bluuebunny/crossref_metadata_2025 huggingface dataset:
Accumulated temperatures for predicting the time of emergence in the spring of the cabbage root fly,Delia radicum(L.) (Diptera: Anthomyiidae)
Authors: Collier Rosemary H. , Finch S.
Published: July 2009

Laboratory experiments showed that 4°C, rather than 6°C as used previously by most authors, was a suitable base temperature for calculating the number of day-degrees C required to predict the time of emergence in the spring ofDelia radicum(L.); 1 February was an appropriate date to start the accumulation, as more than 50% of the pupae had completed diapause by this time and were therefore able to proceed with their development.The time of 50% fly emergence in the spring was estimated more accurately from accumulated day-degrees 6 cm deep in the soil, the average depth of overwintering puparia, than from accumulated air day-degrees calculated from standard meteorological measurements of air temperature. At Wellesbourne, England, approximately 179 ± 8 soil day-degrees above 4°C or 230± 10 air day-degrees above 4°C were required for 50% emergence in the spring. In general, males emerged 25–50 day-degrees above 4°C (4–8 days) before females. A further 60–170 day-degrees above 4°(2–5 weeks) then elapsed before maximum fly activity occurred in new host crops.
Persistent populations of males of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae), in Malawi
Authors: Nyirenda G. K. C.
Published: July 2009

Regular catches of males of Spodoptera exempta (Walker) were made in 41 pheromone disc traps scattered throughout Malawi in 1978–82. Each trap had a vial, replaced monthly, containing 2 mg of a 13·3:1 mixture of two sex-pheromone components of the female. Over the five-year period, males were caught every month at a majority of sites throughout the country, suggesting that they came from populations resident in Malawi. Sites at which moths were regularly caught had areas with green grass throughout the year which could have sustained larvae within their vicinity. A few sites at which moths were caught only occasionally had very dry immediate surroundings in the dry season, and it is suggested that moths caught at these sites are primarily migrants from either within or outside Malawi. There was no obvious relationship between site elevation, monthly rainfall and monthly moth catches or whether moths were caught persistently or irregularly. The results strongly suggest that some of the moths captured throughout the year in Malawi developed locally while some originate in other countries such as Mozambique.
Factors affecting infestation by larvae of Phyllophaga spp. (Coleoptera: Scarabaeidae) in Costa Rica
Authors: King A. B. S.
Published: July 2009

Observations were made on the behaviour of some Costa Rican species of Phyllophaga. Studies of oviposition and early larval survival under controlled conditions indicated that P. menetriesii (Blanchard) laid most eggs under a ground cover containing grasses and that the presence of living roots in the soil was important to the survival of the young larvae of the two most common species, P. menetriesii and P. vicina (Moser). At Turrialba, Costa Rica, the destruction of young maize plants by larvae of these two species and the consequent reduction in yield were significantly greater in land which was weedy or in close association with stands of old cassava plants, than where weeds had been effectively controlled and cassava was absent. Both plant loss and yields of maize were significantly correlated with larval densities. The best correlations were with numbers of second- and third-instar larvae sampled in July and with the total numbers of third-instar larvae sampled. Regression analyses established that 4·45 seedlings, or approximately 170 kg dry grain/ha, were lost per larva per square metre sampled during the seedling stage in July. An expression to calculate the economic threshold was determined. Significantly more larvae of P. vicina were found in maize growing on ridged than on unridged land, and where applications of lime and phosphate fertilizer had been made to an acid soil. The significance of weed control on infestation is discussed.
The whitefly genus Dialeurolonga (Hemiptera: Aleyrodidae) on citrus, with the redescription of a Malagasian species
Authors: Martin J. H.
Published: July 2009

Following the emergence of Dialeurolonga simplex Takahashi as a pest of citrus in Mauritius, the species is redescribed and illustrated. A key is presented to the three species of Dialeurolonga known to colonize Citrus species worldwide.
Blood-feeding and resting behaviour in theAnopheles punctulatusDönitz complex (Diptera: Culicidae) from coastal Papua New Guinea
Authors: Charlwood J. D , Dagoro H. , Paru R.
Published: July 2009

Samples of engorged outdoor-resting females of the complex ofAnopheles punctulatusDönitz, primarilyA. farautiLaveran, were obtained from villages in Madang Province, Papua New Guinea, in 1981–83 and their blood-meal sources identified. The proportion of the population feeding on man varied considerably from village to village according to the number of animals, particularly pigs, available as alternative hosts. Using a unique host in a mark–release–recapture experiment, the distance flown by engorged females ofA. farautiwas found to be generally less than 50 m. In one village, the gonotrophic age of a subsample of 1523 females ofA. farautiwas obtained and in 503 of these the electrophoretic pattern of the enzyme phosphoglucomutase (PGM) determined. Tests of association were per formed on the data. However, no significant relationship was found between host source, gonotrophic age and allelic type of PGM. Thus, separate subpopulations ofA. farautiwere not identified within this village. The relevance of the results to the epidemiology of malaria is discussed.
Studies of elemental composition as a biological marker in insects. III. Comparison of apterous and alate cereal aphids, especially Rhopalosiphum padi (L.) (Hemiptera: Aphididae), from oats and wheat, and from oats infected with or free from barley yellow dwarf virus
Authors: Bowden J. , Sherlock P. L. , Digby P. G. N.
Published: July 2009

