bluuebunny/crossref_metadata_2025 huggingface dataset:
The susceptibility of cocoa to mealybugs (Pseudococcidae) and other honeydew-producing Homoptera in Ghana
Authors: Campbell C.A.M.
Published: July 2009

Population densities of mealybugs and other honeydew-producing Homoptera were assessed in six cocoa (Theobroma cacao Linnaeus) trials by inspecting trees from ground to eye level, and also by dissecting samples of terminal buds. A total of 68 cocoa progenies was examined, mainly inter-crosses of six clones. Progenies differed in their levels of infestation with total mealybugs, Planococcoides njalensis (Laing), Planococcus citri (Risso), Phenacoccus hargreavesi (Laing), (Pseudococcidae), Toxoptera aurantii (Boyer de Fonscolombe) (Aphididae), and Mesohomotoma tessmanni (Aulmann) (Psyllidae). Crosses with Amelonado or T63/971 were generally more densely infested with mealybugs than those for example of NA34 and T63/967. Trees of T17/524 parentage were sparsely infested with mealybugs. Rankings of progenies by infestation with mealybugs from the two different sampling procedures were positively correlated, but the relative abundances of individual mealybug species on the trunk and in the canopy differed. Several species of mealybug found in buds were either rare or never found by inspecting trees up to eye level. Correlations between rankings of progenies by order of abundance of Planococcoides njalensis and Planococcus citri were positive and statistically significant, as were those between mealybugs and infestation of buds by T. aurantii or M. tessmanni. The above rankings were negatively correlated with those by aphid and psyllid abundance assessed from inspecting trees up to eye level. The two sampling procedures were complementary but, for economy, samples of buds gave the clearest indication of a progeny's suitability for mealybugs.
Some factors affecting the efficiency of sticky board traps for capturing the carrot fly, Psila rosae (Diptera: Psilidae)
Authors: Collier Rosemary H. , Finch S.
Published: July 2009

The relative attractiveness of coloured sticky board traps to the carrot fly (Psila rosae (Fabricius)) is described by a model in which fly catch is related positively to the amount of light reflected from the trap in the green-yellow (550–570 nm) band of the spectrum and negatively to the amount reflected in the violet-green (390–550 nm) band. The model allows the performance of new coloured traps to be predicted solely from spectral reflectivity measurements. Similar numbers of carrot flies were caught/unit area on traps varying in size from 150 cm2 to 4800 cm2. Most flies were caught on traps resting on the ground. The number of flies caught was reduced by 0.84% for each cm the trap was raised above 10 cm from the ground. One-sided sticky traps angled at 45° to the vertical doubled the numbers of carrot flies caught/unit trapping area and reduced by 90% the numbers of non-target species caught.
Simulated field studies with three formulations ofBacillus thuringiensisvar.israelensisandBacillus sphaericusagainst larvae ofMansonia bonneae(Diptera: Culicidae) in Sarawak, Malaysia
Authors: Chang Moh-Seng , Ho Beng-Chuan , Chan Kai-Lok
Published: July 2009

The susceptibility levels ofMansonia bonneaeEdwards larvae toBacillus thuringiensis israelensis(B.t.i.) SkeetalR,B.t.i.BactimosRbriquettes andBacillus sphaericusRB80 were evaluated under field conditions. Satisfactory control of larvae was achieved during 24 h–48 h post-treatment. At 72 h after treatment with a 48 h exposure period, over 90% reduction was achieved by SkeetalRat both applied dosages and byB. sphaericusRB80 at the higher applied dosage. BactimosRbriquettes achieved less control at both applied dosages, due to slow, sustained release ofB.t.i.spores. SkeetalRandB. sphaericusRB80 released their toxic ingredients as early as 2 h after treatment, after which the spore counts (CFU/ml) increased steadily in the middle and bottom water layers and reached maximum level at 72 h post-treatment. However, SkeetalRdisplayed very little residual activity as evidenced by the drastic decline of spore counts as well as larval reduction at one week post-treatment. By contrast, BactimosRbriquette andB. sphaericusRB80 prolonged their residual toxicity throughout the four week period. The peaks of spore counts in the middle and bottom water layers for SkeetalRandB. sphaericusRB80 preceded the corresponding peaks for larval reduction rates by 24 h and 48 h and 1 week to 2 weeks, respectively. The spore counts of BactimosRbriquette at the high applied dosage fluctuated closely with the reduction rates of larvae throughout the four week period.
A new species of Anagyrus (Hymenoptera: Encyrtidae) from India attacking Rastrococcus invadens (Homoptera: Pseudococcidae), a pest of mango and citrus in West Africa
Authors: Noyes John S.
Published: July 2009

Anagyrus mangicolasp. n., an encyrtid parasitoid of Rastrococcus species on mango in India, is described and compared with related species. The parasitoid has been the subject of laboratory studies and may be introduced into West Africa to supplement the activities of previously introduced natural enemies of the mango mealybug (R. invadens Williams).
Laboratory apparatus and techniques for the rearing and insecticidal treatment of whiteflyBemisia tabaci(Homoptera: Aleyrodidae) under simulated field conditions
Authors: Rowland Mark , Pye Barry , Stribley Mary , Hackett Barbara , Denholm Ian , Sawicki Roman M.
Published: July 2009

