The timing of sprays in relation to the stage of development of wheat plants and larvae of the wheat-bulb fly, Leptohylemyia coarctata (Pall.), was studied in the laboratory and field. The main growth of young wheat plants was of the centre shoot and such plants died when the centre shoot meristems were destroyed. Older plants survived by growth of lateral shoots. Sprays of dimethoate, trichloronate and thionazin applied before the larvae had emerged did not kill many larvae in the soil, and only insecticide that entered the plants was effective. Severely attacked two-leaf plants yielded little, whether sprayed or not, whereas three-leaf plants sprayed in early March gave a worth-while increase in yield: older plants had enough shoots to give moderate yields even when not sprayed.

In a large field trial, plants from two sowing dates, 22nd October and 1st November, were both at the late two-leaf stage of growth in late February. Wheat-bulb fly larvae had entered nearly all the shoots but plants from both sowings had buds or small lateral growths hidden beneath the outer leaves. The yields of October-sown plots sprayed on 22nd February, 2nd March, 9th March or 16th March were 28·2, 28·8, 25·5 and 23·2 cwt. grain per acre, respectively, (yield of unsprayed plots = 18.9 cwt./acre) and of November-sown plots were 31·0, 27·5, 17·9 and 14·9 cwt. per acre, respectively, (yield of unsprayed plots = 116 cwt. per acre). Sprays had most effect when applied soon after larvae had entered the plants. Spraying severely-attacked late two-leaf to three-leaf plants gave the greatest benefits because these plants recovered by growth of lateral buds or small lateral shoots.

Laboratory and field tests were made to investigate the toxicity, mode of action and persistence of technical DDT and γ BHC when applied to cacao in Ghana to control the Mirids, Distantiella theobroma (Dist.) and Sahlbergella singularis Hagl. The insecticides were tested at concentrations previously used in field trials. D. theobroma, S. singularis and Tribolium castaneum (Hbst.) were used as test insects. Preliminary tests with aldrin, chlordane and dieldrin were also made.

Cacao pods were sprayed to drip point with the test insecticides and the deposit was allowed to dry. Mirid nymphs were placed on the pods and the rate of knockdown and the mortality after exposure for a test period was recorded. These tests showed that BHC had a higher toxicity and acted much more quickly than DDT. BHC greatly reduced feeding.

Fumigant action was tested by spraying cacao leaves to drip point with the test insecticides, allowing the deposit to dry, and then exposing Mirid nymphs and adults over discs cut from the leaves. BHC had a powerful but transient fumigant action; adults, fifth- and second-instar nymphs were killed after, respectively, ½, 4 and 3 hours’ exposure at 28–30°C. over leaves treated with 0·25 per cent, γ BHC. No fumigant effect was observed after prolonged exposure over leaves treated with 2·5 per cent, technical DDT.

Persistence was studied by treating cacao leaves and pods growing under natural conditions and then testing the residual deposit at intervals. Tests with T. castaneum showed that when leaves were sprayed to drip point the residual toxicity of 1·25 and 2·5 per cent, technical DDT fell steadily and was negligible after an interval of three and six weeks, respectively; that of 0·25–2 per cent, γ BHC was negligible after 2–3 days. Corresponding tests with Mirids on pods were less consistent but suggested that 2·5 per cent, technical DDT was still effective against first-instar nymphs after three weeks; 0·25 per cent, γ BHC had a residual toxic effect for at least several days and depressed feeding greatly for at least a fortnight. It is suggested that BHC may have a local systemic action which persists after the surface deposit becomes ineffective.

Of the other insecticides tested, aldrin had a high toxicity and powerful fumigant action and appeared to be the most promising alternative to BHC.

It was concluded that BHC would be more effective than DDT when treating mature cacao because, in addition to its higher toxicity and quicker action, its fumigant action would compensate for incomplete coverage by low-volume spraying.

The Oshogbo and Ilesha districts of Southern Nigeria are contiguous and are situated in the north-east corner of the Western Province. They are bounded on the north and east by Northern Nigeria, on the west by the Oyo district, and on the south by the Ibadan and Ondo districts of the Western Province, and by a small part of the Central Province.

