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1.
Abstract

The rationale is presented for the development of techniques for applying insecticides by helicopter in small-scale field trials against Glossina tachinoides, an important vector of human sleeping sickness. This approach has been adopted in view of the difficulty of applying non-residual insecticides to the riverine forest habitat by fixed-wing aircraft and the need to test the efficacy of new insecticides to ascertain effective dosages. Six insecticides were tested; endosulfan, decamethrin, permethrin, azamethiphos tetrachlorvinphos and fenthion. The trials were carried out in the River Komoe valley, a typical humid savanna area with savanna woodland, woodland/floodplain ecotones, moist riverine forest and dry forest as the main vegetation types. Glossina tachinoides was the only tsetse fly present in sufficient numbers for it to be used for evaluation in the trials, it feeds on bushbuck and carries Trypanosoma grayi, a parasite of crocodiles and Varanus spp. The area was divided into an untreated control zone, droplet penetration study area and experimental airspray blocks. Prior to the trials themselves it was necessary to undertake equipment tests and droplet size and spray penetration studies in selected typical riverine forest habitats; to determine the most effective method of aerosol application in the riverine forest and to ascertain, through meteorological studies, the most appropriate time of day to apply the pesticide. It was also necessary to monitor the effects of the insecticide applications on the non-target organisms inhabitating or associated with the gallery forest. Detailed reports of these activities are given in accompanying papers.  相似文献   

2.
Abstract

Trials were carried out in Upper Volta to assess equipment for the application of insecticides as aerosol from helicopters for the control of riverine tsetse flies (G. tachinoides). Flying techniques were developed to direct aerosols in the downwash of the helicopter to tsetse breeding sites close to the water's edge. Good penetration of droplets below the riverine canopy was achieved during the late afternoon and early morning when weather conditions were very stable.  相似文献   

3.
Abstract

The effects of aerosol dosages of different categories of insecticide were tested against Glossina tachinoides when applied by helicopter to riverine forest habitats of the River Komoe, Upper Volta, West Africa. The method of application, droplet characteristics of the aerosols and meteorological conditions are described in accompanying papers. Comparative trials based on field dosages calculated initially from dosage mortality curves obtained from topical application studies in the laboratory were carried out. Endosulfan applied at 5.4 g a.i./ha and 9.0 g a.i./ha reduced G. tachinoides populations (determined by Challier/Laveissière traps) by more than 90% in all age and sex categories and evidence is presented which indicates a residual effect at the higher of these dosages. Good results were also obtained with the synthetic pyrethroid decamethrin at a dosage of 0.36 g a.i./ha; another synthetic pyrethroid, permethrin, gave promising results at a dosage of 1.9 g a.i./ha. At the higher dosage of 4.3 g a.i./ha disappointing results were obtained, which were considered to be more attributable to a weakness in the application technique under challenging field conditions, than to a limitation of the insecticide. The organophosphate compounds tested, fenthion, azamethiphos and tetrachlorvinphos although known from laboratory tests to be appreciably toxic to G. tachinoides, performed poorly under field conditions. This was thought to be due to the formulations employed and the authors feel that further small-scale field testing of different formulations of these compounds is warranted. The compounds considered most worthy of larger scale field evaluation were endosulfan and permethrin. Although decamethrin was also very toxic to G. tachinoides it was considered inadvisable to field test this compound on a larger scale, until more information was available on its impact on aquatic food chains. The trials demonstrated that it is not always possible to extrapolate from laboratory-obtained comparative dosage/mortality data (in ng/fly) the field dosages of insecticides (in g a.i./ha) required to produce a certain level of mortality in target populations of G. tachinoides.  相似文献   

4.
Abstract

The experimental application by helicopter of six insecticides to riverine forest galleries of the Komoe River in Upper Volta against Glossina tachinoides Westw. was monitored for its effects upon non-target organisms, in particular birds, fish, insects and crustaceans inhabiting the experimental area. There was no recognisable mortality associated with applications of these insecticides on birds or fish. Aerosol applications of permethrin and decamethrin produced mortalities in two species of crustacea and very high mortalities occurred from a residual treatment of decamethrin at 12.5 g a.i./ha.  相似文献   

