LD50 doses of chloropicrin, ethylene oxide, ethylene dibromide, acrylonitrile plus 8% carbon dioxide, and acrylonitrile plus ethylene dibromide were found to decrease the productivity of adults of Sitophilus oryzae (L.) and Tribolium castaneum (Hbst.). Acrylonitrile, acrylonitrile plus methyl iodide and phosphine caused a reduction in productivity in S. oryzae but not in T. castaneum. Carbon dioxide decreased the productivity of T. castaneum. Carbon tetrachloride, methylene chloride, methyl bromide, methyl iodide, acrylonitrile plus carbon tetrachloride and acrylonitrile plus methylene chloride had little influence on the productivity. The productivity of T. castaneum exposed to trichloroethylene and acrylonitrile plus trichloroethylene was higher than in control batches. After exposure to acrylonitrile, reduced productivity was noted in adults of Callosobruchus chinensis (L.) that had been exposed as adults or pupae, and in T. castaneum but not S. oryzae that had been exposed as pupae.

The development of a stock of Corcyra cephalonica (Stnt.) from Burma was followed carefully on a diet of wheatfeed, glycerol and yeast at constant temperatures ranging from 15 to 37°C and humidities from 15 to 90% RH. Two other stocks, from Nigeria and Malawi, were also studied under a few conditions. Limits for complete development from egg hatch to adult emergence were about 17 and 35°C at 70% RH. At 15°C, all larvae died early in development, but at 37·5°C a few managed to pupate. Highest survival and most rapid development occurred at 30–32·5°C and 70% RH. Development was completed in the range 15–80% RH, but few adults emerged at 15% RH and none at 90% RH unless a mould-inhibitor was present in the food. No second-generation larvae were obtained from adults reared and kept at 20°C and 70% RH. Egg period was influenced by temperature but not by humidity in the range 20–80%, RH. Eggs hatched at temperatures from 17·5 to 32·5°C. Hatch was adversely affected by low humidity, and very few hatched at 20% RH. Considerable variation in the rate of egg hatch between the three stocks may have been due to differences in the length of time each stock had been reared in the laboratory. Cold tolerance of eggs of the Nigerian stock was low. All eggs died at 10°C after a seven-day exposure, and at 15°C, although a few 0–1-day-old eggs exposed for 14 days hatched, none completed development to the adult stage. Although older eggs were slightly more cold-tolerant than younger ones at 10°C, they were less so at 15°C. Adult males tended to emerge earlier and live longer than unmated females. Adults of the recently collected Malawi stock were heavier and lived longer than those of the Burma stock that had been reared in the laboratory for many generations.

To determine the extent to which the distribution of ovipositing Heliothis armiger (Hb.) might be ‘clumpy’ rather than random, the numbers of eggs on cotton throughout the 10 000 km2 Sudan Gezira were subjected to analyses of variance. It was found that at any time there was less variability within than between areas, highly significantly less for units of 600–700 km2. Within all areas, the numbers of eggs varied very significantly with time and many-fold increases in numbers of eggs occurred simultaneously over thousands of square kilometres. In every three-day period, there were two or more significantly different levels of infestation, each extending over areas ranging from a few hundred to several thousand square kilometres; the boundaries of such areas changed continuously, and no consistent differences or patterns were found. These findings suggest that redistribution of mobile populations of moths takes place over large distances. At all times there were areas with egg numbers below those considered economically serious; this has been utilised in new control strategy and tactics which have been effectively implemented experimentally. Larval spraying appeared also to reduce oviposition for at least three days and could in part account for some, but certainly not all, of the differences between areas.

A ground survey to map the distribution of Glossina prior to the initiation of a control programme was undertaken in an area of more than 100 000 km2 in the Sudan and Guinea savanna zones of Mali. The area extends from 11°13′ to 14°15′N. and 5°53′ to 10°24′W. The Challier-Laveissière trap was the main survey tool, but other methods were used when the traps did not catch flies in areas suspected of being suitable for Glossina. The results are compared with existing distribution maps of the area, including one based solely on interpretations of earth satellite photography of the area. Infestation by G. morsitans submorsitans Newst. was continuous west of 8°20′W. and intermittent east of this. Apparent recent advances of G. m. submorsitans and G. palpalis gam-biensis Vanderplank were noted, but G. tachinoides Westw. seemed to have receded. Possible reasons for these differences between species are discussed.

