Through the courtesy of Dr. G. A. K. Marshall I have had the opportunity of examining specimens of a beetle belonging to the subfamily Hispinae of the Chrysomelidae, which is reported to be injurious to oil palms (Elaeis guineensis, Jacq.) in the Gold Coast. Concerning this insect Mr. W. H. Patterson, Government Entomologist in the Gold Coast, writers as follows:—“The beetle has suddenly become a pest, being reported as having destroyed all the expanded foliage of many thousands oil palms in one district. A similar epidemic occurred in 1909, but entirely disappeared during the following rainy season, since which time the beetle has been very rare”. From this it would appear that the extent of damage is considerable when the insect becomes numerous. Although Mr. Patterson does not indicate the nature of the damage there is no doubt that the larvae mine into the young shoots and the adults defoliate the young leaves. In a recent work (Hispinae and Cassidinae, Fauna of Brit. Ind., London 1919, pp. 10–18) I have reviewed all the Hispid pests of plants useful to man. Only two African Hispids have hitherto been noted as harmful, and these attack maize in East Africa.

Regular catches of males of Spodoptera exempta (Walker) were made in 41 pheromone disc traps scattered throughout Malawi in 1978–82. Each trap had a vial, replaced monthly, containing 2 mg of a 13·3:1 mixture of two sex-pheromone components of the female. Over the five-year period, males were caught every month at a majority of sites throughout the country, suggesting that they came from populations resident in Malawi. Sites at which moths were regularly caught had areas with green grass throughout the year which could have sustained larvae within their vicinity. A few sites at which moths were caught only occasionally had very dry immediate surroundings in the dry season, and it is suggested that moths caught at these sites are primarily migrants from either within or outside Malawi. There was no obvious relationship between site elevation, monthly rainfall and monthly moth catches or whether moths were caught persistently or irregularly. The results strongly suggest that some of the moths captured throughout the year in Malawi developed locally while some originate in other countries such as Mozambique.

Cartographical analysis of the distribution of recorded swarming populations of Locusta migratoria migratorioides (R. & F.) in western Africa for the first four years of the 1928–41 plague of this species has shown seasonal latitudinal displacements in each year with a nroth-to-northweastward movement of swarms during the monthe February-March to August-September, and a south-to-south-westward return during the priod October until the end of the year or January or Ferbruary of the following year.

Changes in the position of the northern limit of distribution of swatms in western Africa from month during 1931 have indicated a probable relationship between its position and that of the Intertropical Front, in its seasonal displacement, the position of the surface front being inferred from that of the 10-mm. isohyet. From February to September 1931, following the northward displacement of the Intertropical Front and the northward penetration of south-westerly winds, a general northward displacement of swarms occurred. Similarly, following the southward advance of northerly winds, there was a southward displacement of swarms.

There was an eastward movement in the main latitudinal displacement. This was particularly marked in 1929 and 1930. By September 1929, the infestation that in April had been restricted to parts of south-western Guinea and norther Sierra Leone had spread north-eastwards to cover the greater part of the Voltaic Republic and southern Mali; from December 1929 to January-February 1930, following the south-westward movement from late September to November 1929 which confined swarms to the countries bordering the Atlantic and the Gulf of Guinea. there was a spread eastwards along the coastal areas from south-eastern Ghana to southern and eastern Nigeria; and following the main northward movement of swarms which began in western AFrica in April 1930, there was, from May-June onwards, a pronounced eastward migration to the central and eastern parts of the continent. Each of these eastward movements occurred in areas where, at that particular time of year, the prevailing winds would be from the south-west.

The deduced movements suggest that swarms of Locusta in western Africa move downwind, and that the principal seasonal changes in the distribution of swarms in that area occur in response to the latitudinal displacement of the Intertropical Front and its associated wind field.

Long-term records of aphid catches on two sticky traps, one at Rothamsted (1942–64) and one at Broom's Barn (1960–64) are extended to 1973 and are supplemented by data from up to 12 sticky traps in sugar-beet crops in eastern England (1960–73). The incidence of yellowing viruses of sugar-beet between 1965 and 1973 showed no relation to aphid numbers, but between 1942 and 1973 the pattern of annual incidence was similar to that of numbers of Myzus persicae (Sulz.) trapped in May and June. Linear regressions of the incidence of yellowing viruses on numbers of M. persicae in May and June accounted for 28–57% of the variance, and on Aphis fabae group for 2–40% of the variance. It is concluded that sticky traps provide useful information for advisory entomologists and that there has been no general increase in aphid numbers over the last 30 years.

