Costs associated with subterranean termite damage and control are estimated to approach $2 billion annually in the United States alone. The Formosan subterranean termite, Coptotermes formosanus Shiraki, is one of the more economically important subterranean species. In recent years, the shortcomings associated with conventional chemical control methods have prompted policymakers and scientists to evaluate the potential for biological control of subterranean termites (C. formosanusin particular), that is, to determine the potential for natural enemies –predators, parasitoids and pathogens – to suppress termite populations. Ants are the greatest predators of termites, and may have a considerable local impact on termite populations in some areas of the world. A few parasitoids of termites are known, but their potential for regulating termite populations seems negligible. Characteristics of the colony, such as a protected, underground location (and, for the C. formosanus nest, its modular and dispersed nature), are likely to limit the impact predators and parasitoids have on subterranean termites. Thus, there seems little potential for use of these agents for subterranean termite control. For various reasons, pathogenic organisms, such as viruses, bacteria, Protozoa, nematodes and most fungi, have shown little promise for use in biological termite control. However, research suggests that strains of two well-studied, endoparasitic fungi, Beauveria bassiana and Metarhizium anisopliae, when employed in baiting schemes, may offer the potential for at least some measure of subterranean termite control, although their successful use is compromised by a number of inherent biological limitations and logistical problems that have yet to be solved. Although not strictly in the realm of classical biological control, recent studies suggest that natural products, such as ant semiochemicals and fungal metabolites (siderophores), or their synthetic analogues, eventually might find a use in termite control programmes as repellents or insecticides in wood treatments or soil applications if stable formulations can be developed.

The Old World screw-worm fly, Chrysomya bezziana Villeneuve, occurs in Africa, the Middle East, Malaysia, Indonesia and Papua New Guinea, but it is not found in Australia. Introduction into Australia from any of these source areas would threaten the viability of much of the grazing industry in the northern part of the continent. Proposed control by the sterile insect release method (SIRM) would be compromised by the existence of sibling species within C. bezziana. This study examines the degree of genetic differentiation throughout the extensive range of the fly to assess if the degree of geographic differentiation indicates the existence of sibling species and, allows identification of the source of any introduced flies. Electrophoretic analysis of 23 loci from samples collected in southern Africa, the Middle East, Malaysia, Indonesia, and Papua New Guinea revealed 11 polymorphic loci. Overall, populations show remarkably little divergence given the geographic distribution of sample sites. None of the populations sampled were fixed for alternative electromorphs. There is no evidence from this study for the presence of sibling species within C. bezziana.

The aphid sex pheromone component (4aS,7S,7aR)-nepetalactone is considered to be a potential tool for enhancing biological control of aphids. Studies have confirmed its potential to attract parasitoids, increase parasitism rates in the field and also alter the spatial distribution of parasitoids. An important aspect that has been overlooked is the impact that the introduction of nepetalactone may have on aphid populations already present in field or glasshouse environments. The most prevalent pest aphid populations in glasshouse and field environments are the asexual morphs, which are capable of exponential growth if populations are not controlled. The short-term implications of the sex pheromone on asexual aphids were observed through their behavioural response. Using Y-tube olfactometry, it is shown that virginoparae of the peach-potato aphid, Myzus persicae, are repelled by high concentrations of nepetalactone. Long-term effects of the pheromone which may span the aphid's life, or even generations, were assessed via mean relative growth rate (MRGR) and the intrinsic rate of natural increase (rm). Electroantennography also demonstrated that asexual female aphids are able to detect aphid sex pheromone components. To our knowledge, this is the first time it has been reported that M. persicae virginoparae are able to detect aphid sex pheromone components or that their behavioural response and/or performance has been studied. The implications of these results and their significance in understanding semiochemical communication are discussed.

