bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insect infestations and their effects on the growth and yield of field crops: a review
Authors: Bardner R. , Fletcher K. E. 
Published: July 2009

AbstractA knowledge of the often complex relationship between insect populations and their effects on the yield-forming processes of crops is useful for assessing pest status and for devising methods of minimising the effects of infestation on yield. After a preliminary section on definition of terms, consideration is given to ways in which insects injure plants and crops, particularly annual crops. Investigations into the yield-forming processes of unattacked crops can often provide useful insights into the likely effect of insect injuries on yield. The differences between the characteristics of individuals and populations are discussed, both of insects attacking plants, and plants responding to the attacks of insects. The distribution of insects on plants and on crops and the effect that this has on damage is considered, as is the time and duration of the attack in relation to the growth cycle of the crop. The components of plant resistance to insect attack are then discussed, especially tolerance and the various ways in which plants and crops compensate for injury. The review concludes with an examination of the quantitative relationships between numbers of insects or injuries and their effects on yield. The generalised response is a sigmoid curve relating an upper and lower plateau of yield where changes in the numbers of insects or injuries have little effect. Most relationships conform to some part of this curve, though few show all its features.
Pullus impexus(Muls.) (Coleoptera, Coccinellidae), a Predator ofAdelges piceae(Ratz.) (Hemiptera, Adelgidae), with notes on its Parasites
Authors: Delucchi Vittorio 
Published: July 2009

The biology ofPullus impexus(Muls.), a Coccinellid beetle predacious onAdelges piceae(Ratz.) in Switzerland, Germany and France, was studied during 1950–1952. The present work is a part of the research on the complex problem of factors in the control of the Balsam Woolly Aphid in Canada.The morphology of both the larva and the adult has been studied. Some information has been provided on the probable distribution of the species.P. impexushas only one generation a year. The eggs are deposited during the late summer or early autumn on infested trees and the larvae hatch in April. The larvae develop and adults appear in May. The adults of the new generation are to be found in June together with adults of the old generation. In the biology, particular attention has been directed to the diet of the insect in each of its stages, in order to establish the value of the species from the standpoint of biological control.Two new species of Hymenopterous parasites were found in Switzerland and in Germany,Scymnophagus mesniliFerr., a parasite of pupae, andCentistes scymniFerr., a parasite of the imagines. The life history of these species has been briefly studied. A cephaline gregarine species was noted in the mesenteron of adults ofP. impexusand a nematode in the abdominal cavity of a female. The two Hymenopterous species provide an important limiting factor in the increase of the population ofP. impexus.
Variation with Age in the Susceptibility to DDT and the Respiration Rate of male and female Drosophila melanogaster Mg.
Authors: Kerr R. W. 
Published: July 2009

DDT in odourless distillate was topically applied to individual males and females of the Rothamated wild type of Drosophila melanogaster Mg. The lines for the regression of mortality in probits on log. dosage of DDT for males and females, five days old, were parallel, and males were 1·86 times as susceptible as females. Susceptibility was high in young flies, but rapidly decreased with age, to a minimum at about five days, thereafter increasing rapidly in males and not significantly in females. The need for sexing and standardising age in flies used for toxicological investigations was thus demonstrated.Respiration rate in untreated flies was measured by a modified Barcroft method. In males it increased with age up to five days, and then decreased; in females it increased with age up to nine days. Variations with age in respiration rate and susceptibility to DDT were negatively correlated.
The Freezing Process of Frost-hardy Caterpillars
Authors: Asahina E. , Aoki K. , Shinozaki J. 
Published: July 2009

