The Colorado potato beetle (Leptinotarsa decemlineata, family Chrysomelidae), a phytophagous insect, which feeds preferably on potatoes, constitutes a serious pest of this crop and causes extensive damage to tomatoes and eggplants. It has a remarkable ability to develop resistance quickly against insecticides and shows a diversified and flexible life history. Consequently, the control of this pest has become difficult, requiring the development of new alternative biotechnology-based strategies. Such strategies require a thorough knowledge of the beetle's genome, including the repetitive DNA. Satellite DNA (stDNA), composed of long arrays of tandemly arranged repeat units, constitutes the major component of heterochromatin and is located mainly in centromeric and telomeric chromosomal regions. We have studied two different unrelated satellite-DNA families of which the consensus sequences were 295 and 109 bp in length, named LEDE-I and LEDE-II, respectively. Both were AT-rich (70.8% and 71.6%, respectively). Predictive models of sequence-dependent DNA bending and the study of electrophoretic mobility on non-denaturing polyacrylamide gels have shown that the DNA was curved in both satellite-DNA families. Among other features, the chromosome localization of both stDNAs has been studied. In situ hybridization performed on meiotic and mitotic nuclei showed chromosomes, including the X chromosome, with zero, one, or two stDNAs. In recent years, it has been proposed that the repetitive DNA may play a key role in biological diversification processes. This is the first molecular and cytogenetic study conducted on L. decemlineata repetitive DNA and specifically on stDNA, which is one of the important constituents of eukaryotic genomes.

The behaviour of Myzus persicae (Sulz.) on plant surfaces treated with emulsions of saturated fatty acids was investigated in three types of test. Aphids showed no clear preferences for settling or larviposition when the acids were applied to whole Chinese cabbage plants or to leaf discs from several different plant species, but settling on halves of Chinese cabbage leaves treated with undecanoic, dodecanoic or heptadecanoic acids was significantly decreased.

The Warehouse beetle, Trogoderma variabile (Coleoptera: Dermestidae), is an internationally significant invasive pest of packed goods and stored grain. When it was first documented in Australia at Griffith, New South Wales, in 1977, an eradication campaign was initiated. After several years and considerable effort, the eradication campaign was abandoned. To monitor the presence and spread of T. variabile, surveys were carried out by government agencies in 1992 and 2002. When survey data was compared, it was concluded that the distribution of morphologically identified T. variabile had doubled in most Australian states. Here, we used samples from the 2002 survey to conduct a phylogenetic study using partial sequences of mitochondrial genes Cytochrome oxidase I and Cytochrome B, and the nuclear gene 18S, to examine the distribution and dispersal of T. variabile and detect the presence of misidentified species. Based on our molecular results, we show that only 47% of the samples analysed were T. variabile, and the remaining were a mixture of six putative species. In addition, T. variabile was found in only 78% of the trapping sites. We discuss the importance of correct diagnosis in relation to the eradication campaign.

The paper deals with the control of insects by hand-collection. An experimental study of the method as used against Antestia on coffee in Kenya is described. The rate of increase of the yield of insects collected falls off in a definite and measurable manner as the time spent on the work increases. The formula for the curve fitting the results is P = 100(1 − (V.e.)−t) where “ P ” is the percentage collected of the total Antestia present, “ t ” is the time spent collecting, and “ V ” is a coefficient which has different values according to the conditions prevailing. In practice one careful experimental picking provides data for the calculation of the formula which may be used to determine the cost of hand-picking any percentage.

The results show that in theory 100 per cent. of the insects can never be obtained by hand-picking, and that in practice the cost of picking an adequate percentage is almost invariably prohibitive.

It is probable that the experimental results obtained will prove valid in other cases of hand-picking. Much of the expenditure on this method is unproductive.

Details of a thorough long-continued attempt to control Antestia on thirty-five acres of coffee by hand-picking are given. The attempt proved unsuccessful, and it is suggested that it may actually have been responsible for the maintenance of the severe attack.

The kind co-operation and assistance of a number of coffee planters are acknowledged. Except for the first experiments in 1933 Mr. H. Naismith Jones assisted me throughout, and the investigation owes a great deal to his careful supervision of much of the field work.