Dietary delivery of bacterially expressed double-stranded RNA (dsRNA) has a great potential for management of Leptinotarsa decemlineata. An important first step is to discover possible RNA-interference (RNAi)-target genes effective against larvae, especially the old larvae. In the present paper, five putative Broad-Complex (BrC) cDNAs (Z1-Z4, and Z6) were identified in L. decemlineata. The expression of the five LdBrC isoforms was suppressed by juvenile hormone signaling, whereas the transcription was upregulated by 20-hydroxyecdysone signaling at the fourth (final) instar larval stage. Feeding of bacterially expressed dsBrC (derived from a common fragment of the five LdBrC variants) in the third- and fourth-instar larvae successfully knocked down the target mRNAs. For the fourth-instar LdBrC RNAi hypomorphs, they had a higher larval mortality compared with the controls. Moreover, most dsBrC-fed beetles did not pupate normally. After removal of the apolysed larval cuticle, a miniature adult was found. The adult head, compound eyes, prothorax, mesothorax, metathorax were found on the dorsal view. Distinct adult cuticle pigmentation was seen on the prothorax. The mouthparts, forelegs, midlegs, and hindlegs could be observed on the ventral view of the miniature adults. For the third-instar LdBrC RNAi specimens, around 20% moribund beetles remained as prepupae and finally died. Therefore, LdBrC is among the most attractive candidate genes for RNAi to control the fourth-instar larvae in L. decemlineata.

In July, 1926, a severe outbreak of a Hemipterous pest was reported from the village of Kattuputhur, in the Trichinopoly District, which threatened the total destruction of the standing paddy crop, and the writer was deputed to visit the locality, investigate the pest and advise suitable control measures. The present paper has been prepared with the object of presenting the results of the investigation made and the remedial measures tried.

The village of Kattuputhur is situated about three miles from Kattalai Railway Station and a mile and a half from the Cauvery River. The affected area is roughly about ten miles long with an average breadth of a mile and a half, and includes numerous villages around Kattuputhur. It is adjoined by a canal from the River Cauvery, giving a never-failing and plentiful supply of water, so that the crops of the area are no longer dependent on the monsoon. As the soil is fertile, intensive cultivation is carried on within this tract, paddy being the principal crop.

The opinion that trypanosomiasis of the T. pecorum type is, under favourable conditions, transmissible amongst domestic stock through the agency of blood-sucking flies other than Glossina has been expressed by several observers.

An experiment was done in Kenya to test several formulations of lindane and malathion dusts as protectants of bagged maize, with which they were mixed, against reinfestation (post-fumigation infestation) by store pests. The experiment was in the form of a 9 x 9 Latin square employing 162 bags. Sampling initially and after 4 and 5¼ months gave data on bag weight-losses, dust present per bag, numbers of adults of Tribolium castaneum (Hbst.), Oryzaephilus surinamensis (L.), Cadra cautella (Wlk.) and Sitophilus oryzae (L.), and moisture-content changes.

The dust weights (which were expected to be the most reliable measure of treatment efficacy) showed that there was very little difference between malathion admixed at 8, 4 and 2 parts per million. The other six treatments were far less satisfactory and all were significantly different from one another, with the following order of values: lindane at 6, 3 and 1·5 p.p.m., diatomite, kaolin and control. All the other data generally supported these results.

The extreme importance in this experiment of cross-infestation from nearby stacks has been shown in the analysis and has been illustrated by plotting numbers of T. castaneum against dust-weight data. Interpretation of this curve has lent support to work with lindane and malathion published by E. A. Parkin in 1960.

The results emphasise the significance of the contribution of grain and mould metabolism to the total bag weight-losses. Some estimates are made of the savings relevant to the admixture of malathion.