The ‘Eugenia psyllid’ or ‘Lilly pilly psyllid’, widely recognized in Australia and in the USA as Trioza eugeniae Froggatt (Hemiptera: Triozidae), is not T. eugeniae, but rather T. adventicia Tuthill. In this study we assessed morphological comparisons of materials from throughout the native and introduced ranges and re-examined original descriptions of both taxa, together with Froggatt's type specimens of T. eugeniae. Furthermore, through DNA barcoding analyses, we confirmed the validity of both T. adventicia and T. eugeniae as separate species. We re-described both species to include additional characters not previously included and designated a lectotype for T. eugeniae. T. eugeniae has smaller fore wings that are slightly more elongate. These lack infuscation around veins R and R1, vein Rs is relatively longer, meeting the costa closer to the wing apex; with certain veins bearing long, fine divergent setae, a character not previously described. It has consistently three inner and one outer metatibial spurs. The male parameres appear narrowly pyriform with a weak dorsolateral lobe and weakly sclerotized apices. T. adventicia has larger fore wings that are slightly more ovate with dark infuscation around veins R and R1; vein Rs is relatively shorter, meeting the costa further from the wing apex, with veins lacking long, fine divergent setae. The usual configuration of two inner and one outer metatibial spurs, previously used to separate the two species, appears inconsistent. The male parameres appear a little more broadly pyriform with slightly more sclerotized apices. T. eugeniae refers to a distinct species which has a restricted distribution only in its native range in southern subcoastal New South Wales, Australia. T. adventicia refers to a separate species, with a natural distribution in eastern subcoastal Australia, but has been introduced widely in southern Australia, to New Zealand and the USA. This study elucidates a long history of misidentification of T. eugeniae in the nursery industry and in almost 30 years of literature on its biological control in the USA. Regardless, the biological control program, unknowingly, targeted the correct species of psyllid, T. adventicia, in its foreign exploration and importation of the appropriate parasitoid as a biocontrol agent in the USA. Despite being firmly entrenched in both the nursery trade and scientific literature, the name T. eugeniae is misapplied. While the acceptance of the valid name, T. adventicia, might be regarded as both problematic and protracted, this is the correct taxonomical attribution.

The species of the genus Pyrilla Stål (Fulgoroidea: Lophopidae) found in India and Ceylon are reviewed on the basis of population samples from different localities. It is considered that two polytypic species are present: P. perpusilla (Wlk.), widespread in India and now recognised as extending to Ceylon and to Thailand, and P. aberrans (Kby.) (sensu stricto), formerly regarded as being confined to Ceylon, but now found to occur also in south India. Ten geographical subspecies of the former and five of the latter are described and named.

The biology and host range of the two root-mining weevils Diplapion confluensKirby and Coryssomerus capucinus (Beck), two potential agents for the biological control of scentless chamomile Tripleurospermum perforatum (Mérat) Laínz, were studied in the field in southern Germany and eastern Austria, and in a common garden and under laboratory conditions in Delémont, Switzerland from 1993 to 1999. Both weevils were univoltine, and females started to lay eggs in early spring. Diplapion confluens had three and C. capucinus five instars. Larvae of both species were found in the field from mid-April until the end of July; later instars preferentially fed in the vascular cylinder of the shoot base, root crown or root. Although larvae of both species occupy the same temporal and spatial niche within their host plants, they occurred at all investigated field sites together, and showed a similar distribution within sites. No negative or positive interspecific association was detected. Host-specificity tests including no-choice, single-choice, and multiple-choice tests under confined conditions, as well as tests under field conditions with natural and augmented insect densities revealed that both herbivores were specific to plant species in the tribe Anthemideae. However, their development to mature larva or adult on several cultivated plants, as well as on one plant species native to North America, rendered them unsuitable for field release in North America. It was concluded that to investigate non-target effects reliably, host-specificity tests with biological control agents should be carried out under a variety of conditions, particularly with augmented insect densities, as are expected to occur naturally after release.

