Authors: Lewis D. J. , Lainson R. , Shaw J. J.
Published: July 2009

Previous work on Phlebotomines has shown that most parous flies in many species may be recognised by the dark residual secretion in the accessory glands; parity can be confirmed by inspection of ovarioles. In the present study 12 species of Lutzomyia were caught in forests near Belém, Brazil, mainly with rodent-baited oil-traps. Many females of the predominant species, L. flaviscutellata (Mangabeira), were parasitised by the protozoan Monocystis. Parous rates based on examination of ovaries were subject to an error of about 5% due to diminution or disappearance of follicular relics. Two successive dilatations of the tunica were seen in L. davisi (Root), suggesting that it had laid two batches of eggs. Biting rates by parous flies varied little during the night, and were somewhat less than those of nullipars. In eight species the dark-gland rate approximated to the parous rate as shown by the ovaries; a small error may have been due to discharge of all secretion, disappearance of follicular relics and premature activity of glands. In contrast to this concordant pattern, four species showed discordance, possibly due to autogeny. It seems advisable to omit oil-trapped blood-fed flies when estimating parous rates by examining glands. Monocystis may increase the dark-gland rate, but it is non-pathogenic or has little effect on life span, and does not hinder blood-sucking.
The range of attraction of single baits for some West African mosquitoes
Authors: Gillies M. T. , Wilkes T. J.
Published: July 2009

Field experiments were conducted in the Gambia to measure the convergence of mosquitoes towards single bait-animals (calf or man) or to an equivalent source of carbon dioxide, the mosquitoes being caught in ramp-traps. Catches of unfed females of Anopheles melas Theo. fell off steeply with increasing distance up to 15 yd from animal bait; with carbon dioxide as bait, raised catches were only recorded out to 10 yd. Catches of other Anopheles spp. with calf-bait gave similar results to those for A. melas. A positive effect of the calf on densities at 15 yd was obtained for Culex tritaeniorhynchus Giles but this was less clear-cut in the case of C. thalassius Theo.; with carbon dioxide as bait, raised catches of both species were recorded at 10 yd but not at 15 yd. Both types of bait gave raised catches of the C. decens group only at 5 yd. It is concluded that A. melas and other Anopheles spp. were detecting and responding to the single animal bait from 15–20 yd, C. tritaeniorhynchus and C. thalassius from 10–20 yd, and the C. decens group from 5 yd. In all except the last named group, as also for the other Anopheles spp., on which data are lacking, the range of attraction of carbon dioxide was less than 15 yd. Olfactory cues were therefore held to be responsible for long-range orientation in these three species of mosquitoes, the effect being most marked with A. melas.
Tick infestation patterns in the southern province of Zambia
Authors: MacLeod John
Published: July 2009

The species-patterns and incidence level of ticks on the larger wild animals and on rodents were examined between 1966 and 1969 in the Southern Province, Zambia. The rodents, except for the elephant shrew, porcupine, and hare, were infrequently infested. The antelopes, except for the eland, had a mean infestation of under nine per individual, the buffalo, zebra, suids and the eland over 20. Twenty species of ticks were found on these hosts. On the ruminants Hyalomma rufipes Koch was absent, and H. truncatum Koch was the most frequent; Rhipicephalus simus Koch, R. tricuspis Dön. and R. pravus group were common. Boophilus decoloratus (Koch) was rare, R. evertsi Neum. infrequent except on zebra and lechwe, and R. appendiculatus Neum occurred on only four of the 15 ruminant species examined. Except on the elephant, Amblyomma was represented solely by A. pomposum Dön.

Periodic deticking of cattle, sheep and goats yielded precise quantitative information on the seasonal changes in incidence and species-patterns of ticks. Eighteen species were found on the domestic herbivores. On cattle B. decoloratus was usually numerous and often dominant, except where controlled by dipping or spraying. Compared with infestations on wild animals, H. rufipes was frequent, A. pomposum was replaced by A. variegatum (F.), and R. evertsi and R. appendiculatus were numerous; R. simus, R. tricuspis and the R. pravus group were usually in relatively low numbers.