The seasonal abundance and rates of parasitism of three species of Mesoclanis seed flies was studied in South Africa. The three species occur on Chrysanthemoides monilifera, and were recorded during most months of the year, whenever C. monilifera was flowering. At three sites in KwaZulu-Natal, numbers of eggs per capitulum of Mesoclanis polana Munro were highest on C. monilifera rotundata between June and November (winter/spring), towards the end of the main flowering flush. Parasitism of M. polana was between 50% and 90% for most of the year. Two other species of Mesoclanis (M. magnipalpis Bezzi and M. dubia Walker) occurred together on C. m. rotundata in the Eastern Cape (St Francis Bay), where parasitism during the year was between 55% and 95%. Peak numbers of eggs per capitulum (M. magnipalpis and M. dubia combined) occurred in May/June (winter), in the latter part of the main flowering flush. Mesoclanis magnipalpis was the only species recorded on C. m. pisifera in De Hoop Nature Reserve (Western Cape), where there was only one peak of oviposition (May/June), coinciding with the short and discrete flowering period of this subspecies. Parasitism was between 50% and 65%. At least nine species of parasitoid were reared from immature Mesoclanis stages. Eurytoma sp. (Eurytomidae) was a dominant parasitoid at all sites. Results are discussed in relation to the possible effectiveness of species of Mesoclanis seed flies as biological control agents of C. monilifera in Australia.

Two series of all-night hourly catches of Mansonia (Mansonioides) uniformis (Theo.) on the verandah of a house and at an outdoor open site with man as bait and a third series at the same outdoor site with calf as bait were carried out during 1960–62 on an open mixed rubber and coconut estate overlooking a swamp, in Aggona, a village three miles south-east of Colombo. The physiological age of the mosquitos captured was determined by a count of the follicular relies in the ovarioles.

The mosquitos were active only at night; the biting cycle on human bait showed two peaks in both situations—a well-defined early peak and an irregular late peak on the verandah and a minor early peak and a larger lat peak at the outdoor site. In the verandah series the two oldest age-groups, 2-parous and 3-parous females, showed more activity during the second peak, while in the outdoor series the oldest age-groups were most active during the early peak, a result suggesting a difference in behaviour on the part of the older females compared with the overall population in both situations. M. uniformis was strongly attracted to cattle bait; much activity was recorded at this bait site during the first four hours of the night.

Age-composition of the populations in all three series was found to be similar irrespective of the site and bait used. The results were more or less constant from month to month in spite of weather changes. Daily mortality of M. uniformis taken at the two baits was similar and showed consistency from month to month.

A large proportion (73.4%) of females returned to feed directly from oviposition.

The aphelinids Encarsia adrianae sp. n. and E. cibcensis sp. n. are described from material in culture ex Bemisia tabaci (Gennadius) on beans at the C·A·B International Institute of Biological Control, Ascot, UK. They are descendants of material collected in Rawalpindi, Pakistan, from B. tabaci on Lantana camara.

Oil has been used as a mosquito larvicide for about forty years, since L. O. Howard in 1892 first recommended its use, and a large literature has accumulated on the subject, but the physical and chemical properties which make an oil a suitable material for this work are very imperfectly understood. It is clear that the problem is one that can very favourably be studied in the laboratory, for it requires above all an answer to the question “How do larvae die under oil treatment?” which can only be answered by microscopic examination of the larvae.

As a consequence of geographical variation in diapause mechanism in the cabbage beetle, Colaphellus bowringi, the southern strains enter diapause as an adult in response to long photoperiod, whereas the northern strains enter diapause in response to temperature. In the present study, we examined the inheritance of diapause by crossing a southern Xiushui strain (XS) with a most-northern Harbin strain (HB). The southern XS strain showed a clear short-day response for the induction of diapause, whereas the most-northern strain entered diapause regardless of photoperiod. Interestingly, the XS×HB progeny showed a short-day response, but the HB×XS progeny had no photoperiodic response, indicating that photoperiodic induction of diapause is influenced by maternal genotype. The incidence of diapause of F1 progeny was intermediate between their parents under short daylengths of 12 and 13 h. However, there was a sexual asymmetry, with the female parent exerting a greater effect on diapause incidence than the male parent, indicating a sex linkage in the inheritance of diapause induction. The χ2 test in C. bowringi revealed that the inheritance of diapause does not fit an additive hypothesis and also that the capacity for diapause is transmitted genetically (or possibly epigenetically) in a manner of incomplete dominance. These results suggest that a number of genetic factors are associated with differences in diapause capability in this beetle.

