bluuebunny/crossref_metadata_2025_split huggingface dataset:
Description and Bionomics of Frankliniella insularis Franklin (Thysanoptera)
Authors: Davidson J. , Bald J. G. 
Published: July 2009

(1) Frankliniella insularis (Franklin) is found on various food-plants, including tomatos, in the Adelaide area.(2) The life-history and bionomics of the species have been investigated, particularly on tomato plants under glasshouse conditions. The various stages of the insect have been described.(3) The eggs are laid in the tissues of the tomato leaf, and the larvae feed on the leaves or in the flowers; when mature they leave the plants and pupate in the débris on the surface of the soil or penetrate into the upper layers of the soil. Sometimes they pupate on the plant in rolled leaves, depressions in the stem or other similar situations; this habit has been also observed on tomato plants growing in the open during the summer. In carnation flowers eggs were laid in the tissues of the sepals and petals.(4) The duration of the egg stage for 64 examples varied from 9–14 days when the mean daily temperature was 64·5° F. In a number of other observations it was found to vary from 3 days, when the mean temperature was 100° F., to 15 days, when the mean temperature was 63·1°F. The rate of oviposition is markedly affected by temperature: with a mean temperature of 77·5° F., one female laid an average of 3·9 eggs daily; two other females laid an average of 1·2 and 1·7 eggs daily when the mean temperature was 68·2°F.; and another female laid an average of 1·3 eggs when the mean temperature was 67·7° F. Below 60° F. the rate of oviposition is greatly retarded, but egg-laying may extend over a long period: one female continued oviposition over a period of 157 days. The largest number of eggs laid by a single female was 92 over a period of 70 days.(5) The duration of the larval stages for 32 individuals varied from 9 to 13 days when the mean temperature of the periods varied from 66·6° F. to 65·7° F. In a number of observations on other individuals at various times the period varied from 7 to 14 days when the mean temperature varied from 74·9° F. to 63·4° F.(6) The duration of the pupal stages obtained from 19 individuals varied from 7 to 14 days when the mean temperature of the periods varied from 72·8° F. to 66·7° F.(7) The complete life-cycle under glasshouse conditions occupied 36–39 days when the mean temperature of the period was about 66° F. Observations made on a number of individuals at various periods gave a variation in the period of the complete life-cycle from 13 to 41 days with mean temperatures varying from 89·5° F. to 64·1° F.(8) The chief distribution of Frankliniella insularis appears to be the region of Central America. It is common in the Adelaide area during the warmer period of the year (approximately November to April), and rare or absent during the remaining months. Its seasonal occurrence appears to be due to temperature, since it was readily reared at all periods of the year on tomato plants in the glasshouse.(9) The economic importance of the species is due to the fact that G. Samuel and J. G. Bald have shown experimentally that it can transmit the virus of spotted wilt disease of tomatos.
The Use of adhesive Agents in DDT Sprays
Authors: Barnes Sarah 
Published: July 2009

