Following a long and varied history, Glossina control has become increasingly dependent upon the use of insecticides. There have been substantial successes with the use of chemicals, but reinvasion has been a constant, wide-spread problem. It is increasingly obvious that tsetse control must be approached on a large scale and requires international funding. Despite the proven ability of insecticides to reduce tsetse infestations there is a general reluctance to expand their usage and non-chemical methods are receiving increasing priority. In this paper, an attempt is made to put tsetse control into perspective. The literature relating to various insecticidal methods and tsetse control operations involving ground spraying, helicopter residual spraying, application of low dosage aerosols from fixed-wing aircraft and chemically impregnated traps is reviewed, and research and development relating to both the entomological and application aspects of chemical control are discussed. It is concluded that, given our present state of knowledge, insecticides provide the most reliable method for large-scale tsetse eradication. Of the methods available, applications of low dosage aerosols from fixed-wing aircraft have the greatest potential for rapid and effective control over large areas with minimal risk of non-target contamination, although refinements to improve efficiency and economy are needed. An integrated insecticidal approach combining the attributes of various chemical, and possibly non-chemical, control methods with the proven large-scale capability of spraying from fixed-wing aircraft could provide a realistic answer to the persistent Glossina and trypanosomiasis problems.

Microencapsulated gossyplure or its component Z,Z-isomer were applied to 0·04-ha field plots in Arizona for disruption of sexual communication in adults of Pectinophora gossypiella (Saund.). In an initial efficacy test, the materials were placed on cotton plants in 50-μl drops by hand at a rate of 3·7 g a.i./ha (24 690 drops/ha). Trap catches were reduced by averages of 92 and 81% for the Z,Z-isomer or gossyplure treatments, respectively, during a one-week test period. Mating in mini-mating stations was reduced by 100 and 91% for Z,Z-isomer and gossyplure treatments, respectively. In a further test, sprays were applied using a Micron Herbi 77 hand-held spinning disc applicator that was calibrated to deliver 1·97 × 108 spray droplets/ha (about 250 μm in diameter and 0·01 μl/drop). The spray and drop methods were used to apply rates of 2·5 or 12·3 g a.i./ha of both materials to 0·04-ha field plots. The 12·3 g/ha rate of microencapsulated materials was necessary to give about 90% reductions in trap catches for the 9–12–day test periods. Gossyplure and its Z,Z-isomer gave similar reductions in catches when the same rates and method of application were used. However, comparisons of results for 50-μl drops vs. spray indicated that the drops generally resulted in significantly lower trap catches than sprays at the 2·5 g/ha dose rate. The results indicate that spray application of microencapsulated gossyplure or its Z,Z-isomer have potential for communication disruption of P. gossypiella.

Intensive monitoring of uncaged summer populations of Metopolophium dirhodum (Wlk.) (alienicolae) on winter wheat in southern England was carried out, mainly in 1979. Estimates for rates of development and reproduction are presented for both apterous and alate morphs. Relative nymphal instar lengths were calculated as percentages of the total juvenile period (instars I–IV inclusive), at a given mean temperature. The durations of the first three nymphal instars were uniform, but longer was spent in instars IV-apterous (21%) and IV-alatiform (45%) than in previous ones. Development rates are shown, firstly as cumulative summations of regression lines for individual instars, and secondly as a single regression for the whole period (I to IV inclusive), plotted separately against corresponding mean temperatures. A method of calculating the development threshold was devised that yielded an estimate of about 5°C for both morphs. Average and maximum daily rates of deposition (larviposition) are given for both morphs and, for apterae, results on the effects on this of leaf, date, temperature and aggregation are presented and discussed. Comparisons are made between this field study, and previous ones using M. dirhodum under constant temperature conditions in the laboratory. Development rates appeared to be similar under both constant and fluctuating temperatures, although slower in the field at low temperatures (10 or 11°C). Reproductive rates under the field conditions of this study appeared to be higher (on a daily rate basis) than those of previous studies, both in the laboratory (at constant temperature) and in the field. Reproduction in the field by apterae is considered to be concentrated over a shorter span of adult life than in the laboratory.