One hundred and fifty six species, two subspecies and seven varieties of Culicidae are known to occur in the Sudan. The present paper shows the known distribution of members of the genera Dixa, Chaoborus, Toxorhynchites, Harpa-gomyia, Hodgesia, Uranotaenia, Aëdomyia, Theobaldia, Ficalbia, Taeniorhynchus and Eretmapodites, and includes taxonomic and other notes on several species.

Some aspects of distribution are discussed, particularly the exchange of species between the Ethiopian and Palaearctic Regions in which movement has been mainly from the latter to the former.

Brief notes are given on the practical importance of some species.

Components of dried citrus pulp were isolated and tested for arrestant activity for Atta cephalores (L.) and Acromyrmex octospinosus (Reich). Both lipid and non-lipid components contributed to the acceptability of the pulp. Arrestant activity was greater in the non-lipid fraction. Sucrose was found to be the most active single component of the non-lipids. The arrestant properties of the pulp were attributable to the particular balance of constituents rather than to any single component. The results are compared with the response of other insects to similar phytochemical stimuli.

For nine weeks from 14 April to 13 June 1975 an average of over 500 double translocation heterozygote male Aedes aegypti (L.) were released daily into a village where the estimated adult mosquito population was 1200. The two purposes of this release were to suppress the A. aegypti population by sterility induced by chromosomal translocations and to assess the effect of rainy season conditions on the population dynamics of the indigenous and released mosquitoes. As a result of the releases, hatchabirity of eggs from females collected during landing-biting catches dropped from over 93% to 30–40%. For eight weeks following the termination of the releases, hatchability remained below 70% while that of the reference village averaged between 80 and 99% hatch. A relative population decline observed in the release village is not attributed solely to the effect of the releases, partly because it occurred before sufficient time had elapsed to allow induced sterility to build up in the field population.

An investigation was carried out into the use of water traps for sampling Glossina morsitans submorsitans Newst. and G. tachinoides Westw. in Yankari Game Reserve in sub-Sudan savanna in northern Nigeria. The traps consisted of coloured trays filled with water plus small quantities of formalin and detergent. Colour was thought to be the major factor attracting flies to the traps, white traps being most effective for G. m. submorsitans and black ones for G. tachinoides. Water traps were compared with biconical traps, and both methods showed similar changes in catches in different vegetation types over a year. Males and females of both species showed a marked expansion in distribution in the rains and a contraction to riverine woodland in the dry season, though females of G. m. submorsitans could be caught in the adverse deciduous woodland and open savanna all year round. Water traps are considered a very cheap and practicable sampling method for ecological studies on these species of Glossina, providing specimens well preserved upon capture for later morphometric and analytical studies.

It was in December 1929 that the writer first tried to reduce the terrible mosquito nuisance which each winter plagues the City of Calcutta. His efforts were naturally confined to an attempt to alleviate conditions in the Bengal-Nagpur Railway's Headquarters Colony at Garden Reach, but it soon became obvious that by control in the relatively small area of land belonging to the railway very little could be accomplished, and that to achieve anything appreciable a very much larger acreage would have to be put under control. So when in the ensuing winter of 1930–31 other property owners in the vicinity became aware that this railway was attempting to do something and evinced interest in the matter, advantage was taken of this to form the Garden Reach Anti-Malaria Association, the initiation of which also received a considerable impetus from the virulent outbreak of malaria in the previous autumn at Budge Budge, some 18 miles down-river from the City. This outbreak, and the organisation of and area covered by the Association, are described by Covell (1932).

