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1.
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   

2.
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   

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.
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5.
Abstract

Trials to determine if the costs of eradicating G. morsitans by aerial application of endosulfan (Park et al 1972) might be reduced, were carried out using lower quantities of the pesticide. Area dose rates were varied by altering; the swath width, the insecticide output per unit flying time and the insecticide concentration. The trials were judged by the reduction of the adult tsetse population after a single application. Results indicated that eradication of G. m. morsitans under the conditions prevailing in N.W. Botswana, is possible by the repeated application, at 21 day intervals, of 20% endosulfan at 3.0 //km2 (0.6 kg a.i./km2). Applications should be made at a swath interval of 274m, using a single AU 3000 Britten-Norman Micronair unit to produce spray droplets mostly smaller than 40μm diam. The cost (1973) of each application (aircraft and insecticide only) was approximately US $13.00/km2 for an area in excess of 1000 km2.  相似文献   

6.
Adult mosquitoes from two strains of Anopheles gambiae and from three strains of Anopheles stephensi were exposed to 0.25% fipronil‐treated papers in WHO test kits or to 500 mg fipronil m−2 impregnated mosquito netting in bioassay spheres. For comparison, tests were also carried out with the pyrethroid permethrin, using the same methods and doses, and on papers treated with 0.4 and 4% of the cyclodiene insecticide dieldrin. Compared with the same doses of permethrin, fipronil showed less and delayed activity. Two of the An stephensi strains were resistant to fipronil and dieldrin. To investigate whether this was due to a resistance mechanism in the An stephensi strains acting against both insecticides, the most fipronil‐ and dieldrin‐tolerant strain was further selected in two separate lines with one of the insecticides, followed by tests with the insecticide that the line had not been selected with. This indicated a concomitant rise of resistance to dieldrin in the fipronil‐selected line and vice versa. Repeated back‐crossing of the two lines with a susceptible strain and re‐selection with either dieldrin or fipronil gave evidence for the involvement of a single resistance mechanism to both insecticides. Permethrin resistance in both lines declined with selection for dieldrin or fipronil and confirms the absence of cross‐resistance between fipronil and pyrethroids. © 2001 Society of Chemical Industry  相似文献   

7.
BACKGROUND: Glyphosate drift from aerial application onto susceptible crops is inevitable, yet the biological responses to glyphosate drift in crops are not well characterized. The objectives of this research were to determine the effects of glyphosate drift from a single aerial application (18.3 m swath, 866 g AE ha?1) on corn injury, chlorophyll content, shikimate level, plant height and shoot dry weight in non‐glyphosate‐resistant (non‐GR) corn. RESULTS: One week after application (WAA), corn was killed at 3 m from the edge of the spray swath, with injury decreasing to 18% at 35.4 m downwind. Chlorophyll content decreased from 78% at 6 m to 22% at 15.8 m, and it was unaffected beyond 25.6 m at 1 WAA. Shikimate accumulation in corn decreased from 349% at 0 m to 93% at 15.8 m, and shikimate levels were unaffected beyond 25.6 m downwind. Plant height and shoot dry weight decreased gradually with increasing distance. At a distance of 35.4 m, corn height was reduced by 14% and shoot dry weight by 10% at 3 WAA. CONCLUSIONS: Corn injury and other biological responses point to the same conclusion, that is, injury from glyphosate aerial drift is highest at the edge of the spray swath and decreases gradually with distance. The LD50 (the lethal distance that drift must travel to cause a 50% reduction in biological response) ranged from 12 to 26 m among the biological parameters when wind speed was 11.2 km h?1 and using a complement of CP‐09 spray nozzles on spray aircraft. Published 2010 by John Wiley & Sons, Ltd.  相似文献   

8.
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   

9.
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   

10.
Abstract

V.I.v. captafol spray treatments applied using a 1.8m swath (3.3 kg a.i./ha/application) were more effective than treatments using a 3.6 m swath (1.67 kg a.i./ha/application). At sites with more than 700 mm rainfall during the crop's field life weekly applications were more effective than spraying at 10- and 14-day intervals, but at the drier sites (< 650 mm rainfall) spraying at 10 days was adequate.  相似文献   

11.