Hourly and nightly catches of Heliothis armiger (Hb.) and H. punctiger Wllgr. at a site adjacent to 2000 ha of commercial cotton in the Namoi Valley of New South Wales, were analysed in relation to various environmental factors and showed that wind speed, temperature, night-length and (H. armiger only) moonlight exerted a significant influence on trap-catch. For H. punctiger and H. armiger respectively, these factors accounted for 80 and 60% of the deviance in hourly catches but only 70 and 40% of the variation in nightly catches. Wind speeds of more than 1·7 m/s suppressed the catch of both species but had a greater effect on H. punctiger than H. armiger. Whereas with both species, the optimum temperature for trapping was about 27°C, temperature had a greater influence on the catch of H. punctiger than of H. armiger. Bright moonlight was estimated to reduce the catch of H. armiger by 49%, but no significant effect was detected for H. punctiger. The analysis revealed a number of occasions for both species in which the hourly distribution of catch and/or the change in catch between successive nights was aberrant. With H. armiger, these inconsistencies appeared to be associated with changes in population due to adult emergence, whereas for H. punctiger the most likely cause seemed to be changes due to movement. The combined effects of wind speed, temperature, night-length and moonlight were used to adjust the nightly catches of each species according to the environmental conditions prevailing on a ‘ standard’ night. This was defined as a typical summer's night with temperatures decreasing from 28·8°C at dusk to 20·6°C at dawn and ideal catching conditions, i.e. no moon and wind speed never exceeding 1·7 m/s. As such, the adjusted catches could be taken as indices of moth abundance. These showed that H. armiger had three discrete periods of abundance, characterised by the presence of large numbers of young moths and spaced at intervals suggesting successive generations. A similar pattern was lacking in H. punctiger, which was abundant only during the first half of the season. Except during periods of emergence (H.armiger), or once when spraying occured during daylight, the aerial application of insecticides to the cotton adjecent to the light-trap resulted in marked reductions in the populations of both species.

In the Camargue in southern France, catches of tabanids in a Manitoba trap in 1976–78 gave seasonal, daily and hourly records of numbers. Concurrently, some interactions of the flies with a group of free-ranging horses were observed directly. The tabanids were present from May to October annually, with the main peak of abundance between late May and early July. The number trapped in each hour of the day increased with the ambient temperature in the morning, was stable during the hottest time of the day and declined in the late afternoon. Their alighting on a horse always elicited reactions aimed at dislodging them. When tabanids became very abundant and active, the horses would move as a group from where they were feeding to a traditional open bare area (‘chomadou’) where they would stay without feeding, sometimes for hours, even though large numbers of tabanids were still worrying them. Analyses of data on an index of the abundance of tabanids on or about the horses in a group showed the horses did not reduce the fly load by moving to and resting on their chomadou area. The number of responses by a horse to the tabanids on or about it was shown to be dependent not only on the number of flies but on their activity. Analysis of the responses revealed a negative effect of wind speed on the activity component which was separate from its known negative effect on the number of flies present. A hypothesis is proposed that movement to the chomadou can be explained as the horses going to an area ‘known’ to be usually exposed to the prevailing wind.

Palmicultor palmarum (Ehrhorn), a species of pseudococcid found mainly on coconut in Micronesia and Hawaii, is recorded for the first time from the Bahamas. Planococcus lilacinus (Ckll.) is discussed from Guyana, the first record for the New World, and Pseudococcus microadonidum Beardsley is recorded from the Seychelles causing damage to coconut.

The literature on the history and biology of the cassava mealybug in Africa Phenacoccus manihoti Matile-Ferrero is reviewed, and reports on the search for natural enemies of this species in the Neotropics for biological control purposes are summarised. Further records of the distribution of P manihoti in Africa are presented. A new closely-related species of Phenacoccus, P. herreni sp. n., which causes distortion to cassava in the Neotropical Region is described, and a key is provided to separate it from P. manihoti and from a similar species from the Neotropical Region, P. surinamensis Green, which apparently does not occur on cassava. P. surinamensis is redescribed and illustrated.