Laboratory apparatus and techniques are described for the rearing and insecticidal treatment of whitefly,Bemisia tabaciGennadius, under simulated field conditions. Insects were reared on cotton plants inside large population cages and treated from an overhead sprayer. The effects of these treatments were assessed accurately, without interfering with insects or plants, by monitoring adult numbers with an endoscope over one or more generations. Examples of single-generation and multiple-generation tests with cypermethrin are described. The apparatus is suitable for testing strategies for delaying the selection of resistance (e.g. using insecticides applied singly, alternately, or in mixture, at various application rates and frequencies), for controlling populations already resistant to insecticides, and for integrated pest management using chemical and biological control agents together.
Suppression of Aedes aegypti (Diptera: Culicidae) using augmentative release of dragonfly larvae (Odonata: Libellulidae) with community participation in Yangon, Myanmar
Authors: Sebastian Anthony , Sein Myint Myint , Thu Myat Myat , Corbet Philip S.
Published: July 2009

A pilot field study, involving periodic augmentative release of predatory larvae of a dragonfly, Crocothemis servilia (Drury), to suppress a mosquito, Aedes aegypti (Linnaeus), was conducted during the rainy season in Yangon (Rangoon). More than 90% of pre-adult A. aegypti occurred in domestic water-storage containers. Evaluations of larval and adult numbers of A. aegypti were made half-monthly three times before, and seven times after, treatment began. Four laboratory-reared, three-week-old C. servilia larvae were placed in each major source of A. aegypti larvae immediately after the third evaluation and then monthly for three successive months. Such treatment reduced the larval population of A. aegypti to a very low level in two to three weeks and suppressed it progressively until the trial ended; the adult population was greatly reduced after about six weeks and was progressively diminished thereafter until the trial ended. The trial's success was ascribed to: the virtual confinement of pre-adult stages of the target mosquito to containers accessible to control operators; the behaviour, growth rate, survival and ready availability of the chosen species of dragonfly; and the awareness and enthusiastic participation of local householders.
Laboratory observations on the flight activity of the plague locust, Chortoicetes terminifera (Walker) (Orthoptera: Acrididae)
Authors: Lambert M. R. K.
Published: July 2009

Flight activity characteristics of Chortoicetes terminifera (Wlk.) were recorded in adults suspended on a simple flight balance in a wind tunnel. Ninety-one per cent, of flights by post-teneral (>5-day-old) insects lasted less than 60 s, and only 11% of adults flew for a full 20-min test period at 30°C. The flight capacity ranged from a few or many short flights to continuous flights. Females flew for a greater proportion of the time than males. Flight activity increased with food-deprivation, and only fully hardened (>9-day-old) insects flew continuously throughout a 45-min test period at 26–41°C. Gravid females also made long flights. The frequencies of flight durations by laboratory-reared insects were strikingly similar to the day flight of milling field populations in eastern Australia. Flight performance observations indicated that lift declines with time in flight, wing-beat frequency initially being 33·2 Hz in males and 30·0 Hz in females. The results are discussed in relation to field studies.
Effects of endosulfan on pregnant females of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) and their offspring
Authors: Kwan W. H. , Gatehouse A. G. , Kerridge E.
Published: July 2009

Exposure of pregnant females of Glossina morsitans morsitans Westw. to a standard dose of 14·8 ng/fly of endosulfan confirmed that they acquire a higher level of tolerance of this insecticide than young unmated females. The development of tolerance was rapid, from threefold 48 h after larviposition, to eightfold midway through the pregnancy cycle at 4–5 days, and reaching 10- to 14-fold 24–28 h before the next larviposition. The acquisition of substantial tolerance preceded the periods of major growth of the larva in utero and of the developing oocyte, and it is suggested that the development of tolerance is associated with the diversion of insecticide by partitioning into lipid components of the milk as they are synthesised. The level of tolerance attained at equivalent stages of the pregnancy cycle appeared to be largely independent of the age of the fly between the second and fifth cycles, but that reached in the first cycle was lower. Some females survived repeated exposure to endosulfan in successive cycles. The offspring of treated females showed no apparent effects until shortly after adult eclosion, when substantial but variable delayed mortality occurred. However, surviving females and their offspring continued to reproduce normally. It is concluded that tolerance of the insecticide in pregnant flies accounts adequately for the observed survival following non-residual applications of endosulfan, and strategies for preventing this survival, and achieving eradication, are discussed.
External sexual characters of larvae of Spodoptera littorails (Boisduval) and S. exempta (Walker) (Lepidoptera: Noctuidae) and their use for sexing live larvae
Authors: Haines Linda C.
Published: July 2009

External sexual characters are described for the larvae of Spodoptera littoralis (Boisd) and S. exempta (Wlk.). The characters on the female consist of two pairs of pits on the ventral surface of the eighth and ninth abdominal segments. These pits are visible under a light microscope and can therefore be used for the accurate sexing of live larvae from the third instar onwards. The first- and second-instar larvae of both species could not be sexed using external characters because of their small size. In the males of both species, there are no obvious external sexual characters until the last instar, and therefore the sexes are most easily separated by the presence or absence of the female characters. Third- to sixth-instar larvae of both species were examined for the presence or absence of the female pits and were then sexed by dissection. The accuracy of sexing using the external characters was 90–98% for S. littoralis and 100% in all cases for S. exempta. The histology of the female pits and their appearance under the scanning electron microscope is described. These pits in the female larvae give rise to the external openings of the adult reproductive system.
The identity of Chilo kanra (Fletcher) (Lepidoptera: Pyralidae), a stem-borer of wild and semi-cultivated Saccharum in northern India
Authors: Bradley J. D.
Published: July 2009