Energy dispersive X-ray spectrometry was used to make quantitative determinations of the elemental composition of plasma-ashed apterous and alate individuals of Metopolophium dirhodum (Walker) and Rhopalosiphum padi (L.). Both morphs of M. dirhodum were reared on wheat grown in potting compost as were the morphs of R. padi but the latter were reared also on oats, free from or infected with barley yellow dwarf virus (BYDV), grown in potting compost. The data were statistically analysed by various multivariate methods, which demonstrated that alatae of both species were more readily separated by their chemoprints than were apterae. There were also clear differences, again in both species, between the two morphs from wheat and the two from oats; the main discriminant elements for R. padi were Fe, Al and Mn, and for M. dirhodum they were Cl, Ca and Al. Alatae of R. padi from healthy and BYDV-infected oats were clearly differentiated from each other and from their apterae; both groups of apterae could also be separated but not as distinctly as the alatae. The discriminant elements for these separations were Fe, Zn and Mn, and possibly Al. The differences between alates, and between alates and apterae, may reflect fundamental differences in homeostatic and metabolic processes in alate and apterous morphs of R. padi.
A comparison of various traps for Glossina spp. (Glossinidae) and other Diptera
Authors: Flint S.
Published: July 2009

Several new traps were designed and tested against Glossina morsitans morsitans Westwood and G. pallidipes Austen in Zimbabwe. The best of the new traps, the F2, was three times as effective as a beta trap and ten times as effective as a biconical trap for G. pallidipes. A white biconical trap was only half as effective as an F2 trap for females of G. m. morsitans. The catch of males of G. m. morsitans was similar in all traps. The F2 trap was up to ten times as effective as a beta trap for Stomoxyinae. Catches doubled when acetone was released at 0·5 or 5·0 g/h near the traps. Catches from traps made of white cloth declined by 90% as the cloth yellowed with exposure but were restored when the cloth was painted white.
Field trials of baits to control populations of Glossina morsitans morsitans Westwood and G. pallidipes Austen (Diptera: Glossinidae)
Authors: Vale G. A. , Hargrove J. W. , Cockbill G. F. , Phelps R. J.
Published: July 2009

An island of 4·5 km2 in Lake Kariba, Zimbabwe, was stocked with cattle and infested with Glossina morsitans morsitans Westwood and G. pallidipes Austen in 1979. From February 1980 to April 1981, the tsetse populations, estimated by mark, release and recapture, increased about ten times, to contain about 3000 males of G. m. morsitans and 2000 males of G. pallidipes. From May 1981 to May 1983, six traps, with carbon dioxide and acetone as odour attractants, were used to capture 0·1–0·3% per day of the G. m. morsitans population and 1–4% per day of the G. pallidipes population. Captured flies were retained and killed, or were automatically sterilized with metepa and released. In May 1983, when the populations of G. m. morsitans and G. pallidipes had declined by about 90 and 99%, respectively, the traps were replaced by 20 targets with acetone and 1-octen-3-ol as attractants. The targets were coated with dieldrin or, later, deltamethrin and killed about 2% per day of G. m. morsitans and 5% per day of G. pallidipes. Both populations then declined rapidly, G. pallidipes disappearing in 11 weeks and G. m. morsitans in nine months. Targets offer a cheap, simple and effective means of eliminating isolated populations of tsetse.
Correct name for the species of Chilozela (Lepidoptera: Pyralidae) whose caterpillars damage cassava in South America
Authors: Becker Vitor Osmar
Published: July 2009

Chilozela trapeziana (Sepp) comb. n. is the senior name for the pyralid whose larvae damage cassava leaves in South America, and Botys jatrophalis Walker syn. n. and Phlyctaenodes bifilalis Hampson syn. n. are junior synonyms.
Tick (Acari: Ixodidae) ecological studies in Tanzania
Authors: Tatchell R. J. , Easton E.
Published: July 2009

Ticks were regularly collected from cattle along transects in Sukumaland and the Southern Highlands, Tanzania, and from locations near Tabora, Mbeya, Arusha and Dar es Salaam from 1973 to 1976. Marked seasonal variation in abundance occurred in Rhipicephalus appendiculatus Neumann in the Southern Highlands (but not in Sukumaland) and in Amblyomma variegatum (F.) near Tabora. It was possible to detect Theileria parva antibodies in cattle sera from the Southern Highlands only during the season of R. appendiculatus adult abundance. Despite this there was no evidence of enzootic instability of the disease. The results demonstrate that the behaviour and distributions of these and the other species of ticks found are not fixed and constant but vary according to a complicated interplay of factors as yet imperfectly understood, such as climate and vegetation and host density, susceptibility and grazing habits.
Evidence of persistent populations of the African armyworm, Spodoptera exempta (walker) (lepidoptera: noctuidae), in east-central Tanzania
Authors: Merrett P. J.
Published: July 2009