5.
Abstract

The results of a discriminative spray application of decamethrin from a helicopter to fringing forest habitats of Glossina tachinoides in the Komoe valley, Upper Volta, are described. The insecticide formulated as a 2.5% emulsion concentrate was diluted with river water and applied from a Bell 47G-4A helicopter to the fringing forests of a 14 km long stretch of the River Komoe at a dosage of 12.5 g a.i./ha. The insecticide application equipment was so adjusted that when the helicopter was flown at 30 km/h, the effective swath width was about 30 m and the vmd of emitted spray was c.150 μm. Insecticide swaths were applied to the inner edges of fringing forests that were up to 100 m wide. Forests wider than 100 m received an additional insecticide swath.

The experimental area was protected from reinvasion by the establishment of dieldrin barriers at its extremities and along some tributaries and woodland/floodplain ecotones. The dieldrin was applied by the same method as was used to apply the decamethrin. The single discriminative application of decamethrin was extremely effective in controlling G. tachinoides for a period of at least 38 days, at the end of which time the wet season had commenced and there was evidence that flies were entering the experimental area from nearby unsprayed areas. The authors discuss the possible practical applications of the technique and make suggestions on how it might possibly be refined in order to reduce undesirable river water contamination and operational costs. The authors draw attention to the need for field trials, such as that reported upon, to be conducted on a sufficiently large scale and for the experimental areas to be well protected against reinvasion, if meaningful evaluation data are to be obtained.  相似文献   

6.
Abstract

Helicopter applied insecticides used for tsetse control were investigated for their potential to reduce populations of Simulium damnosum s.l. in riverine forest in the Guinea savanna zone of southwestern Upper Volta. Populations of aquatic stages and biting females were sampled before and after spraying. Deltamethrin applied at 12·5 g a.i./ha to a 30 km length of riverine vegetation almost eliminated adults for a period of about nine days. Residues which fell into the water killed all larvae in the river. Endosulfan at 100 g a.i./ha applied to a similar stretch of vegetation caused a reduction of over 60% in biting adults for 11 days, but residues falling into the river killed only young larvae. Neither dieldrin at 400 g a.i./ha, endosulfan at 10 g a.i./ha nor deltamethrin at 12.5 g a.i./ha applied to a 5 km insecticide barrier between the experimental blocks and the untreated river appeared to have much effect. This suggests that most S. damnosum were traversing the barrier without coming into contact with the insecticides.  相似文献   

7.
Abstract

Studies on the use of 22 chemical attractants for Glossina tachinoides were undertaken in Côte d'Ivoire following earlier work on G. m. morsitans and G. pallidipes in Zimbabwe. While catches of G. m. morsitans and G. pallidipes increased by several times when traps were baited with some of these substances, catches of G. tachinoides were only marginally increased. G. tachinoides is slightly attracted by octenol and acetone, alone or in combination, and its response to CO2 is much weaker than that of the species tested in Zimbabwe. Phenol and indol mixtures both showed dose‐response relationships with catch. The indols were more potent in the lowest of the tested dosages (catch increase of 52%, P < 0001) whereas the phenols showed better attractiveness in their higher concentrations (catch increase of 42%, P < 0.05). Odour is probably less important in host finding for the riverine species G. tachinoides than it is for the savanna species studied in Zimbabwe.  相似文献   

8.
Phorate residues in peat blocks and lettuce were determined following incorporation of the insecticide into different block and ‘Speedling’ cell sizes. Between-block variability was influenced little by block size. Phorate oxidation was most extensive in the largest blocks containing the smallest dose. Total residue concentrations in the lettuce declined from the time of planting to harvest, although accumulation of insecticide continued and was related more to dose than to block or cell size. Residues in the lettuce at harvest exceeded the proposed maximum limit of 0.2 mg kg?1 in some treatments. Residues at planting comprised mainly the parent sulphoxide and sulphone, but by harvest, the oxygen analogue sulphoxide and sulphone predominated. Lettuce weight was not influenced by dose but was related directly to block size. Carbofuran and chlorfenvinphos residues were determined in calabrese sown into two sizes of blocks. At planting time, carbofuran residue concentrations were 100 times greater than those of chlorfenvinphos but residues of both insecticides in the mature heads were < 0.01 mg kg?1. Seedling weights in both sowings declined with increasing concentrations of the insecticides. It was concluded that manipulations of block size and the dose of insecticide need to be evaluated for individual insecticide/crop combinations to exploit the technique fully.  相似文献   

