bluuebunny/crossref_metadata_2025_split huggingface dataset:
Notes on Diconocoris hewetti (Dist.) (Hemiptera: Tingidae) a pest of pepper in Sarawak (Malaysian Borneo)
Authors: Rothschild G. H. L. 
Published: July 2009

An account is given of Diconocoris hewetti (Dist.), a sporadic pest of pepper in Sarawak. Most of the observations were made during a single outbreak in 1964. The egg and the five nymphal stages are described. The life cycle is completed in about 30 days at 27 ± 1°C., 80 ± 2 per cent. R.H. and the duration of individual stages is as follows: egg, at least ten days; first instar, four days; second instar, three days; third instar, three days; fourth instar, four days; fifth instar, five days; adults in laboratory cultures lived, on average, for 27 days.Eggs are laid singly in the flowering inflorescences, and nymphs do not generally move far from their hatching sites during nymphal life. Both nymphs and adults feed on the inflorescences and infestation is particularly heavy on those spikes in which fertilisation of the flowers has ocurred but where the developing fruits do not yet exceed 1 or 2 mm. in diameter.A survey of 60 holdings in the Kuching area showed that numbers of Tingids are very low during non-outbreak periods, only 0.4 individuals per vine (adults and late nymphal instars) being obtained during the flowering season. Numbers deceased to 0.03 insects per vine during the fruiting period. In the outbreak studied, numbers per vine varied from 3 to 10, a ten- to one hundred-fold increase over the normal levels; these figures are relative estimates only as there was no satisfactory method of estimating absolute densities in the time available.It is suggested that serious outbreaks of Diconocoris may be due to exceptional prolongation of the flowering period of pepper vines in a district, due to cultural practices or climatic factors.Yield losses due to Tingids in the area studied were estimated at about 30 per cent. Diconocoris can be satisfactorily controlled with sprays of various insecticides including BHC, DDT, malathion, carbaryl (Sevin) and nicotine.
Effect of gamma-radiation on Glossina pallidipes Aust.
Authors: Dean G. J. W. , Clements S. A. 
Published: July 2009

Sufficient pupae of G. pallidipes Aust. for testing were available from the Zambezi valley only between September and early November and were of all ages. These pupae or the adult fly were exposed to gamma-radiation from a 60Co source at rates between 54 and 122 rads per min., and reproduction and mortality were studied by described procedures.Effective pupal mortality due to radiation increased, and the proportion of males among the viable emerging flies decreased, with dosage between 4,000 and 16,000 rads. Eeproduction and survival of adult males emerging from treated pupae decreased with an increase in dosage and a decrease in pupal age at the time of treatment. Irradiation of adult males within three days of emergence produced slightly lower levels of sterility and similar survivals. Complete male sterility was rarely obtained with any of the treatments, though all the females, with one exception, were sterilised from 4,000 rads upwards, but the flies were fully competitive with untreated males and reduced reproduction below expected values. Treated males were fully capable of inseminating female flies and the sperm was motile and apparently behaved normally. Dominant lethality in the males appeared to be expressed by the failure to produce pupae and in the females by the complete failure of oogenesis.
The susceptibility of sorghum to attack by the weevil Sitophilus oryzae (L.)
Authors: Davey Pauline M. 
Published: July 2009

