bluuebunny/crossref_metadata_2025 huggingface dataset:
Dispersal of the sugar-cane scale Aulacaspis tegalensis (Zhnt.) (Hem., Diaspididae) by air currents
Authors: Greathead D. J.
Published: July 2009

By means of sticky traps and a suction trap, it was demonstrated on a plot of sugar-cane at Kawanda Research Station, Uganda, that large numbers of crawlers of Aulacaspis tegalensis (Zhnt.) become airborne (up to 10/m3). The numbers increase with wind speed up to about 2·0 m/s and then remain constant, but are depressed by increasing humidity. In laboratory experiments, crawler survival was reduced by high temperatures (30°C) and low humidities (30% r.h.), but some individuals should survive the extreme conditions sometimes experienced if airborne from morning until evening. On hatching, crawlers move upwards and towards the light, but downwards in the dark; movement is inhibited by high humidity. These behaviour responses indicate hat the presence of crawlers in the air is not accidental but a dispersal mechanism. At Arusha Chini, an isolated sugar estate in Tanzania, sticky-trap catches downwind of a windbreak confirmed that airborne dispersal of crawlers is a major source of infestation. It is shown that air currents could have carried crawlers to Arusha Chini from a source on the Kenya coast, 260 km to the east.
Field and laboratory studies on the adults of Ascotis selenaria reciprocaria (Wik.) (Lep., Geometridae), a pest of arabica coffee in Kenya
Authors: Abasa Ruben O.
Published: July 2009

In arabica coffee estates at Kahuguni and Magogoni, Kenya, female giant looper moths, Ascotis selenaria reciprocaria (Wlk.), rested on coffee tree stems at 60·7 ± 9·8 cm above ground and males at 65·7 ± 6·6 cm; most eggs were laid less than 122 cm above ground. In the laboratory, females laid on average 693 eggs in 5·3 batches; peak oviposition and fertility were 2–3 days after emergence. Life span was 8·3 days for females and 10·4 days for males; at death females contained 1·4 spermatophores each (1·1 in field-collected specimens). It is concluded that hand-picking of moths will have little control value unless done the day after emergence, but that tree-banding with residual insecticide 122–130 cm above ground would kill 90% of the emerging larvae.
Insect chemosterilants: a review
Authors: Campion D. G.
Published: July 2009

In this paper the present status of insect chemosterilants is reviewed. Chemosterilants may be categorised into eight main chemical groups. Practical control measures involving the use of chemosterilants are discussed, also the persistence of these substances when applied to the insect. The gross effects of chemosterilants on insect reproductive systems and also the effects on egg develpment when female insects are mated to chemosterilised males are described, including dominant lethality, reciprocal translocation, enzyme inhibition and sperm inactivation. The possibilities of recovery of fertility and insect resistance to the sterilising effects of chemosterilants are discussed. Endocrine misfunction and chemosterilant action are related. The only practical chemosterilants as control agents are the aziridines although mutagenic hazards associated with these substances preclude their widespread usage. The sterilising activity of certain insect hormone analogues and related substances encourages the belief that safe insect specific sterilising agents can be found.
Cacao pollination: Microdiptera of cacao plantations and some of their breeding places
Authors: Winder John A. , Silva Pedrito
Published: July 2009

Counts were made of Microdiptera hatching in emergence traps from samples of organic substrates from cacao plantations in Bahia, Brazil. Rotten cacao pods provided the best substrate with regard to species diversity and total numbers of insects collected, and also for the subgenus Thyridomyia. Leaf-litter was found to be an important breeding place for the subgenus Forcipomyia, especially F. {F.} genualis (Lw.), and for Atrichopogon species. Epiphytic bromeliads may be an important breeding place for the pollinating subgenus Proforcipomyia.
New species of Exitianus Ball (Homoptera, Cicadelloidea, Euscelidae) from Africa
Authors: Ghauri M. S. K.
Published: July 2009

Exitianus curvipenis (representing a new sixth species-group) from rice-field grasses in Nigeria, and E. upenis (okahandia-group) from open grassland in Abyssinia are described as new.
A comparison of the susceptibility of the rice varieties, IR8 and Warangal 1263, to attack by the gall midge, Pachydiplosis oryzae (Wood-Mason)(Dipt., Cecidomyiidae)
Authors: Modder W. W. D. , Alagoda A.
Published: July 2009

Daily observations were made of the developmental stages of Pachydiplosis oryzae (Wood-Mason) on laboratory-infested IR8 and W1263 rice seedlings at Peradeniya, Ceylon. The previously observed resistance of W1263 was attributed to the inhibition of moulting of first-instar larvae in 40% of the terminal shoot apices. In comparisons of the two varieties, differences in the following parameters were not significant or of no importance: the numbers of P. oryzae eggs laid and their hatching time, the mortality rates of the developmental stages, the number, body length and activity of the larvae and pupae at the terminal apices, and gall length.
Distribution, biology and ecology of Dentichasmias busseolae Heinr. (Hym., Ichneumonidae), a pupal parasite of graminaceous stem-borers (Lep., Pyralidae)
Authors: Mohyuddin A. I.
Published: July 2009