The identity of Chilo kanra (Fletcher), an obscure stem-borer of the wild and semi-cultivated grasses Saccharum fuscum and S. arundinaceum in northern India, is ratified on the basis of recently collected material from Bihar. A neotype is designated, and the adults and genitalia are illustrated. The species is differentiated from its congener C. partellus (Swinh.), a widely distributed pest of sugar-cane and other graminaceous crops in India and Africa. A neotype is also designated for C. saccharicola Fletcher, a stem-borer described at the same time as C. kanra and now found to be conspecific and a junior synonym.
The distribution of the mealybug genus Planococcus (Hemiptera: Pseudococcidae) in Melanesia, Polynesia and Kiribati
Authors: Williams D. J.
Published: July 2009

After checking the identity of numerous mealybugs of the genus Planococcus from the south Pacific, many of which were previously recorded as P. citri (Risso), it was established that the most widespread is the recently described species P. pacificus Cox. P. citri is present in some islands, but the collection dates are recent, suggesting a recent introduction. Although P. pacificus is known from the area since the first quarter of the present century, it may have been introduced also. P. lilacinus (Ckll.) possibly arrived from southern Asia and P. dioscoreae Williams from the eastern part of the Oriental Region. The known host-plants are listed.
Flight initiation inTriatoma infestans(Klug) (Hemiptera: Reduviidae)
Authors: Lehane M. J. , Schofield C. J.
Published: July 2009

Flight initiation of adults ofTriatoma infestans(Klug) was recorded in a laboratory apparatus. The proportion of individuals initiating flight depended on the nutritional status of the insects, and flight activity was greatest about 12–18 days after feeding. From measurements of the weight and length of the insects, it was possible to assign the probabilities of flight initiation and thus predict the proportion of an adult population likely to fly. The predictive model should be of use to field workers studying dispersion ofT. infestansbetween infested houses.
Seasonal population dynamics of the immature stages ofAedes africanus(Theobald) (Diptera: Culicidae) in Zika Forest, Uganda
Authors: Sempala S. D. K.
Published: July 2009

The seasonal population trends of the immature stages ofAedes africanus(Theo.), an important vector of yellow fever virus and other arboviruses, were studied in Zika Forest, Uganda, for two years during 1974–75. Data were collected from natural breeding places in tree holes and from bamboo pots placed 80 cm above the ground. Developing larvae and pupae were present at all times of year, and there were monthly, seasonal and annual fluctuations in density. These fluctuations followed the seasonal distribution of rainfall and were more marked in the natural breeding places, which were subject to irregular fluctuations in water level, than in the bamboo pots, which were constantly supplied with water. Thus, in addition to the drought-resistant eggs whose erratic hatching by instalments could ensure the presence ofA. africanusthroughout the year, there are probably also present at any given time females that are capable of ovipositing. As a measure of the seasonal population changes, it was found that both the percentage of positive containers index and the mean number per container index were almost equally sensitive.
Interactions between immature Aedes africanus (Theobald) and larvae of two predatory species of Toxorhynchites (Diptera: Culicidae) in Zika Forest, Uganda
Authors: Sempala S. D. K.
Published: July 2009

Studies conducted in Zika Forest, Uganda, on the breeding interactions between Aedes africanus (Theo.) and two mosquito predators, Toxorhynchites brevipalpis conradti Grünb. and T. kaimosi (van Som.), revealed a significant reduction in the numbers of A. africanus larvae and pupae in tree holes that were also inhabited by the predator larvae. There was a tendency for seasonal peaks in numbers of A. africanus to be followed two months later by peaks in Toxorhynchites spp. Cannibalism appeared to play an important role in the regulation of the population size of the two species of Toxorhynchites. The implications of these results in relation to the possible use of Toxorhynchites mosquitoes for biological control of A. africanus and other mosquitoes breeding in tree holes are discussed.
Behaviour of newly hatched larvae of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) associated with their establishment in the host-plant, sorghum
Authors: Bernays E. A. , Chapman R. F. , Woodhead S.
Published: July 2009

The climbing behaviour of newly hatched larvae of Chilo partellus (Swinh.) on sorghum plants was studied in the laboratory and in the field in India. The upward movement is directed by light, while the final downwards movement into the whorl is probably a response to the contrast of light above and dark below. Many larvae fail to reach the whorl, and success is reduced by high winds and rain, and by some physical features of the plants. Two sorghum cultivars, IS 1151 and IS 2205, differed in the extent to which larvae successfully reached their whorls, and their relative susceptibilities altered with age.
Development of a monitoring trap for the olive fly, Dacus oleae (Gmelin) (Diptera: Tephritidae), using a component of its sex pheromone as lure
Authors: Jones O. T. , Lisk J. C. , Longhurst C. , Howse P. E. , Ramos P , Campos M.
Published: July 2009