Records of oviposition by blowflies on test groups of sheep, over a five-year period, were examined for relation between the rate of oviposition per day and the conventional meteorological indices of daily weather conditions. There was a definite correspondence with the maximum shade temperature for the day. The relation was not straight-line, the slope changing at between 18 and 20°C. The association with the minimum temperature was not significant. Insolation, as measured by the difference between maximum temperatures in the sun and shade, was positively associated with oviposition.

The humidity indices—evaporating power of the air and the saturation deficit—and the ratio of the daily totals of rain and evaporation, showed a low correlation ; the rainfall correlation was barely significant. The association was in no instance statistically reliable.

Morphological studies of different populations of what was previously considered to be a single species, Aphanogmus hakonensis Ashmead, revealed the presence of a complex of species which are extremely difficult to distinguish without detailed studies of male genitalia. Several of these species have been misidentified during biological control programmes or parasitoid surveys. These misidentifications are corrected, and two new species, Aphanogmus captiosus and Aphanogmus thylax are described. The hakonensis-complex is diagnosed. As far as is known, all species are hyperparasitoids of lepidopteran larvae via various hymenopteran or dipteran primary parasitoids.

Ultraviolet-light and fermentation trap catches of adults of Mythimna convecta (Walker) in Victoria, Australia, could be related to the times of various stages of larval development in oat crops by means of a day-degree accumulation model. Mated females were more attracted to fermentation than ultraviolet-light traps, and predicted oviposition times closely coincided with fermentation trap catches. The phenological model successfully mimicked the observed larval instar development in the field. Peak moth flights occurred within three periods. The first peak period (October to mid-November) usually contained mated moths which generated larval populations in maturing oat crops; in 1983, these moths probably occurred in late August. The second (mid-November to December) contained unmated females; in 1983–84, moth flights during this period could be related to the emergence of moths from crops 70–130 km north of the trap site. The third peak period (January to February) also comprised unmated moths which had usually emerged locally and were probably emigrating.

Oil palms in parts of the oil palm belt in the Gold Coast Colony have suffered at intervals from the attacks of a leaf-mining beetle. Specimens of the adult beetle and full-grown larva were sent by Mr. W. H. Patterson, Government Entomologist to the Gold Coast, to the Imperial Bureau of Entomology in 1920. These were determined by Mr. S. Maulik as a new species of the genus Coelaenomenodera (family Hispidae) and described under the specific name elaeidis (Bull. Ent. Res., x, p. 171). This species is indigenous to the West Coast of Africa, and hitherto has not been recorded outside the Gold Coast, but no doubt occurs throughout the West Coast oil palm belt. According to Mr. Maulik, 32 species of this genus are known, of which four only are recorded from Africa, the remainder being from Madagascar.

An economical method of tsetse control aimed at reducing fly numbers to a low level prior to human settlement was tried in northern Tanganyika in 1964–65 in an area containing Glossina morsitans Westw., G. swynnertoni Aust. and small numbers of G. pallidipes Aust. The major central part of the infested area, about 7½ square miles, was sprayed four times at three-weekly intervals with endosulfan from an aircraft, and the remaining peripheral parts were sprayed from the ground. In the aerial applications, the volume of spray averaged 0·0121 gal./acre per application and the amount of endosulfan averaged 0·0242 Ib./acre (a total of about 1 Ib. per 10 acres for the whole operation). The results indicated that the tsetse population was probably eradicated in the part sprayed from the air. Though the ground spraying of the surrounding parts was not completely satisfactory, the tsetse population in the whole area a year later was only about ten per cent, of its original level. The cost of the air-spraying was £88 per sq. mile.