A previous investigation by the writer established that the minimum deposit of DDT on both cement and old painted wood necessary to ensure complete mortality of bed-bugs 48 hours after spraying was 0·2 mg. per sq. cm., and that the toxicity of both surfaces diminished slowly over a period of six months. The present work has shown that when DDT is applied with an adhesive agent, the minimum deposit of insecticide necessary on these surfaces to yield a similar kill at the same interval after treatment was only 0·06 mg. per sq. cm. The addition of an adhesive agent to a DDT spray thus effects considerable economy in the use of DDT. Campbell and West (1944), investigating the toxicity to houseflies of coumarine resin and DDT dissolved in white spirit, have reported an increase in the efficiency of DDT when sprayed with an adhesive agent. These authors confined their investigation to a resin only and they suggested that the coumarone resin conferred, in a manner not specified, increased insecticidal activity on the DDT. The present work has shown that relatively small doses of DDT are highly effective in the presence of at least three dissimilar adhesive agents. It is possible, therefore, that instead of increasing the activity of DDT, the agent merely blocks the minute pores of the treated surface, and by minimising absorption of the solution, increases the amount of DDT available to the insect. Alternatively, the adhesive agent may have some affinity for substances on the surface of the bug's tarsi and so assist transfer of DDT from the sprayed surface to the insect.The residual toxicity of cement treated with DDT and an adhesive agent, like that of a similar surface treated with DDT alone, diminished slowly. The toxicity of painted wood, on the other hand, treated with doses of DDT and adhesive agent ranging from 0·005 to 0·02 mg. per sq. cm., decreased within one month, irrespective of the adhesive agent used. This fall in toxicity is puzzling, particularly in view of the fact that no such decrease occurred when the surface was treated with a heavier deposit of DDT and adhesive agent, namely 0·06 mg. of each per sq. cm. This latter observation seems to preclude a possible interference with the efficiency of DDT by a slow interaction of the paint constituents and the adhesive agent.The application of these adhesive agents, even in relatively high doses, failed to prevent the removal of DDT from a smooth surface by repeated washing and rubbing; furthermore, an increase in the deposit of adhesive agent does not markedly increase the insecticidal efficiency of a given deposit of DDT.
Factors influencing the Interaction of insecticidal Mists on flying Insects
Authors: David W. A. L. , Bracey P. 
Published: July 2009

Experiments are described which illustrate some of the ways in which the results of exposing insects to a spray mist are dependent on either their behaviour or physiological state. Only fine mist dispersals with particles below 10 microns in diameter are considered and in such mists the flight movements of the insects are very largely responsible for the collisions between the insect and the droplets. An increase in flight activity leads to the accumulation of a greater number of spray droplets and consequently a higher kill. Under these conditions insecticides such as pyrethrins which exert a strong irritating action on Aëdes in minimal amounts are superior to DDT which does not have this effect. For practical applications under circumstances where the sprays depend on mist action to produce their effect it is advantageous to mix pyrethrum with the DDT sprays so that the maximum dose of the latter may be accumulated.Further experiments are concerned with the relative resistance of male and female Aëdes aegypti to insecticides and the change of resistance which takes place on ageing or as a result of a blood meal. It is shown that the male is innately more susceptible to both pyrethrins and DDT and that the resistance of the females is higher after a blood meal. There is also a progressive decrease in resistance with age.
A Machine for Nicotine Fumigation of field Plots
Authors: Wilson A. R. 
Published: July 2009

The construction of an inexpensive, simple, hand-drawn fumigator for field plots is described. The general principle employed is the injection of liquid nicotine under pressure into the exhaust system of a two-stroke engine, close to the port. The liquid is vaporised by the heat of the exhaust stream and distributed by it below a drag sheet at the rear of the machine.The machine is of simple and robust construction, utilising standard plumbing fittings, angle iron, strip iron and second-hand motor-cycle parts and can, therefore, be made where only limited facilities are available.The machine is self-contained and easily transportable as it can be towed behind a car from one locality to another. It is suitable for use on a wide variety of crops since the track is variable between 43 in. and 67 in. and the clearance between 16 in. and 34 in. With the 18 ft. long sheet used it can fumigate, in good conditions, one acre in about five hours. It is pointed out that the use of a lightweight sheet about 54 ft. long would decrease the time required per acre to about if hours and would enable the machine to be drawn by a tractor if desired; these suggestions have not, however, been tried.The machine has been in use since 1941 for controlling aphis infestation in connection with work on virus yellows of sugar beet and has given most satisfactory results. Tests showed that a kill of 88–99 per cent, of Aphids was obtained.
Some Observations on the Hunger-cycle of the Tsetse-fliesGlossina swynnertoniandG. pallidipes(Diptera) in the Field
Authors: Vanderplank F. L. 
Published: July 2009