The Asian long-horned beetle (ALB), Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae: Lamiinae), is a wood-borer and polyphagous xylophage that is native to Asia. It infests and seriously harms healthy trees, and therefore is a cause for considerable environmental concern. The analysis of population genetic structure of ALB and sibling species Anoplophora nobilis (Ganglbauer) will not only help to clarify the relationship between environmental variables and mechanisms of speciation, but also will enhance our understanding of evolutionary processes. However, the known genetic markers, particularly microsatellites, are limited for this species. SSRLocator software was used to analyze the distribution and frequencies of genomic simple sequence repeat (SSR), to infer the basic characteristics of repeat motifs, and to design primers. We developed SSR loci of 2–6 repeated units, including 10,650 perfect SSRs, and found 140 types of repeat motifs. A total of 2621 SSR markers were discovered in ALB whole-genome shotgun sequences. 48 pairs of SSR primers were randomly chosen from 2621 SSR markers, and half of these 48 pairs were polymorphic containing 4 di-, 7 tri-, 2 tetra-, and 11-hexamer SSRs. Four populations test the effectiveness of the primers. These results suggest that our method for whole-genome SSR screening is feasible and efficient, and the SSR markers developed in this study are suitable for further population genetics studies of ALB. Moreover, they may also be useful for the development of SSRs for other Coleoptera.

Field trials were conducted to compare toxicity and residual activity on cattle of 18 acaricides against Rhipicephalus appendiculatus Neum., Amblyomma variegatum (F.), and Boophilus decoloratus (Koch). Ticks were counted one, four and seven days after the cattle were sprayed. Each of the seven experiments involved three sprayings at seven- to eight-day intervals.

Toxaphene at 0.25 per cent., included as a standard, was relatively slow acting compared to organophosphorous and carbamate acaricides, but was equal to or better than most of the new acaricides in residual activity and over-all effectiveness. Carbaryl, Mopham and toxaphene were tested at the highest concertration, 0.5 per cent., and found to have the maximum over-all effectiveness, including maximum residual activity. Nevertheless, even these treatments did not protexct cattle against tick attachment and engorgement for as long as seven days.

All acaricides tested were very effective against B. decoloratus and A. variegatum, but none completely prevented attachment of R. appendiculatus foe as long as four days, even though all were very toxic to this tick. The smallest number (1.8 per beast) of R. appendiculatus attaching in four days occurred on the cattle sprayed with 0.5 per cent. carbaryl, but by seven days after spraying there were many ticks attached and some were already partially engorged. The inference is that none of the compounds tested gave promise of prevention of tick-borne disease transmission when used on a seven-day schedule. No inference is made concerning tick-borne disease control by reduction of tick numbers on the pasture land.

Mortality among ticks on the cattle one day after treatment was greatest for 0.1 per cent. coumaphos, 0.25 per cent. Prolate, 0.05 per cent. Bayer 9053, 0.2 per cent. Geigy GS 13006, 0.2 per cent. and 0.5 percent. carbaryl, 0.1 per cent dioxathion, 0.05 per cent. Bayer 9037, 0.1 per cent. prothidathion, 0.1 per cent. Dursban, 0.2 per cent. and 0.5 per cent. Mobam, 0.025 per cent. and 0.05 percent. chlorfenvinphos, 0.2 per cent. fenitrithion and 0.1 per cent. ethion. Mortalities of 83.1 per cent. to 88.5 per cent. were given by 0.05 per cent. diazinon, 0.1 per cent. bromophos-ethyl, 0.025 per cent. Dursban, and 0.5 per cent. toxaphene. Mortality below 74 per cent. was caused by 0.25 per cent. toxaphene, 0.2 per cent. bromocyelen, and 0.1 per cent. carbophenothion.

In the course of general studies on control of Culex pipiens fatigans Wied. in British Guiana, the indigenous shrub Ryania speciosa, proven to possess insecticidal activity against certain agricultural pests, was investigated.

Aqueous extracts of the dried stem were shown to possess toxic properties against all larval stages of C. pipiens fatigans under clean laboratory conditions. Under conditions simulating a water-logged pit latrine, however, toxicity was greatly reduced by adsorption of the active agent ryanodine, rendering the crude stem relatively ineffective after 16 days. Because of the great bulk of unprocessed material required for even this limited result in pit latrines—which constitute an important local problem—Ryania was not considered of practical value in C. pipiens fatigans control.

