Trials to control the American bollworm, Helicoverpa armigera (Hübner) by the technique of mating disruption were carried out in the Pakistan Province of Punjab during the 1996 cotton season. A slow release PVC resin formulation, Selibate®HA, containing a 97:3 mixture of the major (9Z-hexadecenal) and minor (11Z-hexadecenal) components of the female sex pheromone of H. armigera was applied at a rate of 40 g active ingredient ha−1 during August 1996. The formulation was applied around the terminal portion of the cotton plant by hand using local labour at a rate of c. 250 pieces per hectare. The efficacy of the formulation was compared to conventional insecticide regimes to control H. armigera on four farmer practice fields situated at least 1 km to the north, south, east and west of the pheromone treated area. A high degree of trap catch shutdown (indicating mating suppression) was observed throughout the pheromone treated area during the whole of the season compared to non-pheromone treated farmer practice fields. Night observations confirmed that mating disruption occurred in the pheromone treated area as a smaller percentage of mated females were collected from this area compared to farmer practice fields. A majority of mated females collected from the pheromone treated area mated only once, whereas females in farmer practice fields had undergone multiple matings. A greater percentage of tethered female H. armigera moths retrieved from farmer practice fields had successfully mated compared to tethered females retrieved from the pheromone treated area. Release rate data of H. armigera pheromone from the formulation show that c. 70% was released during the two month trial period. However, the highly dispersive pre-oviposition flight behaviour of females meant that the area treated was not sufficient to eliminate the problem of gravid females migrating in from surrounding areas, and ovipositing therein. The implications of using the technique of mating disruption to control large strong flying insects like H. armigera are discussed.

In this critique it is argued that the genetic basis of the evolution of resistance is dependent on how the phenotypic, and underlying genotypic, variation is channelled during a selective response. A polygenic response is preferentially favoured if selection acts within the phenotypic distribution of susceptibles; a monogenic response is predicted if selection screens rare mutations with phenotypes outside that susceptible distribution. The relevance of this model to the method of genetic analysis, the prediction of resistance mechanisms to novel insecticides, the generation of resistant beneficial insects and the development of the most effective resistance and integrated pest management programmes is discussed.

The coffee berry borer, Hypothenemus hampei Ferrari, is a serious problem for the majority of the world‘s coffee growers and has proved to be one of the most intractable of present day pests. Despite a great deal of research, control still depends largely on the application of the organochlorine insecticide endosulfan, which is damaging to the environment, or a series of cultural and biological control methods which give variable and unpredictable results. This review summarizes the most important aspects of the biology and ecology of H. hampei and its control and identifies weak points in the knowledge about this pest. Emphasis is placed upon an analysis of the non-chemical control methods available and suggestions are offered for novel ecological and environmental factors worthy of further research, in the search for viable and sustainable control methods.

The biological consequences of mating interactions between indigenous and exotic biotypes of Bemisia tabaci (Gennadius) in Australia were studied using a combination of field and laboratory experiments. The key results of the interaction between the B and eastern Australian biotypes were reduced population increase, a marked increase in the proportion of male progeny, fewer eggs produced by females paired with males of different biotype and no difference in the numbers of eggs per unmated female and females paired with males of the same biotype. In addition, there was no change in the proportion of eggs hatching, mixed biotype pairs spent more time courting than single biotype pairs and a low level of hybridization in field cages and small containers was observed. These observations suggest three possibilities. The first is the ‘distracting male hypothesis’ in which mating pairs made up of different biotypes apportion more time to courtship and less time to egg laying than single biotype pairs. The second invokes the ‘single-locus complementary sex determination model’ in which the production of non-viable diploid male zygotes may explain the reduction in eggs laid. The third is cytoplasmic incompatibility between biotypes caused by Wolbachia. The results also suggest that the geographical distribution of clusters of related biotypes both overseas and in Australia may be explained by between-biotype interactions leading to the formation of parapatric populations.

Aptesis nigrocincta Gravenhorst is a bivoltine ectoparasitoid of apple sawfly cocoons, hosts that must be found and parasitized by females at a depth of 10–25 cm in the soil. Females are significantly smaller than males and nearly wingless. After encountering a host, females needed 29.3 min at 20°C and 19.9 min at 25°C to deposit an egg on the host. Development from egg to adult took 39.6 days for females and 38.0 days for males at 20°C. This small difference was significant. At 20°C, the longevity of females that had no opportunity to oviposit was on average 72.5 days, significantly higher than male longevity (50.6 days). The longevity of females given access to hosts throughout their lifetime averaged 58.6 days. Females were able to mate immediately after emergence and copulation lasted on average 21.7 s. After a pre-oviposition period averaging 5.8 days, females laid 20.2 eggs during their lifetime, thus less than one egg per day. Neither the fecundity nor longevity of individual females was correlated with body size. If females were deprived of food, longevity as well as lifetime fecundity were drastically reduced. Field studies were carried out in one organically managed apple orchard in Switzerland. Aptesis nigrocincta showed parasitism rates ranging from 12.1 to 39.7 % within single parasitoid generations, thereby constituting the most important mortality factor of apple sawfly cocoons.