The proportions of the different species on cattle varied widely between the stations and at different seasons. Intensive stocking, with resultant grazing down of the fieldlayer, increased the R. evertsi numbers markedly throughout the year, and depressed the numbers of Hyalomma sp., A. variegatum and of the less common Rhipicephalids during the dry season; except for A. variegatum, their numbers and those of R. appendiculatus rose, however, during the wet season to higher levels than on the less intensively stocked paddocks. Some evidence is presented that Barotse cattle are more heavily infested than Sindhi and Boran cattle.
The identity and pest potential of Oxycarenus spp. (Hem., Lygaeidae) in Ghana
Authors: Leston Dennis
Published: July 2009

The distribution, habitat and cultivated and wild host-plants of the four species of Oxycarenus found in Ghana are given. O. hyalinipennis (Costa), primarily a savanna species, attacks the seeds of okra, kenaf and cotton; the other species are unlikely to attain pest status. A key to the species is given.
Studies on effects of sublethal doses of p,p'DDT on oogenesis in the house-fly (Musca domestica L.) and on possible causes of abnormal oogenesis
Authors: Walker T. F.
Published: July 2009

In experiments covering many successive generations of Musca domestica L. (strains NS and WHO/SRS/MHSCO domestica/1), sublethal doses of p,p'DDT applied topically to adults or fed to larvae or adults had no effect on the numbers of abnormal follicles, but the numbers of normal follicles increased in F1–3 when larvae were fed with diet containing 10 parts per million of DDT. These results conflict with those of previous workers. Other possible causes of abnormal oogenesis were examined. Sublethal doses of o,p'DDT and DDE (an impurity and metabolite, respectively of p,p'DDT) had no effect, whereas inbreeding and high-density rearing caused the numbers of normal follicles to fall; the latter caused the numbers of abnormal follicles to increase. There were also heritable differences in oogenesis among three strains of house-fly.
A self-checking coding technique for mark-recapture studies
Authors: White E. G.
Published: July 2009

A technique is described in which twelve symbols or fewer can be chosen to code insects with individual marks suitable for mark-recapture studies. The method has been tested on Acrididae and has the advantages that (i) the code is self-checking against loss of marks, (ii) the application is practical, as only one colour is applied to a given individual, (iii) the versatility of the coding permits thousands of individuals to be distinguished, and (iv) an individual can be identified in the field from distances up to three metres without disturbance or rehandling. Guitar oil paints gave the most persistent marks, and were applied with a fine tubular-nib pen.
On the taxonomy of some African Eulophidae (Hym., Chalcidoidea) associated with oil palm, coffee and mango
Authors: Kerrich G. J.
Published: July 2009

Three species of Pediobius Walker associated with the oil palm Hispid beetle are studied. One is identified as P. coffeicola (Ferrière), comb.n. The other two are described as new, and a key separating one of them from P. nigripes (Waterston), comb.n., and P. amaurocoelus (Waterston), comb.n., is given. Two new species of Achrysocharis Girault are described, one a parasite of Dipterous leaf-miners in coffee, one reared from galls on mango.
Laboratory studies of the microsporidian Plistophora culicis (Weiser) infecting Culex pipiens fatigans Wied
Authors: Reynolds D. G.
Published: July 2009

Populations of Culex pipiens fatigans Wied. were exposed to infection by Plistophora culicis (Weiser) by allowing eggs to hatch in water containing a known concentration of spores. At 26°C–28°C (mean 27°C) exposure of newly hatched larvae to a concentration of 6 000 spores/ml resulted in a 12–9% reduction in the net reproduction rate, and exposure to a concentration of 12 000 spores/ml to a reduction of 24·0%. These reductions were due to an increase in the rate of female mortality and an increase in the number of eggs laid which were non-embryonated and hence did not hatch. At 33°C–35°C (mean 34°C), although the spores of the microsporidian were not killed, development of P. culicis in the mosquito was inhibited. At 19·5°C–20·5°C (mean 20°C), the net reproduction rate of a population exposed as newly hatched larvae to a concentration of 1 890 spores/ml was reduced by 35·6%, due to a greatly increased rate of female mortality. P. culicis, with the inocula tested, is not considered of practical use against C.p. fatigans; more infective spore inocula are not feasible with the present methods of propagating the parasite.
Recent developments in the ecology and methods of control of tsetse flies (Glossina spp.) (Dipt., Glossinidae)—a review
Authors: Jordan A. M.
Published: July 2009

The literature published during 1964–72 concerned with the ecology and control of Glossina is reviewed and put into context with previously published information. Thirty species or subspecies of Glossina are recognised. Improved methods of sampling have been developed which catch many more females of the morsitans group than other methods and allow more accurate estimates of population density and structure to be made than has been possible hitherto. New concepts of the activity and behaviour patterns of G. morsitans Westwood have been developed from work carried out both in the field and in the laboratory. Detailed studies on resting sites have been followed by successful control campaigns based on the selective use of insecticides. Most large-scale control campaigns during the period under review were based on applications of insecticides from the ground; other control methods used were aerial applications of insecticides, mechanical clearing of vegetation, selective game destruction and a small-scale project using the sterile insect release method. Techniques for identifying and assessing trypanosome infections in Glossina are described and a Table is given of infection rates in various species of tsetse. Differences in observed infection rates can result according to the time and method of sampling but actual infection rates are affected by a variety of factors including the maintenance temperature of puparia and adults, the age of the fly at the time of the infective feed, the age structure of the tsetse population and the hosts on which it feeds. Genetic differences in infectibility may occur between different individuals of a single species and certainly occur between different species.
Effect of temperature on the cereal aphids Metopolophium dirhodum (Wlk.), Rhopalosiphum padi (L.) and Macrosiphum avenue (F.) (Hem., Aphididae)
Authors: Dean G. J.
Published: July 2009