Studies on populations of Zeiraphera diniana (Gn.) in Britain, where the tortricid has recently attained pest status, revealed differences in their structure and host-plant relationships when compared with populations at other European localities. A switch from the predominance of larch (Larix decidua) as a host in alpine Switzerland to pine (Pinus contorta) in upland Britain was governed by temperature which, during the egg stage, altered the phenological relationships between hatching caterpillars and foliage on the two conifers. Larvae which originated from populations on pine had higher survivorship on foliage of spruce (Picea) and larch than populations which originated on larch. Larval age heterogeneity, induced by a prolonged egg hatching period, was a marked feature of British populations and could have significant demographic consequences including an occasional reduction in the degree of temporal separation of racial units at the adult stage. Patterns of polymorphism in larval samples from Pinus contorta and Larix spp. in a variety of forests in Britain gave support to a hypothesis of racial hybridisation at the edge of the insect's range. There were overall differences between colour-type structure of larvae on larch at an English site and at a comparable Swiss locality, and also a similar trend in the change of a colour-type index with changes in population density between years. This suggests that similar selective forces may apply to the population dynamics of Z. diniana throughout its range.

A rickettsia-free (aposymbiotic) stock of Aedes polynesiensis Marks (POLY-A) was crossed with (a) three symbiont-infected stocks of A. polynesiensis (POLY-S from Samoa and POLY-N and POLY-T from Fiji), (b) A. pseudoscutellaris (Theo.) (PSE) from Fiji, (c) A. alcasidi Huang (ALC), A. scutellaris katherinensis Woodhill (KATH), A. s. malayensis Colless (MAL) and A. s. scutellaris (Wlk.) (SCUT), which occur to the west of Fiji and (d) an aposymbiotic stock of A. cooki Belkin (CO) from Niue. It was bidirectionally compatible with CO, but in all other crosses compatibility was high when POLY-A was the male parent and very low when it was the female parent. Backcross data suggested that the crossing type was maternally inherited. ALC and KATH were bidirectionally compatible; both were virtually incompatible with POLY-S and PSE, compatible with SCUT when the latter was the female parent, and compatible with CO when the latter was the male parent. POLY-S females were moderately compatible with a third Fijian stock of A. polynesiensis (POLY-V), and POLY-N and POLY-V were compatible with PSE. If, as in Culex pipiens L., rickettsia-like symbionts are responsible for cytoplasmic incompatibility, then aposymbiotic males should cross successfully with symbiont-infected females, whereas the reciprocal cross should be unsuccessful. Since PSE, MAL and SCUT contain symbionts, their crossing relationships are consistent with the hypothesis. However, ALC and KATH appear to be aposymbiotic and their crossing relationships conflict with the hypothesis. There is little evidence of behavioural barriers to mating between species, but whereas male hybrids of two eastern species were capable of normal insemination, male hybrids between western and eastern species gave very low insemination rates. The egg-hatch rates from backcrosses of female hybrids between western and eastern species to the parents were reduced.

In populations of overwintering pupae of Delia radicum (L.) collected from ten sites in England and Wales, parasitism varied from 0% at Newcastle to 42% at Evesham. Unlike their hosts, few of the parasites were in extended diapause. Irrespective of when collected at Wellesbourne, emergence of 50% of the ichneumonid parasite Phygadeuon trichops Thoms., the eucoilid parasite Trybliographa rapae (Westw.) and the staphylinid parasite Aleochara bilineata Gylh. occurred after 14, 21 and 28 days, respectively, at 20°C. Early-emerging populations of D. radicum were more heavily parasitised than intermediate- or late-emerging populations. During the winters of 1979–80, 1980–81 and 1981–82, T. rapae and A. bilineata emerged in similar numbers from 37% of the field-collected pupae from Wellesbourne. Less than 1% of the pupae were parasitised by P. trichops. D. radicum adults emerged from a further 25% of the pupae, and the remainder, approximately 38%, were dead. Most dead pupae were recovered from heavily parasitised populations. When parasites were present in high numbers, many of their progeny probably died from multiple parasitism and superparasitism. Comparison with earlier studies indicated that parasitism should be expressed as a percentage of the total pupae, and not just as a percentage of the living insects, if the data are subsequently to be of use for studies on the population dynamics of this pest.