Factors affecting the susceptibility of seeds of sorghum (Sorghum vulgare) to attack by Sitophilus oryzae (L.) were investigated in the laboratory. It was known that varieties in which a majority of the seeds have a predominantly vitreous endosperm (vitreous varieties) are less attacked than those in which the majority have a predominantly mealy endosperm (mealy varieties). A method of measuring the relative amounts of vitreous and mealy endosperm in a seed was devised, and was used to classify samples from ten varieties of sorghum that had been grown in East Africa. The varieties ranged from vitreous to mealy, and the seeds from them formed the test material.Adult weevils confined singly in tubes with seeds of either a vitreous or a mealy variety consumed more per day of the latter than of the former (about 0·2 and 0·15 mg., respectively, per mg. body-weight of weevil). When females were allowed to oviposit in seeds and the next-generation adults were counted, greater numbers were obtained from mealy than from vitreous varieties, the extreme results from a range of five being in the ratio of about 20:1. Seeds of vitreous varieties have a lower moisture-content than those of mealy ones at the same humidity, but this was not the cause of the differing numbers of adults, for the results were similar when the experiment was repeated with seeds of a vitreous and a mealy variety treated so that the moisture contents were identical. Attempts to compare the numbers of eggs laid in seeds of these two varieties gave inconclusive results; it was shown that none of the methods used was entirely reliable; in two experiments, no difference could be detected, but in a third, in which the seeds were examined by means of X-rays as well as by other means, significantly more eggs were laid in seeds of the mealy than of the vitreous variety. There was no evidence of a preference for any particular size of seed of either.The hardness of the seeds of all ten varieties was estimated by grinding equal quantities in a mill and weighing the amounts that then passed through a 60-mesh sieve. This was done twice, with seeds at 10 and 14 per cent, moisture content. The order of hardness was not appreciably affected by moisture content, and was clearly correlated with the proportion of seeds with predominantly vitreous endosperm; the more vitreous varieties had harder seeds than the more mealy ones. It is inferred that hardness of the seed is the principal factor responsible for resistance to weevil attack.
The toxicity of insecticides to larvae of the codling moth, Cydia pomonella (L.). I.—Intrinsic toxicity and persistence
Authors: Gratwick M. , Sillibourne J. M. , Tew R. P. 
Published: July 2009

The deposits found on apples at various times after application of 11 insecticides were determined by chemical analysis of samples from an orchard in south-eastern England sprayed in 1959 and 1960. The results, from samples taken simultaneously, of studies of the effectiveness of these and other chemicals for control of the codling moth, Cydia pomonella (L.), have already been reported.The period in which 50 per cent, of an initial deposit disappeared in the field (half-life) was calculated from the chemical data and used as a measure of persistence. For comparisons of intrinsic toxicity, the levels of fresh deposits causing 50 per cent, mortality of newly emerged codling-moth larvae (LD50) were determined in the laboratory by chemical and biological tests on apples dipped in a range of concentrations of commercial formulations. The LD50's, in μg./cm.2, were less than 0·025 for carbophenothion, parathion and diazinon, between 0·025 and 0·05 for azinphos-methyl and -ethyl, between 0·05 and 0·10 for malathion, DDT and carbaryl, between 0·1 and 0·5 for DDD and dimethoate, between 0·5 and 1·5 for lead arsenate and above 1·5 for phenkapton.Chemicals with an LD50 exceeding about 0·1 μg./cm.2 were considered not worth further investigation as codling-moth larvicides. The LD90's of the remainder were found and were taken as the minimum deposits that would have an adequate effect from the standpoint of control (minimum effective levels). From the half-life values, the periods for which the deposits found in the orchard in 1960 should have remained above the minimum effective levels were calculated; these were 24 days for DDT emulsion, 22 for DDT wettable powder, 15 for carbophenothion, 14 for carbaryl, 12 for azinphos-ethyl, 11 for parathion, 7 for malathion and 6 for diazinon. They were in good agreement with the results of the biological tests except in the case of DDT emulsion, the effectiveness of which was unexpectedly short-lived.
The replacement of Culex nebulosus Theo. by Culex pipiens fatigans Wied. (Diptera, Culicidae) in towns in Nigeria
Authors: Service M. W. 
Published: July 2009