The effect of temperature within the range 10–30°C on Metopolophium dirhodum (Wlk.), Rhopalosiphum padi (L.) and Macrosiphum avenae (F.) was measured in controlled environment cabinets. Development rates increased with temperature to a maximum at 20°C for Metopolophium dirhodum, 22·5°C for Macrosiphum avenae and 25°C for R. padi, decreasing thereafter to zero by 30°C when all the nymphs died. The fourth instar and pre-reproductive adult appeared to be affected at temperatures below those for the younger instars. Mortalities of immature M. avenae were similar between 10° and 25°C, but more immature Metopolophium dirhodum died at high, and R. padi at low, temperatures. Survival rates decreased with increase of temperature, and fecundity was largest at 20°C. Rates of increase became largest at 20°C for M. dirhodum and Macrosiphum avenae and at 25°C for R. padi. Above 15°C, R. padi had a 4–16 times larger capacity for increase than the other two species because it developed faster and achieved its rate of maximum fecundity sooner.
A new procedure and counting instrument for acaricide tests
Authors: Bonin W. , Hilgner W.
Published: July 2009

After exposure for 24 h in polypropylene envelopes impregnated with the test substance, larvae of Boophilus microplus (Can.) are placed on a hot-plate (40°C) under light to stimulate movement among the survivors. The larvae are drawn one at a time into a suction bottle through a metal capillary into which is built a photo-electric cell that is actuated by each larva as it passes through. The electric impulses are transmitted to a counting device and recorded.
The Solana-group of Empoasca Walsh (Homoptera, Cicadelloidea): its generic status and a new species from pawpaw
Authors: Ghauri M. S. K.
Published: July 2009

Leafhoppers collected from dying pawpaw trees in Dominica are described as new under the name Solanasca dominica. This genus is created for the solana group of Empoasca Walsh which is characterised by the shape of the aedeagus; a key is given to the 26 species now known.
The bionomics of Entypotrachelus meyeri meyeri Kolbe and E. m. micans Hust. (Col., Curculionidae) on Tea in East Africa
Authors: Benjamin D. M. , Demba W. M.
Published: July 2009

Adults of two subspecies of Entypotrachelus meyeri Kolbe defoliate tea established on land cleared of montane rain forest, E. m. meyeri Kolbe occuring in Kenya and Tanzania to the west of the Great Rift Valley and E. m. micans Hust. only in the foothills of Mt. Kenya east of the Rift. Both subspecies are polyphagous and the host-plants are listed. Oviposition by E. m. meyeri occurs throughout the year; eggs hatch in 10–29 days, and the larvae feed on the roots of tea and various woody plants. The adults cannot fly, but field observations showed they could disperse 2–23 m in 14 days; mark-recapture data showed that 50% of the females lived 32 days, and males 37 days. The bionomics of E. m. micans were similar, but adults lived longer (50% of the females lived 55 days, males 49 days). The leaf area consumed by adults of E. m. micans was 66 mm2/day whereas the total leaf area of a seedling is 30–50 cm2, and it is shown that three adults per plant could effect defoliation in 21 days, assuming no new leaves are formed; leaf destruction at this rate is not considered economically important. Larvae of E. m. micans caused 37% rejection of tea seedlings through destruction of the tap root.
Laboratory investigations to evaluate the possible use of brood Pheromones of the leaf-cutting ant Atta cephalotes (L.) (Formicidae, Attini) as a component in an attractive bait
Authors: Robinson S. W. , Cherrett J. M.
Published: July 2009

In experiments with laboratory-maintained colonies of Atta cephalotes (L.) the responses of foraging workers to brood and brood extracts encountered outside the nest were assessed. Ants returned many of the brood to the nest from about one metre, but few from eight metres; any not returned were dumped over the edge of the foraging table. Living and dead pupae were not distinguished by the ants, but to some extent living and dead larvae were. There was some evidence that brood from their own and from other nests were also distinguished. Attempts were made to simulate brood, using extracts and homogenates on filter paper discs, but in no case did the responses suggest that brood pheromones could be used as arrestants in leaf-cutting ant baits.
Bivoltinism, survival rates and reproductive characteristics of the Scottish biting midge, Culicoides impunctatus (Diptera: Ceratopogonidae) in Scotland
Authors: Blackwell A. , Mordue (Luntz) A.J. , Young M.R. , Mordue W.
Published: July 2009

