It is fitting that this, first, Guest Editorial to the new-format Bulletin should be devoted to stored-product entomology since 1990 celebrates 50 years of the formal establishment of stored-product insect research and control programmes in Britain. It was in 1940 that the Pest Infestation Laboratory was established at Slough under the, then, Department of Scientific and Industrial Research, consolidating the work begun some 15 years earlier under Professor J. W. Munro in the Entomology Department of Imperial College; almost at the same time, the Infestation Control Division of the Ministry of Food (now MAFF) was set up as an inspectorial and advisory body. Much has been achieved and many organisational changes have taken place since then. The original organisations have come together under the umbrella of the Ministry of Agriculture, Fisheries and Food (MAFF) whilst the group which was initiated at Slough in 1951 to address problems of storage in tropical areas is now the Storage Department of the Overseas Development Natural Resources Institute (ODNRI), the scientific unit of the Overseas Development Administration, UK (ODA). Slough has become synonymous with stored product research in Britain and beyond; sadly, however, the ‘Slough connection’ is destined to end—the ODNRI department will move this year to join its sister departments in the institute's new major laboratory development at Chatham, Kent, whilst plans are in hand for the eventual relocation of the MAFF laboratory as part of the Central Science Laboratory of the Agricultural Development and Advistory Service (ADAS).

Phymastichus coffea, a new genus and species of tetrastichine Eulophidae, is described. This species is parasitic on the coffee berry borer, Hypothenemus hampei (Ferrari), in Africa and is currently under investigation as a possible biological control agent for this borer

Adult male German cockroaches were exposed to deposits of amorphous precipitated and pyrogenic silicas in continuous and discontinuous contact bioassays. LC50S of precipitated silicas in the former case generally increased with oil adsorption capacity of the dusts; variability in response in discontinuous contact bioassays was apparently due to grooming of appendages following pick-up of dust aggregates. The toxicity of silica deposits in half-treated choice boxes varied with relative humidity and was effectively eliminated at 95% r.h. or when free water was provided. Cockroaches accumulated in the untreated side of the box irrespective of r.h.; the mechanism of this effect is discussed.

The amidinohydrazone insecticide hydramethylnon, exhibited delayed toxicity to workers of Reticulitermes santonensis Feytaud and Microtermes lepidus Sjöstedt over a range of concentrations, with deaths starting two to six days after exposure. R. santonensis workers which had been exposed to hydramethylnon passed the insecticide to untreated termite workers, larvae and nymphs by trophallaxis. Laboratory colonies of R. santonensis exposed to hydramethylnon were killed completely within 20 days. The possible use of hydramethylnon impregnated baits for the control of subterranean termites is discussed.

Individual cereal aphids of the species Sitobion avenae (Fabricius) and S. fragariae (Walker) were differentiated by their peptidase electrophoretic banding patterns; S. avenae has three diagnostic isoenzyme bands (PEP-3 to -5), whereas S. fragariae has one (PEP-1). Over 90% of 5389 individuals of these two species, collected from the grass Dactylis glomerata within 50 km of Rothamsted over the course of several years, were S. fragariae. The importance of D. glomerata and other non-cereal Gramineae species as alternative summer and overwintering hosts for S. avenae is discussed in relation to this finding.

The aphids, Cinara cupressi (Buckton), Eulachnus rileyi Williams and Pineus pini (Macquart), have invaded conifer plantations in southern and eastern Africa between 1968 and 1986. Conifer plantations, and particularly pine plantations, are a new habitat in this region, having been established in the 1960s and 1970s. These aphids are the first non-native pests to colonize these forest plantations. As exotic pests, the aphids are suitable targets for classical biological control through the importation of natural enemies from Europe, the region of origin of the three aphids. The opportunities for biological control are explored and the prospects are encouraging. Details of the natural enemy complexes of the target pests in Europe are provided and discussed in relation to previous successful biological control programmes against conifer pests in other continents.