An account is given of the disappearance in Kaduna, Northern Nigeria, of Culex nebulosus Theo. from the town streams and drains and other polluted collections of water, habitats in which until comparatively recently it appears to have been the dominant species, and its replacement by C. pipiens fatigans Wied., which was formerly rarely recorded in these sites. Similarly, the latter species has replaced the former as the commonest Culicine mosquito resting in houses. Increased urbanisation and the widespread use of residual organo-chlorine insecticides within recent years have both been advanced as possible explanations for this change.A laboratory experiment with larvae of C. p. fatigans from Kaduna and of C. nebulosus from villages on its perimeter showed the latter species to have a slightly, but significantly, quicker rate of larval development than C. p. fatigans; this would possibly confer an advantage on it in circumstances where the two species are in competition for the same larval habitats. Field and laboratory observations showed that both species can tolerate high organic pollution in their larval habitats. There appeared to be little evidence in Kaduna, or in other towns in Nigeria, to support the theory that urbanisation has been responsible for the replacement of C. nebulosus by C. p. fatigans. Laboratory and field trials demonstrated that larvae of C. nebulosus were extremely sensitive to DDT, and although resistance was not found in C. p. fatigans, this species showed tolerance of the insecticide. It is believed that, in Kaduna and most probably in other towns, the application of DDT as a larvicide to streams and drains has been responsible for the eradication of C. nebulosus there, and in the absence of competition from C. nebulosus and because of the greater tolerance of DDT shown by C. p. fatigans the latter has been able to establish itself as the dominant species.
Observations on four species of Sitona (Coleoptera, Curculionidae) occurring in Israel
Authors: Melamed-Madjar Venezia 
Published: July 2009

The four commonest species of Sitona injuring leguminous crops in Israel were found during a survey in 1957–62 to be S. lividipes Fhs., S. hispidulus (F.), S. crinitus (Hbst.) and S. lineatus (L.). Adults of all four were collected in the field in December-January each year, at the termination of diapause, and kept in the laboratory for observations on their bionomics. Larvae and pupae did not survive in the laboratory, and therefore these stages were reared in the soil outside (where suitable food-plants had been grown) from eggs laid by the adults in the laboratory and kept at known temperatures until they were about to hatch. The soil was later examined daily for pupae.Egg-laying began in December, larvae were found in January–March, pupae in March–April, and adults of the new generation in April–May. These adults fed freely but did not oviposit, and in June–July they sought shelter and entered diapause, which lasted until the close of the year. Feeding was then resumed, oviposition began shortly afterwards, and death occurred up to 250–300 days later.The eggs of all four species are creamy or yellowish white when laid but soon become glistening black. High humidity was necessary for hatching; no eggs of S. lividipes or S. hispidulus hatched at relative humidities of 76 per cent., or less, and virtually none of S. crinitus or S. lineatus at 56 per cent, or less. In favourable humidities, the percentage hatching was reduced at constant temperatures exceeding 25°C., except in S. lineatus, in which it was not affected up to 29°C. The threshold temperatures for development of eggs of S. lividipes, S. hispidulus, S. crinitus and S. lineatus were 4·8, 4·6, 5·8 and 6·5°C., respectively, and the thermal constants were 180, 211, 166 and 145 day-degrees C. The mean larval and (in brackets) pupal periods outdoors were 52 (23), 58 (34), 36 (25) and 38 (21) days, respectively. The average numbers of eggs laid were 843, 719, 519 and 1,113 per female, and the mean numbers laid per day were 10·2, 8·5, 9·6 and 17·5. These data were obtained by feeding adults on a variety of food-plants throughout their life in the laboratory. In another series of observations, adults were fed on the same type of food-plant throughout. Egg production of S. lividipes and S. hispidulus was greatest on clover (Trifolium alexandrinum) and least on broad bean (Vicia faba) and pea, respectively; that of S. crinitus and S. lineatus was greatest on pea and least on broad bean and clover, respectively.
A taxonomic study of the species ofAntestiopsis(Hemipteea, Pentatomidae) associated withCoffea arabicain Africa
Authors: Greathead D. J. 
Published: July 2009