Dentichasmias busseolae Heinr., an important pupal parasite of Pyralid graminaceous stem-borers in East Africa, is widely distributed in the Ethiopian Region but is more abundant in areas with an equatorial humid climate. In the laboratory adults mated immediately after emergence and started oviposition the same day. The female oviposits only in a borer pupa without a cocoon in a stem, and oviposition is stimulated by the presence of the frass of Chilo partellus (Swinh.) larvae. D. busseolae does not attack Busseola fusca (Fuller), Sesamia calamistis Hmps. or Eldana saccharina Wlk. in the field but these were accepted for oviposition when exposed in C. partellus pupation tunnels or with frass of C. partellus larvae, and were suitable for development. D. busseolae could complete its development in one- to eight-day-old C. partellus pupae when the pupal period of C. partellus was 10·5 days. The life-cycle was completed in 15–19 days at a mean temperature of 25°C, but could not be completed at a constant temperature of 30°C; temperatures fluctuating between 22°C and 30°C were not detrimental. At Namulonge (Uganda) percentage parasitism showed a positive correlation with rainfall, with a lag of about a month.
Descriptions of new Eulophid parasites (Hym., Chalcidoidea) from Africa and the Canary Islands
Authors: Bouček Z.
Published: July 2009

Three new species and one new genus of Eulophidae are described, namely,Wichmannia pictipennissp.n., reared from small bark beetles living inEuphorbiain the Canary Islands,Myrmokata diparoidesgen.et sp.n. which parasitises ants of the genusCrematogasterin Cameroun, andColpixys gigassp.n. which destroyed more than 80% of the larvae of a Languriid beetle in the stems of elephant grass in Ghana. The generaWichmanniaRuschka andColpixysWaterston previously each included only one species.
A new genus and species of Coelidiinae (Homoptera, Cicadelloidea) from Iraq
Authors: Ghauri M. S. K.
Published: July 2009

Iraqerus neveosparsus sp.n. is described from Quercus spp. in Iraq and a key is given separating the new genus from Stegelytra Mulsant & Rey and Iberia Kirkaldy.
The seasonal incidence of biting flies (Diptera) in Rwenzori National Park and Kigezi Game Reserve, Uganda
Authors: Kangwagye T. N.
Published: July 2009

Between January 1965 and August 1967 49 species of biting flies were caught in Langridge and Fredeen traps and from bait animals in western Uganda. Catches were recorded daily, and monthly catches (geometricmeans) of the species most frequent on bullocks were plotted as percentages of the year's catch. Haematobia minuta (Bez.) was the only species to show a unimodal peak; this is attributed to maintenance of soil conditions suitable for the larvae during the short rains (September-November). Bimodal peaks are shown by Haematopota brunnescens Ric, H. patellicorne (End.),Tabanus par Wlk., Stomoxys inornata Grünb., S. nigra nigra Macq. and Haematobosca squalida (Grünb.) (adversely affected by severe dry conditions), by T. taeniola P. de B. and T. thoracinus P. de B. (emergence from pupae coincides with the beginning of the rainy seasons (March-May and September-November)), by Stomoxys omega Newst. and Haematobiaspinigera Mall, (minimum numbers in the wet months September-October), and by species of Haematopota, Tabanus, Chrysops, Stomoxys and Haematobosca(breeding occurs in the rainy seasons). Ill defined cycles are shown by Chrysops distinctipennis Aust, C. longicornis Macq., S.ochrosoma Speiser and females of S. calcitrans (L.) ; Glossina fuscipesNewst., G. fuscipleuris Aust. and G. pallidipes Aust. showed minimum numbers in September-October.
The range of attraction of birds as baits for Some West African mosquitoes (Diptera, Culicidae)
Authors: Gillies M. T. , Wilkes T. J.
Published: July 2009

The long range orientation of West African mosquitoes to birds was studied using ramp-traps set up 3–23 m from the bait. The baits comprised chickens, ducks, pigeons and the carbon dioxide equivalent of the chickens. From the pattern of convergence of mosquitoes to the baits, it was shown that Anopheles melas Theo. and Culex thalassius Theo. were orienting to all the bird-baits from distances of at least seven metres. Responses to carbon dioxide were only apparent at a distance of three metres indicating the greater range of effect of the chickens over their carbon dioxide equivalent. Mosquitoes of the largely bird-biting C. decens group showed no long range response to any bait, even though they were entering pigeon-baited traps and to a limited extent feeding on the birds. Catches of A. melas in bird-baited traps were larger at the foot of a tall tree than in the foliage at 5·33 m; for Culex spp. the converse was true. Catches of Culex at 5·33 m outside the tree were smaller than within the foliage.
Effects of light-trap design and illumination on samples of moths in an English woodland
Authors: Taylor L. R. , French R. A.
Published: July 2009

Operated in sheltered woodland, the samples obtained by Rothamsted tungsten-filament and Robinson mercury-vapour traps are best described by a spatial model different from that used in a site exposed to wind. Differences between the proportions of Noctuidae and Geometridae were accountable to differences in height of flight. The Rothamsted traps gave more consistent samples than the Robinson traps and averaged about onequarter the number of moths.
Life-cycle variation ofMyzus persicae(Sulz.) (Hom., Aphididae) in different parts of the world, in relation to genotype and environment
Authors: Blackman R. L.
Published: July 2009