9.
Abstract

Large scale field trials were undertaken with emulsifiable concentrates of different organophosphorus insecticides to control Pyrilla and whitefly, two serious pests of the sugarcane crop in the Peshawar Division of West Pakistan. All emulsifiable concentrates excepting Dimecron were applied in concentrate form without diluting with water. Of the seven insecticides tested against Pyrilla adults and nymphs, Dimecron, Lebaycid, Nexion (Bromophos) and Malathion gave superior control. In the case of whitefly, Dimecron, Lebaycid and Malathion gave almost equal mortality of adults and 3rd instar nymphs when applied at 8, 8 and 17 oz a.i./ac respectively, but much higher dosages would be required to get satisfactory control of the 4th instar nymphs. The cost of operations for the ultra-low-volume technique (excluding cost of insecticide) was 66% less than for the conventional method.  相似文献   

10.
A summary is given of the results of three sets of electrophysiological experiments on the American cockroach (Periplaneta americana). The effects of DDT and S-bioallethrin [bioallethrin (S)-cyclopentenyl isomer] on single giant axons were studied using the voltage-clamp technique. Whereas both molecules induced long tails of inward (sodium ion) current, the voltage and time-dependency of these tails differed. With DDT, the tail was proportional to the activation of the peak current and decreased with the duration of the pulse, suggesting that the molecules were bound to open sodium channels and delayed their closing. With S-bioallethrin, the voltage dependency of the tail was different from that of the peak current, and the tail current increased exponentially with the duration of the depolarisation, suggesting that the pyrethroid insecticide modified resting (or silent) sodium channels into slowly activating channels. Modified action potentials, mimicking those produced by the two molecules, were computed on the basis of these results. Deltamethrin, one of the most potent pyrethroid insecticides, was applied topically on a leg mechanoreceptor and was found to have little effect on the local ‘receptor potential’ but to inhibit action potential production. The effects of topical applications of deltamethrin on the dorsal part of the abdomen, on nervous activity in the abdominal connectives, were studied under different experimental conditions. The results suggest that the insecticide molecules diffused rapidly through the cuticle, were concentrated in the haemolymph, and eventually reached the central nervous system, where they inhibited nerve activity.  相似文献   

11.
BACKGROUND: Egg and larval stages of citrus peelminer Marmara gulosa Guillén and Davis infesting zucchini squash Cucurbita pepo L. var ‘Revenue’ were exposed in the laboratory to a wide range of insecticide classes used in California citrus (organophosphate, carbamate, pyrethroid, neonicotinoid, insect growth regulator, fermentation products and sulfur) to determine peelminer response with and without a non‐ionic adjuvant or oil. RESULTS: All of the insecticides tested except sulfur reduced egg hatch and mine initiation. When the larval stage was treated, only buprofezin failed to reduce larval and pupal development. Cyfluthrin and spinosad, with the addition of adjuvant or oil, and abamectin combined with oil allowed no survivors at 7 days after treatment (DAT). The slower‐acting insect growth regulators pyriproxyfen and diflubenzuron applied in combination with adjuvant or oil allowed no survival of peelminer 21 DAT. A field trial showed 62.6–68.5% reduction in mined citrus fruit after two applications of diflubenzuron and no significant improvement of control with the addition of cyfluthrin. CONCLUSION: Bioassays indicate that M. gulosa is relatively susceptible to a wide range of insecticide classes in the laboratory. Lack of efficacy experienced in field trials would then be due to characteristics of the fruit or canopy that limit coverage, rather than to the effectiveness of the insecticides. Copyright © 2008 Society of Chemical Industry  相似文献   