There is a growing body of evidence to suggest that low density populations of Spodoptera exempta (Walker) in the solitary-phase can persist during the dry season in certain localities in eastern Africa. Moths were caught in simple pheromone traps for several months after the estimated dates of emergence of larval outbreaks in central Tanzania in 1980 and from 1982 to 1984. This provided evidence for the occurrence of a shifting population between the Uluguru Mountains and the swampy coastal areas, in east-central Tanzania, for a large part of the year. Central Tanzania is an important area for the development of the first outbreaks of the season in eastern Africa and for any control strategy. It has been suggested that S. exempta fits the criteria for an r-selected species. However, the low migratory capacity of low-density populations indicates rather that the species spreads out its risks in space and time. A theoretical genetic mechanism controlling the distance flown by moths may enable the species to exhibit both migratory and non-migratory strategies. Thus both ephemeral and continously favourable habitats may be exploited.
An evaluation of a sequential aerial spraying operation against Glossina pallidipes Austen (Diptera: Glossinidae) in the Lambwe Valley of Kenya: aspects of post-spray recovery and evidence of natural population regulation
Authors: Turner D. A. , Brightwell R.
Published: July 2009

An attempt to eradicate Glossina pallidipes Austen from the Lambwe Valley of western Kenya by sequential aerial application of endosulfan aerosol spray is described. The operation was ultimately unsuccessful, even after nine sprays of relatively heavy dosages of insecticide. Survivors were present throughout after each spray, and females mated and bred between sprays. The population was reduced by over 99·9% in main habitats of thicket and woodland and by about 90% in conifer plantation. The outcome of a model of spray effectiveness suggested, however, that the final reduction in population size was the cumulative effect of only about a 90% kill per spray application. Post-spray monitoring showed that the tsetse population in thicket returned to its pre-spray level in little more than 12 months and became stabilized thereafter. Elsewhere, recovery was much slower and more variable. Evidence was found for population regulation by density-dependent emigration of flies. Calculations of population growth rate gave an instantaneous rate of increase of 0·0148/day, equivalent to a finite rate of increase of 1·568/month or a doubling time of 47 days. This permitted a 90-fold increase in population size over a ten-month period of unrestricted growth. The failure to achieve eradication is discussed in terms of certain operational shortcomings and environmental constraints which exist in the Lambwe Valley.
Influences of weather and time of day on trap catches of bush fly,Musca vetustissima Walker (Diptera: Muscidae)
Authors: Vogt W. G.
Published: July 2009

Field populations of Musca vetustissima Walker were sampled in a region of New South Wales at 2-h intervals on 35 occasions between spring 1984 and autumn 1985 using wind-oriented fly traps. Ambient temperature, solar radiation, relative humidity and wind speed explained 84·3% of the within-day deviance of total catches (both sexes combined). Temperature and solar radiation jointly explained 82·6% of this deviance (71·1 and 11·5%, respectively), indicating that the other variables, although significant, did not greatly affect trap catches. As air temperature increased, log catch rates increased non-linearly up to a maximum at 27·5°C and declined thereafter. Log catch rates increased linearly as solar radiation increased and declined linearly as relative humidity and wind speed increased. Changes in log catch rates with time of day were explained almost entirely by the four weather variables, i.e. when weather effects were removed, time of day effects were no longer significant. These weather variables also accounted for 79·9% of the between-day variation in logarithms of trap catches. Relative responses of males and females to traps differed significantly with respect to relative humidity, wind speed and time of day. Male catches tended to increase relative to female catches between 1200 h and 1800 h and also declined more slowly with increases in relative humidity and wind speed. Separate models are presented for standardization of male and female catch rates; the estimates differ from those obtained from observed sex ratios and total catch rates, but the differences are small compared to the observed day-to-day variation in catch rates.
Cold hardiness of laboratory-maintained and seasonally-collected populations of the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae)
Authors: O'Doherty Rose
Published: July 2009

The cold hardiness of Aphis fabae Scopoli was assessed by determining the ability of individual aphids to supercool. All stages of A. fabae maintained parthenogenetically at 20°C on broad bean (Vicia faba) were capable of extensive supercooling ability to below −20°C; first- and secondinstar nymphs were the most cold hardy individuals. First instars and adult apterae of A. fabae collected from natural summer populations on broad bean and sugarbeet in England showed levels of supercooling similar to that of laboratory-maintained aphids. Compared to aphids on herbaceous hosts, all those associated with the woody host, spindle (Euonymus europaeus), showed a substantially poorer ability to supercool, often to less than −15°C, both in the autumn (oviparae) and spring (fundatrices and fundatrigeniae). All samples of eggs supercooled to below −30°C, becoming fully acclimatized in mid-winter, and lost supercooling potential prior to hatching in spring. The influence of feeding on woody and herbaceous plants on the cold hardiness of A. fabae was confirmed in a series of host-plant transfer experiments in which aphids that were transferred to bean from spindle acquired good levels of supercooling and then lost over 10°C of supercooling potential when transferred back to spindle. The shift from poor (spindle-associated) to good (bean-associated) supercooling was more difficult to achieve and suggested the presence of a nucleator in the spindle sap.
Feeding patterns of mosquitoes (Diptera: Culicidae) in relation to the transmission of Ockelbo disease in sweden
Authors: Jaenson Thomas G. T. , Niklasson Bo
Published: July 2009