Life-cycle variation, involving alternative methods of overwintering (holocycly and anholocycly), is found in many important pest aphids, and may have considerable ecological, genetic and economic significance. The occurrence of life-cycle variation in Myzus persicae (Sulz.) in different parts of the world is reviewed. The holocycle ofM. persicae, with sexual reproduction and overwintering of eggs on Prunus, occurs in the temperate regions of every continent, and although anholocycly is widespread in warm climates there are indications that the potential for sexual reproduction may be retained throughout the whole range of the species. The environmental factors involved in the determination of sexual morphs are considered. Photoperiodism provides the timing mechanism for sexual morph production, and the photoperiodic response is probably tuned to different regional conditions and buffered against other environmental variables within certain limits. The only other environmental factor clearly implicated in sexual morph production is temperature, and an attempt is made to correlate the global pattern of life-cycle variation inM. persicaewith temperature differences between regions, by dividing the world into six zones delimited by selected isotherms. The overall pattern of life-cycle variation can be explained largely on the basis of climatic differences between zones, and the effects of these differences on gene and genotype frequencies within the species. Clones of androcyclic character seem to be widespread and, although genetically isolated anholocyclic biotypes undoubtedly exist, androcyclic clones could be the principal source of parthenogenetic overwinterers in all parts of the world where life-cycle differences exist within populations.
A field comparison of the modes of action of aldrin and mirex for controlling colonies of the leaf-cutting ants Atta Cephcdotes (L.) and Acromyrmex Octospinosus (Reich) (Formicidae, Attini)
Authors: Peregrine D. J. , Cherrett J. M.
Published: July 2009

Two toxic baits, one containing aldrin and the other containing mirex, were compared for their effectiveness in killing field colonies of Atta cephalotes (L.) and Acromyrmex octospinosus (Reich) in Trinidad, West Indies. The fate of these two toxicants within tie nests was followed by using radiolabelled bait. Of the two baits, mirex appeared to be more acceptable to both species of ant. With Acromyrmex, the ratio of living to dead fungus gardens was not affected by the bait used, whereas with Atta there was a significant difference, aldrin killing many more gardens than mirex. For both species the proportion of medium-sized workers radiolabelled was significantly greater than for the other castes, and mirex marked greater numbers of all castes than did aldrin. Greatly different proportions of Atta workers were radiolabelled in the different fungus gardens of a nest with both baits. More radioactivity was detected in the fungus gardens treated with mirex, the difference being significant for Atta but not for Acromyrmex. Mirex bait particles incorporated into the fungus gardens were significantly smaller than aldrin bait particles, indicating different degrees of comminution by the ants.
The economics of controlling froghopper (Aeneolamia varia saccharina (Dist.) (Hom., Cercopidae)) on sugar-cane in Trinidad
Authors: Norton G. A. , Evans D. E.
Published: July 2009

The management of the sugar-cane crop in Trinidad involves widespread aerial spraying against the sugar-cane froghopper (Aeneolamia varia saccharina (Dist.)). For control decisions to be made on an economic basis, information concerning the damage and control relationships associated with this pest is required. Assuming a linear damage function, a cost-effective analysis based on the relative cost of eliminating adult-days is made concerning the choice of insecticide and the decision—when to spray. It appears that a first-brood spraying strategy is more cost-effective than a strategy of later-brood spraying alone, provided that the density and duration of the first-brood can be accurately monitored.
Descriptions of the stages of Milionia Isodoxa Prout (Lepidoptera, Geometridae), a defoliator of hoop pine in papua New Guinea
Authors: Wylie F. R.
Published: July 2009

The egg, five larval instars and pupa of Milionia isodoxa Prout are described, and the adult is redescribed. Setal maps for the first and fifth larval instars are presented.
Feeding and associated behaviour of the adult cabbage root fly Erioischia brassicae (Bch.) (Dipt, Anthomyiidae) under laboratory conditions
Authors: Finch S.
Published: July 2009

Adults of the cabbage root fly (Erioischia brassicae (Bch.)) reared in culture were inactive on the day of emergence but they fed on carbohydrate (sucrose) and protein (Yeastrel) on day 2. Without food, the egg follicles increased to approximately one-third of their maximum size and were then resorbed. When food was available, females ingested sucrose on days 2 and 3 to mature the first batch of eggs, without any stimulus from mating. Without either a mate or a suitable oviposition site, females retained most of their eggs. Females obtained sufficient food for egg maturation by day 4, when their egg follicles were 400 μm, approximately half the size of the mature eggs. Only females mating on day 4 laid eggs at the expected time 6±0·3 days after emergence. With a suitable oviposition site, these females laid 299±48 eggs, approximately twice as many as any other females, and ten times as many viable eggs. When males were not allowed to mate, peak ingestion was delayed from days 8–12 to days 14–18. Mated females provided with an oviposition site laid most eggs on days 5 and 6 and fed again on day 7. This second peak of feeding was delayed until day 9 when mated females were denied, or unmated females were given, an oviposition site. Similar volumes of sucrose were imbibed by females whether they laid or retained their eggs. Females denied both a mate and a suitable oviposition site laid less than 1% of the expected eggs.
A new species of Actia R.-D. (Diptera, Tachinidae) parasitic on the coconut leaf moth, Agonoxena pyrogramma Meyrick, in New Britain
Authors: Crosskey R. W.
Published: July 2009