Aqueous and alcoholic extracts of Ryania speciosa had no contact insecticidal properties against adults of this species.

The effect of a sub-sterilizing gamma radiation dose on Dacus ciliatus adults was investigated to assess the suitability of the sterile insect technique (SIT) as an alternative method to control this pest. Late pupae (48 h prior to adult emergence) from a laboratory strain were irradiated with 120 Gy of gamma rays emitted by a 60Co source. Following adult emergence, the mortality of irradiated and non-irradiated cohorts was recorded. Over a period of 50 days after emergence, no significant negative effects of irradiation upon the longevity of male or female laboratory flies were observed. A laboratory competitiveness study (Fried test), using irradiated laboratory and wild males at a ratio of 3:1 was conducted to assess the ability of irradiated males to reduce the egg hatch rates of a wild population. The overall competitiveness was found to be ca. 0.32, suggesting a reduced, but satisfactory, quality of irradiated laboratory as compared with wild males. Based on the above findings, we calculated and proposed effective male release ratios for field application of SIT against D. ciliatus.

A fortunate stay of a few days in July 1919 at Fort Johnston, Lake Nyasa, while waiting instructions, enabled the writer to proceed to the village of Mzeze near the Livingstonia Peninsula, where in 1914–15 some work was carried out on the various insects parasitic on the puparia of this fly.

Field experiments conducted on cotton in southern Sri Lanka, where the main pests were Heliothis armigera (Hb.), Earias vittella (F.) and Pectinophora gossypiella (Saund.), indicated that a damage action threshold of five squares and six bolls per 30 plants could be used for forecasting and early warning in pest management. A parallel sampling study indicated that a sample size of 30 plants would reduce the sampling error to acceptable levels as well as being a more convenient number in the field. An expression that corrects experimentally established thresholds for changes in the cost of control and the market price of the yield is given.

Observations were made on crowded, laboratory-reared. 18–20-day-old males of Schistocerca gregaria (Forsk.) taking off in a wind tunnel. Depending upon the time of day, take-off, which was usually upwind, particularly at higher wind speeds, was related to food availability. Few locusts with full foreguts took off, especially at low air temperatures (20°C), while at high temperatures (35°C), 95% of ones starved for 6 h took off. At 30°C, there was little further increase with starvation for 24–30 h. Females containing large oocytes took off less readily than those with small ones. Take-off was also sometimes initiated by decreases in wind speed and light intensity, and sudden changes in air temperature. A distinct passing shadow stimulated take-off, but not the flickering shadows of other flying locusts. A period of flight immediately beforehand inhibited take-off. The results are discussed in relation to field observations.

This paper describes part of an extensive programme of research on new methods of controlling body lice carried out during 1940–1942. The work was initiated by Professor P. A. Buxton, F.R.S., with whom the writer was privileged to collaborate, and financed by grants by the Medical Research Council. The results proved for the first time the possibility of continuous protection against body lice over a period of several weeks after treatment. To some extent, the materials and methods of achieving this have now been improved or superseded; but it has seemed worth putting on record some details of technique and the results for their scientific interest.

(1) The Kabaw and Kale Valleys, separated by a low watershed and both draining through lateral gorges, have a combined length of some 250 miles and a width of between 4–10 miles. They lie at an altitude of approximately 500 feet above sea level.

(2) There is heavy rainfall during the months of June to September inclusive and little or no rain in the months November to April inclusive. The Kabaw Valley, the more northerly of the two, is forested and there are only small isolated clearings, but a big area in the centre of the Kale Valley has been cleared. Rice is the main crop grown.

(3) There appears to be no pre-war information about mosquitos and malaria. Information during the war was gathered by several different types of Unit engaged on different types of work but there is sufficient to give a fairly complete picture.

(4) The valleys are highly malarious throughout their length and breadth; only one village out of twenty-three examined had a spleen rate under 60 per cent.

(5) Transmission of malaria takes place throughout the year and is intense during the months May to December inclusive.