An investigation of the diversity and distribution of wild crucifer species and their importance for cultivated crucifers was conducted during 2005 and 2006 in the highland and mid-altitude semi-arid areas of Kenya. Thirteen species of wild crucifers in nine genera were recorded: Raphanus raphanistrum, Erucastrum arabicum, Sisymbrium officinale, Crambe kilimandscharica, Capsella bursa-pastoris, Rorippa nudiuscula, Ro. micrantha, Ro. microphylla, Lepidium bonariense, Coronopus didymus, Brassica rapa, B. juncea and an unidentified Brassica species. Highland areas had significantly higher species diversity and species richness than mid-altitude semi-arid areas. Species richness, diversity and evenness varied with season and location. Raphanus raphanistrum was the dominant non-cultivated species in the highlands followed by E. arabicum, which was also present and dominant in the semi-arid study sites. Diamondback moth (DBM) was recorded from ten wild crucifer species and R. raphanistrum and E. arabicum were the preferred host plant species. Overall, four larval, one larval-pupal and one pupal parasitoid of DBM were recorded: Diadegma semiclausum, D. mollipla, Apanteles sp., Cotesia plutellae, Oomyzus sokolowskii and Brachymeria species, respectively. Diadegma semiclausum was the most dominant species on all crucifers. We conclude that wild crucifers act as alternative hosts for DBM and provide refugia for DBM parasitoids, which risk local extinction through pesticide application or competition from introduced exotic parasitoid species. The wild crucifers also act as recolonization sites for DBM parasitoids.

Gel electrophoresis was used to study isoenzyme variation in Panolis flammea Denis Schiffermüller from a total of eight forest sites in England and Scotland dominated by either Scots or lodgepole pine. Four polymorphic loci (esterase, malate dehydrogenase, isocitrate dehydrogenase and 6-phosphogluconate dehydrogenase) were examined in adult moths. Most of the genotype frequencies conformed to Hardy-Weinberg expectations. An estimate of standardized gene frequency variance (Fst=0.109 ±0.032) indicated that there was significant genetic differentitation between populations. There was in addition a latitudinal cline in allele frequency at the 6-phosphogluconate dehydrogenase locus. The possible role of variation between P. flammea populations in contributing to regional differences in pest status is briefly discussed.

The oriental fruit fly Bactrocera dorsalis (Hendel) is a destructive insect pest of a wide range of fruit crops. Commensal bacteria play a very important part in the development, reproduction, and fitness of their host fruit fly. Uncovering the function of gut bacteria has become a worldwide quest. Using antibiotics to remove gut bacteria is a common method to investigate gut bacteria function. In the present study, three types of antibiotics (tetracycline, ampicillin, and streptomycin), each with four different concentrations, were used to test their effect on the gut bacteria diversity of laboratory-reared B. dorsalis. Combined antibiotics can change bacteria diversity, including cultivable and uncultivable bacteria, for both male and female adult flies. Secondary bacteria became the dominant population in female and male adult flies with the decrease in normally predominant bacteria. However, in larvae, only the predominant bacteria decreased, the bacteria diversity did not change a lot, likely because of the short acting time of the antibiotics. The bacteria diversity did not differ among fruit fly treatments with antibiotics of different concentrations. This study showed the dynamic changes of gut bacterial diversity in antibiotics-treated flies, and provides a foundation for research on the function of gut bacteria of the oriental fruit fly.

Dung beetles provide important ecosystem functions in semiarid environments, improving the physiochemical characteristics of the soil through tunnelling and burying nutrient-rich dung. In sub-Saharan Africa, diverse indigenous mammal communities support highly abundant dung beetle populations in savannah ecosystems. However, the conversion of landscapes to livestock agriculture may result in changes in the abundance and diversity of wild mammal species. This is likely to have significant impacts on dung beetle communities, particularly because domestic livestock dung may be contaminated with toxic residues of veterinary parasiticides. The environmental impact is likely to be affected by the degree of niche overlap between the beetle communities that colonize cattle dung and those that colonize the dung of wild mammals. We compared dung beetle communities between a pristine national park habitat dominated by large wild herbivores, and a pastoral farming community dominated by domestic livestock. Diurnal dung beetles were attracted to cattle dung in greater abundance and diversity compared to elephant, zebra or giraffe dung. Nocturnal/crepuscular dung beetles were attracted to non-ruminant dung (elephant and zebra) in higher abundance compared to ruminant dung (cattle and giraffe). Although there were no clear trophic specializations, three diurnal species showed an association with cattle dung, whereas eight nocturnal/crepuscular species showed an association with non-ruminant (elephant and zebra) dung. Diurnal species may be at greater risk from the toxic effects of residues of veterinary parasiticides in domestic livestock dung. Although many species showed trophic associations with wild herbivore dung, these beetles can utilize a wide range of dung and will readily colonize cattle dung in the absence of other options. As more land is converted to livestock agriculture, the contamination of dung with toxic residues from veterinary parasiticides could therefore negatively impact the majority of dung beetle species.