Using mainly the overwintering prepupae of a “ slug caterpiller ”,Cnidocampa flavescens(Walk.), the mechanism for the frost-resistance in insects was investigated.Though the freezing point of the blood shows the value of about −2°C. the prepupae are very readily supercooled. When cooled below −20°C., however, the insect body suddenly congeals hard. Insects frozen thus, even for a long period of 100 days, usually withstand the solidification of their bodies without any harmful effect upon either the further development or upon the next generation.Judging from the shape of the freezing curves of the prepupae and the freezing processes of the blood and isolated tissues, it is inferred that the most probable freezing process of the caterpillar is as follows. At first, the blood freezes rapidly, and consequently the grade of supercooling of the tissue cells is very much lessened by the latent heat of fusion of ice. Extra-cellular freezing of the tissue cells then takes place, in which case the properties of the blood as well as some property of the plasmic surface layer of the cells may play an important role in the prevention of the transmission of freezing into the cell. With the advance of the blood freezing, the tissue cells undergo dehydration and contraction; neverthless, they usually withstand such a condition for a long period, provided that the freezing temperature is not too low. Consequently, the so-called anabiotic state of a frozen insect does not necessarily mean the destruction of the cell structure.
Toxicity of the Botanical Insecticide Ryania speciosa to Culex pipiens fatigans Wied.
Authors: Charles L. J. 
Published: July 2009

In the course of general studies on control of Culex pipiens fatigans Wied. in British Guiana, the indigenous shrub Ryania speciosa, proven to possess insecticidal activity against certain agricultural pests, was investigated.Aqueous extracts of the dried stem were shown to possess toxic properties against all larval stages of C. pipiens fatigans under clean laboratory conditions. Under conditions simulating a water-logged pit latrine, however, toxicity was greatly reduced by adsorption of the active agent ryanodine, rendering the crude stem relatively ineffective after 16 days. Because of the great bulk of unprocessed material required for even this limited result in pit latrines—which constitute an important local problem—Ryania was not considered of practical value in C. pipiens fatigans control.Aqueous and alcoholic extracts of Ryania speciosa had no contact insecticidal properties against adults of this species.
Mesoclanis seed flies (Diptera: Tephritidae) on Chrysanthemoides (Asteraceae) in South Africa: distribution, attack strategy and impact on seed production
Authors: Edwards P.B. , Brown E.M. 
Published: July 2009

AbstractThree species of Mesoclanis flies that attack the developing seeds of Chrysanthemoides monilifera in South Africa are being assessed for their potential as biological control agents of C. monilifera in Australia. Surveys in South Africa indicated that M. polana Munro is restricted to C. m. rotundata along the subtropical northern coast, M. magnipalpis Bezzi and M. dubia Walker occur on all three subspecies sampled (C. m. rotundata, C. m. monilifera, C. m. pisifera), although M. dubia is less abundant and has a more restricted distribution than M. magnipalpis. Mesoclanis eggs are laid into a wide range of flowerhead stages of C. m. rotundata over a period of approximately 12–14 days, from very small flowerheads with involucral bracts still completely closed, to flowerheads with the laminae of ray florets (petals) starting to elongate. Levels of oviposition by M. magnipalpis into C. m. pisifera are low in very young flowerheads, possibly as a consequence of a heavy layer of indumentum on young C. m. pisifera flowerheads. The pattern and location of feeding and pupation within flowerheads differs slightly for the three Mesoclanis species, but none of the species is associated with the formation of gall tissue. The effect of Mesoclanis activity on ovule development was assessed on four occasions. Mesoclanis destroyed all the ovules in some capitula, and the maximum level of ovule destruction recorded for a site was 64%.
Effects of sugar-formulated triflumuron-treated targets on reproduction in the olive fruit flyBactrocera oleae(Diptera: Tephritidae)
Authors: Mazomenos B.E. , Stefanou D. , Langley P. , Pantazi-Mazomenos A. 
Published: July 2009