The species of Diadegma that attack Plutella xylostella(Linnaeus) are revised. Following a morphometric study involving principal components and discriminant analyses, seven distinct morphospecies are recognized. One species is described as new: D. novaezealandiae from New Zealand. Diadegma mollipla(Holmgren) is the name for the species from sub-Saharan Africa and some Indian Ocean and South Atlantic islands. Diadegma varuna Gupta syn. nov. and D. niponicaKusigemati syn. nov. are both synonymized with D. fenestrale(Holmgren). Diadegma xylostellae Kusigemati is strongly presumed to be a synonym of D. semiclausum (Hellén). An illustrated identification key is provided and each species is described in a standard way.

Larvae of the South African tephritid flies Mesoclanis polana Munro and M. magnipalpis Bezzi feed in the developing seeds of Chrysanthemoides monilifera. Host specificity evaluation using 109 plant species from 25 families indicated that complete development was restricted to their natural host C. monilifera. Minor feeding and limited development was detected on 18 species, but was of no ecological or economic significance. Mesoclanis polana and M. magnipalpis have been released in Australia and M. polana has established and dispersed widely. Mesoclanis magnipalpis has not yet become naturalized. Parasitism of M. polana in Australia by several species of Hymenoptera has been detected, but is not expected to limit the establishment and impact of these flies.

Antibiosis and resistance of six Cucurbita and two Lagenaria accessions to the carmine spider mite, Tetranychus cinnabarinus Boisduval, were evaluated in the laboratory. Significant differences among accessions were observed three days after the inoculation of detached leaf discs. The Lagenaria accessions, Slawi and Sus, proved to be the most resistant to mites, with average populations of mite eggs, 87 and 95%, respectively less than that of the susceptible C. pepoaccession, Orangetti. The Cucurbita accessions, Tace, Brava, Tetsukabuto, Phoenix and TZ-148 had mite egg totals 4, 9, 13, 26 and 40%, respectively, less than those of accession Orangetti. The Sus accession of Lagenaria was resistant to T. cinnabarinus from the four-leaf stage until fruit set in laboratory and field tests. Grafting the susceptible Brava onto Sus rootstock increased the resistance of the scion to the same level as that of non-grafted Sus. Grafting the susceptible Cucumis melo Noy Yizre’el on resistant or susceptible rootstocks of Cucurbita and Lagenaria accessions did not affect its susceptibility to T. cinnabarinus. The results indicate that resistance to T. cinnabarinuscan be transferred by grafting from Lagenaria stocks to Cucurbita scions but not in the opposite direction.

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.

Genetic similarities between 13 samples belonging to nine reference biotypes and two field populations of Bemisia tabaci (Gennadius), one field population of B. medinae Gómez-Menor and another of B. afer Priesner &Hosny, were evaluated using amplified fragment length polymorphism (AFLP) markers. The results indicate that B. tabaci biotypes can be grouped together with a minimum similarity coefficient of 0.32 and separated from the two other species with a similarity coefficient of 0.07. Bemisia tabaci biotypes were grouped in four clusters which comprised: (i) Near East and Indian subcontinent biotypes; (ii) B and Q biotypes plus a Nigerian population from cowpea; (iii) New World A biotype; and (iv) S biotype and a Nigerian population from cassava. These results were consistent with a previous grouping of biotypes based on RAPD-PCR analysis. The AFLP assay allowed the scoring of a total of 354 polymorphic bands in two reaction events with the use of two primer combinations.

There is a need to identify potential biological control agents for use against lepidopterous pests in greenhouses. The solitary endoparasitoid Meteorus gyrator(Thunberg) attacks a range of macrolepidopterous larvae, including those of some important horticultural pest species. Laboratory trials designed to investigate the biology of M. gyrator on larvae of the tomato moth, Lacanobia oleraceaLinnaeus, reveal that this parasitoid is capable of parasitizing all larval stages of its host, third instars being parasitized most frequently. Each female parasitoid lives for up to 40 days (at 25°C), ovipositing into an average of 78 hosts. Preadult development is rapid (~ 2 weeks), and the sex ratio of offspring is 1:1. Parasitism by M. gyrator suppresses the growth of both early and late host instars, and there is a concomitant reduction in the amount of food consumed (overall feeding reduction over a 12 day period is 68%). Our results indicate that inoculative releases of M. gyrator could provide effective biological control of L. oleracea and other noctuid pests of greenhouses.