The diamondback moth (Plutella xylostella) and small white cabbage butterfly (Pieris rapae) are the two main serious pests of cruciferous crops (Brassicaceae) that have developed resistance to chemical control methods. In order to avoid such resistance and also the adverse effects of chemical pesticides on the environment, alternative methods have usually been suggested, including the use of plant enzyme inhibitors. Here, the inhibitory effects of proteinaceous inhibitors extracted from wheat, canola, sesame, bean and triticale were evaluated against the digestive α-amylases, larval growth, development and nutritional indecs of the diamondback moth and small white cabbage butterfly. Our results indicated that triticale and wheat extracts inhibited α-amylolytic activity in an alkaline pH, which is in accordance with the moth and butterfly gut α-amylase optimum pH. Dose-dependent inhibition of two crucifer pests by triticale and wheat was observed using spectrophotometry and gel electrophoresis. Implementation of specificity studies showed that wheat and triticale-proteinaceous extract were inactive against Chinese and purple cabbage amylase. Triticale and wheat were resistant against insects’ gut proteases. Results of the feeding bioassay indicated that triticale-proteinaceous extract could cause a significant reduction in survival and larval body mass. The results of the nutritional indecs also showed larvae of both species that fed on a Triticale proteinaceous inhibitor-treated diet had the lowest values for the efficiency of conversion of ingested food and relative growth rate. Our observations suggested that triticale shows promise for use in the management of crucifer pests.

The southern African shrubs Chrysanthemoides monilifera monilifera and C. m. rotundata (Compositae) are serious weeds of native vegetation in Australia and are targets for classical biological control. In host specificity tests using 69 species from 25 families, two leaf-feeding chrysomelid beetles, Chrysolina picturata (Clark) and Chrysolina sp. B, were able to complete development on only Chrysanthemoides monilifera and C. incana. The subspecies Chrysanthemoides m. monilifera was the superior host for both Chrysolina picturata and Chrysolina sp. B. Feeding and limited development of both species occurred on Calendula officinalis; limited development by Chrysolina picturata larvae occurred on Helianthus annuus, Tussilago farfara and Cymbonotus priessianus. Chrysolina picturata and Chrysolina sp. B are considered to be Chrysanthemoides-specific and have been approved for release in Australia. Potential release sites for both Chrysolina species were chosen by comparing the climate of the insects' African distribution with climate stations within the range of Chrysanthemoides monilifera in Australia. Chrysolina picturata and Chrysolina sp. B are suited for release within the western distribution of Chrysanthemoides m. monilifera in coastal areas of south eastern South Australia.

Meteorus loxostegei, Vier., is another important endoparasite of Loxostege sticticalis, L. It is perhaps second to Bracon vulgaris, Cress., in general importance as a control agent; it appears to be somewhat more variable in numbers than the latter species, but neither in the present work has been seen to reach the degree of parasitism shown by Phytodietus in Alberta in 1942.

The effect of various infestation levels of Chilo partellus Swinhoe on resistant and susceptible sorghum genotypes was assessed under artificial infestation in two field trials, conducted over two seasons. In the first season, infestation levels were 0, 10, 20, 40, 60 and 80 larvae per 2 m plot row. In the second season, additional treatments of one and two larvae per plot were included. A series of all infestation levels on susceptible plants was also included with an insecticide application 5 days after inoculation. Non-linear relationships between infestation level and yield loss were observed. In susceptible plants, small increases in initial larval infestation levels resulted in sharp increases in yield loss. An opposite tendency was observed in resistant plants where a tolerant reaction at lower infestation levels was observed. Gain threshold (GT) value, indicating the yield increase necessary to compensate for control costs, economic injury level (EIL) and economic threshold level (ETL) at which control actions should be initiated were determined for each genotype. Insecticide application on susceptible plants resulted in a 10% reduction in yield loss. However, the yield was still less than that of unsprayed resistant plants. The GT values indicated that insecticide application was economically warranted at an ETL of 20% and 2% of plants with visible symptoms of whorl damage, for the resistant and susceptible genotypes respectively.