The mean hunger-cycles ofG. swynnertoniandG. pallidipeshave been studied in the field by marking tsetses with cut proboscidae, which have been released and subsequently recaptured.The length of time that hungry flies are able to survive before dying from starvation varies with the season, probably according to the amounts of reserve fats and atmospheric humidity.The mean hunger-cycle also varies with the season and correlates significantly with the evaporation rate or other measurements of humidity. The variation of temperature experienced in these experiments was not sufficient to have any appreciable effect on the hunger-cycle.G. pallidipes, a thicket haunting fly and larger thanG. swynnertoni, a thorn bush species, frequently than the latter under moist conditions, but frequently under adverse conditions.Smaller individuals probably feed more frequently than larger individuals.
Sandfly Control with DDT Residual Spray. Field Experiments in Palestine
Authors: Jacusiel F. 
Published: July 2009

Field experiments carried out in 1945 at Rosh Pina in Palestine have proved the great efficiency of DDT residual spray in houses against sandflies.A high degree of protection against P. papatasii, P. major and P. chinensis was obtained by inside spraying of rooms with DDT in kerosene.The residual action lasted for 52–58 days during the hot summer months. At the end of this period the effect was still undiminished but the end of the sandfly season made further observations impossible. Judging from observations made elsewhere it may be assumed that the residual effect would have lasted not more than another two weeks.Dosage of 1 g. per m2 (100 mg. DDT per sq. ft.) was fully effective, and 2 g. per m2 gave no better results. The best method of application is the treatment of all internal surfaces (walls and ceiling). As sandflies tend to congregate in the angle between wall and ceiling, treatment of walls and this angle only gives equally good results.An attempt to protect a house by spraying “barriers” (vertical surfaces of stone walls etc., within a radius of 50 metres) failed. Sandflies on the outside surfaces disappeared after the DDT treatment but the observations recorded here and those reported by other authors suggest that much larger areas would have to be sprayed in order to make this method effective.A marked reduction of sandflies in untreated rooms followed the spraying of other Tooms in the same house with DDT. The mechanism of this phenomenon is explained. A general reduction of the sandfly population can be expected when large-scale DDT treatment is carried out in a village or camp area.
The Mosquitoes of Bwamba County, Uganda. VI.—Mosquito breeding in Plant Axils
Authors: Haddow A. J. 
Published: July 2009

1. A study of mosquito breeding in plant axils was carried out in Bwamba County, an area with much heavy forest in the extreme west of Uganda. Attention was directed mainly to Aëdes (Stegomyia) simpsoni, a known vector of human yellow fever in Bwamba.2. The various plants studied are described.3. The results of preliminary surveys are discussed. These confirmed that, as far as mosquito breeding is concerned, the most important plants in Bwamba are the lowland colocasia (Xanthosoma sagittifolium), the “gonja” variety of cultivated banana and the pineapple (Ananas comosus). It was shown that A. simpsoni is the commonest axil-dwelling larva in the inhabited lowland areas, and that it occurs in widely different types of lowland country. Records are given of the occurrence of larvae of Aëdes (Stegomyia) aegypti in plant axils.4. A survey of 12 different kinds of plants is described, and it is shown that the larval populations depend to a considerable extent on the amounts of water retained by the axils of the various plants concerned. In Bwamba, medium-sized axils with a capacity of 4 to 8 cc. appear to be the most favourable. Certain plants which yielded large numbers of larvae—such as the wild banana (Musa sp.)—were not found to harbour A. simpsoni. Apparently this is due to the fact that they are confined to forest and mountain areas, where A. simpsoni is scarce or absent.5. A monthly survey of Xanthosoma axils, carried out over a period of 12 months, showed that A. simpsoni larvae were continually present and that the fluctuations in larval population were dependent on growth and harvesting of the plants rather than on rainfall.6. Scrapings from dry Xanthosoma axils, taken during a short period of drought, were placed in bowls of water in mosquito-proof cages. Larvae of A. simpsoni and Harpagomyia taeniarostris hatched from this material in 2 to 3 days.7. Temperature measurements in a Xanthosoma axil showed that the water therein was cooler than the surrounding air and also that the axil temperature was remarkably equable.8. Systematic collections of pupae from Xanthosoma axils showed that the mosquito output (which cannot be gauged directly from the population of larvae) is high and constant. It is estimated that a plot of 500 plants of this species may, under favourable conditions, produce something like 5,000 A. simpsoni (2,000 females) per month.The influence of predatory larvae (Eretmapodites spp.) on the populations of other species is thought to be considerable.9. The fauna of plant axils, apart from mosquito larvae, is described briefly.
Effect of Defoliation on Reproduction of Cordia macrostachya
Authors: Callan E. McC. 
Published: July 2009