A major component of the sex pheromone of Dacus oleae (Gmel.) has recently been identified as a spiroacetal. The use of this compound as a lure for use in the development of a monitoring trap for that species is described. Polyethylene vials gave a slower release rate of the spiroacetal than rubber septa or microfibres, but even in polyethylene vials a loading in excess of 10 mg was required (optimum 20 to 25 mg) to obtain catches in delta traps which were comparable with those in unbaited vertical yellow sticky traps. In studies in an olive grove near Granada, Spain, a 25-mg spiroacetal lure used with a vertical yellow trap gave catches of males of D. oleae which were four times as great as those in delta traps with the same lure or in unbaited yellow traps. The height of the trap had no apparent effect on catch. Previously recorded components of the sex pheromone did not prove to be effective when combined with the spiroacetal. Combined monitoring of Prays oleae (Bern.) and D. oleae, using their respective pheromones in the same trap, appears to be feasible with delta traps.
The influence of host-plant on the development of the adult brown planthopper, Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), and its significance in migration
Authors: Padgham D. E.
Published: July 2009

The development of adults of Nilaparvata lugens (Stål) reared on one susceptible and one resistant variety of rice plants of different ages was compared. Throughout the range of plants tested there was an overall trend for the newly moulted adult to synthesise and store a reserve of lipid and to lose most of the stored glycogen accumulated during the nymphal stage. N. lugens has two wing morphs, and whilst lipid deposits were greatest in the macropterous ‘migrant’ males, in females it was the brachypterous ‘reproductive’ insects that had the highest lipid deposits and also the greatest residual body weight. However, because of their lower body weight, the macropterous females had the greater percentage of lipid. Both flight willingness and the percentage of macropterous females showing flight-orientated physiological development increased with the age of the host-plant. Both survival and migration potential were lower in insects reared on the resistant rice variety compared to those reared on the susceptible variety. The pattern of post-flight resynthesis of fuels suggests that more than one major migration is unlikely.
The biology of Bubas bison (L.) (Coleoptera: Scarabaeidae) in southern France and its potential for recycling dung in Australia
Authors: Kirk A. A.
Published: July 2009

The biology of Bubas bison (L.) was studied in southern France. It was active from September to the end of May. Adult emergence lasted from September to January; 8 % of the female population was parous and laying eggs in September, and 100% were parous from February to the end of June. Females exhibited extraovariolar egg resorption, which may have been a response to adverse conditions. Eggs laid in October, November, February and March hatched synchronously in May. Adults resulting from eggs laid in March emerged in early September. The rate of oviposition varied from 0–03 egg/day in January to 0·5 in March. Females stopped laying eggs for three weeks in January. The structure of the nests formed from buried dung brood-masses was studied. Each brood-mass contained two eggs, one at each pole. About 12 brood-masses were formed under each dung pad in October 1981. The mean length of each mass was 96 mm and the dry weight 10–5 g. The mean number of masses in a nest was 24, with a mean number of 4–9 nests under each dung pad. The dry weight of dung buried under a pad in October 1981 was 1239 g, 66–6%, of the mean dry weight of an experimental dung pad. B. bison has the potential for recycling large amounts of dung in climatic areas of Australia equivalent to southern France.
Inheritance and activity of some esterases associated with organophosphate resistance in mosquitoes of the complex ofCulex pipiensL. (Diptera: Cnlicidae)
Authors: Villani F. , White G. B. , Curtis C. F. , Miles S. J.
Published: July 2009

Eighteen strains of the complex ofCulex pipiensL. from Africa, Asia and Europe were bioassayed for resistance to chlorpyrifos and electro-phoresed and stained for esterases. Susceptible strains showed only low activity esterase bands. The resistant strains ofC. quinquefasciatusSay from hot countries (Liberia, Nigeria, Sri Lanka, Tanzania, Thailand) all showed the same two high intensity esterase bands (Rm 0·60 + 0·82). Different patterns of high esterase were found in resistantC. pipiensstrains from cooler localities in Nairobi, Kenya (Rm 100), and Mont-pellier, France (Rm 0–50). Selection experiments on strains originally polymorphic for resistance and esterase pattern showed, without exception, that high esterase remained associated with resistance, and it is concluded that the association is almost certainly causal and not merely due to genetic linkage. The high intensity esterase bands were probably due to alleles of the loci Est-l, Est-2 and Est-3, separated by crossover distances of approximately 2·4 and 5·5 units, respectively. Strains monomorphic for what appeared to be the same high esterase pattern varied markedly in resistance level. Enzyme assays showed a direct relationship between levels of enzyme activity and resistance. Bioassays with fenthion and chlorpyrifos revealed differences in the relative resistance ofC. quinquefasciatusfrom Colombo (Sri Lanka) and Dar-es-Salaam (Tanzania). Despite these differential degrees of cross-effectiveness, it is concluded that high intensity esterases are reliable indicators of organophosphate resistance in mosquitoes of theC. pipienscomplex, although the possibility of other resistance mechanisms means that the lack of abnormally active esterases does not necessarily indicate the absence of resistance.
New species of Platygastridae (Hymenoptera) from India which parasitise pests of mango, particularly Procontarinia spp. (Diptera: Cecidomyiidae)
Authors: Austin A. D.
Published: July 2009