The taxonomy of African species ofAntestiopsis, some of which are important pests of coffee, has hitherto been in confusion owing to the difficulty of finding decisive morphological characters. In the present study an attempt is made to clarify the relationships of the coffee pest species and some of their close allies by the use of both biological and morphological characters.The species ofAntestiaandAntestiopsisoccurring on coffee in Africa are differentiated in a key, and descriptions are given of the following:Antestiopsis orbitalis(Westw.), with three clearly distinguishable subspecies,orbitalis, bech-uana(Kirkaldy) andghesquiereiCarayon, several local colour forms of these, and a few variable populations that cannot be referred definitely to any one of the subspecies;A. intricata(Ghesq. & Carayon); A.facetoidessp.n. for the species hitherto known as “ faceta ” in eastern Kenya and Tanzania;A. crypta, sp.n. confined to Katanga;A. falsa(Schout.), a rare and imperfectly known species;A. lepelleyisp.n., which does not feed on coffee; andA. littoralissp.n., from the Kenya coast, known to the writer only from museum specimens.Evidence for the arrangement adopted is discussed, and the taxonomic value of certain morphological characters is assessed. The distributions presented on maps are discussed, and it is concluded that the activities of man are unlikely to have obscured the natural patterns. A list is given of known host-plants, which, except for those ofA. orbitalis orbitalisand formfacetus, are with only a single other exception members of the Eubiaceae. The distribution on a local scale and recent changes of abundance of species in competition are discussed, and it is shown thatA. orbitalis ghesquiereiandA. o. bechuanaappear to be spreading at the expense ofA. intricatain Uganda andA. facetoidesin Tanzania, respectively. Kesults of crossing East African species and forms show that those here regarded as species will not cross but that the subspecies ofA. orbitaliswill do so, producing intermediates that, when allowed to interbreed, are not as viable as pure strains. Finally an attempt to find morphometrical characters is discussed, and the results are given of a calculation of discriminant functions based on two characters. These, while, not conclusive, support the conclusions drawn from other evidence.
Seasonal and diurnal variations in physiological age and trypanosome infection rate of females of Glossina pallidipes Aust., G. palpalis fuscipes Newst. and G. brevipalpis Newst
Authors: Harley J. M. B. 
Published: July 2009

A series of 24-hr. catches of Glossina from bait-oxen was carried out during 16 months in 1962–63 at Lugala, Uganda, where G. pallidipes Aust., G. palpalis fuscipes Newst. and G. brevipalpis Newst. occur. Female flies were dissected to determine their physiological age and the presence or absence of trypanosomes. Five age-categories were distinguished, depending on whether a fly had ovulated 0, 1, 2, 3 or more (4 + ) times. Flies remained in each of the first four categories for about 11 days and the fifth therefore comprised those over 40–50 days old. Trypanosome infections were classified as brucei-type, vivax-iype or congolense-type (i.e., attributable to trypanosomes of the groups of Trypanosoma brucei, T. vivax and T. congolense) according to the sites in which they were found.In all three species of Glossina, vivax-tjpe infections were commonest and alone showed seasonal fluctuations in incidence. Infections of the brucei-type were rare. The total infection rate (all types) in G. pallidipes and G. palpalis fuscipes was highest in or immediately after months of greatest rainfall and relatively lower in dry months; the highest infection rates in G. brevipalpis occurred a month later than those of the other two species. Over 80 per cent, of infections in all three were found in category 4+ flies, the percentage of which in the catches varied in much the same way as the total infection rate, suggesting not only that the flies live longest during wet periods but also that fluctuations of infection rate are largely due to changes in mean age. The regression of total infection rate on percentage of category 4 + flies was significant for G. palpalis fuscipes over 14 months, and for G. pallidipes over 12 months, but insignificant for G. brevipalpis.The age-composition of catches of G. pallidipes and G. brevipalpis but not G. palpalis fuscipes varied during the day. In G. pallidipes, the percentage of older flies was higher in the middle of the day than in the early morning and late evening, and these contrasts were reflected in the infection rate, which was highest in samples taken in the middle of the day. In G. brevipalpis, the percentage of oldier flies and also the infection rate were lower during the night than during the day.Estimates were made of the mean number of bites by infected females that would be received by one ox in one day. The number varied from month to month, with peaks shortly after periods of high rainfall, mainly as a result of changes in fly density and relatively little as a result of changes in infection rate. G. pallidipes, the most numerous species, was responsible for most of the potentially infective bites.
The ecology of the swede midge, Contarinia nasturtii (Kieff.) (Diptera, Cecidomyiidae). I.—Life-history and influence of temperature and moisture on development
Authors: Readshaw J. L. 
Published: July 2009