Responses of Stomoxys spp. to electrified targets (1 × 1 m) that differed in pattern and colour were investigated over a three month period at Rekomitjie Research Station, Zimbabwe. In the first experiment, a target baited with a blue and black cloth insert caught more flies (315 ± 117) than a target baited with blue cloth insert (202 ± 69). Next, a blue-cloth baited target caught more flies (491 ± 150) than a black-cloth baited target (164 ± 69) and a target containing a cloth with a black diamond on a blue background caught more flies (997 ± 326) than a target containing a cloth with a black square on a blue background (680 ± 125). Finally, a target fitted with a cloth consisting of a vertically oriented black stripe on a blue background caught almost three times as many flies (1366 ± 356) as a target fitted with a cloth consisting of a horizontally oriented black stripe on a blue background (545 ± 150). Hourly collections of Stomoxys spp. from a blue and black target, baited with and without carbon dioxide, indicated that daily activity was bimodal, with a small morning peak and a large late afternoon peak.

This paper describes the development of rapid immunodiagnostic tests for the detection of storage mite infestations in cereals and cereal products. The study's first phase (proof of concept) involved the production of a species-specific enzyme-linked immunoassay (ELISA) for the flour mite, Acarus siro (L.), a major pest of stored commodities. The specificity of this new assay was assessed against key stored product contaminants (13 species of mites of which three were predatory, five species of insects and five species of fungi) in the presence and absence of grain. The assay was species-specific (no cross-reactivity to other storage contaminants) and was unaffected by the presence of cereal antigens in the extract. In the study's second phase, species- and genera-specific ELISAs were developed for a range of key storage mite pests: the cosmopolitan food mite (Lepidoglyphus destructor), the grocers' itch mite (Glycyphagus domesticus), the grainstack mite (Tyrophagus longior), mites of the Tyrophagus and Glycyphagus generas, and all storage mites. All tests were demonstrably specific to target species or genera, with no cross-reactions observed to other storage pest contaminants or cereals. The final, validation phase, involved a comparative assessment of the species-specific A. siro and the genus-specific Tyrophagus ELISAs with the flotation technique using laboratory and field samples. Both ELISAs were quantitative (0–30 mites per 10 g wheat) and produced good comparative data with the flotation technique (A. siro r2=0.91, Tyrophagus spp. r2=0.99).

The population dynamics of Pineus pini (Gmel.) was examined in two locations in the Kenya Highlands where the mean annual precipitation ranges from 620 to 1400 mm. Variations in population densities were related to rainfall. Generally, there was a marked decrease in population during the three months of heavy rainfall in March to May and a significant increase during dry weather from August to October. This was followed by a slight decrease in the rate of population build-up, until the long rains in April again resulted in another population collapse. Nine species of predatory insects were identified, and population fluctuations of the most common of these, Exochomus spp., was studied. Predators seemed to remove about 12% of the aphid population. Other mortality factors included heat and crawler dispersion. The greatest mortality occurred early in the life-cycle and was mainly due to eggs and crawlers being washed off the host-tree by rain.

The Imperial Institute of Entomology has received from Mr. N. C. E. Miller, from Malaya, some interesting Chalcids, which have been bred from the eggs of Batocera rubus, L. Parasites of Cerambycidae are generally little known everywhere and only very-few egg-parasites of beetles have yet been described. Mr. Miller's breedings are therefore of special interest and importance. We understand that he has made some biological observations, which he intends to publish; therefore, although very few specimens of these parasites have been received so far, we venture to describe them here with the material at hand. One species belongs to the Cleonymidae and to a very striking new genus, which can be confused with no other known genera; the other is the first species of Ooencyrtus known to attack eggs of Coleoptera.

The means whereby sugar-beet yellows viruses and their predominant vector, Myzus persicac (Sulz.), overwinter in Britain are reviewed. M. persicae overwinters mainly on cultivated secondary host plants that are not associated with the viruses: the viruses overwinter principally in the mangold and sugar-beet seed crops, which are the main source of infection in the following summer; mangold clamps may be a minor source and weeds seem unimportant.

Despite autumn certification of first-year sugar-beet seed crops, visible infection within them in the following June is never negligible, and rapid spread of virus within these crops during their second year can cause a high proportion of the plants therein to be infective, although still symptomless. The many aphids that may leave these crops and the uncertified seed crops are an important source of infection for the root crop.