Studies on Culicoides spp. biting midges in south-west Scotland in 1991 revealed that Culicoides impunctatus Goetghebuer, the dominant species throughout the season (May-September), was bivoltine, with a generation period of six weeks. Unseasonal climatic conditions during much of June resulted in a low proportion of first generation females surviving to the parous stage and a reduction in the overall, expected size of the second generation. Distinct behavioural phases of the female midges, such as resting, dispersal and host-seeking, were shown to be directly related to parity states (determined by fat body condition and ovarian development) during the gonotrophic cycle. Female flight activity increased after laying the first, autogenous egg batch, whereas males never flew far from the emergence site. The mean parous rate formula was used to calculate the survival rate of second generation nulliparous females, which was 0.57 per gonotrophic cycle.
Developmental studies on Anagyrus mangicola (Hymenoptera: Encyrtidae), a parasitoid of the mealybug Rastrococcus invadens (Homoptera: Pseudococcidae)
Authors: Cross A.E. , Moore D.
Published: July 2009

Anagyrus mangicola Noyes, a primary parasitoid of the mealybug Rastrococcus invadens Williams, a pest of fruit crops in West Africa, was studied under controlled conditions at 27°C and 75% r.h. Data are given on the larval stages, their morphology and duration of immature development. The sex ratios of emerging parasitoids, adult longevity, host stage preference, the relationship of the size of the emerging parasitoid to host stage and development time are also investigated.
Activity rhythms of tsetse flies (Glossina spp.) (Diptera: Glossinidae) at low and high temperatures in nature
Authors: Hargrove J.W. , Brady John
Published: July 2009

Glossina morsitans morsitans Westwood and G. pallidipes Austen were caught hourly on electric nets from dawn to dusk in the Zambesi Valley, Zimbabwe, in cold and hot weather. When middle of the day temperatures reached only 24°C, activity of G. morsitans was at a low level from dawn to early afternoon but then rose to a dusk peak (most marked in males); G. pallidipes behaved similarly, but showed almost no activity before noon. When dawn temperatures rose above ca. 24°C (and afternoon temperatures above 38°C) the evening peak disappeared, to be replaced by a peak at dawn (and with almost no activity occurring through the rest of the day). This reversal of the more usual field activity pattern of late afternoon maxima reveals that the positive correlation between activity level and temperature at dusk (Brady & Crump, 1978) breaks down above ca. 33°C, although the earlier conclusion that the typical U-shaped activity pattern of tsetse flies is mainly driven by endogenous timing is still valid for moderate temperatures.
Prey choice and substitution in Chilocorus spp. (Coleoptera: Coccinellidae)
Authors: Hattingh Vaughan , Samways Michael J.
Published: July 2009

Choice between prey species by Chilocorus nigritus (Fabricius) and C. bipustulatus (Linnaeus) adults and larvae was determined. Strong preferences were absent and differences in the predators' feeding histories, were not reflected in their choices. The deleterious effects of a prey substitution, during larval development and adult maintenance, were investigated using C. nigritus with supplementary work on C. bipustulatus. These diet changes significantly retarded larval development rate, and subsequent adults were smaller than control individuals. Prey substitutions in the adult diet, suppressed oviposition for several days and feeding rate was reduced at one day after substitution. Larvae were more sensitive than adults to such diet changes. This was not a case of classical unsuitability of the new prey, as the fecundity and feeding rate returned to the same levels as before the substitution after a few days of exposure to the new prey. Furthermore, both prey types were suitable for larval development of C. nigritus when they fed on one exclusively, but unsuitable when substitutions were made. The effects of prey substitutions may possibly be attributed to the presence, in the new prey, of plant toxins, which the predators are initially not physiologically capable of dealing with in large quantities. These results present difficulties for the concepts of monophagy and polyphagy, being less well defined than normally thought. In view of coc-cinellid foraging behaviour and larval habitat selection by adults, the temporary reduction in fitness following a diet change is considered to be adaptive.
Effects of temperature and photoperiod on development and pre-reproductive period of the silver Y mothAutographa gamma(Lepidoptera: Noctuidae)
Authors: Hill J.K. , Gatehouse A.G.
Published: July 2009