In the province of Hälsingland in central Sweden, mosquitoes were sampled in 1983 with rabbit-, guineapig-, hen- and dove-baited and unbaited suction traps and similarly baited net traps. Blood-meals were identified by the precipitin test. Aedes cantans (Meigen), Ae. cinereus Meigen, Ae. communis (De Geer), Ae. diantaeus Howard, Dyar & Knab, Ae. excrucians (Walker) s.l. and Ae. intrudens Dyar were mainly attracted to the mammals, and Culex pipiens pipiens L., Culiseta morsitans (Theobald) and Cs. ochroptera (Peus) mainly to the birds. Significantly larger numbers of Cx. p. pipiens and Cs. morsitans were caught in dove- than in hen-baited traps. Of all identified feeds of engorged Aedes females, 95% were from mammals and 5% from birds. Only feeds from birds were found in engorged Cs. morsitans females. Movement of engorged females between the traps was demonstrated. Some Aedes females entered baited traps shortly after having fed on cervids and/or cattle. In the study area, suspected vectors between birds of Sindbis virus, the causative agent of Ockelbo disease, are Cx. p. pipiens, Cx. torrentium Martini and Cs. ochroptera in late spring and summer and Cs. morsitans in late summer. The isolation of this virus from Cx. p. pipiens and Cs. morsitans females captured in this area supports their role as suspected primary vectors. Ae. communis and other abundant Aedes species are suspected vectors of this virus from birds to man. Ae. cinereus may be a vector of tularaemia (caused by Francisella tularensis) in this area.
Mangoma spinidorsum gen. et sp. n. (Hymenoptera: Eurytomidae) associated with mango leaf galls
Authors: Subba Rao B. R.
Published: July 2009

Mangoma spinidorsum gen. et sp. n. reared from the galls of Procontarinia matteiana Kieffer & Cecconi at Bangalore, Karnataka, India, on mango leaves is described.
An analysis of colour effects in the performance of the F2 trap against Glossina pallidipes Austen and G. morsitans morsitans Westwood (Diptera: Glossinidae)
Authors: Green C. H. , Flint S.
Published: July 2009

F2 traps of 53 different colours, selected from measurements of spectral reflectivities in the colour range visible to Glossina, were tested in a field study against G. morsitans morsitans Westwood and G. pallidipes Austen in Zimbabwe. Trap effectiveness depended mainly on reflectivity in four different wavelength bands, two of which, blue-green and red, were positively correlated with trap score; and two of which, ultraviolet and green-yellow-orange, were negatively correlated with trap score, the most important effects coming from the blue-green and green-yellow-orange bands. The ‘best’ trap material was a royal blue cotton, which reflected blue-green strongly but very little ultraviolet or green-yellow-orange. This material together with the lowest-scoring colours (green and yellow) gave results outside the range of a set of grey traps, indicating that the flies employ colour information and not intensity-contrast information alone in trap- orientated behaviour. No significant differences in colour preferences were found between sexes or species.
Interpreting ultraviolet-light and fermentation trap catches of Mythimna convecta (walker) (Lepidoptera: Noctuidae) using phenological simulation
Authors: Smith A. M. , McDonald G.
Published: July 2009

Ultraviolet-light and fermentation trap catches of adults of Mythimna convecta (Walker) in Victoria, Australia, could be related to the times of various stages of larval development in oat crops by means of a day-degree accumulation model. Mated females were more attracted to fermentation than ultraviolet-light traps, and predicted oviposition times closely coincided with fermentation trap catches. The phenological model successfully mimicked the observed larval instar development in the field. Peak moth flights occurred within three periods. The first peak period (October to mid-November) usually contained mated moths which generated larval populations in maturing oat crops; in 1983, these moths probably occurred in late August. The second (mid-November to December) contained unmated females; in 1983–84, moth flights during this period could be related to the emergence of moths from crops 70–130 km north of the trap site. The third peak period (January to February) also comprised unmated moths which had usually emerged locally and were probably emigrating.
Torymus apiomyiae sp. n. (Hymenoptera: Torymidae), a parasite of Apiomyia bergenstammi (wachtl) (Diptera: Cecidomyiidae) on pears in Yugoslavia
Authors: Bouček Z. , Mihajlović L.
Published: July 2009

A chalcidoid wasp, Torymus apiomyiae sp. n., is described from material reared in southern Yugoslavia. The host is Apiomyia bergenstammi (Wachtl), a gall midge galling young fruit-bearing twigs of pear trees, which is locally a serious pest.
Planococcine mealybugs of economic importance from the Mediterranean Basin and their distinction from a new African genus (Hemiptera: Pseudococcidae)
Authors: Cox Jennifer M. , Ben-Dov Y.
Published: July 2009

A key is provided to distinguish the three species ofPlanococcusoccurring in the Mediterranean Basin,P. citri(Risso),P. ficus(Signoret) andP. vovae(Nasonov), and their nomenclatural histories are reviewed. Notes on economic importance, host preferences, distribution and taxonomy are given for each species.Pseudococcus citrioidesFerris is synonymized withPlanococcus ficus(Signoret),Pseudococcus lindingeriBodenheimer is transferred toPlanococcoides, Pseudococcus inamabilisHambleton is synonymized withPlanococcus vovae,andAllococcusEzzat & McConnell is regarded as a subjective junior synonym ofPlanococcusFerris. A new genus,Delottococcus,is erected to contain a group of species previously placed inAllococcus.
The ecology of Aedes albopictus (Skuse) (Diptera: Culicidae) in a rubber estate in Malaysia
Authors: Sulaiman Sallehudin , Jeffery John
Published: July 2009