Five new species of Platygastridae associated with mango pests in India are described. Synopeas procon sp. n., S. temporale sp. n., S. mangiferae sp. n. and Inostemma oculare sp. n. parasitise mango leaf gall midges, Procontarinia spp. (Cecidomyiidae), while Inostemma apsyllae sp. n. is associated with the psyllid Apsylla cistellata (Buckt.). Notes on a further two species, the platygastrid Trichacoides indicus Jackson and the ceraphronid Aphanogmus sp., associated with Procontarinia are given. A key to separate these parasites as well as comments on their biology and distribution are presented.
Factors affecting resistance to insecticides in house-flies, Musca domestica L. (Diptera: Muscidae). III. Relationship between the level of resistance to pyrethroids, control failure in the field and the frequency of gene kdr
Authors: Farnham A. W. , O'dell Kate E. , Denholm I. , Sawicki R. M.
Published: July 2009

Tolerance of bioresmethrin, permethrin, deltamethrin and the natural pyrethrins with and without synergists (piperonyl butoxide and propyl prop-2-ynyl phenylphosphonate), and the frequency of kdr homozygotes (flies surviving a discriminating dose of DDT+FDMC (1,1-bis(4-chlorophenyl)-2,2,2-trifluoroethanol)) was investigated in 42 strains of Musca domestica L. collected on British pig farms and in one Canadian strain. Although all field strains were at least 4–10 times more tolerant of synthetic pyrethroids at the LD50 than the standard susceptible Cooper strain, and 27 strains (26 British + 1 Canadian) had detectable levels of kdr, pyrethroids failed to control flies on only nine farms where 10% of flies or more were homozygous for kdr and/or the LD50s (in μg/female) in bioassays equalled or exceeded 0·1 for bioresmethrin, 0·12 for permethrin, 0·012 for deltamethrin or 1·1 for pyrethrins. These figures correspond to resistance factors (Cooper strain = 1) of 20, 15, 30 and 4, respectively. Regression analyses showed a close relationship between the LD50s to pyrethroids and the frequency of kdr homozygotes. Cross-resistance to trichlorfon, which in part results in the 4–10-fold increased tolerance to pyrethroids observed in strains lacking kdr, was insufficient to cause control failure. The quantification of the relationship between the frequency of an insecticide-resistant genotype, levels of resistance as measured by bioassays and control failure in the field provides the means of forewarning when control failure is likely to occur and of confirming resistance as the cause when it has taken place.
Relative fitness of organophosphate-resistant and susceptible strains of Culex quinquefasciatus Say (Diptera: Culicidae)
Authors: Amin A. M. , White G. B.
Published: July 2009

The effects of chlorpyrifos resistance on fitness in Culex quinquefasciatus Say was evaluated in terms of life-span, fecundity, fertility and rate of development, and these parameters were integrated by calculating the intrinsic rate of natural increase. A chlorpyrifos-resistant strain from Tanzania had very significantly reduced biotic fitness compared to a standard susceptible strain, CfCA, from Sri Lanka. However, after five generations of backcrossing the resistant gene into the genetic background of the susceptible strain, fitness was found to be closer to that of the susceptible strain. The reduced fitness of the original Tanzanian strain therefore appears to be mainly due to background genetic factors rather than to the major resistance gene itself.
Studies in South America of arthropods on the Salvinia auriculata complex of floating ferns and their effects on S. molesta
Authors: Forno I. W. , Bourne A. S.
Published: July 2009

Insects and mites associated with each species in the Salvinia auriculata complex were recorded in Trinidad, Venezuela, Guyana, Brazil, Uruguay, Paraguay and Argentina. There was a consistent pattern of herbivore-plant association throughout the range of the complex. Field studies showed that three insects, the curculionid Cyrtobagous sp., the pyralid Samea multiplicalis Gn. and the pauliniid Paulinia acuminata (Deg.), together contained Salvinia molesta at a density slightly below the carrying capacity of the environment in coastal areas of Brazil.
A field study of the predators of the grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae), in winter wheat in Britain
Authors: Holmes P. R.
Published: July 2009

In a field study of Sitobion avenae (F.) in winter wheat at Cranfield in southern England, the main predators were found to be the larvae of the staphylinid Tachyporus sp. and syrphids. Most predation occurred overnight. These predators were active during the period when the wheat crop was most suitable for aphid population increase, and in 1982 were apparently responsible for preventing an outbreak at Cranfield.
Winter mortality, development and reproduction in a field population of Myzus persicae (Sulzer) (Hemiptera: Aphididae) in England
Authors: Harrington R. , Xia-Nian Cheng
Published: July 2009

Population change in Myzus persicae (Sulz.) overwintering on spring cabbage in south-eastern England was studied in relation to meteorological and biological factors. Leaf surface wetness and temperature were correlated significantly with rate of population change, but rainfall and wind were not. Growth and development continued slowly throughout the winter, and the relationship with temperature is shown. Hymenopterous parasites, the fungus Entomophthora and predatory spiders did not affect winter survival.
On the accuracy of age-grading neotropical Phlebotomines by counting follicular dilatations: first laboratory experiments, using colonies of Lutzomyia flaviscutellata (Mangabeira) and L. furcata (Mangabeira) (Diptera: Psychodidae)
Authors: Ready P. D. , Lainson R. , Wilkes T. J. , Killick-Kendrick R.
Published: July 2009