Adults ofAutographa gamma(Linnaeus) make regular, seasonal migrations into areas where they are unable to breed continuously. Individuals migrate into Britain each spring, and after one, two or three generations, offspring of the spring migrants return to over-wintering areas in North Africa and the Middle East. The larvae are highly polyphagous and have been recorded damaging many crops, especiallyBrassicaspp. Insects usually migrate during the adults' pre-reproductive period (PRP). The length of this period is therefore an index of migratory potential since individuals with longer PRPs have more time to express their capacity for flight and to travel further. Individuals reared outside in Britain in autumn have longer PRPs than individuals reared outside in summer. Laboratory experiments show that PRPs are extended at low temperatures and under short photoperiods and there is some evidence that PRPs are also extended under gradually decreasing photoperiods. By extending PRPs in response to environmental conditions typical of Britain in autumn, individuals are able to increase their potential for pre-reproductive migratory flight and therefore their potential for reaching suitable overwintering sites further south.
Oviposition patterns and the supplementary role of a seed-feeding weevil, Rhyssomatus marginatus (Coleoptera: Curculionidae), in the biological control of a perennial leguminous weed, Sesbania punicea
Authors: Hoffmann J.H. , Moran V.C.
Published: July 2009

A seed-feeding curculionid, Rhyssomatus marginatus Fåhraeus, was introduced into South Africa for biological control of a perennial leguminous weed, Sesbania punicea, from South America. R. marginatus has become established even though its larval food source, seeds in ripening pods, is severely depleted by another biological control agent, an apionid, Trichapion lativentre (Beguin Billecocq), which destroys nearly all the flower-buds produced by the plants and reduces seed-set by 98% on average. In spite of this indirect competition, R. marginatus destroys up to 88% of the remaining seeds that develop on S. punicea, regardless of host plant location. Detrimental intraspecific interactions between larvae of R. marginatus are minimized, and the utilization of a depleted food source is optimized, through meticulous selection of oviposition sites by the female weevils. Although numerically inferior, R. marginatus is an important supplementary agent to T. lativentre and together the two species of weevils have almost arrested the reproductive potential of S. punicea.
Trypanosome infection rates in tsetse flies (Diptera: Glossinidae) and cattle during tsetse control operations in the Kagera River region of Rwanda
Authors: Mihok Steve , Otieno Leonard H. , Tarimo Christopher S.
Published: July 2009

Trypanosome infections were monitored in three species of tsetse fly (Glossina pallidipes Austen, G. morsitans centralis Machado, and G. brevipalpis News-tead) at four locations in the Kagera River region of Rwanda from May 1989 to September 1990. Two of the four areas (Mpanga Ranch and Bukora Ranch) were subjected to tsetse fly suppression operations with odour-baited traps. Proboscis infections of the Trypanosoma congolense and T. vivax types accounted for roughly equal numbers of the 207 mature infections detected (3.8%). Variation in infection rates was area-specific rather than tsetse species-specific. Order of magnitude differences in tsetse fly densities among areas were not correlated with differences in infection rates at the start of tsetse fly suppression operations. Similarly, declines in population density on both control and experimental areas were not associated with significant changes in infection rates. The prevalence of trypanosomiasis in cattle at Bukora Ranch was not affected by a roughly 90% reduction in Glossina densities. T. congolense accounted for 79% of the infections at an overall prevalence rate of 5.5%. Trypanosomiasis in cattle persisted at extremely low densities of about 0.1 fly/trap/day. Treatment of cattle with diminazene aceturate (BereniR) suggested that many T. congolense parasites were drug resistant, and hence, were cycling among cattle due to the few Glossina present.
Variation between biotype E clones ofSchizaphis graminum(Homoptera: Aphididae)
Authors: Shufran Kevin A. , Margolies David C. , Black William C.
Published: July 2009

Phenotypic and genotypic variation was investigated between biotype E clones of the greenbug,Schizaphis graminum(Rondani).S. graminumwas collected from wheat and sorghum fields in seven Kansas counties, USA. Colonies representing single maternal lineages (clones) were initiated and maintained in an insectary, and were verified as biotype E. An allozyme survey among clones did not detect any polymorphism at 24 enzymatic loci. We were unable to detect interclonal variation for nymphal survivorship, age at first reproduction, fecundity, and reproductive lifespan. Variation among genetically homogeneous daughters within clones was as great as variation among different clones for the above parameters, due to microenvironmental effects. However, by using the intergenic spacer in the rDNA cistron as a molecular fingerprinting tool, we identified 56 unique maternal lineages among 61 clones tested. The length of the intergenic spacer varied within individualS. graminum, and different maternal lineages had unique sets of spacer sizes. However,S. graminumwithin a single clone shared the same sets of spacer sizes. Extensive molecular genetic variation was found among biotype E clones, despite a lack of variation in additive genetic traits. Thus, biotype E populations are made up of many genetically distinct clones and do not represent an asexual proliferation of one or a few maternal lineages.
Odour-baited targets to control New World screwworm, Cochliomyia hominivorax (Diptera: Calliphoridae): a preliminary study
Authors: Torr Stephen J. , Hall Martin J.R.
Published: July 2009