AbstractAdult olive fruit fliesBactrocera(Dacus)oleaeGmelin were exposed for 24 h to 25 × 10 cm polyester target devices, impregnated with 3% a.i. triflumuron (2-chloro-n-[[[trifluromethoxy]phenyl]amino]carbonyl]benzamide), a chitin synthesis inhibitor, formulated in 10% w/v sugar solution and air-dried. Treated insects were tested for egg hatch inhibition and larval mortality. Inhibition of egg hatch and F1 larval mortality depended on the sex exposed and the elapsed time after exposure. Egg hatch was reduced to 37.6% and F1 larval mortality reached 100% when both exposed sexes were mated. Exposure of one sex prior to mating resulted in a lower level of egg inhibition and larval mortality; but exposure of females was more effective at inhibiting egg hatch and larval survival than exposure of males in these crosses. In flies exposed once, the residual activity of triflumuron decreased gradually, fifteen days post-exposure egg hatch and larval mortality reached 62% and 44% respectively. Target devices aged under natural conditions reduced egg hatch to an average of 39% and inhibited completely larval development for a period of four months.
Mitochondrial DNA characterization of populations ofLutzomyia whitmani(Diptera: Psychodidae) incriminated in the peri-domestic and silvatic transmission ofLeishmaniaspecies in Brazil
Authors: Ready P.D. , Day J.C. , de Souza A.A. , Rangel E.F. , Davies C.R. 
Published: July 2009

AbstractA comparative analysis was performed on 18 mitochondrial DNA sequences, or haplotypes, ofLutzomyia (Nyssomyia) whitmani(Antunes & Coutinho) isolated by PCR from 28 individual flies originating from 10 Brazilian locations 150–2500 km apart. A phylogenetic analysis using maximum parsimony indicated support for three to four major lineages (Outgroups were haplotypes ofLutzomyia (Nyssomyia) intermedia(Lutz & Neiva)). OneL. whitmanilineage was found in the Atlantic Forest zone of the North East, including the species' type locality, and is distinct from a second monophyletic group of haplotypes located in the drier interior of Brazil, stretching from the Tropic of Capricorn to Teresina just outside Amazonia. This provides no support for a previous hypothesis thatL. whitmanisensu stricto is a single form widely-distributed south of Amazonia, and characterized by derived anthropophilic and synanthropic behavioural traits. The ranges of both lineages include populations incriminated in the peri-domestic transmission ofLeishmania braziliensissensu stricto. A third, Amazonian, group of haplotypes was less well-defined. It appears to consist of two sub-lineages which, like the twoLeishmaniaspecies associated with them, are strictly silvatic and are separated by the Amazon floodplain. The zoophily of the Amazonian populations was not shown to be an ancestral trait. The geographical distributions of the Brazilian lineages are concordant with the broad patterns of bioclimate believed to have persisted since the late Tertiary period. These findings are part of ongoing research on the behavioural genetics ofL. whitmanisensu lato aimed at understanding the evolution and maintenance of peri-domestic transmission of human cutaneous leishmaniasis.
Observations on Mosquito Behaviour in Native Huts
Authors: Hadaway A. B. 
Published: July 2009

Mosquitos continue to enter occupied, untreated native huts throughout the night, with peak periods of entry at dusk and dawn. Early morning mosquito catches do not give a true picture of the numbers entering and leaving huts during the night.In a series of catches 63 per cent. of 5,576 mosquitos and 79 per cent. of 506 Anopheles gambiae were caught resting on the underside of the thatch roof.By using five traps inserted in apertures one foot below the top of the wall, the numbers of mosquitos attempting to leave a hut were determined. Of 1,014 mosquitos entering huts before 10 p.m., 63 per cent. remained inside until 6.30 a.m., that is for 8½ hours. Catches to estimate numbers entering and leaving at different times during the night were also made.Treatment of huts with DDT wettable powder and DDT-kerosene solution did not interfere with the normal behaviour of mosquitos as far as entry was concerned. Biting occurred in the treated huts.The DDT wettable powder appeared to be more effective than the DDT-kerosene solution.Some mosquitos entered the treated huts, fed and then left before acquiring a lethal dose. After making contact with treated surfaces mosquitos became restless but, under the conditions existing in the huts during the experiments, activation did not result in more leaving the treated huts than the untreated one. Unfortunately there were few A. gambiae and the predominant species entering the huts was Taeniorhynchus fuscopennatus.Some of the female A. gambiae released into unoccupied DDT-treated huts escaped into the traps before acquiring a lethal dose. Although there was a tendency for more to enter the traps of a DDT-treated hut than those of an untreated hut, the data are insufficient to show a significant difference.The majority of mosquitos entering the traps did so within one hour of their release.No mosquitos were still alive 12 hours after their release in huts treated 17 weeks previously with DDT wettable powder or DDT-kerosene solution, or in the hut treated 12 weeks previously with "“Gammexane” wettable powder.
The Wetting of Insect Cuticle
Authors: Pal Rajindar 
Published: July 2009