Insects migrating above the surface boundary layer were efficiently and economically sampled over long periods using a large diameter tow net suspended beneath a kite. In a series of trials in Australia, sequential samples were obtained by day and night at predetermined altitudes, in the range 50–500 m. The net was raised and lowered independently of the kite, so that when conditions were calm in the lower atmosphere the kite could remain aloft in the geostrophic airflow. Potential contamination of insects flying below the sampling height was minimised during net ascent, by reducing the airflow through the net. A radio-operated net-closing and releasing mechanism prevented contamination during the free fall of the net. The catch was converted to absolute values of aerial density and migration rate or flux. Aerial sampling was originally developed to identify upper air migrants under observation by the CSIRO entomological radar and to provide quantitative measurements of those species too small to be individually detected by radar. The technique was subsequently operated independently of radar to quantify microinsect migrations, but not those of macroinsects because of their relatively low catch rate.

Resistance of cocoa to Planococcoides njalensis (Laing) was assessed in the laboratory in Ghana by rearing the mealybug from birth until death on seven cocoa progenies, and determining survivorship, duration of reproduction, gross reproductive rate and live weight. Field evaluation was by sampling both P. njalensis and Planococcus citri (Risso) on the tree trunks and in terminal buds. Progenies 85D/176A × M7/537 and T12/116 × T62/977 were judged the most resistant using the parameters determined in the laboratory. The resistance factor is attributed to antibiosis. The mealybug populations in the field did not show any significant differences among the progenies, but the trend followed the laboratory results. It is suggested that the laboratory method reported here is adequate in assessing resistance, has the advantage of being faster than the field technique and can be used in combination with existing methods for assessing cocoa progenies for resistance to the virus disease.

Mylabris designata var. hacolyssa Rochebrune is a pest of a variety of crops, particularly okra, in the central and western provinces of the Sudan. A study is reported of the responses of the beetle to visually attractive traps which were used to measure daily and seasonal flight activity. Blue-coloured traps were more attractive than red, lavender, white or black traps. The catching efficiencies of Manitoba traps and sticky targets were recorded by direct observation: 43·3% of approaching beetles were captured by a blue Manitoba trap whereas the initial 50–80% efficiency of blue sticky targets decreased to 10–20% over three days due to an increasing close range olfactory repellent effect on the beetles. The potential for the use of such traps as a cheap and environmentally acceptable alternative to the use of insecticides for control of M. d. hacolyssa is discussed.

Five species of Muscidae were found to be commonly associated with dairy heifers in three areas in southern England. The biting flies Haematobosca stimulans (Mg.) and Stomoxys calcitrans (L.) were relatively rare and fed from the back, flanks and legs. The horn fly, Haematobia irritans (L.), was present in highest numbers; it rested on the back and fed on the legs, belly and occasionally on the teats. Musca autumnalis Deg. was found mainly on the head and had a restricted season. Hydrotaea irritans (Fall.) had a marked diurnal variation in activity, being most abundant in the morning and evening. It was found on the head but predominantly on the belly and teats. When judged by its site preference on cattle, it is the fly most likely to be involved in the transmission of summer mastitis.

Screened and unscreened eucalyptus trap-logs infested by Phoracantha semipunctata (F.) were used to examine the excavating habits of the Syrian woodpecker (Picoides syriacus), its annual course of predation and its effect on the survival rate of Phoracantha semipunctata larvae in Israel. The bird excavated predation holes only in trap-logs with larvae within the bark. Predation holes density increased during the spring and summer. Towards the autumn, egg-masses were killed too. The average mortality due to predation was 29·21% of total larval mortality and 78·7% among larvae that survived intraspecific competition. The mortality caused by the woodpecker decreased with increasing density of larvae. The natural control of P. semipunctata in Israel and the borer-woodpecker ecosystem are discussed.