During recent work on the coconut leaf moth, Agonoxena pyrogramma Meyr., in New Britain, Mr. R. W. Paine has found that this insect, whose larvae live in the leaflets of the coconut palm, is parasitised by a very small Tachinid fly which belongs in the genus Actia R.-D.; this same Tachinid was briefly alluded to as an unidentified dipterous parasite of Agonoxena pyrogramma by O'Connor (1954). The Actia species concerned belongs in the group of species in which the fifth wing-vein (M3 + 4) is setulose, and seemed on first examination to be almost indistinguishable from A. darwini Mall., an Australian species common in Queensland. However, examination of the male genitalia has shown striking differences from A. darwini and it is evident that a new, closely allied, species is involved; this new species is described below. Following the description I have given a key to the Indo-Australasian species of Actia in which the fifth vein is setulose, so that A. painei sp.n. can be placed.
The larva and pupa of Mansonia (Coquillettidia) buxtoni (Edwards), 1923, (Diptera, Culicidae)
Authors: Coluzzi M. , Contini C.
Published: July 2009

In 1923, Edwards described under the name of Taeniorhynchus (Coquillettidia) buxtoni four cotype females captured by Buxton in September 1922 at Huleh, Jordan Valley (Palestine). A few years later, some females of the same species (determined by Edwards) were found by Brumpt in Corsica (Galliard, 1928): the Mediterranean and southern distribution of this mosquito was confirmed by the record of Mansonia buxtoni in Syria (Parr, 1943). Lastly, Aitken (1954) captured in Sardinia and Corsica some adults of M. buxtoni and described the structure of the male terminalia. The early stages, however, have remained unrecognised, and we have accordingly been led to make a morphological study of the larva and pupa, the results of which are presented here.
An all-metal cage for rearing locusts in the laboratory
Authors: Dudley B. , Gregory G. E. , Payne D. W.
Published: July 2009

Details are given of the construction of an all-metal form of locust rearing cage which possesses several advantages over the more usual wooden type.
Investigations on insecticidal seed dressings, soil treatments and foliar sprays for the control of Melanagromyza phaseoli (Tryon) in Ceylon
Authors: Wickramasinghe Nallini , Fernando H. E.
Published: July 2009

Three methods of chemical control of Melanagromyza phaseoli (Tryon) on bean (Phaseolus) have been investigated, these comprising seed and soil treatments and spraying of the foliage.

Organophosphorus and chlorinated hydrocarbon insecticides have been tested, chiefly as seed soaks, in the control of the pest. Applied in this way, the former gave poor protection, whereas the chlorinated hydrocarbons, especially the cyclodiene compounds, aldrin, dieldrin, endrin and chlordane, gave adequate protection. Reduction of the period of soaking led to better germination of treated seed. When seed-borne diseases were present, soaking in water or insecticidal solution enhanced their incidence. Bean varieties varied in their response to soaking in water or the insecticidal fluids used, the germination of most varieties being adversely affected. Endrin 20 per cent, emulsifiable concentrate (E.C.) used at a dilution of 1:250 as a soak for six hours or at a dilution of 1:125 for three hours or 1:50 for momentary dipping or up to an hour's soaking, gave good germination and protection from M. phaseoli with the climbing bean variety Kentucky Wonder but reduced very considerably the germination of several other varieties.

Where soil was treated with various insecticides for control of M. phaseoli. pre-sowing treatment was more effective in protecting the bean plant from this seedling pest than treatment given after seedling emergence. Soil treatment with endrin did not induce phytotoxic symptoms in those varieties that were adversely affected when the seeds were soaked in emulsified solutions of endrin.

Foliar spraying with DDT 18 per cent. E.C. at one fl. oz. per gal., endrin 20 per cent. E.C. at 0·5 fl. oz. per gal. or parathion 46 per cent. E.C. at 2 ml. per gal. at weekly intervals up to the time of flowering was very effective in controlling M. phaseoli.

The efficient control of the pest obtained with pre-sowing treatment of soil or seed suggests that the insecticides concerned may have been acting systemically. Laboratory studies on the life-cycle of the pest in plants derived from treated and untreated seed show that endrin (which was the only insecticide studied in detail in this way) has a larvicidal effect when used as a pre-sowing treatment.
Oviposition in DDT-resistant and susceptible strains of Aedes aegypti (L.): time from blood-meal to oviposition
Authors: Wood R. J.
Published: July 2009

Oviposition time (the time from blood-meal to egg deposition) has been investigated in five strains of Aedes aegypti (L.), two being DDT-resistant (from Trinidad and Haiti) and three susceptible (from West Africa (2) and Haiti). All the strains except the two DDT-resistant ones differed significantly from one another in mean oviposition time.

There was a close correlation between mean oviposition time, oviposition period (the over-all period during which eggs are laid) and ‘oviposition light preference’, both the former being greater in the ‘dark-laying’ strains than in the ‘light-laying’ ones. There was a positive correlation amongst four of the strains between degree of DDT-resistance and both mean oviposition time and oviposition period; the fifth, which combined long oviposition time with susceptibility to DDT, was a recently colonised West African strain.

In small mass crosses between two strains differing markedly in mean oviposition time, this character showed no dominance; it appears to be under poly genie control. Evidence is given which indicates that there is no close genetic connection between oviposition time and DDT-resistance. There is also no obvious genetic association between oviposition time and ‘oviposition light preference’.