The best method of assessing the wetting powers of liquids is to measure the contact angle formed with a particular solid surface. In order to study the wetting of insects by spray liquids, it was necessary to measure, as rapidly as possible, the contact angles of very small droplets on restricted surfaces (such as portions of the insects). The apparatus used projected a greatly enlarged image of the drop, the outline of which could be traced very quickly and used for subsequent calculations.Under practical conditions, spray droplets impact on insects with some relative velocity either due to drift of the spray particles or to flight movements of the insect.Measurements were therefore made of the contact angles formed by droplets of water of known size falling on to insects (or to a beeswax surface) at a known speed. It was found that with rather large drops (5 mm. diameter) the contact angles formed were somewhat lower than the normal advancing contact angle. With small droplets (0·1-0·5 mm. diameter) there was no difference. Biological tests were made with 30 species of insects, differing widely in the nature of their integument and habitat. The resistance to wetting was found to vary greatly, not only from species to species but also on different parts of the body of a single insect. In general, most of the insects were readily wetted by oils and unwetted by water. Insects withhard cuticular lipoids, such asTenebrio, were more hydrophobic than the Blattidswith greasy cuticular waxes. A few species were both lipophilic and hydrophilic (larvae ofMamestra, Polia, Musca). Apart from the chemical nature of the cuticle, irregularities and the presence or absence of hairs were important. Increased roughnesslowers the contact angles of liquids with good wetting powers, but has the opposite effect with liquids with poor wetting powers. Measurements were made of thecontact angles formed on individual hairs ofArctia cajalarvae by spray droplets. The contact angles formed on these hairs by plain liquids were strongly correlated with the angles formed on smoothTenebriocuticle or on an artificial beeswax surface; but there was only very rough correlation between the three sets of data when aqueous solutions of wetting agents were tested.The test liquids included saturated and unsaturated hydrocarbons, mineral oils with varying aromatic contents, organic esters, alcohols and aqueous solutions. Among the hydrocarbons, members of the aliphatic series wet insect cuticle more readily than the aromatic group. The aromatic contents of the oils did not, however, affect their very high wetting powers.The effects of adding surface active agents to aqueous sprays were investigated. Of the samples tested, the most effective wetting agents were those with neutral un-ionised molecules.
The Biology and external Morphology of the Larvae of Epilachninae (Coleoptera, Coccinellidae)
Authors: Kapur A. P. 
Published: July 2009

The Epilachninae constitute one-sixth of the known species of the family Coccinellidae. They are herbivorous and include a number of well known pests of cultivated plants in different parts of the world. Their adults present a great uniformity of external structure, with the result that nearly all the known species have been placed in one genus, Epilachna Hope. Their identification is made more difficult by the employment of characters such as the elytral markings and spots which may vary a great deal in one species or be almost identical in two quite unrelated species. Lately, there has been a tendency to split the genus by employing more reliable morphological characters, including genitalia. A greater knowledge of the biology and morphology, including that of the immature stages, particularly the larvae, is necessary to evolve a natural classification. Relatively little was known of the larvae. This paper deals with 14 species belonging to six different genera.In addition to discussion of the relationship of this subfamily with other Coccinellidae in the light of the extensive larval material examined, it is observed that larvae belonging to different genera, including those recently erected or revived, show considerable morphological differences that support a division of Epilachna (s.l.) based on adult characters. A study of the larvae of nine species that are still retained in the genus Epilachna shows that they are separable into several groups, which may well indicate where further division of the genus may be made.
The Mediterranean Fruit Fly in Israel
Authors: Rivnay E. 
Published: July 2009