Biconical, F3, and wind oriented (WOT) traps, and black cloth targets, baited with the odour attractant swormlure-4, were assessed as catching and killing devices for the New World screwworm fly, Cochliomyia hominivorax (Coquerel), in Mexico. Among the traps, the WOT was significantly better than the others, with a mean catch 2.7 and 86.4 times better than those of the biconical and F3, respectively. Release of swormlure-4 could be reduced from the standard 10 ml'day to 2 ml'day without a reduction in the numbers caught in a WOT. Use of electric nets demonstrated that a large visual target was not necessary for the precise location of a swormlure-4 source by C. hominivorax. Target colour was important with respect to the landing response on targets: in a two-choice situation, flies landed much more frequently on black than on blue or yellow, and more on these two colours than they did on white. C. hominivorax tend not to circle a target before landing on it: about 75% of the flies caught on a combination of electrified black target plus electric flanking net were caught on the target. The potential for use of insecticide-impregnated cloth targets in suppression of adult C. hominivorax is discussed.
Survival and infection probabilities of anthropophagic anophelines from an area of high prevalence of Plasmodium falciparum in humans
Authors: Charlwood J.D. , Smith T. , Billingsley P.F. , Takken W. , Lyimo E.O.K. , Meuwissen J.H.E.T.
Published: July 2009

Delayed and immediate oocyst rates; parous rates and sporozoite rates were obtained in Anopheles gambiae Giles, A. arabiensis Patten and A. funestus Giles from two villages in the Kilombero Valley, southern Tanzania during the wet season of 1991. Collection methods included light trap, indoor resting collection and nets with holes cut in their side. Mosquito survival estimates from parous rates obtained from light trap collections, were compared with estimates from capture–recapture experiments and from that obtained during a population decline. Methods of estimating the proportion of feeds infectious to mosquitoes, K, were also compared. This proportion varied between villages and species and was highest in the village with the greatest proportion of A. gambiae. We propose that absolute estimates of K should be obtained by determining the immediate oocyst rate and measuring the parous rate using the same host seeking mosquitoes. This estimate was only available from one village and ranged from 1.9% for A. gambiae s.l. to 3.4% for A. funestus.
The effect of bednets on unprotected people: open-air studies in an Afghan refugee village
Authors: Hewitt S. , Ford E. , Urhaman H. , Muhammad N. , Rowland M.
Published: July 2009

The possibility that mosquitoes are diverted from protected people sleeping outdoors in a bednet to an unprotected person immediately adjacent was investigated during field trials conducted in an Afghan refugee village. The presence of an untreated bednet covering three people sleeping adjacent to the subject did not cause a significant rise in the biting rate on that subject. At the dose rates studied, biting rates in the presence of an ImperatorR treated bednet fell slightly (although not significantly). K-OthrineR treated bednets had no discernible effect on biting rates. Similar studies conducted within giant net traps showed that the ImperatorR treated bednet, and to a lesser extent the K-OthrineR treated bednet, did repel mosquitoes. Within these net traps, biting on the unprotected subject decreased considerably in the presence of the imperatorR treated bednets (P < 0.05 for both culicines and Anopheles stephensi Liston in the presence of the ImperatorR treated bednet). The net traps held in volatile components from the treated bednets in much the same way as the walls of a well ventilated room. We conclude that while sleeping next to a treated bednet may be of considerable benefit inside, where one sleeps in relation to a bednet outside is of little importance. Further studies revealed that for each mosquito species, insecticide induced mortality was highest when the bednet contained the preferred host of that species. This suggests that selection for pyrethroid resistance by bednets may be relatively slow to develop in areas where the primary vectors of malaria are zoophilic.
Jumping plantlice (Hemiptera: Psylloidea) attacking avocado pear trees,Persea americana, in the New World, with a review of Lauraceae-feeding among psylloids
Authors: Hollis D. , Martin J.H.
Published: July 2009

Four species of the psylloid genusTriozadamagePersea americanain Central and South America; two of these species,T. aguacateandT. godoyaeare described as new; an identification key is provided for the sixTriozaspecies known to develop onPerseaspecies in the New World. A review is given of the psylloid species associated with the plant family Lauraceae.
Seasonal trends in the rate of population increase of Frankliniella occidentalis (Thysanoptera: Thripidae) on cucumber
Authors: Jarošík V. , Koliáš M. , Lapchin L. , Rochat J. , Dixon A.F.G.
Published: July 2009