12.
BACKGROUND: Because bedbugs, Cimex lectularius L., have not been a problem in the USA for over 40 years, few insecticide products are labeled for their control. Most products that are labeled for bedbugs are pyrethroids. However, recent studies indicate that field‐collected bedbugs may be resistant to pyrethroids. There are also non‐pyrethroid products labeled for bedbugs, but, like the pyrethroids, none of these products has been evaluated for field efficacy. This study evaluated the efficacy of two insecticide treatment regimens for bedbugs in multi‐unit housing. Both of the treatments included multiple products currently being used by the pest management industry. RESULTS: The ‘traditional’ treatment consisted of applications of pyrethroid products and an insect growth regulator. The ‘novel’ treatment consisted of applications of non‐pyrethroid products. The traditional treatment significantly reduced the number of bedbugs from 39.8 ± 10.1 per unit prior to treatment to 2.2 ± 1.0 at the end of the test period (P = 0.02; 95% reduction). The number of live bedbugs in the ‘novel’ treatment was also significantly reduced from 71.4 ± 25.3 bedbugs per unit to 10.2 ± 4.4 after 8 weeks (86% population reduction). CONCLUSIONS: Although both treatment regimens reduced bedbug numbers, the fact that bedbugs were not eliminated after multiple applications suggests that the insecticides, applied at the current label rates, were inadequate. These results suggest that a more integrated approach to bedbug control is necessary in multi‐unit housing situations. Copyright © 2008 Society of Chemical Industry  相似文献   

13.
The use of insecticide mixtures for resistance management has been a controversial topic for many decades. Here, we provide a reassessment of the fundamental theory of insecticide mixtures. First, we examine how mixtures differ from other strategies. We suggest that the fundamental strategy concept of a mixture is defined by the simultaneous use of insecticides and their overlapping exposure. Second, we provide a simple, illustrative model to show how mixtures affect resistance evolution. Following the existing literature, we identify a role for ‘redundant kill’ acting against resistant individuals, which we link to the overlapping exposure of insecticides. We also identify the occurrence of ‘additional kill’ acting against susceptible individuals, which is the immediate consequence of the simultaneous use of insecticides. Third, we take a basic approach to the comparison of mixtures and other strategies using a simple model. We find that a common comparison of the time to resistance alone leaves the effects of additional kill unaccounted for. Moreover, we demonstrate that different approaches to comparison can lead to different results because of biases that are introduced in the comparison setup. Fourth, still using the same model, we showcase a more sophisticated approach to comparison using optimised strategies. We find that optimised mixtures always perform better than other strategies due to the combination of redundant and additional kill. We suggest that the comparison of optimised strategies is unbiased because each strategy is performing the best that it can. On this basis, in theory (but not necessarily practice), we believe that mixtures are better than other strategies and, through the steps of our argument, we can tie this success back to the fundamental properties (of simultaneous use and overlapping exposure) that distinguish mixtures from other strategy concepts. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

14.
为对Bt杀虫蛋白与化学杀虫剂的协同使用提供理论指导,通过蛋白互作分析方法,以黑腹果蝇Drosophila melanogaster为模型,对化学杀虫剂与Bt杀虫剂作用受体以及抗性相关蛋白的互作网络进行研究。结果表明,Bt杀虫蛋白的27个受体在黑腹果蝇中共存在50个互作蛋白,其中有39个蛋白只与Bt杀虫蛋白抗性相关,11个蛋白还与化学杀虫剂抗性相关,这2类杀虫剂抗性互作网络交集较小,并且重叠蛋白的变异引起交互抗性的概率不大。表明Bt杀虫蛋白与化学杀虫剂产生交互抗性的概率较小,可以将Bt杀虫剂与化学杀虫剂协同使用,提高害虫防治效果,并有效克服或延缓害虫抗性产生。  相似文献   