The status of the Mediterranean fruit fly in Israel is reviewed briefly. Apricots, peaches and guavas are the most severely attacked of the summer fruits.The ecology of the various stages of the insect is discussed. It is pointed out that, in addition -to temperature, the type of food influences the length of development of the larva. The threshold of development in the temperature development hyperbola has been calculated and found to be between 10–11°C.The threshold of development of the pupae was found to be close to 11CC. A daily exposure of the pupae for six hours at a temperature of 32–37°C. caused no injury, but a similar exposure at 42°C. brought about a heavy mortality. At 46°C. one hour's exposure resulted in considerable injury whilst three hours' exposure killed 80 per cent, of the pupae. This explains the very high mortality of the pupae in the groves during June, July and August.A study of the development of the eggs in the ovarioles at various degrees of temperature indicated that at 18–22°C. no appreciable development took place and at 23–25°C. it was still retarded. The optimum development temperature was found to be 27–29°C, whilst 33–34°C. was actually detrimental.A study of the length of life of the adult showed that survival was longest between 16–19°C. at which temperature it took 100 days to reach 50 per cent, mortality and 200 days a 100 per cent, mortality.The fluctuation of the fly population in Israel is discussed in detail. It is pointed out that the prevalence of host fruits is one of the great factors responsible for these fluctuations. An analysis of the climatic conditions month by month and its influence upon the fly population is discussed. The curve depicting the fluctuations of the fly in the coastal plain has two depressions, one between December and January, and the other in July and August. In the Upper Jordan Valley, the summer depression was more clear-cut than in the maritime plain, and the spring population reached a much greater height than that in the autumn.The fly appeared about two months later in the hills than in the plain, namely towards early June, and it disappeared also earlier, presenting a single peak in July and August.
A Method of distinguishing the larval Stages ofAgriotes sputator(L.) (Col., Elaterid.)
Authors: Basden Joan F. 
Published: July 2009

The different instars ofAgriotes sputatorlarvae cannot be distinguished by measurements of total length or of various parts of the wireworm.The number of teeth on the mesothoracic and abdominal spiracles increases with age, and an examination of 700 wireworms showed that the average numbers of teeth on the two thoracic or on all the abdominal spiracles fell into eight groups. These criteria were valid for populations collected at different times of the year.The number of teeth on the thoracic spiracles of a larva in any particular group approximates to that on the abdominal spiracles of a larva in the next larger group.The eight groups formed by counting either the thoracic or the abdominal spiracle teeth representgrowthstages and not necessarily instars.The larvae may sometimes moult without growth, a phenomenon probably caused by an inadequate supply of food. At such an ecdysis the number of spiracle teeth does not increase.The larvae pupate after attaining an optimum size, and reach this size in seven or eight growth stages.A quick method of determining the growth stage to which a larva belongs is given, whereby more than 80 per cent, of the larvae are placed in their correct growth stages by counting the teeth on one spiracle only ; for less than 1 per cent, of the larvae is it necessary to examine as many as five spiracles ; an accuracy of more than 97 per cent, can be maintained.The possibility of determining the relationship of growth stage and age is discussed.The division of the larvae into those which will pupate after seven, and those which will pupate after eight growth stages is apparent at a very early stage in the life history. One larva was found which appeared to be in its ninth growth stage.The cause of this difference in growth stage number is unknown. It may be due to the size of the egg, to the time of the year at which hatching occurs, or to heredity.