The developmental rate of Frankliniella occidentalis (Pergande) was determined on cucumber Cucumis sativus cv. Sandra over a range of constant temperatures. The lower developmental threshold (LDT) and the sum of effective temperatures (SET) for the pre-imaginal development were 10.7°C and 231.1°C, respectively. The rate of population increase was assessed as the sum of effective temperatures above the lower developmental threshold by monitoring the numbers of thrips on individual leaves of cucumber under commercial greenhouse conditions. Population growth was characterized by an early stochastic phase, corresponding to pre-imaginal development of the first generation, and followed by an exponential phase starting with the second generation, the rate of which did not vary between plants. Throughout the exponential phase, the rate of population growth increased with time/age of plant. As significant damage to cucumber may occur during the exponential phase of population increase, the sum of effective temperatures of 231°C can be used to predict when damage is likely to start to occur.
Influence of intercropping on the abundance, distribution and parasitism of Chilo spp. (Lepidoptera: Pyralidae) eggs
Authors: Päts P. , Ekbom B. , Skovgård H.
Published: July 2009

Two of the most common and serious pests of maize and sorghum in the coastal areas of East Africa are the pyralid species, Chilo partellus (Swinhoe) and C. orichalcociliellus (Strand). Maize monocrop (with high and low plant density) and maize/cowpea mixed intercrop field experiments were conducted in Kenya to test if intercropping decreased the number of egg batches laid, altered the distribution of the egg batches and influenced egg parasitism. There was no significant difference in the number of egg batches per plant between treatments and the egg batches were randomly distributed on and among plants in most of the plots for all three treatments. There was a tendency for higher egg parasitism in the intercrop. The proportion of eggs parasitized was significantly correlated with total number of eggs per plot suggesting a positive density dependent response. It is concluded that intercropping does not affect C. partellus nor C. orichalcociliellus oviposition behaviour but egg parasitism is likely to be augmented.
Selectivity of insecticides to Encarsia pergandiella (Hymenoptera: Aphelinidae), an endoparasitoid of Bemisia argentifolii (Hemiptera: Aleyrodidae)
Authors: Stansly P.A. , Liu T.-X.
Published: July 2009

Encarsia pergandiella Howard is the most abundant parasitoid of silverleaf whitefly, Bemisia argentifolii Bellows & Perring, in south Florida vegetable fields and can contribute significantly to natural biological control of this and other whitefly species. However, quality standards, costs, and risks in commercial tomato production are high, resulting in frequent recourse to chemical control. Therefore, successful utilization of biological control could depend on compatibility of the parasitoid with selective insecticides. We tested a wide range of potentially selective insecticides, represented by a mineral oil, an insecticidal soap, a neem seed extract and synthetic and natural sugar esters, against eggs, first and third instar larvae, pupae and adults, using a pyrethroid, CaptureR (20 g bifenthrin/1 EC), for comparison. CaptureR residues on nymphs exposed to adult parasitoids reduced parasitization more than other materials tested, and were most toxic to all parasitoid stages. Mineral oil caused high mortality to immature parasitoids, and residues reduced parasitization of E. pergandiella. However, oil residues were much less toxic to adults if applied as a spray to leaf surfaces than as a dip to a leaf and especially glass surfaces. In contrast, the toxicity of CaptureR was high regardless of bioassay method. Neem extract, insecticidal soap and both sugar esters tested had little or no effect on E. pergandiella. These latter materials could be considered selective in respect to E. pergandiella and might be used to suppress B. argentifolii without decimating parasitoid populations.
Chilo partellus (Lepidoptera: Pyralidae) moth and larval response to levels of antixenosis and antibiosis in sorghum inbred lines under laboratory conditions
Authors: van den Berg J. , van der Westhuizen M.C.
Published: July 2009

Two experiments were conducted to determine Chilo partellus (Swinhoe) moth and larval response on sorghum lines differing in levels of antibiosis and antixenosis. The inbred lines were E 302, IS 2205, IS 2122 and SA 2681, all reportedly varying in levels of antibiosis and ovipositional and larval antixenosis to C. partellus. Ovipositional antixenosis was evaluated in choice tests under cage conditions and significant differences were observed in the average number of egg batches per line. E 302 received the greatest number of egg batches. Antibiosis and larval antixenosis was evaluated with artificial infestation in a greenhouse. Significant differences occurred in larval numbers and mean larval mass on different lines, with E 302 possessing the greatest level of antibiosis resistance. This study indicates that resistant genotypes such as E 302 may exhibit high levels of antibiosis or larval antixenosis, but may also be preferred for oviposition. The size of egg batches was not influenced by ovipositional antixenosis. The potential effect of ovipositional antixenosis mechanisms on pest populations under field conditions is discussed.
Off-target effects of ivermectin on insects and on dung degradation in southern Alberta, Canada
Authors: Floate K.D.
Published: July 2009