Psyllaephagus yaseenisp.n. is described from Mexico, Central America and the Caribbean as a parsitoid of the nymphs of Heteropsylla cubana Crawford. The psyllid is a serious pest of Leucaena leucocephala, a shade tree and animal fodder in the tropics.

Video was used to provide objective measurements of the behaviour of tsetse around an electric net. Data were collected on: (1) the number and behaviour of flies which actively avoided the net; (2) the number and fate of flies which hit the net; (3) the distribution on the ground around the net of electrocuted flies. This allowed estimates to be made of net efficiency (=No. of flies sampled/No. sampled + No. escaped%). The three components of an electric net system (netting/grids, inverter-transformer (‘spark box’) and battery) were varied to determine the effect of each on efficiency: neither the condition (age) of the netting/grids nor the design or condition of the ‘spark boxes’ had a significant effect on efficiency, but efficiency was lower with partly-charged batteries than with fully-charged ones. When account was not taken of flies which behaviourally avoided the net, the best system had an efficiency of 55% (range 49–61%), (cf. a previous estimate of 94%); when the behavioural avoiders were included in the estimate the efficiency was only 46% (range 43–49%). The efficiency of the system is discussed in terms of the way the high voltage across the electric grid is generated, and also how it might affect interpretation of sample data.

A heterogeneous population (Pel) of Culex quinquefasciatus Say was selected, by single family rearing, to give a strain, Pel SS, which had low levels of hydrolysis of the esterase substrates α and β-naphthyl acetate. The level of temephos resistance was three-fold lower in this strain than the original parental population, and the levels of resistance to malathion, fenitrothion, pirimiphos-methyl, chlorpyrifos and permethrin were also reduced. In contrast, temephos selection increased the temephos-resistance in the Pel-RR strain ten-fold compared to the original parental population and 29-fold compared to Pel SS. The level of temephos-resistance in Pel RR compared to Pel SS at the LC50 level was 37-fold. Larval cross-resistance, at different levels, was observed to the organophosphorus insecticides, malathion, fenitrothion, parathion, pirimiphos-methyl, chlorpyrifos, fenthion and phoxim, and to the carbamates, propoxur and bendiocarb, but the level of fenthion, propoxur and bendiocarb resistance was less than three-fold. Adults showed cross-resistance to malathion and fenitrothion, but not to propoxur. There was negative cross-resistance to permethrin in both the larvae and adults of Pel RR compared to the Pel and Pel SS strains.

The taxonomy and host-records of 11 Telenomus species recorded from eggs of ten species of pyralid pests in Africa are reviewed. Three species, T. bini, T. creusa and T. nemesis, are described as new. Primary type material of nine previously described species was examined: T. applanatus Bin & Johnson, T. etielliphaga (Risbec) (comb. n.), T. nephele Nixon, T. procas Nixon, T. soudanensis (Risbec), T. thestor Nixon, T. tolli Risbec, T. ullyetti Nixon and T. versicolor Bin & Johnson. A lectotype is designated for T. etielliphaga (Risbec), which is transferred to Telenomus from Micromymar. Lectotypes are also designated for T. soudanensis and T. tolli. The monotypic genus Micromymar Risbec is synonymized with Telenomus. A method for the preparation, mounting and identification of Telenomus specimens reared from eggs of African pyralid pests is given. Host-records based on previously misidentified Telenomus spp. are corrected, and records in which the host has been apparently misidentified are commented upon. The relevance of Telenomus spp. to biological control and integrated pest management of African pyralid pests is discussed.

Immature stages of bush fly, Musca vetustissima Walker, were reared at constant temperatures ranging from 18°C to 39°C. Mean egg to adult development times ranged from 7.0 to 25.8 days. Eggs, larval instars I, II and III, and pupae averaged, respectively, 3.1, 4.4, 5.5, 36.4 and 50.6% of the total development time. Mean development rate was a non-linear function of temperature. A non-linear development rate model accurately estimated mean development times of immature stages under both constant and fluctuating temperature regimes. Simulation of dung pad temperatures, from air temperature and solar radiation records, predicted development times of soil- and dunginhabiting stages of M. vetustissima to within 4% of those observed under field conditions.