Natural enemies of Aonidiella aurantü (Mask.) were counted in suction-machine samples taken fortnightly over 41 months from an orchard of orange trees in the Swaziland lowlands, a region where biological control of the scale is difficult. Changes in the log population intensity/‘twig’ (Δ log N) of four species were, in each case, calculated over four thermal constants of 5000, 10 000, 15 000 and 20 000 hour– degrees above 12°C (h°>12C). The middle two constants were assumed to approximate to the thermal constants of the generation times of the natural enemies. For each natural enemy, Δ log N measured over each thermal constant was related by regression analysis to climatic and biotic indices to see how the interval over which population change was measured affected the conclusions. The longer the interval, the greater was the percentage of the explained variation in Δ log N, and the greater the number of indices that became significant. However at 20 000 h°>12°C, population change was measured over rather long intervals for short–lived species like Aphytis. At both 10 000 and 15 000 h°>12°C, the number and the identity of the significant indices in the regression tended to be the same. Consequently, conclusions about the factors affecting the natural enemies were based on these regression results. A. africanus Qued–nau, Comperiella bifasciata How. and Rhyzobius lophanthae (Blaisd.) responded directly to changes in their host's numbers, but Habrolepis rouxi Comp. responded inversely and was unlikely to have been effective. Furthermore, it was sensitive to high summer temperatures, as was A. africanus and possibly R. lophanthae. C. bifasciata was not sensitive to high summer temperatures but was adversely affected by the hyperparasitoid Marietta javensis (How.). None of the natural enemies was affected by prevailing saturation deficits.

Understanding pest population dynamics and seasonal phenology is a critical component of modern integrated pest-management programs. Accurate forecasting allows timely, cost-effective interventions, including maximum efficacy of, for example, biological control and/or sterile insect technique. Due to the variation in life stage-related sensitivity toward climate, insect pest population abundance models are often not easily interpreted or lack direct relevance to management strategies in the field. Here we apply a process-based (biophysical) model that incorporates climate data with life stage-dependent physiology and life history to attempt to predict Eldana saccharina life stage and generation turnover in sugarcane fields. Fitness traits are modelled at two agricultural locations in South Africa that differ in average temperature (hereafter a cold and a warm site). We test whether the life stage population structures in the field entering winter and local climate during winter directly affect development rates, and therefore interact to determine the population dynamics and phenological responses of E. saccharina in subsequent spring and summer seasons. The model predicts that: (1) E. saccharina can cycle through more generations at the warm site where fewer hours of cold and heat stress are endured, and (2) at the cold site, overwintering as pupae (rather than larvae) confer higher relative fitness and fecundity in the subsequent summer adult moths. The model predictions were compared with a large dataset of field observations from scouting records. Model predictions for larval presence (or absence) generally overlapped well with positive (or negative) scout records. These results are important for integrated pest management strategies by providing a useful foundation for future population dynamics models, and are applicable to a variety of agricultural landscapes, but especially the sugarcane industry of South Africa.

Thrips palmi and Frankliniella occidentalis (order Thysanoptera) are thrips species that represent major plant pests. They are polyphagous insects capable of adversely affecting crop production. As such, in the European Union, these thrips species should be regulated as quarantine organisms. T. palmi and F. occidentalis can cause considerable damage to susceptible plants by feeding on them and transmitting several viruses responsible for serious plant diseases. Successful pest control strategies are based on an early, fast, and reliable diagnosis, which precedes the selection of appropriate steps to limit the effects of harmful organisms. We herein describe a novel diagnostic approach that enables the sensitive and species-specific detection (and differentiation) of these pests in a duplex polymerase chain reaction assay, which was adapted for both standard and real-time quantitative assays. Our method is based on the amplification of a 5.8S-internal transcribed spacer 2 ribosomal DNA fragment that is conserved between T. palmi and F. occidentalis.