(6) 17 species of Anopheles are recorded. Common species during the rains are A. minimus, A. leucosphyrus, A. philippinensis, A. jeyporiensis, A. annularis, A. hyrcanus and A. vagus. A. minimus is only locally abundant at this time; A. leucosphyrus is widespread but confined to the forest.

(7) When the rain ceases, species such as leucosphyrus and vagus, which breed in pools and similar habitats, become reduced in numbers. Species such as philippinensis, jeyporiensis, annularis, hyrcanus and barbirostris, which breed in larger bodies of stagnant water such as rice fields, also become reduced in numbers during the dry season, though more slowly, because their breeding places disappear less rapidly. As the streams and rivers settle down, after the rains have stopped, conditions for A. minimus and A. maculatus become good and these are the only two common and widely distributed species in the dry season.

(8) During the dry season, sporozoite rates of A. minimus were 1/159=0·63 per cent, in October, 19/519=3·66 per cent, in December and 10/514=1·94 per cent. in May and it is an important vector and the only vector. A. maculatus does not apparently attack man and plays no part in malaria transmission. In September the sporozoite rate of A. minimus was only 1/332=0·31 per cent, and the important vector of the period of the rains appeared to be A. leucosphyrus with a sporozoite rate of 2/134=1·49 per cent.

(9) The status of A. leucosphyrus as a vector in the Indo-Burmese border region is discussed. There is good evidence that, under wartime conditions with troops operating in the forest, it is an important vector during the rains. Its significance in peacetime is less easy to assess; as only a few people live in the forest or at the forest's edge, its importance is probably not great. On the other hand it does not rest indoors, and, as in the past reliance has been placed on day catches, it may have been overlooked. There is, however, evidence that military operations in the forest produce conditions which lead to an increase in the numbers of this species.

(10) Adult collections were nearly all made at night in camps or villages. The species found in large numbers near man were A. minimus, A. leucosphyrus, A. philippinensis, A. jeyporiensis, A. annularis, and A. hyrcanus. A. minimus and A. leucosphyrus, the two definitely incriminated vectors, were the most successful at obtaining blood when the host, man, was protected by a mosquito net. The other four species, however, were sometimes filled with blood, undoubtedly of human origin and all may play some part in malaria transmission under war conditions. The chances of a specimen becoming infected were reduced under the conditions existing when the dissections were made and so moderately long series of negative dissections (Table XI) cannot be taken as conclusive evidence that any one species played no part in malaria transmission. In peacetime these four species may feed mainly on cattle, though a description is given of a night catch in a village where A. philippinensis was caught attacking man although cattle were available.

(11) In September very few of any of the eight common species were resting by day in the place where they fed at night and it is presumed that they spent the day in the forest. Unfortunately very few inhabited houses were visited and almost the only available catching places were Army tents and shelters. The results suggest, however, that all the species tend to rest in the forest rather than indoors. In December in the Kale Valley A. minimus rested in houses by day; in May in the Kabaw Valley it did not. It is believed that where, as in the Kabaw Valley, forest comes up to the edge of the village, A. minimus seeks shelter for the day in the forest, but that where, as in the Kale Valley, the village stands in a clearing, it rests by day in the houses near where it has fed. The facts observed, however, do not preclude the possibility of a seasonal change in resting habit. It is clear that A. minimus is not invariably a house rester and the importance of catching by night to gain a true picture of the mosquito population is stressed.

(12) A. hyrcanus was usually the first species to appear after dark, followed by A. philippinensis, A. leucosphyrus and A. minimus in that order, the last named being usually most abundant in the second half of the night. Time of greatest activity was, however, variable in all species. There were only a few isolated instances of Anophelines biting in the forest by day.

(13) A. hyrcanus was attracted to light.

(14) Larvae identified as A. pallidus with the aid of the standard Indian keys invariably proved to be A. philippinensis on emergence.

(15) The variation found in A. minimus was considerable and is briefly discussed. The only constant difference between A. minimus and A. aconitus was found to be the flavescence on the proboscis.