Insect activity was significantly reduced in dung from cattle treated with a recommended topical dose (500 μg/kg) of the endectocide, ivermectin. Reductions affected an ecologically and taxonomically diverse group of insects including coprophagous flies, parasitic wasps, and both predacious and coprophagous beetles. Whereas some species appeared unaffected by faecal residues, the emergence of other species was reduced in dung voided ≤ 12 weeks post-application. The species most affected were the flies, Sepsis sp. and Coproica mitchelli (Malloch). eucoilid wasps. and the beetles, Cercyon quisquilius (Linnaeus) and C. pygmaeus (Illiger). Results were consistent within and between years. Similar reductions have been reported previously, but typically for a much shorter post-application period. The greater duration of effect observed in the current study is attributed to a more accurate bioassay, species-level identifications, and the use of sample sizes generally larger than those used in previous studies. Reduced insect activity was associated with slower dung pat degradation. When ivermectin was added directly to dung, at levels previously reported to occur in dung from treated cattle, the treated dung had not appreciably degraded after 340 days in the field. In contrast, untreated dung pats deposited at the same time and place had largely degraded after 80 days in the field. The effect of ivermectin use on pasture quality is probably ‘moot’ in southern Alberta because of the current pattern of use. Should this pattern change, however, results of the present study validate the need for future studies to assess the off-target effects of ivermectin use on pasture quality.
The magnitude of site and time interaction effect in tsetse fly (Diptera: Glossinidae) trap catches
Authors: Odulaja A. , Mihok S. , Abu-Zinid I.M.
Published: July 2009

Site and time effects are important factors determining trap catches of tsetse flies. These factors may interact significantly and therefore confound interpretation of time series data used for population monitoring. We therefore investigated the magnitude and importance of site × time interactions in trap catches of Glossina pallidipes Austen and G. longipennis Corti using a 2200 trap-days (400 trap-months) data set. The interaction was found to be siginificant (p<0.05) in 46–100% of the combinations of different numbers of months and sites between 2 and 12. The mean percent variance due to the interaction ranged between 4% and 28% for G. pallidipes and 12% and 36% for G.longipennis. The interaction was usually less important than the effect of site alone but more important than the effect of time alone. These results suggest that tsetse researchers should examine critically the adequacy of existing approaches to population monitoring with traps and to testing new traps and odour baits.
Estimates of population density and dispersal in the blowflyLucilia sericata(Diptera: Calliphoridae)
Authors: Smith K.E. , Wall R.
Published: July 2009

To investigate the population density and dispersal of the sheep blowflyLucilia sericata(Meigen) mark-release-recapture trials were carried out in lowland pastures in south west England. In three trials, 2142, 1351 and 451 fluorescent dust marked flies were released of which 4%, 14% and 10% were recaptured using a grid of sticky, odour-baited targets, placed between 8 m and 1000 m from the release point. There was no significant effect of wind direction on dispersal pattern and no apparent directional movement of the flies from the release point. Using the method described by Hawkes (1972) the mean distance travelled by all the flies on the first day of each of the three trials was calculated to be 108 m, 128 m and 137 m respectively. Using the method described by Fletcher (1974) the mean distances travelled were calculated to be 135 m (±42), 118 m (±27) and 183 m (± 61) on the first day of each of the three trials, respectively. The median distances travelled by the flies on the first day of each of the three trials were calculated to be 109 m, 130 m and 150 m, respectively. A Lincoln Index was used to estimate the population density of wild femaleL. sericata.The number of female flies was estimated to be zero in June, approximately one per hectare in July and six per hectare in August in 1994.
Influence of the host plant of the cassava mealybugPhenacoccus manihoti(Hemiptera: Pseudococcidae) on biological characteristics of its parasitoidApoanagyrus lopezi(Hymenoptera: Encyrtidae)
Authors: Souissi R. , Le Rü B.
Published: July 2009

The influence of the host plant of the cassava mealybug,Phenacoccus manihotiMatile Ferrero on the encyrtid parasitoidApoanagyrus lopeziDe Santis was studied in the laboratory. Four different host plants were used: two cultivars of cassava,Manihot esculenta(Euphorbiaceae), cv. Incoza and cv. MM79; Faux caoutchouc, a hybrid ofM. esculenta × M glaziovii;and talinumTalinum triangularae(Portulacaceae), a common weed in cassava fields. Plants were selected for different levels of antibiotic resistance toP. manihoti. Mealybug mortality due to host feeding by the adult parasitoid and the percentage of mealybugs parasitized were significantly lower when mealybugs were reared on theManihotcultivars and hybrid than when reared on talinum. However, the encapsulation rate was significantly lower inP. manihotireared on talinum. The highest percentage parasitism and the lowest rate of emergence were recorded on cv. Incoza, the most resistantManihotcultivar. The sex ratio did not vary significantly with the host plant used. The total developmental time and size of male and female progeny ofA. lopezidiffered significantly betweenP. manihotireared on different host plants. AmongManihotplants, parasitoid size was positively correlated with development time and negatively with plant resistance. Results suggest that the parasitoid,A. lopezi, might perform better if cassava cultivars were selected for their strong antixenosis but low antibiotic characteristics.