The ecology of Aedes albopictus (Skuse) was studied in a rubber estate near Kuala Lumpur, Malaysia, in 1982–84. The rainfall fluctuated from month to month and year to year. However, there was close correspondence between rainfall and the numbers of eggs, larvae and pupae, and females throughout the two years. The mortalities of larvae and pupae observed were 87·5% in 1983 and 73·5% in 1984. Larvae of the dytiscid Lacconectus punctipennis Zimmermann were the major predators of the mosquito larvae, and the spider Heteropoda venatoria (L.) was the main predator of the adults. A species of Coelomomyces was found infecting the ovaries and an unidentified species of neogregarine was seen in the Malpighian tubules. The presence of Dirofilaria immitis larvae in the proboscis of A. albopictus was an indication that it is a potential vector of diseases of veterinary importance in Malaysia.
Laboratory evaluation of bisazir as a practical chemosterilant for the control of tsetse, Glossina spp. (Diptera: Glossinidae)
Authors: Langley P. A. , Carlson D. A.
Published: July 2009

The sensitivity of males and females of Glossina morsitans morsitans Westwood to the vapour phase of bisazir was tested in the laboratory in a moving air stream at temperatures ranging from 12 to 20°C. Similar tests were conducted in still air in closed systems. Bisazir was used in its granular form or absorbed onto silicone rubber or cellulose fibre surfaces from solution in dichloromethane. As a crystalline solid, it lost only 5% of its weight in a moving air stream over 12 days. However, even in relatively still air, bisazir absorbed onto cellulose fibre discs lost 70% of its weight at 20°C and 80% at 30°C in 24 days. Estimations of the amounts of bisazir present on a surface by weight difference were higher than those estimated by gas chromatographic analysis. Hence, in addition to being volatile, bisazir must be regarded as somewhat unstable. Nevertheless, sufficient active ingredient remained over a long enough period for it to be considered as a practical means of sterilizing tsetse in the field. Females were found more sensitive to bisazir than males, but exposure times required to produce total sterility in both sexes did not affect survival. Exposure times of only a few minutes were sufficient to induce a significant reduction in female fecundity or male fertility at 30–35°C, temperatures which might be expected under field conditions in a device to sterilize automatically tsetse attracted to traps in the field. The degree of sterility induced was permanent, and at these short exposure times the temperature had no effect on female fecundity.
The use of odour attractants for sampling Glossina pallidipes Austen(Diptera: Glossinidae) at Nguruman, Kenya
Authors: Dransfield R. D. , Brightwell R. , Chaudhury M. F. , Golder T. K. , Tarimo S. A. R.
Published: July 2009

Various ketones and 1-octen-3-ol were used as odour attractants with biconical traps at Nguruman, south-western Kenya, to assess their effects on the catch size and composition of Glossina pallidipes Austen. Acetone, methyl ethyl ketone and 1-octen-3-ol were found to be effective in increasing catch size by up to 2–4×, but the two ketones differed in their dose-response curves. Acetone was more effective for males than females, as was 1-octen-3-ol. The age composition of samples from baited and unbaited traps differed only slightly. The level of variability between traps was reduced by the use of odour. Acetone with cow urine produced increases in catch of 9–25×, and significant differences were found between samples in sex ratio and age composition. The index of increase for cow urine plus acetone, when used with a biconical trap, was correlated with temperature changes during the day. This could only be partially accounted for by variability in dose rates. Cow urine with acetone is considered to be a potentially useful combination of baits for community participation tsetse control schemes.
Studies of elemental composition as a biological marker in insects. V. The elemental composition of Rhopalosiphum padi (L.) (Hemiptera: Aphididae) from Prunus padus at different localities
Authors: Sherlock P. L. , Bowden J. , Digby P. G. N.
Published: July 2009

Energy dispersive X-ray spectrometry was used to make quantitative determinations of the elemental composition of plasma-ashed apterous and alate individuals of Rhopalosiphum padi (L.). The aphids were collected as fundatrigenae at various localities in England and Scotland, mostly from their main overwintering host, Prunus padus, but at one site also from P. virginiana. Robust-means principal components analysis of the data confirmed that there were differences, unrelated to source, between the elemental composition of apterae and alatae, with lower concentrations of S, K and Cl in the alatae. There were, however, no clear separations of sources in either morph except between some extreme groups; it is possible that genetic uniformity limits variation in elemental composition and, therefore, the existence of detectable source-related chemoprints in R. padi. Elements that provided some discrimination were S, Cl, Ca, Zn and possibly Al, and, except for S, their mean concentrations were all less than 1% of weight of the sample examined; difficulties in detecting differences at these low concentrations may have prevented detection of source-related chemoprints in R. padi.
Seasonal abundance of fleas (Siphonaptera) on grassland rodents in Lake Nakuru National Park, Kenya, and potential for plague transmission
Authors: Schwan Tom G.
Published: July 2009