The importance of finding the effect of defoliation on the reproductive capacity of Cordia macrostachya is explained in view of the proposed introduction of two species of leaf-eating beetles from Trinidad into Mauritius for the control of this weed.An account is given of experiments in which the production of inflorescences and fruits was compared in defoliated and control plants.The results show that defoliation has a significant effect in reducing the reproductive capacity of the plant.
A Method of assessing the acaricidal Properties of DDT and “Gammexane” Preparations in Field Trials
Authors: Wilson S. G. 
Published: July 2009

DDT and “Gammexane” have many advantages over arsenic as acaricidal agents.The sites of attachment of the common tick species on bovines are recorded and the killing properties of various dilutions of DDT and “Gammexane” are assessed by observations on R. appendiculatus attached on the ears and A. variegatum attached on the udder and flanks of cattle.The preparations were usually applied as sprays by means of a flit-gun, an Aerograph spray gun, and Kent sprayer or “Solo” hand pump. A “swirling-jet” nozzle was found most suitable. A possible combined spraying-dipping method using a shallow bath is also described.In preliminary experiments, a spray containing 2·5 per cent. DDT and a preparation containing 1:10 of the “Gammexane” dispersible powder P.530 killed all ticks attached at time of spraying but the residual effects were lost about the 4th day after spraying. Field experiments gave similar results, but 1:20 of the P.530 powder (0·325 per cent. active gamma) proved equal in killing value to the 1:10 preparation.The addition of coumarone resin did not increase the residual effects of a 2·5 per cent. DDT emulsified solution.
Successful Methods of trapping Trombicula (Acarina) with Notes on rearing T. deliensis, Walch
Authors: Cockings K. L. 
Published: July 2009

The parasitic larvae of a number of Trombiculid mites are of economic importance as they include the vectors of scrub typhus, and scrub-itch mites of considerable nuisance value. Methods of trapping these mites and various field and laboratory observations on them are described. The methods were evolved and observations made during the course of work, sponsored by the Medical Research Council, in Imphal, Assam and Compton, Berkshire.Live unfed larvae in the field may be concentrated and trapped by use of a low cover with a central light-admitting aperture and collecting apparatus. This method proved very efficient in trapping harvest mites (Trombicula autumnalis) in England. The rise in temperature within the trap can be made advantageous.Guineapigs were chosen as bait animals for the collection of T. autumnalis at Compton, most of the larvae attaching near the anus and genitalia. The larvae fed for between 30 and 60 hours.Engorged larvae may easily be collected as they leave their host (or dead animals and débris) by the funicular laboratory light-trap described.Observations are made on the collection of adult mites, and to a lesser extent nymphs, from soil flotation in water. The vertical migration of adults in relation to soil moisture and temperature is discussed.Observations on the appearance of larvae of T. autumnalis on a chalk-down at Compton showed a sharp seasonal peak in September, 1946, and some evidence is adduced that this was related to a peak in oviposition.Observations are made on attempts to rear T. deliensis, the scrub typhus vector in Assam, and notes are added on the behaviour of larval and nymphal mites.
The common House-fly,Musca domestica, L., and its Behaviour to Temperature and Humidity
Authors: Dakshinamurty Sonti 
Published: July 2009