‘Blind’ trials using laboratory-bred females that had completed 0–3 gonotrophic cycles showed that Polovodova's method of assessing parity, by noting the presence of follicular dilatations, is applicable to Lutzomyia flaviscutellata (Mangabeira) and L. furcata (Mangabeira). However, at the resolution of the techniques used, classification is limited to a simple division into nulliparous and parous flies. The presence of granules in the ovarian accessory glands was found to be an unreliable indicator of parity for both species.
Reduced fecundity ofPsoroptes ovis(Hering) (Acari: Psoroptidae) on calves treated with ivermectin
Authors: Guillot Frank S. , Wright Fred C.
Published: July 2009

Ivermectin injected subcutaneously into calves at the rate of 200 μ/kg body weight completely eliminated females ofPsoroptes ovis(Her.) in 22 days. Injection of ivermectin also adversely affected the number and hatch of eggs and the proportion of adult males forming attachment pairs. The reduced number of eggs recovered in skin scrapings was apparently the result of a significantly lower fecundity among females that temporarily survived on treated calves. Females that were exposed to ivermectin for only three days did not recover their full reproductive potential even though they were transferred to calves not injected with ivermectin. The proportion of ovigerous females among survivors was not significantly affected five days after injection. Since the number of eggs recovered in skin scrapings was substantially reduced after only three days, the effect of ivermectin on female fecundity was not primarily gonadal. Reduction in the number ofP. oviseggs three days after treatment probably occurred because of a combination of mortality of adult females and reduced oviposition by ovigerous females surviving in the population.
A new look at thrips (Thysanoptera) mouthparts, their action and effects of feeding on plant tissue
Authors: Chisholm I. F. , Lewis T.
Published: July 2009

To elucidate how thrips feed, the mouthparts of Limothrips cerealium (Hal.) were examined in dead specimens by scanning electron microscopy and plasma-ashing, and in living specimens by cinematography as individuals fed through a transparent membrane on clear liquid containing small polystyrene latex particles that made its flow visible. Close contact with the food substrate was maintained by the labral pad. The single mandible was used to pierce the membrane and was then withdrawn rapidly and replaced by the maxillary stylets, which formed a tube with either a terminal or sub-terminal opening into which food was drawn by cibarial pumping at 2–6 pulsations/s. Oscillations in the surrounding fluid caused by such pumping were detectable up to 58 μm from the maxillary opening. Feeding persisted from a few seconds to up to half an hour, and when complete the stylets were withdrawn either rapidly and together, or more gradually by sliding one against the other. Whole chloroplasts up to 6 μm in diameter were ingested even though the diameter of the maxillary tube was about 1 μm. The thrips consumed the contents of ruptured plant cells at about 8·5 × 1O-5 μl/min, equivalent to almost 12·5% of their body weight per hour. Probing and feeding removed the surface wax from leaves, and the cuticle was so exposed that it often wrinkled. Leaf cells beneath a pierced epidermal cell were usually emptied completely, and little seepage from the wounded tissue occurred after stylet withdrawal. After intensive feeding, many mesophyll cells were totally destroyed and others showed extreme plasmolysis; grana sacks were contorted and large starch grains formed due to desiccation. Above such internal damage the epidermal cells collapsed, and the outer cuticle wrinkled and appeared silvery before turning yellow and brown.
Wing fray inGlossina morsitans centralisMachado (Diptera: Glossinidae)
Authors: Allsopp R.
Published: July 2009

A study of wing fray and ovarian age in females ofGlossina morsitans centralisMachado in Botswana confirmed that although the relationship between the two was strong it varied from month to month. The rate of wing fray with age was greatest in the hot dry season, and in both very young and very old females it was affected by humidity. Both age and activity are manifested as fraying of the wings, but it is considered unlikely that wing fray could be used as a reliable measure of either. It is suggested that wing fray may impose a physiological limitation on the lifespan of tsetse flies and may consequently be a factor in population regulation.
Circadian flight activity ofSimuliumspp. (Diptera: Simuliidae) sampled with a vehicle-mounted net in central Nigeria
Authors: Roberts D. M. , Irving-Bell R. J.
Published: July 2009

A vehicle-mounted net was used to study the circadian flight activity of several species ofSimuliumin a northern Guinea savanna area in Nigeria during the dry season. The sampling method yielded large numbers of both sexes ofSimulium squamosum(Endertein) of the,S. damnosumTheobald complex,S. hargreavesiGibbins,S. voraxPomeroy,S. adersiPomeroy,S. hirsutumPomeroy and other species. The main peak of activity of all species recorded occurred just after sunset and there was a smaller peak just before sunrise. Flies continued to be caught at a low level 2·5 h after sunset when sampling ceased. Differences in the activity patterns ofS. squamosummales and females and of the other species were analysed. Of theS. squamosumfemales caught, 12% were blood-fed; these and gravid females were mainly active in the evening, while the blood-thirsty flies had a high level of activity throughout the day. Differences between species in the relative activity of blood-thirsty and gravid flies, and nulliparous and parous flies are noted.
The effect of larval rearing conditions on flight performance in females of the African armyworm, Spodoptera exempta (Walker) (Lepidoptera: Noctuidae)
Authors: Parker W. E. , Gatehouse A. G.
Published: July 2009