Seasonal abundance of fleas infesting small mammals was studied from July 1975 to August 1976 in a grassland in Lake Nakuru National Park, Kenya. Ten species of rodents and two species of shrews were live-trapped 935 times. The Nile grass rat (Arvicanthis niloticus) was the most abundant species, with 233 individuals captured 690 times, forming 73·8% of all captures. From these grass rats, 4247 fleas were collected, including Dinopsyllus lypusus Jordan & Rothschild (n = 2596), Xenopsylla bantorum Jordan (n = 1396) and Ctenophthalmus calceatus cabirus Jordan & Rothschild (n = 255). D. lypusus and C. calceatus cabirus were more abundant on Nile grass rats during the rains, while ×. bantorum became more abundant during the dry season and peaked during the early part of the rains. The potential for plague transmission by fleas between Nile grass rats probably exists all year. The potential for transmission to people living in close proximity to these rodents may be highest during the seasonal peak of X. bantorum, at the end of the dry season.
Spatial distribution of Scirtothrips aurantii Faure (Thysanoptera: Thripidae) and threshold level for one per cent. damage on citrus fruit based on trapping with fluorescent yellow sticky traps
Authors: Samways M. J.
Published: July 2009

The citrus pest Scirtothrips aurantii Faure shows a positive phototactic response to yellow surfaces, particularly fluorescent yellow with peak reflectance at about 525 nm. A fluorescent yellow sticky trap was devised. Impact of individuals on the trap surface was principally random. Taylor's power law gave a generalized value of 1·42 for slope of b. Widespread geographical locations gave similar values for biologically significant values of b. Habitat differences within one geographical area influenced b, which was highest in natural vegetation and lowest in certain citrus monocultures. Three traps per orchard (>5000 trees) were practicable, and produced statistically realistic results. The period during which S. aurantii can damage fruit was divided into a longer risk period and a shorter, central critical period. Where S. aurantii was present on the traps at less than nine individuals per set of three traps throughout the central critical period and 20 during the late risk period, the percentage of fruit so damaged as not to be of export grade was less than 1·0. This method of monitoring was sufficiently robust to allow for some human error in reading the traps under commercial conditions, and to permit variability in placement of the traps in the orchard.
A theoretical examination of the classical theory of inheritance of insecticide resistance and the genetics of time to knockdown and dry body weight inSitophilus oryzae(L.) (Coleoptera: Curculionidae)
Authors: Holloway Graham J.
Published: July 2009

With the decline in production of new insecticides, the development of resistance is likely to become more of a problem than at present. Models of the spread of resistance genes may become integral parts of many management programmes. A critical examination is made of the classical theory of inheritance of resistance, i.e. the spread of a single resistance- conferring allele through a population. The theoretical considerations suggest that simple Mendelian inheritance is unable always to account for the development of resistance. It is suggested that some resistance factors may be under multigenic control and that such inheritance could account for the rate at which resistance sometimes develops. Following on from the theory, an analysis was made of time to knockdown and dry body weight inSitophilus oryzae(L.). A half-sib experimental design was employed which enabled quantitative analyses of the characters to be made. Both characters had substantial heritabilities and were phenotypically correlated. The analysis also indicated a positive genetic correlation between the characters. The implications for the development of tolerance in the light of the genetic analysis are discussed.
The field responses of tsetse flies, Glossinaspp. (Diptera: Glossinidae), to odours of host residues
Authors: Vale G. A. , Flint S. , Hall D. R.
Published: July 2009

In Zimbabwe, the catches of Glossina pallidipes Austen and G. morsitans morsitans Westwood in traps were roughly doubled by the presence of two bushpig bedding sacks or jars containing 200 ml of urine from ox or buffalo. The main effect of these residues was to increase the trap-entering responses of tsetse once they reached the trap; in addition, the urine brought G. pallidipes to the traps. The efficacy of the residues persisted for at least two months after initial exposure, although urine on soil was ineffective after two days. Efficacies were not affected by the presence of 1-octen-3-ol, acetone or butanone as additional attractants but were lower in the presence of carbon dioxide and lower with electrified visual targets than with traps. A ten times increase in dose caused no clear increase in catches, ten jars of urine being repellent, but catches increased when the urine and sacks were used together.
The effect of seasonal changes in cattle dung on egg production by two species of dung beetles (Coleoptera: Scarabaeidae) in south-western Australia
Authors: Ridsdill-Smith T. J.
Published: July 2009

Egg production by two scarabaeine dung beetles, Onthophagus binodis (Thunberg) and Onitis alexis Klug, was measured in the laboratory in relation to seasonal changes in the characteristics of the cattle dung on which they fed. Dung was collected in two areas of south-western Australia monthly between September and May. Egg production was high on dung from green annual pasture from September to November and on green irrigated perennial pasture from December to May and low on dung from dead annual pasture from December to May. O. alexis was somewhat less affected by these seasonal changes in dung characteristics than Onthophagus binodis.
Trapping as a means of controlling tsetse, Glossina spp. (Diptera: Glossinidae): the relative merits of killing and of sterilization
Authors: Langley P. A. , Weidhaas D.
Published: July 2009