The study of the common house-fly,Musca domestica, L., has not received the attention it merits by medical entomologists. Although the correlation betweenfly-borne diseasesandclimatic factorshas interested several workers, this correlation has not been satisfactorily explained. An investigation of the influence ofclimatic factorson house-flies was therefore undertaken.House-flies can be reared in the laboratory by a proper choice of the breeding medium and suitable technique. Manures, kitchen refuse and synthetic media may be used but the last mentioned is recommended for the production of a supply of standard insects.M. domesticachooses the lower humidity on each of the humidity gradients, 20–40, 40–60, 60–80 and 80–100 per cent., at a constant temperature of 25°C. The choice is significant for both sexes, and for dry and wet flies, except for dry flies at the range 60–80 per cent.The house-fly chooses 30°C. in temperature gradients of 20–30°C. and 30–40°C. at constant humidity, expressed either in the R.H. or the S.D. scale. It chooses 30°C. with dry air if possible, but with moist air if it must. In a gradient of 33–27°C. where dry air is associated with 33°C. in the S.D. scale in the one case, and 27°C. in the R.H. in the other, it chooses 33°C. or 27°C. according as it coincides with dry air. Dry air as represented by low R.H. or high S.D. did not make any difference to its choice, consequently it is not possible to decide whether house-flies choose by the R.H. scale or the S.D. scale. The activity ofM. domesticato different combinations of temperature and humidity shows maximum activity with high temperature and low humidity, minimum with high temperature and high humidity; while in the case of low temperature combinations with either high or low humidity, activity lies intermediate in degree. High and low temperatures and high and low humidity within themselves also show significant results by the χ2test.The experimental results are explained on physiological grounds and the results obtained in these experiments are compared with those of other workers on similar problems on a variety of insects.The general experience with regard to house-flies in the field is explained in the light of these laboratory findings.For a correct analysis of the behaviour of the house-fly in nature, biological stimuli such as feeding, breeding and resting habits must be considered quantitatively in relation to environmental factors such as temperature, humidity, rainfall and light. The present work forms part of such a study.
The Penetration of the Insect Egg-shells. I.—Penetration of the Chorion ofRhodnius prolixus, Stål
Authors: Beament J. W. L. 
Published: July 2009

The unspecialised portion of the shell and the cap ofRhodniuseggs are impermeable to almost all hydrophilic and lipophilic liquids. If water and very small ions pass through the chorion they must traverse a wax layer on the inside of the shell. Certain corrosive materials,e.g., glacial formic acid, may pass through the shell slowly.These conclusions, based on experiments with pieces of shell, have been confirmed in ovicidal experiments. A range of materials with widely differing properties enter the embryo only through the micropyles, of which there are approximately fifteen in the rim of each shell. At least one micropyle must be traversed to kill an egg but many eggs were killed when only one had been penetrated.A cement, applied by the female at oviposition, may occlude the outer orifice of a micropyle. The properties of the cement are described; it appears to be a tanned protein. Cement deposits are much more copious on the eggs laid by younger females. Such eggs are more resistant to ovicides because penetration is delayed. This increased resistance is more pronounced when oleophilic liquids are used owing to the rapidity with which they kill eggs from older females. The random distribution of cement is one cause of the variability of replicates in ovicidal tests.A detailed investigation has been made of factors governing liquids traversing the micropyles. Hydrophilic liquids invade the outer lipophilic part of the micropyle slowly; the displacement of air is the most important factor and small changes in the wetting power of the liquid make little difference to the rate of entry.Aqueous liquids aie absorbed into the protein lining of the inner portion of the micropyle. They reach the wax layer on the inside of the shell by migrating into and through the inner protein layer. The area which is invaded increases linearly with time. Mortality, therefore, increases as the square of the time of immersion, but it is proportional to the increase in concentration of a solute if the period of immersion is constant.Oleophilic liquids wet the micropyle actively. They may by-pass air and flow rapidly to the wax at the inner end of the tube. Wax solvents kill very quickly and are much more toxic than other lipophiles.Water in the micropyle and shell may affect the entrance of either type of liquid. In general it increases the toxicity of aqueous solutions and retards the entry of oils.Wax-emulsifying materials added to aqueous solutions do not produce great increases in toxicity. They are “filtered out” at the protein lining of the micropyle and do not reach the wax layer for a considerable period of time.