It is suggested as a new control measure that seed crops of beet and mangolds should be grown in Britain in alternate years only. Consideration of the low frequencies of winds of a speed and direction suitable for carrying viruliferous aphids from Continental beet-growing areas to Britain, and of the low incidence of virus yellows in areas of Britain that are free of seed crops and comparable, in distance and direction relative to the main British beet-growing areas, with those of the latter in relation to the Continent, suggests that the effectiveness of the proposed measure is unlikely to be nullified by intrusion of infected aphids from the Continent.

Adults of a field strain of Blattella germanica (L.) resistant to dieldrin and bendiocarb were used to evaluate two insecticide bait formulations, 50% boric acid plus 50% porridge oats and 0·25% iodofenphos gel in comparison with gel alone and culture food. All cockroaches from the boric acid plus oats treatment died in less than 20 days, whereas some that fed on iodofenphos gel, culture food or gel blank survived for 30 days. Both insecticides caused females to drop their oothecae prematurely, and fewer eggs from the boric acid plus oats treatments hatched. More cockroaches exposed to boric acid plus oats bait died outside the harbourages than those from the iodofenphos gel treatments. Boric acid plus oats or iodofenphos gel offered together with culture food were eaten throughout the treatments. With iodofenphos gel alone, no bait was eaten after four days, but mortality continued for 21 days. The minimum amount of insecticide bait required to kill all 100 cockroaches was about 1340 mg iodofenphos gel, and 100·0 mg boric acid plus oats. After exposure for 24 h, all cockroaches died within nine days after exposure to boric acid plus oats, whereas with iodofenphos gel some survived after 21 days. Two further applications of gel bait in the iodofenphos experiments on days 13 and 17 failed to increase mortality although some bait was eaten. B. germanica was killed more quickly by both insecticide baits when deprived of drinking water.

Experiments are described in which the concentration-time-mortality relationships with certain insects were investigated for the insecticides DDT and γ-BHC, the insecticides being used in film form. Adults of Tribolium castaneum, the larvae of Plutella maculipennis and adults of the Aphid, Macrosiphoniella sanborni, were used as test insects. T. castaneum proved the most suitable insect for experimental laboratory work on films, since it can be kept in continuous contact with them without difficulty.

A description is given of the techniques employed for T. castaneum and also for the other insects which are able to progress on perpendicular glass surfaces. Techniques are described for experiments in which attempts were made to eliminate as far as possible the fumigation effect of γ-BHC and to differentiate it from that of direct contact. The fumigation effect of this compound is considerable and it appears impossible to eliminate it entirely.

With T. castaneum the characteristic curves connecting log. concentration with percentage mortality varies with time of exposure, from horizontal lines showing on the one hand zero toxicity and, on the other, complete mortality at all concentrations. Sigmoid curves are represented between these limits. The average survival period of T. castaneum adults gradually decreases with the strength of poison in the film.

The surface upon which toxic films are deposited was shown in preliminary experiments to have a definite bearing upon their effectiveness. Waxed surfaces showed least toxicity, and amongst a few leaves used Geum gave the highest and water lily, at lower critical concentrations, the least effect. High concentrations on water lily were little different from others in toxic action.

The parasitic larvae of two species of water mites were studied on resting and biting Anopheles implexus (Theo.) from the Zika Forest near Entebbe, Uganda. Details are given of the mites' morphology, positions of attachment, growth stages and visible effects on hosts. Living larvae of the more numerous mite species (designated as species F, Limnesiidae) were only moderately reliable indicators of the nulliparous state of female hosts, whereas those of the other species (species G, Arrenuridae) were more reliable nullipar indicators, evidently owing to their far more rapid development. The presence of living larvae of either species not completely full-grown denoted the nulliparous state of female hosts with certainty. Male mosquitoes showed consistently lower infestation rates than females from the same resting samples, but the incidence of the different growth classes of species F indicated that these mites departed from hosts of either sex with equal facility and therefore regardless of whether the hosts returned to oviposition sites or not. Frequency distributions of species F on each host sex fitted most closely to highly clumped negative binomials, and biological interpretation of patterns of decline in mite numbers on females in successive Sella's stage groups, and other data, provided evidence of there being at most a negligible amount of mite-mediated host mortality.

The study confirms the usefulness as well as the limitations of the presence of parasitic water mites as a rapid means of age-grading female mosquitoes, and suggests several new applications.