Studies were conducted at the Texas Agricultural Experiment Station research farms located at Munday (1996 test) and Chillicothe (1997 test) to evaluate relay strip crops in combination with a food spray to enhance biological control of bollworms, Helicoverpa zea (Boddie), and cotton aphids, Aphis gossypii Glover, in cotton. The relay crops included fall plantings of hairy vetch, Vicia villosa Roth, and canola, Brassica napus L., and a spring planting of grain sorghum, Sorghum bicolor L. Cotton, Gossypium hirsutum L., was planted between the relay crops or was isolated from the relay crops. Treatments within the two cotton systems included an untreated check plot, a plot sprayed with sugar+yeast (food spray) during summer to attract and hold predator insects, a plot sprayed with biological ('soft') insecticides for bollworm and cotton aphid control (Bacillus thuringiensis and pymetrozine, respectively), and a plot sprayed with harsh insecticides for bollworm and cotton aphid control (zeta cypermethrin and dicrotophos or profonofos, respectively). A split-plot experimental design, with three replications, was used where whole plots included relay and isolated cotton systems and subplots were the four food/chemical treatments. Predator numbers were monitored with a vacuum sampler once a week in relay crops and cotton. Bollworms and cotton aphids were monitored visually once a week in cotton during July and August. Total predator numbers were higher in cotton adjacent to relay crops in 1996, but not in 1997. The food spray did not enhance attraction and retention of predators either year. Bollworm larval numbers were significantly higher in relay cotton, food spray plots in 1996. Bollworm larval numbers were similar in relay and isolated cotton, and larval numbers were significantly reduced only in the plot where zeta cypermethrin (harsh insecticide plot) was used. In 1996, cotton aphid numbers in the relay cotton system were significantly higher in the untreated check plots in relation to numbers in the food spray, soft insecticide, and harsh insecticide plots, which were statistically similar. In the isolated cotton system, aphid numbers were highest in untreated plots, intermediate in food spray and soft insecticide plots, and lowest in the harsh insecticide plots. Aphid numbers increased more rapidly in the harsh insecticide plots that had been treated previously for bollworm control. The food spray and pymetrozine treatments reduced cotton aphids more effectively in the relay cropping system than in the isolated cotton system. Bollworms and cotton aphids did not reach pest status in 1997. The combination of a relay cropping system with a food spray did not enhance predator numbers and did not aid in retention of predators in cotton during August. Sucrose in the food spray attracted high numbers of bollworms in 1996.  相似文献   

12.
Abstract

Hollow‐fibre, laminate‐flake and microencapsulated formulations of the synthetic sex pheromone (Z,Z) and (Z,E)‐7–11‐hexadecadienyl acetate of Pectinophora gossypiella (Saunders) were applied aerially in large scale trials in the Delta region of Egypt in 1985. 100 ha blocks of cotton were treated at regular intervals throughout the season as the only means of controlling the pest and compared with a 100 ha block of cotton sited in the same locality which was treated aerially with conventional insecticide spray applications. Comparisons of numbers of infested bolls, open boll counts and yields of seed cotton showed that adequate levels of control were achieved with all three pheromone formulations which were at least as effective as the insecticide sprays. The costs of the pheromone formulations and their aerial application also compared favourably with the insecticide programme. Greater numbers of beneficial insects were recorded in the pheromone‐treated areas than in the insecticide treated area.  相似文献   

13.

BACKGROUND

Aerial treatments for invasive species management are now common, but we are unaware of any work published in the scientific literature quantifying how the interplay of numerous factors affects flight time and therefore operational costs. Here, we analyse aerial treatment data collected from two ant-eradication programmes, quantifying how the relationships between flight time and area are influenced by numerous aircraft/delivery system/bait/flight speed combinations.

RESULTS

For bait dispersal by helicopters, and when swath widths are equivalent, side-mounted Isolair was significantly more efficient than the simultaneous use of two underslung buckets, and use of two buckets was slightly but not significantly more efficient than one bucket. In this scenario, delivery by Isolair was, on average, 39.8% and 31.5% more efficient than the use of one or two buckets, respectively. However, when the swath width used with Isolair was halved to 10 m and flight speed was increased slightly, flight time was significantly greater compared to the other configurations. For bait dispersed by drone, flights conducted using an upgraded Flight Management System (FMS) and greater flight speed but smaller swath width were significantly more efficient than flights using the older FMS and lower flight speed. Over 10 and 50 ha the helicopter was 2.87 and 4.82 times more time efficient than the drone.