It is concluded that the observed differences in oviposition time may have come about as a result of DDT selection, but could equally well have been the result of a selective influence exercised by the laboratory environment.
The effects of temperature and humidity on the oviposition rate of Tribolium castaneum (Hbst.) (Coleoptera, Tenebrionidae)
Authors: Howe R. W.
Published: July 2009

The rate of oviposition of isolated pairs of Tribolium castaneum (Hbst.) on finely divided wheatfeed was measured over the entire adult life at 25°C. and 70 per cent. R.H. It was also measured over a period of seven weeks from the start of oviposition at 30 and 70 per cent. R.H. at 25, 30 and 35°C., respectively, at 70 per cent. R.H. only at 22·5, 27·5, 32·5 and 37·5°C. and at 2 per cent. R.H. at 30°C.

At 25°C. and 70 per cent. R.H. each female laid, on the average, 360 eggs at the rate of 2·5 per day for about one hundred days and then at a decreasing rate for the next hundred days. When this experiment was repeated over a seven-week period, each female laid on average about 3 eggs per day. At 70 per cent. R.H., the optimum temperature for oviposition was about 32·5°C., at which about 11 eggs per day per female were laid over the seven-week period. These rates fell to just over 2 per day at 22·5°C. Only one egg was laid by 15 females at 20°C. At 37·5°C. the rate was about 10 eggs per day initially but it declined to about 3 per day by the end of seven weeks, whereas at lower temperatures the decline in laying was slight. Compared with 70 per cent. R.H., the oviposition rate at 30 per cent. R.H. was almost halved at 25°C., but was only slightly reduced at 35°C. At 30°C. and 2 per cent. R.H., females laid well, averaging over 4 eggs per female per day. The periodic provision of water for drinking at 25°C. and 30 per cent. R.H. depressed oviposition.

The preoviposition period was 2 days at 37·5°C. and increased steadily at lower temperatures to 10 days at 22·5°C. It also varied more between females at low temperatures.

The number of eggs recovered in this work was lower than the number obtained by Park & Frank (1948), who used considerably more food in their oviposition chambers. In this work, some eggs were eaten by the adult beetles. However, the innate capacity for increase of the species calculated on these data is extremely high, and could not be maintained for long because of the cannibalistic habits of this species.
The age-composition of biting mosquito populations according to time and level: a further study
Authors: Corbet Philip S.
Published: July 2009

The age-composition of mosquitos biting at different times and levels was investigated in Zika Forest, Uganda. The four species studied wereMansonia aurites(Theo.) group (material mainly of actualM. aurites(Theo.) but probably including some examples ofM. microannulata(Theo.)),Aedes africanus(Theo.),A. ingramiEdw. andCulex annuliorisTheo. In each case the biting cycles of nulliparous and parous females were computed separately.

The material examined came from eleven 24-hour catches made by Dr. A. J. Haddow. Samples were taken at seven levels, at 20-ft. intervals, from the ground to a height of 120 ft. The top of the canopy was at 70–80 ft.

In each species the biting cycles of nullipars and pars were closely similar, both at the preferred level and at all levels combined. In only one case (that of the group ofM. aurites) was there a significant and consistent difference in the average age of females at different levels, there being a relative excess of older females above the canopy, as found previously inM. fuscopennata(Theo.). This difference persisted throughout the period of biting activity.

These and other recent findings are briefly discussed. It is concluded that the hypothesis which relates the form of the mosquito biting cycle to the age-composition of the biting population and to the larval habitat of the species concerned cannot be accepted as a valid generalisation.
Studies on Stomoxys calcitrans (L.) in Uganda, East Africa. II.—Notes on life-history and behaviour
Authors: Parr H. C. M.
Published: July 2009

Features of the development of Stomoxys calcitrans (L.) are described, based on observations in Uganda on stocks maintained in laboratory culture at 80°F. and 80 per cent, relative humidity. Eggs hatch within 24 hours of deposition, and the mean viability of 10 random batches was 76·5 per cent. The larvae are about 1 mm. long when newly hatched, reach maximum length (about 11 mm.) in the third (final) instar on the seventh day, and pupate one day later, the puparium being barrel-shaped and about 5 mm. long and 11 mg. in weight. The pupal period is two days. Females mate when six days old and oviposit 1–2 days later. The mean values, for five newly emerged, once-mated females, of total eggs laid, number of batches and duration of egg-laying (in days) were, respectively, 376, 10·6 and 12·2.

To be suitable for breeding of Stomoxys in the field in East Africa, sites require the presence of rotted cattle dung, rotted straw or foliage, and shade. In the dry season, such conditions occur only within cattle enclosures and particularly in the small, grass-thatched structures, provided with straw bedding, that are used for housing calves. In the wet season, suitable breeding conditions occur in open park-land and banana plantations, wherever rotted cattle manure and vegetation occur together.
Laboratory colonisation of Mansoniamosquitos
Authors: Laurence B. R , Page R. , Smith S. A.
Published: July 2009