The cassava green mite, Mononychellus tanajoa (Bondar), is an exotic pest in Africa and is the target of a classical biological control programme. Field data from the Neotropics, where it is indigenous, are presented for the first time, charting the variation in abundance of M. tanajoa over several seasons. This was highly variable, with a characteristic trough mid-year and a peak at the turn of the year. This pattern corresponded positively with rainfall levels, appearing to fit a phenology also characteristic of African studies, where rainfall at the start of the wet season promotes a leaf flush and so growth in M. tanajoa populations. Analyses implied some impact of leaf-inhabiting predatory mites (predominantly Neoseiulus idaeusDenmark & Muma) and a considerable impact of the fungal pathogen Neozygites floridana Fisher on M. tanajoa populations. This pathogen was not observed in the host population for several (generally dry) periods implying survival outside the host, perhaps as resting spores. This is a particularly desirable characteristic of a biological control agent. It is therefore proposed that N. floridanamight be of particular use in drier cassava-growing areas where rainfall at the outset of the wet season is not sufficiently intense to cause heavy M. tanajoa mortality but may be sufficient to stimulate epizootics of the fungal pathogen, protecting the flush of new cassava growth.

The origin of introduction of the cabbage root fly, Delia radicum Linnaeus to the north-eastern coast of North America in the 19th century has been assumed to be from Europe. From that point of introduction, D. radicum gradually spread westward to occupy available ecological niches. DNA fingerprinting and egg micromorphology were used to determine the most likely geographical origin of the North American populations of this species. Forty-five informative RAPD loci obtained from ten primers and three criteria for egg micromorphology were studied. These characters indicated a common origin for the North American populations and a high similarity between populations from North America and north-western Europe. The results suggest a single entrance point of D. radicum into North America, probably via the north-eastern coast (New York area) from north-western Europe. The implications of this study in assisting selection of natural enemies of this important agricultural pest are discussed.

Large-scale eradication campaigns against tsetse flies Glossina spp. are giving way to smaller operations aimed at disease and vector containment. There has been little discussion of the effects of these changes in policy. This study estimates the rate at which tsetse re-infect treated areas after the termination of control efforts. Movement is modelled as a diffusion process with a daily root mean square displacement (λ) of 0.2–1 km−1/2 and population growth as logistic with a growth rate (r) ≤1.5% day−1. Invasion fronts move as the product of λ and √r. For r = 0.75% day−1 a front advances at 2.5 km year−1for each 100 m increment in λ. If there are 0.001% survivors in 10% of the treated area, the population recovers to within 1% of the carrying capacity (K) within three years. If the control area is subject to invasion from all sides, a treated block of 10,000 km2 is effectively lost within two years – except at the lowest values of λ and r. Cleared areas of 100 km2 are lost in a year, as observed in a community-based suppression programme in Kenya. If the treated area is closed to re-invasion, but if there is a block where tsetse survive at 0.0001–0.1% of K, the population recovers within 3–4 years for up to 20 km outside the surviving block. If the surviving flies are more widely spread, re-infection is even more rapid. The deterministic approach used here over-estimates re-invasion rates at low density, but comparisons between control scenarios are still valid. Stochastic modelling would estimate more exactly rates of re-infection at near-zero population densities.

The life cycle, within-field distribution, crop damage and impact of natural enemies of the potato tuber moth, Phthorimaea operculella (Zeller) were investigated in two potato cropping systems. The two systems differed in soil type (sandy vs. loess) which in turn affected the choice of cultivars, irrigation programme, insecticide application method (ground vs. aerial), and planting and harvest times. From mid-April to the end of May, almost twice as many moths were caught in pheromone traps in sandy than in loess fields. Highest infestation of tubers was found before harvest, and infestation was greater in loess than in sandy fields. Larval densities in foliage and tubers were significantly higher at the margins of the fields than in the centre. A significant positive correlation was found between adult catch and larval infestation on foliage in sandy fields but not in loess. Tuber infestation in sand was positively correlated with foliage infestation. No such correlation was detected in loess. Five parasitic wasps emerged from P. operculella larvae collected from commercial fields and volunteer plants: Diadegma pulchripes (Kokujev) and Temelucha decorata, (Gravenhorst) (Ichneumonidae) and Bracon gelechiae Ashmead and two other unidentified Braconidae. The most abundant predators at the field site were Coccinella septempunctata Linnaeus (Coccinellidae), Chrysoperla carneaStephens (Chrysopidae), Orius albidipennis (Reuter) (Anthocoridae) and four ant species (Formicidae). Parasitism rate reached 40% and predation was estimated at 79%. Results are discussed with regard to the development of an integrated pest management programme for this important pest.