Various sampling techniques were employed to study the population dynamics and identify the origin of annually re-occurring infestations of Paratanytarsus grimmii in granular activated carbon (GAC) adsorbers. Larvae overwintered in all adsorbers studied and are the main source of endemic persistent infestations. Significant differences in larval densities were identified between the down-flow cell (mean of 61 larvae per 0.3 l of GAC) and the up-flow cell (mean of 14 larvae per 0.3 l of GAC) of each adsorber. Larvae were distributed uniformly with no significant difference in density at any depth through the 2-m carbon column. Application of anaerobic treatment as a control measure was ineffective at low temperatures due to a slow down in chironomid metabolism. During summer months, ovipositing females have access to all locations within the GAC adsorber building by flight, leading to immediate re-colonisation of anaerobically-treated adsorbers. Regeneration of GAC in individual cells served only to reduce larval numbers but not remove them completely, particularly when only one of the two cells is regenerated at any one time.

Some fire ants of the genus Solenopsis have become invasive species in the southern United States displacing native species by competition. Although the displacement pattern seems clear, the mechanisms underlying competitive advantage remain unclear. The ability of ant workers to produce relatively larger amount of alarm pheromone may correspond to relative greater fitness among sympatric fire ant species. Here we report on quantitative intra-specific (i.e. inter-caste) and inter-specific differences of alarm pheromone component, 2-ethyl-3,6-dimethylpyrazine (2E36DMP), for several fire ant species. The alarm pheromone component was extracted by soaking ants in hexane for 48 h and subsequently quantified by gas chromatography-mass spectrometry at single ion monitoring mode. Solenopsis invicta workers had more 2E36DMP than male or female alates by relative weight; individual workers, however, contained significantly less pyrazine. We thus believe that alarm pheromones may serve additional roles in alates. Workers of Solenopsis richteri, S. invicta, and hybrid (S. richteri × S. invicta) had significantly more 2E36DMP than a native fire ant species, Solenopsis geminata. The hybrid fire ant had significantly less 2E36DMP than the two parent species, S. richteri and S. invicta. It seems likely that higher alarm pheromone content may have favored invasion success of exotic fire ants over native species. We discuss the potential role of inter-specific variation in pyrazine content for the relationship between the observed shifts in the spatial distributions of the three exotic fire ant species in southern United States and the displacement of native fire ant species.

While investigating the biological control of certain Hepialids, a very interesting Ichneumonid parasite, Alomya debellator (F.) was reared from the pupae of the Swift Moth, Hepialus lupulinus (L.).

The systematic position of this parasite has been thoroughly investigated and the members of the special sub-family, Metopiinae, to which it has been assigned, are characterised by the possession of only one trochanter on each foreleg. A. debellator is the sole representative of the tribe Alomyini.

After extensive collecting, and a thorough search of the literature, the conclusion has been reached that the distribution of this parasite is fairly local, but its range in Great Britain and certain other European countries is wide. As a result of the present study H. lupulinus has been definitely proved to be the host of A. debellator.

A fairly full account of the life-history of the parasite has been worked out, and amongst other things, a point of special interest is the arrest in development which occurs in the first-instar larva. Possible explanations of this phenomenon are discussed.

The morphological and anatomical structure of the larva have been fully investigated and described, and useful diagnostic characteristics both for the primary and mature larval stages, have been discovered.

The paper concludes with a discussion on the potential value of A. debellator as a factor in the control of H. lupulinus, and other allied species belonging to the genus Oncopera in Australia. It is maintained, on the evidence collected, that this parasite in some areas is probably the most important single factor of biological control. A note on the feeding habits of Hepialids, and a few remarks about the collecting of parasitised material are appended. Altogether some 7,000 specimens of H. lupulinus larvae and pupae many of which were parasitised by A. debellator were collected from the Willingham area of Cambridgeshire.

Laboratory studies were undertaken to find out if the increased degree of infestation by certain moth species, Cadra cautella (Wlk.), plodia interpunctella (Hb.) and Corcyra cephalonica (Stnt.) following the chemical control of beetles including Tribolium castaneum (Hbst.) in stacks of groundnut (Arachis) in Nigeria could be due to relaxation of inter-specific competition.

All test insects were reared and studied at a constant temperature of 25.5°C. and 70 per cent. ralative humidity. All experiments were conducted on shelled nuts (or germs of nuts) in specimen tubes, crystallising dishes or jam jars. The survival and development of the immature stages of the moth species was studied and the numbers of eggs laid by the adults recorded in the presence of adults of T. castaneum; the reciprocal effects of moth larvae on T. castaneum were also briefly studied.