In Zimbabwe, field studies were made of the extent to which catches of Glossina morsitans morsitans Westw. and G. pallidipes Aust. from stationary visual targets plus ox odour were changed by maintaining the ox on normal, starving or fattening diets. A fattening diet after a week of starvation often produced a several-fold increase in catches in a few days, followed by a declining catch associated with lack of appetite, and a further increase in catch when appetite was restored. Carbon dioxide and acetone emitted by the oxen could not account fully for the level and variations of catches.

Dispensers made of different materials and loaded with the female sex pheromone, (Z)-7-tetradecenal, were field-tested for attractancy for males of Prays citri (Mill.) in Israel. Hollow fibres of low density polyethylene, low density polyethylene chips and natural rubber septa were better than hollow fibres of polypropylene, hollow fibres of a polypropylene-polyethylene mixture, solid fibres of low density polyethylene and PVC tubes. In other tests, funnels with wall angles of 60° were inferior to those with angles between 70 and 80°; polyester funnels were superior to polystyrene and polypropylene ones, which were better than those of PVC or opalin coated with aluminium foil. Kaolin or talcum powder dusted on the inside walls improved the efficiency of polypropylene funnels. The catches in traps consisting of several plastic funnels or tubes under a roof and with insecticide to prevent escape did not differ significantly from those in the sticky traps. A modified version of a new trap with a renewable sticky floor is described; this and the funnel traps are at present the most useful and practical for catching P. citri males.

To improve the precision of understanding of the phenology of Listronotus bonariensis (Kuschel), samples were collected at regular intervals near Canterbury, New Zealand, and the seasonal changes in their reproductive morphology monitored by regular dissection. It was demonstrated that the adult weevils enter hibernatory reproductive diapause in early March and remain in this state until late July when reproductive activity resumes. Adults emerging in February may enter diapause immediately. The existence of diapause was further supported by its associated cessation of mating, increase in body fat and apparent drop in the haemolymph titre of juvenile hormone. Laboratory experiments indicated that a critical photoperiod induces diapause and an eventual reduction in sensitivity to photoperiod allows reproductive activity to resume.

Spodoptera exempta (Wlk.) was reared for one year at three locations in Kenya: Msabaha on the coast, Nairobi, and Mbita Point on Lake Victoria. The potential yearly number of generations was 15·8 at Msabaha, 6·6 at Nairobi and 13·1 at Mbita Point. Average developmental time from egg deposition to adult emergence was 23·1, 54·9 and 27·8 days, respectively. The longest, 77·3 days, was recorded in Nairobi and the shortest, 19·4 days, at Msabaha. The survival rate varied little seasonally at the coast but was erratic inland, with some generations failing and others very successful. Larvae offered a choice of maize and stargrass (Cynodon dactylon) showed a preference for stargrass. Survival was higher on stargrass than on maize but the developmental time was longer. Mortality was highest in the larval stage. In all generations and at all locations, death was usually caused by a nuclear polyhedrosis virus. There was a positive relationship between larval mortality and rainfall, and a negative one between larval mortality and sunshine. Mating was restricted to after midnight. Females oviposited and then mated during the same night. Peak egg-laying took place before midnight, with a smaller peak at about 02·00–04·00 h.

The toxicities at 25°C and 70% RH of methyl bromide at about 4 mg/litre and phosphine at about 0·24 mg/litre were determined for large populations, including all developmental stages, of a number of strains of seven species of stored product beetles from 29 countries for a range of exposure periods. The species tested were Oryzaephilus surmamensis (L.), Rhyzopertha dominica (F.), Sitophilus granarius (L.), S. oryzae (L.), S. zeamais Motsch., Tribolium castaneum (Hbst.) and T. confusum Duv. With both fumigants, some individuals of certain strains of S. oryzae and T. castaneum survived a concentration × time product twice that sufficient to kill every individual of other strains of these species, and this was also true for R. dominica with methyl bromide and T. confusum with phosphine. With methyl bromide, some individuals of six species survived the longest exposure used. For the two species of Tribolium, this was 48 h, and for the three of Sitophilus and R. dominica it was 32 h. With phosphine, individuals in many strains of S. granarius, S. oryzae and S. zeamais survived for 8 days. In several of the species, there was some correlation between the tolerances of immature stages and of adults for both fumigants. Many strains were tolerant to both fumigants.