A technique is described for maintaining colonies of mosquitos belonging to the genus Mansonia, subgenus Mansonioides, which have root-piercing larvae and pupae. The colonies are maintained in the absence of living plants. The females lay their eggs on discs of wet-strength crepe paper floating on the surface of water in small 10 × 6–cm. containers. Sheets of the same paper, 14 × 10 cm., stand vertically in the larval infusion bowls and the larvae attach themselves to, and pupate on, these sheets of paper, which contain air spaces. The papers are changed three times a week and this ensures an adequate air supply for the aquatic stages. The larval infusion is produced by soaking pellets of a proprietary animal-diet (Diet 18) in water, at the rate of 20 g. pellets per 1,500 cc. tap water, allowing to stand 3–7 days and using diluted 1:5 with water. The infusion in each larval bowl is stabilised by a block of turf, and yeast is added three times a week; this ensures a continuous supply of micro-organisms on which the larvae feed. The pupae are removed whilst still attached to the sheets of paper, these being transferred to covered bowls, containing tap water and a turf block, in which the adult mosquitos emerge. Pupal mortality is found to be about 40 per cent. With this technique, monthly production of adults has averaged about 2,000 and 1,300 in two insectaries, but has continued to fluctuate between wide limits. The fluctuations have not shown seasonal periodicity, but the numbers produced per month in the two insectaries are correlated significantly, although the insectaries are managed independently. This may reflect variations in the balance of micro-organisms in the standard nutrient infusions used, which could affect mortality amongst firstinstar larvae.
A rapid method for screening and evaluating mosquito repellents
Authors: Bar-Zeev Micha
Published: July 2009

A method is described by which candidate repellents can be rapidly screened and evaluated by comparing them with a standard repellent or with each other. Mosquitos are confined in a petri dish, of which the top is covered with mosquito gauze and the bottom lined with two semicircular filter papers, one of which is treated with a standard repellent, the other with candidate repellent. The dish is placed in an apparatus through which passes a slow stream of air of standard temperature and humidity. Counts of mosquitos are taken every half minute on and above the two halves of the petri dish, which is jarred after every second count to change the position of the mosquitos. A total of 40 counts is taken, the dish being rotated through 180° after the 20th count. The index of reaction is determined as the mean excess of position records for the candidate repellent over those for the standard one.

The initial effectiveness and the persistence of various repellents have been compared. In tests against Aedes aegypti (L.), the repellency of N, N-diethyl-m-toluamide and of O-chloro-N, N-diethyl benzamide did not differ, but each significantly exceeded that of dimethyl phthalate (DMP). The loss of repellency of DMP with time was approximately linear.

Attention is drawn to various aspects and applications of the method, and to its advantages, particularly for rapid screening of repellents.
A diurnal and seasonal study of the feeding activity ofGlossina pallidipesAust.
Authors: Pilson R. D. , Leggate B. M.
Published: July 2009

In a continuation of studies of diurnal and seasonal feeding activity ofGlossina pallidipesAust. in thick riverine vegetation at Rekomitjie, in the Zambezi Valley, Southern Rhodesia, flies attracted to a stationary black ox were allowed to become engorged, then caught, marked and released. More flies fed per day in the late dry season (November), and fewer during the rainy season (February), than at other times of the year. The proportions of females amongst flies feeding, and of marked flies recaptured, were greatest in May (77·6 and 20·0 per cent., respectively) and least in November (59·2 and 7·7 per cent., respectively). The diurnal pattern of feeding activity was similar in all seasons, there being a well-marked peak of activity at or shortly before sunset.

The trypanosome infection rate was obtained by dissecting flies caught near the experimental site and was combined with figures for the number of flies attacking the ox to give an estimate of the seasonal trypanosome risk (mean number of infected flies that fed on the ox per day); this was greatest in November and smallest in February.

From comparison of catches off a moving and a stationary ox, two stationary oxen standing together, and two standing out of sight of one another, in each case one being red and the other black, it appears that colour of the bait-animal is not of great importance as an attractant toG. pallidipesunless a definite choice is presented, when flies show preference for feeding on a dark surface.
The toxicity of some insecticidal sprays to adult locusts
Authors: MacCuaig R. D.
Published: July 2009

The toxicities of sprays of some insecticides used against locusts have been determined. The LD50's of γ BHC, diazinon, and dieldrin to both flying and settled adults of Schistocerca gregaria (Forsk.) were between 0·9 and 1·5 times those of the same formulations when applied as a single drop to the abdomen. The toxicity of these insecticides was not affected by the size of the spray droplets when these ranged from about 60 to 250 µ in diameter. The toxicity of DNC, however, was always less by spray application than when applied by micro-drop syringe and was affected by the droplet diameter (droplets of 100 µ being 1·5 times as toxic as those of 200–230 µ) and by whether the locusts were sprayed in flight or when tethered on a card (those in flight being about 1·6 times as susceptible to 100 µ droplets as those at rest). A tentative explanation of this effect is given.

The speed of action of the insecticides was compared and the effects of flight activity on susceptibility to the insecticides when sprayed over the flying insects was examined, but none could be detected by the technique used.
The Delphacid species-complex known as Sogata Furcifera (Horváth) (Homoptera: Fulgoroidea)
Authors: Fennah R. G.
Published: July 2009

Ten nominal species of DELPHACIDAE have hitherto been regarded as synonymous with Sogata, furcifera (Horv.), which is notorious as a pest of Graminaceous crops in eastern Asia. In a recent study it was established that two members of this complex represented distinct species, and it was accordingly considered necessary to re-examine the status of the remainder: the results of such a study are reported in this paper. The members of this complex now recognised as distinct species number more than twenty: some are restored from synonymy and others are described as new, and all, as appropriate, are referred to one of three genera, Matutinus Distant, Sogatella Fennah (here accorded generic status) and a new genus, Sogatodes. Most of the species in the complex are redescribed and a key is given for the separation of all.
A technique for exposing insects to insecticidal deposits on detached foliage
Authors: Gratwick M.
Published: July 2009