A deterministic simulation model for Glossina spp. based upon a simple life-history analysis was used to test a variety of effects designed to cause a decline in population numbers. Average daily survival values for pupae were varied to make populations grow at different rates. All age classes were then updated for all life stages each day for a 12-month period. As expected, the population remained stable when Ro = 1·0, and the population doubled in 105 days when Ro = 2·0. Sub-routines were added to test the effects of trapping 0·5 to 2·5% of the population per day and killing both sexes, sterilizing and releasing both sexes or sterilizing and releasing males only, the females not being trapped. Results suggest that killing or sterilizing both sexes is always superior to sterilizing males only and leaving the females unharmed but that this superiority is diminished when either population growth rates are low (<1·0) or trapping rates are high (>2·0% per day). As population growth rate increases or trapping rates decline, there is a proportionately greater advantage to be gained by sterilizing both sexes than by adopting either of the other two strategies. A situation is illustrated where for a trapping rate of 1% per day within a population that is doubling at close to its optimal rate (Ro = 2·0) sterilization of both sexes is the only strategy which will cause a population decline. Results are discussed in terms of development of low technology, cost-effective methods of tsetse control which are non-polluting and therefore environmentally acceptable.
A revision of the west Palaearctic pear psyllids (Hemiptera: Psyllidae)
Authors: Burckhardt D. , Hodkinson I. D.
Published: July 2009

The status and taxonomy of the west Palaearctic Pyrus-feeding psyllids are reviewed, and keys for the identification of adults and larvae are given. The species, now referred to the genus Cacopsylla, have been much confused. They are shown to comprise seven distinct species: C. pyrisuga (Förster), C. pyri (L.) (summer form pyrarboris, winter form pyri), C. pyricola (Förster) (summer form pyricola, winter form simulans), C. bidens (Šulc) (summer form vasilevi syn. n., winter form bidens), C. notata (Flor) sp. rev., C. permixta sp. n. (= simulans sensu Loginova and Gegechkori nec Förster) and C. fera (Baeva). Psylla horvathii Šulc and P. vicina Šulc are synonymized with C. pyricola; P. picta is regarded as a nomen dubium. Information is given on the host-plants and distribution of each species.
The breeding requirements of three members of the Anopheles gambiae Giles complex (Diptera: Culicidae) in the endemic malaria area of Natal, South Africa
Authors: Sueur David le , Sharp Brian L.
Published: July 2009

The breeding sites used by three species of the Anopheles gambiae Giles complex were investigated in northern Natal, South Africa. Those used by the two freshwater species, A. arabiensis Patton and A. quadriannulatus (Theobald) were similar, immature stages of both being collected from the same pool at five out of seven localities from which A. arabiensis was recorded. A. quadriannulatus was the most extensively distributed species of the complex and was found in association with A. arabiensis at only five of 49 localities. The difficulty in locating the breeding sites of A. arabiensis is a product of their low density, presumably as a result of the intra-domiciliary, residual insecticide spray programme. A. merus Dönitz larvae and pupae were recorded only in water with a salinity greater than 5 p.p.t. The pH, dissolved oxygen, pool size, turbidity, shade and association with vegetation of water bodies containing A. gambiae s.l. were also recorded and showed no difference between the three species. The importance of distinguishing between winter and summer breeding sites is discussed, as well as the need for entomological consultation prior to agricultural development in endemic malarious areas.
Models for combining methods of pest control: food-baited and pheromone-baited traps containing either insecticide or chemosterilant
Authors: Barclay Hugh J.
Published: July 2009

Four models are presented which represent the four combinations of two trap types (food-baited or pheromone-baited), each containing either insecticide or chemosterilant. These were then modelled in combination to determine which combinations might be useful for controlling arthropod pest species in which the virgin females produce sex pheromone which attracts males. The most promising results occurred in combinations involving different trap baits but the same pesticide type, i.e. where one trap contains food bait while the other contains sex pheromone, and both contain either insecticide or chemosterilant. This conforms to the principle of complementarity of control methods and at the same time avoids the interference which would occur if insecticide was used in one trap type and sterilant in the other.
Development, oviposition, host feeding and sex determination inEpidinocarsis lopezi(De Santis) (Hymenoptera: Encyrtidae)
Authors: Umeh Ethel-Doris N.
Published: July 2009

Epidinocarsis lopezi(De Santis) was found to parasitize and complete development in all developmental instars of its host,Phenacoccus manihotiMatile-Ferrero. However, parasitoid mortality was high (15·8%) when development took place in the first nymphal instar of the host. Complete development from egg to adult emergence was prolonged in smaller hosts, and developmental periods recorded were 18·8, 17·4, 16·1 and 14·9 days for the first, second, third and fourth nymphal instars, respectively. Irrespective of the age of the host parasitized (with which size is strongly correlated),E. lopezicompleted only one life-cycle during one life-cycle ofP. manihoti. Oviposition commenced within 24 h of emergence and lasted effectively for six days, during which 95% of its eggs were laid and 10·8 large hosts were killed through host feeding. Unmated females ofE. lopeziare arrhenotokous, laying only male eggs; eggs laid by mated females produced males and females in the ratio of 1:3 in favour of females.
The location of floral nectar sources by mosquitoes: an advanced bioassay for volatile plant odours and initial studies withAedes aegypti(L.) (Diptera: Culicidae)
Authors: Jepson P. C. , Healy T. P.
Published: July 2009