Records of braconid parasitoids attacking bees (Apidae) are reviewed and their biology is discussed. The adult of Syntretomorpha szaboi Papp (Braconidae) is redescribed, the female for the first time. The final-instar larva is also described for the first time and the implications of interpreting larval characters are discussed. The Oriental honey bee, Apis cerana Fabricius, is recorded here for the first time as the host of S. szaboi.

Ovarian dissection of Glossina austeni Newstead, G. brevipalpis Newstead, G. morsitans morsitans Westwood and G. pallidipes Austen shows that there are significant interspecific differences in egg-follicle lengths. Differences between G. brevipalpis and G. pallidipes are slight as are those between G. austeni and G. m. morsitans, but the former two species have significantly larger eggs at all ages examined than the latter two. Egg-follicle length is positively related to species size (measured as wing vein length) but only weakly related to the size of individuals within a species. In the ovarian dissection technique for ageing tsetse flies, nulliparous females are usually divided into 0A (one to four days) and OB (five to eight days) categories, depending on whether the first egg follicle is less or more than 0.6 mm in length. The results presented, however, show that at four days the first egg follicle is about 1 mm in length in G. pallidipes and G. brevipalpis and 0.77 mm in length in G. m. morsitans and G. austeni. Thus, application of the 0.6 mm, four-day threshold will result in severe under-estimation of the proportion of females of the former two species of less than five days of age in a population.

In Zimbabwe, catches of Glossina morsitans morsitans Westwood and G.pallidipes Austen at odour baited traps were increased in the presence of residues of a solution of the skin secretions of oxen (hereafter sebum) by 80% and 29% respectively, and catches at F3 traps were significantly increased when sebum was presented on adjacent screens. Testing of fractions of sebum revealed active components(s) in the phenolic and non-acidic fractions but not in the acidic fraction. Furthermore, the activity of the phenolic fraction could not be explained by the presence of the known phenolic tsetse attractants. The effect of sebum was to attract more flies to the target rather than to induce a landing response in a higher proportion of attracted flies. Whether or not tarsal contact responses are involved remains conjectural. However, targets that were electrified over only one quarter of the surface caught more than one quarter the catch of targets electrified over all the surface both with and without sebum, indicating that many tsetse habitually alight more than once on baited targets. Data on the catches of other Diptera are also presented

Two new species of mealybug found on coffee roots are described from Africa. Planococcus fungicolasp. n. from Kenya is the species that has been known in Africa as the coffee root mealybug. This mealybug is almost always associated with the fungus, Diacanthodes novoguineensis (Hennings) Fidalgo. Planococcus radicumsp. n. is from Nigeria and Tanzania. Dactylopius coffeae Newstead is synonymized with Planococcus lilacinus (Cockerell) syn. n.

A host choice experiment was carried out to determine the host range of some potential biological control agents of yellow starthistle (Centaurea solstitialis), a Mediterranean plant which has become a serious rangeland weed in western USA. This paper describes the results of that experiment and discusses its taxonomic implications. The experiment confirmed the extreme host specificity of some species. However, two reputedly polyphagous species, Acanthiophilus helianthi (Rossi) and Urophora quadrifasciata (Meigen), attacked a narrower range of hosts than expected. The results of this and similar host choice experiments are discussed and it is concluded that this sort of anomaly can be caused by the existence of host races, unrecognized sibling species, or by varieties of plants naturally resistant to attack. These complex patterns of host relationship highlight the need to interpret host catalogue data cautiously, as they oversimplify complex biological systems. The identity of one species reared in the experiment, Terellia luteola (Wiedemann), is discussed; a key is presented for its separation from other Terellia species, and it is removed from synonymy with T. colon (Meigen).