In studies in southern England, the relative abundance of the hymenopterous parasites attacking Metopolophium dirhodum (Wlk.) and Sitobion avenae (F.) differed between their hosts, between years (1973–79) and on whether they were assessed using field or laboratory-reared mummies. Species of the complex of Aphidius uzbekistanicus Luzhetzki were usually the commonest parasites, especially from mummies of M. dirhodum, while Aphidius picipes (Nees) was less common and tended to attack mainly S. avenae; Toxares deltiger (Hal.) was common only in 1979. Species of hyperparasites emerged most frequently from mummies of M. dirhodum, except for Dendrocerus carpenteri (Curt.), which emerged most often from S. avenae.

Goniozus antipodum Westw. is redescribed, and three species, G. jacintae sp. n., G. collessi sp. n. and G. mandibulatus sp. n., are described from the females, figured and keyed. All are from Australia, and G. jacintae and G. mandibulatus are parasites of the tortricid Epiphyas postvittana Wlk.

A pyralid moth belonging to the Marasmia generic complex of leaf-rolling defoliators of rice in S.E. Asia is described and named M. patnalis sp. n. It is differentiated from M. bilinealis (Hmps.), M. ruralis (Wlk.), M. suspicalis (Wlk.) and Cnaphalocrocis medinalis (Gn.), with which it had previously been confused because of similarity of the adults and shared host-plant association.

Catches of Musca vetustissima Wlk. in West Australian blowfly traps containing week-old baits were consistently greater (4·5–24·1 times higher) than in traps with fresh baits. Recovery of marked flies within 26·5h of release showed mean dispersal distances of 1·5 ± 0·7 km for males and 1·6 ± 0·6 km for females under favourable weather conditions (mean air temperature 28·8°C and mean wind speed 5·5 m/s). The recovery rate of males (1·3%) and females (1·0%) over this period indicates the feasibility of using single mark-release experiments to estimate absolute fly densities. It is shown that estimates having a 95% probability of being within ± 10% of the true population density could be achieved by the release of 39 000 marked flies.

In a survey of adult ticks infesting livestock in Ethiopia, 33 species and subspecies were identified. The distribution and abundance of each are discussed in relation to ecology (altitude, climate and vegetation). Amblyomma variegatum (F.) is the most widespread and abundant tick parasitising cattle. A. cohaerens Dön. is common on cattle in wetter western habitats but is replaced by A. gemma Dön. in drier eastern areas. A. lepidum Dön. occupies intermediate habitats. The distribution of Boophilus decoloratus (Koch) is similar to that of A. variegatum. Hyalomma truncatum Koch and H. marginatum rufipes Koch are both common except in extremely arid and humid zones. H. anatolicum anatolicum Koch, H. anatolicum excavatum Koch, H. dromedarii Koch, H. erythraeum Tonelli-Rondelli, and H. impeltatum Schulze & Schlottke are usually associated with camels in semi-arid areas of eastern Ethiopia. Rhipicephalus evertsi evertsi Neum., R. sanguineus (Latr.) group and R. simus Koch do not display marked ecological preferences. East of the Rift Valley in semi-arid areas below 2000 m, R. pulchellus (Gerst.) is abundant on cattle and camels. R. longicoxatus Neum. and R. pravus Dön. inhabit drier localities, but R. lunulatus Neum. occurs only in wetter western areas. Species taken infrequently were A. nuttalli Dön., A. sparsum Neum., B. annulatus (Say), Haemaphysalis aciculifer Warb., H. leachii (Aud.), H. parmata Neum., H. spinulosa Neum., Hyalomma marginatum marginatum Koch, H. marginatum turanicum Pom., H. punt Hoogst., Kaiser & Pedersen, Ornithodoros savignyi (Aud.), R. longus Neum., R. muhsamae Morel & Vassiliades, and R. senegalensis Koch. The seasonal dynamics of the common species and observations on their relationships to tick-borne diseases of man and domestic animals are discussed.