A technique is described for exposing insects to insecticidal deposits on detached foliage. Treated leaves are laid horizontally on boards with their petioles projecting through holes into water. Each insect is confined to the leaf surface by a small glass ring coated on its inner side with polytetrafluoroethylene and surrounded by a heavy metal ring to hold the leaf flat. This method is satisfactory for insects that do not spin webs and are unable to take off at a steep angle.
Interaction of two species of Cryptolestes (Coleoptera, Cucujidae)
Authors: Lefkovitch L. P. , Milnes R. H.
Published: July 2009

In order to seek at least a partial explanation of the differential occurrence of Cryptolestes turcicus (Grouv.) and C. ferruginous (Steph.), the interaction between different combinations of the larvae of the two species was studied when each newly hatched larva was provided with 12·5 mg. wheatfeed. It was found that the numbers of C. turcicus surviving to the adult stage in the presence of C. ferrugineus was a linear function of its own initial numbers, whereas the survival of C. ferrugineus seemed to be some function of the size of the environment. This conclusion, taken together with other data, suggests that if the two species were to gain access to cereals together, dry conditions, coarse food, low larval density and the availability of refuges for pupation would favour high populations of C. ferrugineus, whereas moist conditions, fine food, moderate to high larval density and the absence of refuges for pupation would favour high populations of C. turcicus.
Comparative food preferences of soil-, sand-, and wood-inhabiting wireworms (Coleoptera, Elateridae)
Authors: Zacharuk R. Y.
Published: July 2009

In a study of the larval feeding preferences of eleven species of Elateridae, representing Lepturoidini, Pyrophorini and Elaterinae, from soil, sand and wood habitats, all larvae were found to feed more on animal than plant food when these were offered separately. When given a choice, the larvae of only one species, Lepturoides linearis (L.), selected animal food exclusively and only those of Limonius minutus (L.) selected plant food exclusively. No consistent relationship was found between food preferences and taxonomic group, habitat, size, or morphology of the sense organs of the species. It is suggested that under laboratory conditions differences in food preferences among species are mediated primarily by differences in the physiology of their sense organs, and these may be an expression of different nutritional requirements among certain species.
Laboratory studies of insecticides against the coffee leaf-miner Leucoptera Meyricki Ghesq. (Lepidoptera, Lyonetiidae)
Authors: Wheatley P. E.
Published: July 2009

The coffee leaf-miners Leucoptera meyricki Ghesq. and L. caffeina Wshbn. are serious pests of arabica coffee in Kenya. At the present time sprays containing parathion, methyl-parathion or diazinon are used extensively for their control.

To facilitate preliminary investigations into various aspects of insecticidal control of the larval stages of these pests, a laboratory bioassay technique was developed. Larvae were reared on detached coffee leaves placed on moist filter paper in plastic boxes. When the larvae were in their third instar, the leaves were sprayed in a Potter tower and then kept in a moist air stream for three days before the mines were dissected to enable mortality counts to be made.

Of 22 new insecticides screened, only Sumithion (O, O–dimethy1 O–(3–methy1–4–nitrophenyl) phosphorothioate) and fenthion gave mortalities higher than those achieved with diazinon. Parathion gave somewhat higher mortalities than methyl-parathion, and emulsifiable formulations of these insecticides were more effective than wettable powders. The inclusion of additional wetting agents increased the efficiency of commercial formulations of these two insecticides. These results are subject to confirmation in field trials.

The mode of action of parathion was investigated. Dosage/mortality lines were constructed for parathion, methyl-parathion and diazinon so that resistance to these insecticides by L. meyricki could be detected should it develop at some future date. L. caffeina was found to be apparently more susceptible to these insecticides than L. meyricki and this was believed to be due to its greater rate of feeding.
Penetration of diazoxon and acetyl choline into the thoracic ganglia in susceptible and resistant houseflies and the effects of fixatives
Authors: Lord K. A. , Molloy Frances M. , Potter C.
Published: July 2009

The nerve sheath of the thoracic ganglion of the house-fly (Musca domestica L.) is readily permeable to diazoxon but is impermeable to acetyl choline and acetyl thiocholine. Acetone and other lipoidal solvents, but not formaldehyde, were found to destroy the barrier to entry of the substrates, acetyl choline and acetyl thiocholine, and it is inferred that the barrier is lipoidal. At − 16°C., acetone does not destroy the cholinesterase of the ganglion.

Cholinesterase associated with the ganglion could be divided into three regions which showed different inhibition characteristics: (a) ‘ superficial ’ enzyme outside the nerve sheath, inhibited by 3·3 × 10−8M diazoxon; (b) ‘ peripheral ’ enzyme in the cellular region of the ganglion, inhibited by 3·3 × 10−8M and 3·3 × 10−9M diazoxon; (c) ‘ central ’ enzyme in the synaptic area, inhibited by not less than 3·3 × 10−7M diazoxon. Using inhibition of cholinesterase as an indicator of penetration, no difference in permeability was found between the ganglia of the susceptible and resistant strains. No difference was found in the inhibition of cholinesterase by diazoxon in the ganglia of susceptible and resistant strains.