15.
The development of a mathematical model which, by quantifying the interaction of a population of houseflies with an ageing spray cloud, is capable of predicting the knockdown and kill performance of insecticidal aerosol formulations shown against houseflies, Musca domestica L., will be presented in a series of four separate papers. In this first paper, measurements were made of insecticide collected by houseflies during free flight using a standard room-spray technique. With pressure-packed aerosol formulations where the solvent is the principal change, it was shown that both knockdown and mortality responses of the insects were directly related to dose collected. The process of droplet collection was most significantly influenced by their size and availability, dependent upon the time after spraying, the position of insect release and the activity of individual adult M. domestica. The knockdown or mortality response of the insect to given amounts of insecticide was largely unaffected by the remaining solvent, although, with mineral oil, some inhibition was noted at low mortality levels. The amount of insecticide accumulated by houseflies in their initial flight was of prime importance in determining the overall effect. Flies remaining not knocked down at the end of the exposure period were shown to be so because they had accumulated less toxicant and not necessarily because they were more tolerant of the insecticide. The establishment of a relationship between the number of flies in flight and time after release has provided a key function for incorporation into the model.  相似文献   

16.
BACKGROUND: Developing scientifically valid, economically acceptable insecticide resistance management (IRM) programs is critical for sustainable insect management. The diamondback moth, Plutella xylostella (L.), has demonstrated an ability to develop resistance to many different classes of insecticides, including proteins produced by the bacterium Bacillus thuringiensis Berliner (Bt). Recently it has developed resistance to the novel compounds spinosad and indoxacarb. In greenhouse cage experiments, a laboratory‐selected population of P. xylostella resistant to spinosad, indoxacarb and Bt was used to compare population growth and resistance evolution if these three insecticides were rotated or used in a mosaic fashion. RESULTS: The average population density through nine generations was lowest in the treatment in which the insecticide was rotated every generation (R‐1) (x? = 20.7 ± 3.20) compared with the treatment in which the insecticide was rotated every third generation (R‐3) (x? = 41.4 ± 17.6) or where the insecticides were applied as a mosaic (M) (x? = 41.8 ± 6.53). After nine generations, the survival of resistant individuals increased for each insecticide (7.2–73.5%) compared with the population without selection (CK) (0.73–3.1%). Survival on spinosad was significantly lower (23.7%) in the single‐generation rotation than for the other two treatments, both of which exceeded 72%. The calculated survival on all three insecticides treated simultaneously, according to the survival on each insecticide, was 0.26, 0.81 and 1.6% for R‐1, R‐3 and M treatments respectively. CONCLUSION: Results of both population density and resistance development indicated that insecticide rotation every generation was better for IRM than if the insecticide was rotated every third generation or if the three insecticides were applied as a mosaic. Copyright © 2010 Society of Chemical Industry  相似文献   

17.
BACKGROUND: Application of insecticides in modern agriculture in order to enhance legume production has led to their accumulation in soils to levels that adversely affect soil microflora such as rhizobia and exert a negative impact on the physiological activities associated with them. This study was therefore designed to identify rhizobial strains expressing higher tolerance to insecticides fipronil and pyriproxyfen and synthesising plant growth regulators even amid insecticide stress. RESULTS: The fipronil‐ and pyriproxyfen‐tolerant Rhizobium sp. strain MRL3 produced plant‐growth‐promoting substances in substantial amounts, both in the presence and in the absence of the insecticides. In general, both insecticides at recommended and higher rates reduced plant dry biomass, symbiotic properties, nutrient uptake and seed yield of lentil plants. Interestingly, when applied with any concentration of the two insecticides, Rhizobium sp. strain MRL3 significantly increased the measured parameters compared with plants grown in soils treated solely with the same concentration of each insecticide but without inoculant. CONCLUSION: This study suggests that Rhizobium strain MRL3 may be exploited as a bioinoculant to augment the efficiency of lentil exposed to insecticide‐stressed soils. Copyright © 2010 Society of Chemical Industry  相似文献   