The most important harmful effects of T. castaneum were on copulating moths and on moth eggs. Adults were frequently disturbed and sometimes killed or, if they survived, laid fewer eggs; eggs were also eaten, especially those laid loose in the medium. Adults of T. castaneum also attacked and killed moth larvae and pupae, but this was considered to be of minor importance. The silk produced by moth larvae was inimical to larvae of T. castaneum, but the effect on the population of T. castaneum was probably offset by the beneficial effect of moth cocoons, which provide shelter for larvae of T. castaneum from cannibalism.

It is conculaded that as a result of competition for food and/or space between T. castaneum and the moth species the moth populations are likely to be exterminated despite their apparently higher intrisic rate of increase.

The following notes are presented in the simple form in which they were jotted down at the time, as it seems to me that this will be the best way to give a clear idea of what was observed.

The biology of the predacious cricket Metioche vittaticollis (Stål) collected from rice in the Philippines was studied in the laboratory and greenhouse. The cricket preyed on the eggs of a range of insect pests of rice including Chilo suppressalis (Walker), Cnaphalocrocis medinalis (Guenée), Hydrellia philippina Ferino, Mythimna separata (Walker) and to a lesser extent on the eggs of Leptocorisa oratorius (F.). There was no predation on the eggs of Scirpophaga incertulas (Walker).

Brenthia leptocosma is a Microlepidopteron which feeds upon the Boraginaceous bush, Cordia macrostachya. This plant, since its accidental introduction into Mauritius about 1900, has become a pest of considerable agricultural importance. Other food-plants are C. myxa, C. abyssinica and C. holstii, which are all unimportant trees. B. leptocosma has been recorded only from Mauritius. It is not likely to be indigenous for it is restricted to Cordia species, none of which are considered to be native to Mauritius.

The morphology and biology of the various stages are described.

The distribution of B. leptocosma is that of its food-plants: it is extremely numerous in all regions below about 1,500 feet, which is the upper limit for C. macrostachya. The abundance of the moth is due to the excessive growth of C. macrostachya. Owing to its mode of life, it is of no value as a controlling agent of C. macrostachya.

Larval and pupal parasites are recorded.

One exceptional instance of a mycosis, with epidemic character, in white grubs has been studied in Southern Rhodesia.

The hosts were the larvae of Anomala exitialis Pér. and Schizonycha profuga Pér., which are tobacco pests, the entomophagous fungi being Torrubiella sp. (most prevalent), Beauveria bassiana (Bals.) Vuill. and Metarrhizium anisopliae (Metsch.) Sorokin.

Soil with an abnormally high content of nitrogenous organic matter favours the breeding of the two insects but at the same time provides a suitable medium for the survival and development of a high degree of virulence in the cryptogamic pathogens.

A highly significant negative linear correlation (r=– 0·911, P=0·001) was observed between Xyleborus fornicatus Eichh. population levels in tea plants and the crop size in the preceding month. A highly significant negative linear correlation (r=– 0·858, P=0·001) was also observed between Xyleborus population levels and the percentage of healed galleries of the respective samples. Cambial activity, which has a direct relationship with crop size, determines the rate of healing of brood galleries, and this seems to be the critical factor that regulates population size within a pruning cycle. Since the population has an inverse relationship to crop size and as the latter could be predicted in advance using weather parameters, it should be possible to predict population levels of Xyleborus in advance.

Observations on the eggs of the predatory Mirid Blepharidopterus angulatus (Fall.), which plays a part in the control of Panonychus ulmi (Koch) on apple, were carried out in 1963–64. The eggs required chilling at 4.4 or 7.2°C. (40 or 45°F.) for 14–16 weeks to terminate diapause. The reciprocal of the time in days for the first eggs to hatch showed a linear relationship with temperature. The temperature at the threshold of development was found by calculation to be 4.7°C.; 409 day-degress C. were required for the first larvae to hatch and 727 for 50 per cent. of them to hatch. From this information and the daily maximum and minimum temperatures, the expected dates of first hatch at East Malling were calculated for the years 1958–64 and found to agree well with the dates on which the first larvae were observed in the field.