It is concluded from this and previous work that if inhibition of cholinesterase of the nervous system is the cause of death there are no differences between the ganglia of the susceptible and resistant strains which affect resistance; and, furthermore, that inhibition of cholinesterase in the thoracic ganglion is unlikely to be the cause of death.
Mouth-brush dimorphism in larvae of Opifex fuscus Hutton (Diptera, Culicidae)
Authors: McGregor D. D.
Published: July 2009

Among larval populations of the mosquito Opifex fuscus Hutton from supralittoral pools on the east coast of South Island, New Zealand, some individuals in the second, third and fourth instars had only simple hairs in their mouth-brushes, others had pectinate bristles. All first-instar larvae had simple hairs, and samples of these from the same pool were reared in the laboratory at 25°C. Of 13 fed on dehydrated blood serum, only two developed pectinate bristles, but of 15 fed on fish food (particle size 0·1–0·6 mm.), all but one did. Of a later sample of 16 reared at room temperature on fish food in the first two instars and then on the blood serum, all developed pectinate bristles in the second instar but had reverted to simple hairs by the fourth. In nature, larvae of O. fuscus observed to be feeding by filtering were predominantly of the simple-hair type and those browsing of the pectinate-bristle type. Environmentally controlled dimorphism may increase the probability that an individual will develop to maturity.
Descriptions of two species of Eucharitidae damaging tea, with comparative notes on other species (Hym., Chalcidoidea)
Authors: Kerrich G. J.
Published: July 2009

Descriptions are given of Orasema asscctator sp.n. and O. initiator sp.n. (Hym., Eucharitidae) from India, causing damage to the leaves of tea. For purpose of comparison, two species of the same genus are redescribed. The genus Semora Cameron is shown to be synonymous.
Observations on the effect of DDT formulations on the yellow tea mite, Hemitarsonemus latus (Banks), in Uganda
Authors: Davies J. C.
Published: July 2009

The effect of DDT applied to cotton plants four times at 10-day intervals at a rate of 1 lb. active ingredient per acre per application against Hemitarsonemus latus Banks was studied at Serere Eesearch Station, Uganda. DDT applied as a 10 per cent, dust, or in a spray from a 50 per cent, wettable powder increased the damage caused by the mite, while DDT applied in a spray from a 25 per cent. miscible liquid decreased it.

Another trial using a DDT miscible-liquid spray applied at intervals of 10, 15 and 20 days at 1 lb. active ingredient per acre per application demonstrated partial control of the mite. However, when spraying ceased, tea-mite damage increased. At the final count all spray intervals showed significantly less damage than the control and there was an over-all significant difference between spray treatments and the control. In both trials the number of mite-infested plants increased in an exponential manner with time.

It is not considered that the present recommended practice of applying DDT four times, at 15-day intervals, in a spray from 25 per cent, miscible liquid at 1 lb. active ingredient per acre will cause an increase of the mite on peasant-grown cotton in Uganda, although it will only partially control any infestation of it that is present.
Observations on yams attacked by the yam beetle Heteroligus meles (Billb.) (Col., Dynastidae)
Authors: Gregory J. L.
Published: July 2009

Several species of Dynastid beetles are serious pests of yam (Dioscorea) in Nigeria, the adults attacking the setts and new tubers underground. The base of the yam vine and the roots are not generally damaged. The most important species is Heteroligus meles (Billb.).

H. meles does not breed in the yam fields, and the adults fly to them from breeding grounds that are distinct, and to which they return later.

The cultivation and growth of the yam plant in Nigeria are briefly described. Small tubers, or cut pieces of tubers (setts) are planted. The earlier the date of planting and of emergence of the vine from the soil, the heavier the vine and the new tuber.

An account is given of observations on the infestation, in relation to crop growth, of a plot of yellow yams (D. cayenensis) planted near Benin, in Western Nigeria on 29th March 1958.

Adults of H. meles were taken, from 3rd April to 26th June and again from 8th to 21st November, between 7 and 9 p.m., at a light-trap placed at a distance of ¼ mile from the plot.

Beetles entered the soil of yam hills within six inches of the vine, usually before 7 a.m., on mornings following evening flights, the entry holes usually being identifiable. The first vines were seen in the experimental plot on 19th April. Beetles did not enter a yam hill unless the vine had emerged.

The longer the exposure to flying beetles, the more likely were plants to be attacked, and bigger vines attracted more beetles than did smaller ones. Later planting decreased beetle damage, but a lower yield resulted.

At first the beetles fed on the sett, making and increasing the size of fewer lesions than later on the new yam. About the time that the flying period ended, the setts were starting to rot, and the beetles left the immediate vicinity of the yam plant, as no acceptable food was available. Most moved deeper into the soil, but a few left the plant altogether and flew away. After the new tubers had begun to develop, the beetles returned in early August from their positions deeper in the soil to feed on them, constantly making new lesions, more numerous but smaller than those made in the setts, averaging about 4 g. of yam eaten.

During late August and again in late September, a few beetles moved underground from the original plants attacked to others. In mid-November, the beetles left the yam fields altogether, presumably returning to the breeding area.

The reasons why the beetles fly away from the yam fields remain uncertain, but they may include the seasonal decline in rainfall, the maturation of the yam tuber and the development of the gonads.

Factors that can affect the rate of attack are the dates of planting and harvesting in relation to the period during which the beetles fly, the method of cultivation and the variety of yam planted.