The development and testing of a bioassay system to evaluate the potency of floral odours as mediators of long-range floral nectar source location by mosquitoes are described. The bioassay is quantitative and behaviourally discriminating, upwind flying and landing acting as indices of behavioural activity over the 24-h light:dark cycle. In initial tests, the responses ofAedes aegypti(L.) to the flowers and floral odours of ox-eye daisy (Leucanthemum vulgare) were investigated.A. aegyptiexhibited a biphasic diel cycle of nectar-feeding behaviour and landed on modified flowers that retained either their disc or ray florets. Most significantly, the mosquitoes responded in a similar way to the odour ofL. vulgarein the absence of visual stimuli or nutritional cues. They did not respond to solvent extracts of ox-eye daisy flowers.
Differential survival of British and Mediterranean strains of Pieris rapae (L.) (Lepidoptera: Pieridae) on different brassica cultivars
Authors: Gilbert N. , Coaker T. H.
Published: July 2009

In laboratory and field trials in the UK, larvae of Pieris rapae (L.) from the UK survived better than larvae from the Mediterranean region on Brussels sprouts, broccoli and field kale. A similar difference, associated with latitude, was found in Australia. The implications of these results are discussed.
The abilities of the aphid parasitoids Aphidius ervi Haliday and A. rhopalosiphi De Stefani Perez (Hymenoptera: Braconidae) to transfer between different known host species and the implications for the use of alternative hosts in pest control strategies
Authors: Powell W. , Wright A. F.
Published: July 2009

A series of host-transfer trials using both laboratory-cultured and field-collected individuals of the aphid parasitoids Aphidius ervi Haliday and A. rhopalosiphi De Stefani Perez were done in order to clarify inconsistent results from several previous studies. A. ervi cultured on Acyrthosiphon pisum (Harris) produced very few mummies when confined with Microlophium carnosum (Buckton), whereas those cultured on M. carnosum produced as many mummies on A. pisum as they did on their original host. Mummy production was correlated with the attack rate of adult parasitoids on potential hosts. The production of mummies on M. carnosum by parasitoids reared on A. pisum was often greatly improved if their male parent had been reared on M. carnosum, suggesting that genotype strongly influences host preference. Aphidius rhopalosiphi from laboratory cultures produced significantly more mummies on Metopolophium dirhodum (Walker) than on Sitobion avenae (F.) regardless of their original host, but this preference was not shown by parasitoids from field populations. It is concluded that inadvertent selection occurs in laboratory cultures of aphid parasitoids as a result of low founder numbers, genetic drift and genetic bottlenecks and that this can strongly influence experimental results in biology and behaviour studies, which has important implications for biological control workers.
Rastrococcus spp. (Hemiptera: Pseudococcidae) and their natural enemies in India as potential biocontrol agents for R. invadens Williams
Authors: Narasimham A. U. , Chacko M. J.
Published: July 2009

Rastrococcus invadens Williams, a pest of fruit and ornamental trees in West Africa, was introduced from the Oriental Region. In 1986, a search was initiated in India for natural enemies of Rastrococcus spp. with a view to selecting potential biocontrol agents for introduction into West Africa. The results of the survey, laboratory breeding of the hosts and their natural enemies and host-specificity of the natural enemies are reported. Based on host-acceptance tests, two encyrtids, Gyranusoidea tebygi Noyes and Anagyrus sp., have been sent to UK for further screening.
Rubidium marking of the rice pests Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) for field dispersal studies
Authors: Padgham D. E. , Cook A. G. , Hutchison D.
Published: July 2009

The method and evaluation of a field application of rubidium chloride for the purpose of a mark-and-recapture experiment are described. In the Philippines, populations of the rice pests Nilaparvata lugens (Stål) and Sogatella furcifera (Horv.) were successfully marked by a foliar spray of rubidium chloride plus surfactant applied to a rice field at 1·03 g/hill. Individual insects marked with rubidium, which were easily distinguishable from unmarked individuals for at least seven weeks, were generated at this dose level, and even after one year elevated rubidium levels could be detected in pooled samples. Other phytophagous and entomophagous insects also became marked.
Decision trees to assess the risk of cereal aphid (Hemiptera: Aphididae) outbreaks in summer in England
Authors: Dewar Alan M. , Carter Nick
Published: July 2009

Recent studies on the ecology of two cereal aphid species, Sitobion avenae (F.) and Metopolophium dirhodum (Wlk.), are reviewed. The most important factors affecting their abundance were used to construct decision trees to assess the risk of outbreaks of these species in the summer in England. These factors for S. avenae were crop sowing date, the size of the autumn migration, the severity of the winter, the size of the spring migration and the incidence of natural enemies in spring and early summer. For M. dirhodum, only the last two factors were considered as it does not occur on cereals until the spring in England. These decision trees were successfully tested using field data from 1983, when no outbreaks of either species occurred due to the effects of natural enemies.