The effect of quantitative and qualitative differences in maize leaf fed to larvae of Spodoptera exempta (Walker), and of larval density, on flight duration in female moths was investigated using a tethered-flight technique. Neither food deprivation nor diets of water-stressed maize influenced the proportion of moths flying for long periods. However, a significant increase in the incidence of long flights was recorded in moths from larvae reared at high densities. Significant differences were observed in the weights and sizes of moths from the different larval treatments. Wing-loading was shown to be a function of moth weight, with lighter moths having lower wing-loadings. However, wing-loadings of long-flying moths and those of short-fliers were similar, and it is concluded that the migratory potential of females of S. exempta cannot be predicted from moth weight or morphometric data. A feature of the results was the variable proportion of long-flying moths in the test and control groups, irrespective of larval treatment. Re-examination of the data showed that a high incidence of long flights was evident in the experimental insects at approximately one-generation intervals, and it is suggested that there is a major genetic component in the determination of flight capacity in this species.
Interpretation of the flight activity of Nilaparvata lugens (Stål) and Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) based on comparative trap catches and field marking with rubidium
Authors: Perfect T. J. , Cook A. G. , Padgham D. E. , Crisostomo J. M.
Published: July 2009

Detailed studies were conducted over a five-year period at a rice farm in the Philippines on the flight activity of Nilaparvata lugens Stål) and Sogatella furcifera (Horváth). Suction traps were used to measure aerial density, and catches included immigrants, emigrants and insects undertaking trivial flight. Activity was partitioned using a variety of other trap types. Emigration was effectively monitored using net canopy traps and immigration was best measured using green water traps. Yellow water traps also measured immigration, but when macropterous adults were being produced within the plot, insects undertaking trivial flight were also caught. The light-trap caught immigrant and over-flying migrant insects.
Studies on the biology of Aphidius sonchi Marshall (Hymenoptera: Aphidiidae), a parasite of the sowthistle aphid, Hyperomyzus lactucae (L.) (Hemiptera: Aphididae)
Authors: Shu-Sheng Liu , Carver Mary
Published: July 2009

The hymenopterous parasite, Aphidius sonchi Marshall, has been introduced into Australia as a biological control agent of the sowthistle aphid, Hyperomyzus lactucae (L.), the principal vector of lettuce necrotic yellows virus disease. Some aspects of its biology were studied in the laboratory. Females reared at 22°C contained a mean ± s.e. of 179·4 ± 10·26 eggs on emergence, and more eggs were formed during adult life. Unmated females produced male progeny only; mated females produced progeny of both sexes. At 22°C, both males and females mated within 12 h of emergence. Virgin females could mate successfully after having commenced oviposition and switch to producing progeny of both sexes. At 20°C, both virgin and mated females started oviposition within 7 h of emergence. The female oviposited in all nymphal instars and both apterous and alate adults of the host. Only one egg was laid per insertion of the ovipositor. Superparasitization was common, but only one parasite per aphid survived to the adult stage. Females at 22°C and LD 12:12 oviposited during both the photophase and the scotophase; the proportion of eggs laid in the scotophase was correlated with the availability of hosts. Adult females lived longer in the absence of hosts than in their presence and lived longer than males, and those supplied with water and honey lived longer than those without. Facultative diapause occurred. The integumental coloration of adults varied according to the temperature during their immature stages. Females of A. sonchi oviposited readily in Macrosiphum euphorbiae (Thomas), but their progeny did not develop beyond the egg stage. A. sonchi was parasitized by Alloxysta ancylocera (Cameron), Pachyneuron aphidis (Bouché) and Dendrocerus carpenteri (Curtis) in the field.
The use of 1-octen-3-ol, acetone and carbon dioxide to improve baits for tsetse flies, Glossina spp. (Diptera: Glossinidae)
Authors: Vale G. A. , Hall D. R.
Published: July 2009

In Zimbabwe, the catches of Glossina morsitans morsitans Westwood and G. pallidipes Austen in traps were increased by up to three times by releasing 1-octen-3-ol at 0·05–50 mg/h or acetone at 5–5000mg/h near traps, but in some circumstances 1-octen-3-ol at 5–50 mg/h reduced catches. Carbon dioxide at 0·02–20 litres/min increased catches by up to ten times. A mixture of all three chemicals increased the catches by up to 60 times. Each of the three chemicals attracted both species of flies from a distance; carbon dioxide also enhanced trap-entering and alighting responses. Acetone with 1-octen-3-ol can increase by several times the numbers of flies that contact visual baits suitable for exposing them to insecticide. Data for other Diptera are also presented.
Assessment of the field performance of compound chromosome strains compared to laboratory-reared wild-type strains in Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)
Authors: Smith P. H. , Morton R.
Published: July 2009

An assay based on recovery rates of released laboratory-reared flies was used to compare the field performance in Australia of a series of strains bearing compound chromosomes with that of wild-type strains of Lucilia cuprina (Wiedemann). The compound chromosome strains tested all performed less well than the wild-type strains. Four of the former were recovered on average 0·37 times as readily as the average wild-type strain, and one was recovered 0·65 times as readily. The compound chromosome strains differed in the selection pressure they had been exposed to in the field, which had selected among the various compound chromosomes in an original strain and in the extent to which their non-compound chromosomes had been replaced by recently collected field material. The strain that performed best had been exposed to the most severe selection pressure, overwintering in the field, and had had much of its non-compound genome replaced. Among the group of strains with similar performance, some had had their non-compound genome replaced with field genetic material.
Studies on insecticide-impregnated targets for the control of riverine Glossina spp. (Diptera: Glossinidae) in the sub-humid savanna zone of Nigeria
Authors: Oladunmade M. A. , Takken W. , Dengwat L. , Ndams I.
Published: July 2009