Glossina longipennis Corti was studied in Galana Ranch, Kenya over a four year period, in two areas (Tank E and Lali) where the species was abundant and other species were absent or scarce. There was active transmission of trypanosomiasis to cattle in both areas, the parasite species being Trypanosoma vivax Ziemann and T. congolense Broden. Mean infection rates of the G. longipenniswere 1.1% and 0.55% for T. vivax and T. congolenserespectively at Tank E, and 0.88% and 0.15% at Lali. Experimental transmission studies showed that cattle in fly-proof enclosures challenged with wild G. longipennis collected from Galana became infected with both trypanosome species. A tsetse control operation in one area (Tank E) using targets impregnated with deltamethrin in an oil formulation reduced the population of G. longipennisby 98% over one year, despite evidence of re-invasion. Populations of G. longipennis in the other area (Lali) were relatively stable over the whole study period. The effect of tsetse control on the incidence of cattle trypanosomiasis at Tank E was less clear than that on tsetse numbers, probably due to the lack of a sustained reduction in tsetse numbers. However, a significant relationship was demonstrated between fortnightly incidence measurements and electric net catches of G. longipennisat Tank E. A further significant predictor of incidence was rainfall in the previous four to seven weeks. This study confirms the importance of G. longipennisas a vector of bovine trypanosomiasis in areas where it is the predominant tsetse present.

The two alpha-cyano pyrethroid insecticides lambda-cyhalothrin and alpha-cypermethrin were tested as bednet treatments at a target dose of 20 mg m-2. To establish their efficacy, female pyrethroid resistant and susceptible Anopheles stephensi Liston, and the F1-hybrids were allowed to fly freely in a room with a human subject under an impregnated net. Both treatments provided good personal protection by significantly reducing the number of blood fed mosquitoes compared to an untreated control net. Mortality after 24 h was significantly higher for the alpha-cypermethrin treated net when compared to lambda-cyhalothrin. For each insecticide there were no significant differences in the proportion of susceptible homozygotes and F1-hybrids found dead after a 24 h holding period, which suggests that there would be no selection for pyrethroid resistant heterozygotes by either of the insecticides.

The diversity of beetle assemblages in different habitat types (primary forest, logged forest, acacia plantation and oil palm plantation) in Sabah, Malaysia was investigated using three different methods based on habitat levels (Winkler sampling, flight-interception-trapping and mist-blowing). The overall diversity was extremely high, with 1711 species recorded from only 8028 individuals and 81 families (115 family and subfamily groups). Different degrees of environmental changes had varying effects on the beetle species richness and abundance, with oil palm plantation assemblage being most severely affected, followed by acacia plantation and then logged forest. A few species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from the rest. The effects of environmental variables (number of plant species, sapling and tree densities, amount of leaf litter, ground cover, canopy cover, soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities correlated with species richness, abundance and composition of understorey beetles while ground cover correlated only with the species richness and abundance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species and individuals. Environmental changes affected the trophic structure with proportionally more herbivores (abundance) but fewer predators (species richness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this study.

CUF 101, a resistant cultivar of alfalfa, was exposed to 15 clones of Acyrthosiphon pisum Harris collected from alfalfa fields in three regions of France (east, south, central west) to determine whether the level of resistance varied across the different clones. The survival of alfalfa seedlings infested at the cotyledon stage was assessed using a standardized method. Although no difference in seedling mortality was detected between clones grouped by region, there was a significant variation among the 15 pea aphid clones. In particular, two clones of southern origin were more aggressive. In addition, the different pea aphid clones were characterized using allozyme and RAPD-PCR markers. Among the 15 clones, seven allozyme genotypes (plus one when adding colour polymorphism) and 12 RAPD-PCR genotypes were distinguished. The two southern clones differing by their aggressiveness on the resistant alfalfa belonged to the same allozyme and RAPD genotype which was distinct from the other pea aphid clones. Our results reinforce the need to take into account aphid genetic diversity in breeding programmes for resistance in cultivated plants.

The whitefly fauna of Europe and the Mediterranean Basin comprises 56 species that are considered to be native or naturalized, accommodated within 25 genera. Presented here are a check-list, an identification key to puparia, and a brief account of each species including its distribution and host-plant range. The puparium of each species is illustrated. One new nomenclatural combination (Aleuroclava similis, from Aleurotuberculatus) and two new synonymies (Parudamoselis kesselyakiwith Ceraleurodicus varus, Asterobemisia nigrini with A. paveli) are proposed. Three nominal species (Aleurodes capreae, A. fraxini, and Aleyrodes campanulae) are here treated as nomina dubia. Species which, in the study area, have only been recorded from glasshouses are discussed. Four additional species, not yet recorded from the region, are included in the discussion, two of them because a particular quarantine risk is perceived and two because they are notifiable pests in European Union quarantine legislation.