18.
BACKGROUND: The most common ways to control dengue vector Aedes aegypti (L.) are larval source reduction in domestic habitats and ground application of small quantities of aerosol insecticide (ultralow volume). Nevertheless, these actions have been shown repeatedly to be ineffective in controlling Ae. aegypti populations. RESULTS: The efficacy of a new smoke‐generating formulation containing pyriproxyfen and permethrin was evaluated in the laboratory. Smoke‐generating tablets containing each insecticide individually or combined were prepared, and the recovery of the insecticides from the smoke was determined. Recovery values of over 90% were obtained for pyriproxyfen, and around 50% for permethrin. The biological efficacy of pyriproxyfen released in the smoke was evaluated in the laboratory, on late third‐instar or early fourth‐instar Ae. aegypti larvae, using different concentrations of pyriproxyfen and exposure times. Adult emergence inhibition (EI) values of 100% were obtained at 30 min, and a dose‐dependent effect was observed at 5 min. The effect of pyriproxyfen released in the smoke was due to direct contact with the larvicide in the water rather than by inhalation of the fumes. The efficacy of permethrin released in the fumes was also evaluated as knockdown effect (KT50) on adults for a tablet containing permethrin alone or permethrin plus pyriproxyfen. There was no significant difference in KT50 values obtained for permethrin (KT50 = 19.9 min) and permethrin plus pyriproxyfen (KT50 = 19.4 min). CONCLUSION: The excellent laboratory performance of this new formulation on immature stages and adults indicates that a smoke‐generating tablet containing pyriproxyfen and permethrin could be a new tool for controlling mosquitoes. Copyright © 2009 Society of Chemical Industry  相似文献   

19.
Four insecticides, carbofuran, chlormephos, terbufos and benfuracarb, currently used on maize (Zea mays) at sowing, were tested for their compatibility with Azospirillum lipoferum strain CRT1 used as an inoculant to improve maize growth and yield. The growth or survival of A lipoferum was studied in the presence of the insecticides: (1) in liquid and solid cultures of the bacteria, (2) when a commercial inoculant (Azogreen‐m?, Liphatech, Meyzieu, France) was inoculated directly on insecticide granules, (3) when inoculated Azogreen‐m granules were mixed with insecticide granules and (4) when inoculated Azogreen‐m granules were delivered separately to the seed bed. Of the four insecticides tested, only terbufos had a slight effect on growth of A lipoferum in solid cultures. All the insecticides decreased the survival of A lipoferum when the bacteria were inoculated directly on to the granules, or when inoculated Azogreen‐m granules were mixed with an insecticide. We hypothesize that the discrepancies between bacterial culture tests and survival studies might be explained by the conditions of desiccation encountered during inoculation of the granules. Desiccation stress could increase the toxic effect of the insecticides. We therefore suggest including desiccation stress in the biotest used to assess inoculant‐pesticide compatibility. © 2001 Society of Chemical Industry  相似文献   

20.
A search for patterns in the success and failure of microbial insecticides in vegetable crops was conducted through review of four case studies: the use of Bacillus thuringiensis (B.t.) var. tenebrionis for control of the Colorado potato beetle, the use of B.t. var. kurstaki for control of the diamondback moth, the use of various B.t.s for control of lepidopterous pests in tomatoes and celery, and the use of a granulosis virus for control of potato tuber moth. With success defined in terms of achievement of technical goals (efficacy), commercial goals (end-user and insecticide manufacturer satisfaction) and social, or public goals (environmental and health safety), only certain of the case studies could be judged a success. These successes shared a variety of features including: (1) use of the microbial insecticide as a component, rather than as the sole agent, in an integrated crop management program; (2) unavailability of conventional insecticides, due to insecticide resistance, lack of registered products or mandatory IPM programs, provided incentive for the use of microbial insecticides; (3) modification of the expectation that microbial insecticides will perform within the chemical paradigm – fast, lethal and on contact; (4) exploitation of all possible benefits of the microbial insecticide, including safety to natural enemies, as well as efficacy against the target insect, and (5) support from large private and public institutions in the form of research, grower education, scouting programs, subsidized production, and economic and legal incentives to the use of microbial insecticides.  相似文献   

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