1. The first record of important damage due to borers in Mauritius dates from 1856, the species being the spotted borer, Diatraea venosata, Wlk. From 1856 to 1897, two other species of borers were introduced, the pink borer, Sesamia vuteria, Stoll, and the white borer, Grapholita schistaceana, Snell. From 1897 to 1916, the damage caused by these three borers decreased gradually, so that from 1916 to 1928 these pests were considered by planters as being of minor importance. From 1928 to 1932 an increase in the damage due to the spotted borer was observed nearly all over the island.

2. The spotted borer causes important damage on the coast belt during the dry and cold months, i.e., April to July. The pink borer, distributed all over the island, causes damage of medium importance to young canes; it occurs with intensity during the wet and hot months of the year, i.e., December to April. The white borer is also distributed nearly all over the island but causes damage of relatively slight importance in plantations, with the exception of very rare occasions when it occurs sporadically as a serious pest.

3. The losses due to the pink and white borers vary with the localities and are difficult to estimate. As an average, Rs.6·00 per arpent is incurred for control leasures against these pests.

The spotted borer which attacks mature canes causes losses both in the field and in the factory. The reduction in the field, per arpent, averages 15 per cent. The loss in sugar averages 2.3 per cent., i.e., 16 per cent, of sugar in cane. The gross loss per annum for the whole island is about 1½ million rupees, and the net loss approximately Rs.125,000.

4. The proportion of canes attacked by the spotted borer averages 30 per cent. From estimates made according to the method of Wolcott, in Porto Rico, it was found that the percentage of borers per 100 lb. of cane is 39, as a mean, and the number of borers per acre averages 15,698. The mean percentage of stems attacked by 1 to 5, 6 to 10, and 11 to 15 borers is of 87·6, 10·1 and 2·2 respectively. The proportion of nodes attacked varies between 10 and 25 per cent. approximately.

5. The cane varieties that are heavily attacked by the spotted borer are M.55, M.131, D.109, M.1474, White Tanna, B.H.10/12, R.P.6, D.K.74, D.130 and R.P.8.

6. The various methods of control used in the island for the last 15 to 20 years are discussed. Against the pink and white borers the use of trap plants is recommended as well as the collection of larvae. The burning of trash in the fields is to be avoided.

In the case of the spotted borer the destruction of larvae in the tops to be planted is recommended. A practical method consists in the immersion of the tops in cold water during 72 hours, or in hot water at 50–51°C. for 2 to 2½ hours, or 52°C. for 30 minutes, or in saturated lime-water for eight hours.

7. The breeding of the larval parasites is recommended on estates where larva collecting is practised.

8. The advantages or disadvantages of larva collecting and burning of trash are still under consideration.

Studies in southern England on aphids in cereals and adjacent wasteland included observations on the survival of aphid-specific predators (Coccinel-lidae and Syrphidae) and the more polyphagous Chrysoperla carnea (Steph.), with particular reference to their parasites. Counts were made of all the predator stages found on samples of shoots in each plot and, in wheat only, collected with a vacuum sampler. All stages of predators seen were collected and reared in the laboratory to estimate mortality and parasitism rates. Overwintering survival outdoors of Coccinella septempunctata L. was studied in partly sheltered and exposed netting cages over dense ground cover. At least 90% of predator eggs hatched in the laboratory, and no parasites were reared from them or from larvae. In cereals, there were significantly fewer larvae than eggs of Coccinellidae, probably because of cannibalism, whereas eggs and larvae of Chrysoperla carnea and Syrphidae (mainly Episyrphus balteatus Deg.) occurred in similar numbers. Unlike Coccinellidae, however, there were fewer cocoons of C. carnea and syrphid pupae on the shoots than expected. Since larval mortality was apparently small, it is suggested that many larvae pupate in the soil. Two parasite species emerged from coccinellid pupae and one from the adults, compared with two species from C. carnea cocoons and nine species from syrphid pupae. Parasitism rates were usually small (25%). More individuals of Coccinella septempunctata survived overwinter in partly sheltered than in exposed cages.