The life-history of Contarinia nasturtii (Kieff.), a gall-forming pest of swedes, was investigated in northern England in 1958–60, particular attention being paid to the influence of temperature and moisture on development in the soil. Most of the observations were made under controlled conditions in the laboratory, although much of the material came from the field.The adults emerge from the soil, mate, and live 1–3 days. In laboratory conditions, each female developed about 95 eggs, laid in batches of 2–50 on the young leaves of the host plant, and produced 78·7±11·4 unisexual larval progeny. The eggs require moist conditions, and hatched according to temperature after 1–10 days at 30–10°C. The larvae fed for 7–21 days at 25–15°C., producing a gall.The full-grown larvae burrow into the soil. It was found that they either pupated in oval-shaped cocoons just below the surface, producing adults 10–48 days later (at 25–12°C.) or become dormant in spherical cocoons. At 32·5°C. the pupae died, and below 32·5°C. males developed faster than females by about 24 hours.Dormancy is caused either by diapause, in which case the larvae require prolonged chilling before development can be resumed, or by drought, in which case development is resumed immediately in response to wetting.The incidence of diapause increased regularly during the summer generations, probably in response to decreasing day-length, and the larvae tended to avoid diapause when placed in high temperatures (e.g., 25°C.). The firmness of diapause appeared to vary according to the conditions experienced by the feeding and full-grown larvae, but, in general, the larvae completed diapause development after 100 days at 2–5°C. followed by 30 days at 20–25°C., i.e., after exposure to conditions similar to those experienced by the diapause larvae during winter and spring.Dormancy due to drought (quiescence) affected both non-diapause and post-diapause larvae; the former became quiescent on entering dry soil (pF>3·5–4·0), and the latter remained inactive if kept in dry or even in moist soil (pF 3·4) after completing diapause. In both cases, the termination of dormancy occurred immediately in response to a thorough wetting of the soil. The larvae left their spherical cocoons, moved to the surface, re-entered the ground and pupated in oval cocoons as if entering the soil for the first time.Factors that delay pupation of C. nasturtii similarly delay the development of its Hymenopterous parasites and hence synchronise the emergence of the adult parasites with the host's feeding stage.
Species differences in scarab–pasture relationships
Authors: Davidson R.L. , Roberts R.J. 
Published: July 2009

The damage caused by the larvae of four Melolonthine and one Ruteline scarab species to four grasses and Trifolium repens grown in pots was examined for interactions between species with and without manure added to the soil. Only slight interactions between scarab species and plant species were detected in the damage to pastures, and these were caused by a differential insect response to Trifolium. Most scarabs damaged Trifolium as much as they damaged the grasses, but Anoplognathus sp. appeared to avoid Trifolium in the absence of manure. Sericesthis geminata Boisd. caused more damage to Trifolium than S. vigilans (Sharp) or Rhopaca magnicornis Blkb.The addition of manure to soil reduced to negligible proportions the damage to all pasture species except Phalaris tuberos, which suffered significantly greater reduction of foliage than other plants in the presence of manure. The highly significant alleviation of damage by manure occured with all scarab species except S. vigilans, which did not cause damage even in the absence of manure.In this short-term experiment survival and pupation were not influenced significantly by plant species or manure.
Some factors affecting eclosion ofGlossina morsitansWestw. from pupae
Authors: Dean G. J. , Wilson F. , Wortham S. 
Published: July 2009

Observations on biological variablity of pupae ofG. morsitansWestw. collected in the field, and effect on eclosion of the adult fly due to temperature, light and gamma-radiation are reported.The homogeneity of eclosion from wild pupae varied during the year owing to variations in pupal viability. Emergence was lower in the warmer months September to December than in the cooler ones, May to August, and in one season low eclosion rates were connected with a high proportion of runts, although another analysis revealed no correlation.Gamma-radiation redused eclosin by killing all pupae treated during their first ten days after larviposition. MOrtality of male pupae was increased by irradiation between the 15th and 13th day of pupal life, while eclosion was apparently normal with treatments given between the 16th and 29th day. Weight losses indicated that five- to ten-day-old pupae possibly did not die before the 30th day after larviposition while younger pupae containing fourth-instar larvae at the time of treatment were killed either immediately or by the 15th day.Diurnal emergence from wild pupae in the laboratory showed a peak during the afternoon (1400–1730 hr.) which was not affected by light or gamma-radiation. In the field, eclosion occurred primarily between 15° and 27°C. and was apparently inhibited by higher and lower temperatures. Relative humidity did not appear to be involved in the timing of emergence.