Females of Anopheles darlingi Root were the commonest (98·6%) of 5464 anophelines taken in 866 man-hours of human bait catches at night, in or near houses in the rain forest in Suriname during 1979–81, but their abundance could not be related to the prevalence of human malaria. In most endemic areas, few females were taken. At Aseli Kamp (4°17'N, 53°24'W) on the Lawa River, biting females were most abundant from April to June, during the long rainy season and rare or absent from September to March, during the long dry, short rainy and short dry seasons. At Apoma Tapoe, however, only 40 km downstream, they were most abundant in october and November, during the long dry season. Females entered houses to feed, with peak biting activity between 22·00 and 23·00 h, and were observed to rest near the collector for a mean of 7·7 min before and 17·1 min after feeding. No females were found resting by day, in buildings or out of doors. The mean parous rate of 827 females from biting catches was 43·6%. The expected biting rate of females was reduced by 20·3% in a house for six nights after it had been sprayed with DDT wettable powder (2 g/m2 active ingredient), and by a mean of 82·6% during seven nights in a camp where the edge of the surrounding forest was sprayed with an ultra-low-volume mist of 95% fenitrothion (1·3 ml active ingredient per metre of perimeter) on the first, third and sixth days. A. darlingi larvae were found at Aseli Kamp in all seasons along the river's edge between water hyacinth plants (Eichhornia) and floating debris, and during the long rains in flooded forest.

In the Zambezi Valley of Zimbabwe, the numbers of Glossina morsitans morsitans Westw. and G. pallidipes Aust. electrocuted as they arrived near a visual target were increased five times by the release of a mixture of carbon dioxide and acetone vapour at the target. Catches declined to near the no-odour level as the odours were moved to release points 32–40 m upwind or downwind of the baits. This pattern of catches at the target changed when flies were trapped at the odour release points 4–40 m from the target, and changed when the odour was released at each of several points along the axis of the wind instead of at a single point. These changes suggest that the flies responded to a single-point release of the odours at distances of 30–60 m from the release point, that, when the flies arrived at the upwind end of a plume and discovered no visual bait, they flew upwind for a few metres and returned downwind for about 8 m and that the flies navigated effectively up a composite plume made by 2–33 separate release points, 1–8 m apart, along a line up to 30° from the mean direction of the wind. Data for Muscidae are also presented.

Laboratory studies were carried out on different populations of Aphidius ervi Hal., A. picipes (Nees) and A. rhopalosiphi De Stef. collected in England from Acyrthosiphon pisum (Harris), Sitobion spp., Microlophium carnosum (Buckt.) and Metopolophium dirhodum (Wlk.). When mated females from each population were confined separately with 4–5 other species of these and other genera, each population varied in their host preferences, even though individual populations of each species were electrophoretically and morphometrically homogeneous. These host preferences differed in terms of fecundity. Different populations of Aphidius ervi exhibited markedly different host ranges. This behaviour is probably conditioned rather than inherited, and its significance to biological control is discussed. The results suggest a need to assess quantitatively the effect of temperature, host size and host species on the parasitoids' ability to control pest aphids.

Homoptera were assessed by examining branches from mature cocoa trees in an Upper-Amazon 3 × 33 shade × nitrogen, phosphate and potash fertilizer experiment at Tafo, Ghana. Trees in territories of the ants Crematogaster clariventris Mayr and Acantholepis capensis Mayr were sampled. Planococcoides njalensis (Laing), Planococcus citri (Risso), Phenacoccus hargreavesi (Laing), Pseudococcus concavocerarii James, Maconellicoccus ugandae (Laing) and Mesohomotoma tessmanni (Aulm.) were more abundant on unshaded trees than on shaded ones. Steatococcus sp. and Stictococcus sjostedti Ckll. also occurred most frequently on unshaded trees. The abundance of five other infrequently recorded species was unaffected by overhead shade. A species of Gascardia near G. zonata (Newst.) was more common as shade increased. Planococcus citri increased with increasing nitrogen where A. capensis was dominant, and decreased with increasing potassium on heavily shaded trees where C. clariventris was dominant. M. tessmanni decreased with increasing potassium both on unshaded trees where A. capensis was dominant and on trees which had received most phosphate where C. clariventris was dominant. No responses to fertilizers were detected among other species. An estimated 100, 99 and 83%, respectively, of unshaded, lightly and heavily shaded trees were infested with mealybugs, vectors of cocoa swollen shoot virus. These estimates presage little change in the rate of spread of virus due to the continued shade thinning over cocoa in Ghana.