Insecticide-impregnated blue cotton targets 70 × 110 cm weretested for the control of Glossina palpalis palpalis (Robineau-Desvoidy) and G. tachinoides Westwood in riverine fringing forests in central Nigeria, under wet-season conditions. Following exposure to treated cloth for 1·5 min, delta-methrin caused 100% mortality of G. p. palpalis for six weeks at 0·05% and for 13 weeks at 0·1%. Dieldrin at 5% was not very effective. At 4%, endosulfan initially caused a high mortality, but rapidly lost its activity, especially against females. By chemical analysis, 43% of deltamethrin applied to the fabric was found to have been lost within 12 weeks, in which 230 mm of rainfall was recorded. Placed 150 m apart in a fringing forest, targets impregnated with 0·05% deltamethrin caused a rapid decline in the G. p. palpalis population, and after 12 weeks only 5% of the original density was recorded. No further reduction or significant increase was observed during the following six months, though it appeared that flies caught during this period had immigrated from an adjacent undisturbed riverine forest. The effect on G. tachinoides was less dramatic, but this may have been due to the low initial density of this species, and to its greater mobility, giving rise to reinvasion from elsewhere.
An oviposition attractant pheromone in Culex quinquefasciatus Say (Diptera: Culicidae)
Authors: Laurence B. R. , Pickett J. A.
Published: July 2009

Gravid females of Culex quinquefasciatus Say from a laboratory strain originating in Nigeria orientated to a source of the main volatile pheromone component, erythro-6-acetoxy-5-hexadecanolide, isolated from the apical droplets of the egg rafts. Significantly more egg rafts were laid around polystyrene discs treated with the synthetic compound than around untreated discs, and modification of the chemical structure destroyed its biological activity. The response was found at a dose of 0·02μg of the synthetic compound, which is equivalent to one-sixteenth of the total acetoxyhexadecanolide found in an egg raft, and above. Although the apical droplets were contaminated by bacteria, these did not contribute to the production of the acetoxyhexadecanolide, which was present in the eggs before they were laid. It is concluded that the pheromone is released slowly from the apical droplets into the air above the water surface, attracting other gravid females to oviposit around previously laid egg rafts, and there is evidence of attraction over a distance of 5·5 cm.
The influence of weather and time of day on trap catches of males and females of Lucilia cuprina (Wiedemann) (Diptera: Calliphoridae)
Authors: Vogt W. G. , Woodburn T. L. , Morton R. , Ellem B. A.
Published: July 2009

Differences in responses of males and females of Lucilia cuprina (Wiedemann) to carrion-baited traps were examined in Australia in relation to time of day, temperature, wind speed, relative humidity and solar radiation. The differences were small compared with responses obtained for the combined sexes (total catch), but the results were inconsistent over the four seasons of trapping. The seasons with most data (1975–1976 and 1981–1982) gave reasonably consistent results. Seasonal differences, although significant, were small enough to neglect for the purpose of standardizing trap catches. Time-of-day effects were also unimportant, except that males tended to be less active than females during the early morning (dawn-0900 h) and more active than females during the late afternoon (1500 h-dusk). Separate models are presented for standardization of male and female catch rates; the estimates differ from those obtained from total catches, but the differences are small compared to the observed day-to-day variation in catch rates.
Bruchophagus muli sp. n. (Hymenoptera: Eurytomidae), a wasp which galls the fruit of lime in Papua New Guinea
Authors: Bouček Z. , Brough E. J.
Published: July 2009

Bruchophagus muli sp. n. is described and compared to a similar Australian species, B. fellis (Girault). Both wasps attack citrus; B. muli galls the fruit of lime (Citrus aurantifolia) while B. fellis galls the twigs of a number of citrus varieties in Australia, including lemon, orange and grapefruit. B. muli appears to be restricted in distribution to the southern region of Papua New Guinea
Inheritance of the ability of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) to feed and breed on yellow split-pea (Pisum sativum)
Authors: Holloway Graham J. , Smith Robert H.
Published: July 2009

Sitophilus oryzae (L.) is a pest of stored cereals and, because most populations are unable to survive on yellow split-pea and other legumes, admixture of legume with cereal has been suggested as a control method. However, some geographical strains have been found able to feed and breed on yellow split-pea. The ability is heritable and known to be controlled in one strain by a single recessive, autosomal gene. The inheritance pattern of the ability was investigated in three different geographical strains, two of which could feed and breed on yellow split-pea and one which could not. The genetic mechanism controlling the character in these strains was not a simple recessive allele, but differed between the two pea-breeding strains and was co-dominant with the inability to feed on yellow split-pea inthe non-pea-breeding strain. The results indicate there is considerable between-strain genetic variability for the character, which may render cereal-legume mixture of little value as a control method against S. oryzae.
A device for simultaneously homogenizing numbers of individual small insects for electrophoresis
Authors: Brookes C. P. , Loxdale H. D.
Published: July 2009

A simple Perspex and stainless steel device is described suitable for rapid, simultaneous homogenization of numbers (60) of small insects individually for electrophoresis. Since this device significantly decreases the time taken for preparation of samples (commonly a rate-limiting stage in electrophoretic studies), it may be of value to other workers in entomology and insect population genetics.