A survey of 801 poplar trees in central east England in 1999 demonstrated a correlation between crown dieback and infestation by hornet clearwing moth (Sesia apiformis), induced by a period of drought in 1995–1996. To determine whether trees colonised by S. apiformis would subsequently deteriorate and die or whether they could recover despite infestation and damage to the stem, all trees in the original survey were re-assessed in 2001, 2003 and 2005. The repeat surveys showed that trees with 70% or less crown dieback in 1999 replaced their canopy and generally improved by 2005, irrespective of the numbers of S. apiformis in the stem, whereas trees that had 75% or more crown dieback in 1999 either died or declined further. The presence of S. apiformis did not prevent tree recovery, and there was little evidence that infestation slowed the rate of recovery. Populations of S. apiformis, measured in terms of the numbers of adult emergence holes visible in the base of the trees, decreased between 2001 and 2005 at the same time as the amount of dieback visible in the canopy of the poplars markedly decreased. However, the fall in numbers of emergence holes at this time reflected a decline in larval establishment 2–3 years earlier, and indicated that the moth population had responded to a more rapid restoration in the internal state of the trees, which was not reflected immediately by the gradual replacement of dead branches and reduction in dieback symptoms.

Solenopsis invicta Buren (red imported fire ant) are invasive pests that have the capability of major destructive impacts on lifestyle, ecology and economy. Control of this species is dependent, in part, upon ability to estimate the potential spread from newly discovered nests. The potential for spread and the spread characteristics differ between monogyne and polygyne social forms. Prior to this study, differentiation of the two social forms in laboratory test samples commonly used a method involving restriction endonuclease digestion of an amplified Gp-9 fragment. Success of this assay is limited by the quality of DNA, which in the field-collected insects may be affected by temporary storage in unfavourable conditions. Here, we describe an alternative and highly objective assay based upon a high resolution melt technique following preamplification of a significantly shorter Gp-9 fragment than that required for restriction endonuclease digestion. We demonstrate the application of this assay to a S. invicta incursion in Queensland, Australia, using field samples from which DNA may be partially degraded. The reductions in hands-on requirements and overall duration of the assay underpin its suitability for high-throughput testing.

Apanteles thompsoni, sp. n.

♀. Black, shining ; palpi pale ; antennae beneath fusco-testaceous ; clypeus and mandibles rufo-testaceous ; belly at base testaceous ; sides of abdominal segments 1 and 2 fusco-testaceous ; legs testaceous, with hind coxae black or blackish, hind femora and tibiae slightly infuscated at tips, and hind tarsi more or less infuscated. Wings subhyaline, stigma pale fuscous, nervures paler but usually visible to the extreme margin of the wing.

The alarm behavior plays a key role in the ecology of aphids, but the site and molecular mechanism for the biosynthesis of aphid alarm pheromone are largely unknown. Farnesyl diphosphate synthase (FPPS) catalyzes the synthesis of FPP, providing the precursor for the alarm pheromone (E)-β-farnesene (EβF), and we speculate that FPPS is closely associated with the biosynthetic pathway of EβF. We firstly analyzed the spatiotemporal expression of FPPS genes by using quantitative reverse transcription-polymerase chain reaction, showing that they were expressed uninterruptedly from the embryonic stage to adult stage, with an obvious increasing trend from embryo to 4th-instar in the green peach aphid Myzus persicae, but FPPS1 had an overall significantly higher expression level than FPPS2; both FPPS1 and FPPS2 exhibited the highest expression in the cornicle area. This expression pattern was verified in Acyrthosiphon pisum, suggesting that FPPS1 may play a more important role in aphids and the cornicle area is most likely the site for EβF biosynthesis. We thus conducted a quantitative measurement of EβF in M. persicae by gas chromatography-mass spectrometry. The data obtained were used to perform an association analysis with the expression data, revealing that the content of EβF per aphid was significantly correlated with the mean weight per aphid (r = 0.8534, P = 0.0307) and the expression level of FPPS1 (r = 0.9134, P = 0.0109), but not with that of FPPS2 (r = 0.4113, P = 0.4179); the concentration of EβF per milligram of aphid was not correlated with the mean weight per aphid or the expression level of FPPS genes. These data suggest that FPPS1 may play a key role in the biosynthesis of aphid alarm pheromone.