CONCLUSION

We encourage practitioners to publish data from their aerial treatments, and to try new methods, to accelerate improvements in efficiency and reduce the costs of aerial treatments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

14.

BACKGROUND

Multicopters are used for releasing particulates seeds, fertilizer and spray. Their low cost and high manoeuvrability make them attractive for spraying in steep terrain and areas where overspray is undesirable. This article describes a model of multicopter wake and its influence on particulate dispersion, which is computationally economical compared to many computational fluid dynamics (CFD) approaches, yet retains reasonable accuracy.

RESULTS

A model was successfully implemented in OpenFOAM . It features source terms for the rotor wash, Lagrangian particle tracking, an evaporation model, and a porous medium approach to model the effect of the ground vegetation. Predictions were validated against the field tests of Richardson et al. which used a DJI Agras MG-1 multicopter in three different flights with airspeeds of 3.2–4.9 m s−1, ground speeds of 2.1–2.9 m s−1 and cross-wind speeds of 0.04–2.2 m s−1. The effective swath width (30% line separation) was predicted to within one standard deviation. Sensitivity to a rotor rotational speed, flight height, flight velocity, multicopter roll and yaw angles, surface roughness length, plant height and leaf density was checked.

CONCLUSION

In all flight trials, the modelled swath was closest to the experimentally obtained swath when the surface roughness of the fetch was equal to 0.5 m (bushes) and the rotational speed of all rotors was equal to 2475 rpm with 0.75R (0.2 m) tall plant canopy (grass) introduced to the model. The model showed acceptable validity for flight velocities of ≤2.8–5 m s−1 when flight parameters can be approximately estimated. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

15.
A technique for estimating the width of buffer zones required around sensitive areas during pesticide applications has been devised and tested. The technique has been used to estimate the buffer width required around water bodies during ground-based permethrin applications in Canadian forests to prevent significant impact on fish and their food populations. A worst- case scenario was developed for environmental impact in water bodies result ing from ground-based permethrin applications, and a spray application was made under these worst-case conditions. Permethrin deposit on ground sheets was measured downwind of overlaid crosswind swaths. From these measurements the deposit at various downwind distances from a single crosswind swath was calculated, and a curvilinear regression line fitted to these values. Permethrin deposit downwind of multiple-swath applications was computed by adding the contributions from individual swaths. Mortality resulting from various permethrin concentrations was measured for Aedes aegypti larvae. Although these larvae are not an important food species for the fish species of interest, salmon and trout, they are more sensitive to permethrin than most aquatic invertebrates. Predicted mortality in populations of this species and Salmo gairdneri, rainbow trout, at various downwind distances from the permethrin application was calculated from the toxicological and spray-cloud dispersal data. Buffer width was estimated by choosing an acceptably low mortality, and determining the downwind distance at which this value was obtained. For example, a 20 m swath width was found to be adequate to limit mortality in A. aegypti andS. gairdneri populations to 10 and 0.1% during ground-based permethrin applications.  相似文献   

16.
The toxicity of the naturally derived insecticide spinosad was tested against the gypsy moth, Lymantria dispar. Bioassays using red oak leaf disks, treated with spinosad in a Potter spray tower, yielded an LC50 value of 0.0015 µg AI cm−2 (3‐day exposure; 13‐day evaluation; 2nd instar larvae). Applied to foliage to run‐off in the laboratory (potted red oak seedlings) and the field (4 m‐tall birch trees), spinosad effectively controlled 2nd instar larvae at concentrations ranging from 3 to 50 mg litre−1. Toxicity in the laboratory, and efficacy and persistence in the field, were comparable to those achieved with the insecticide permethrin. Laboratory studies supported field observations that control was achieved in part by knockdown due to paralysis. In addition, laboratory results demonstrated that crawling contact activity may play an important role in field efficacy; 50% of treated larvae were paralyzed 16 h after a 2‐min crawling exposure to glass coated with a 4 mg litre−1 spinosad solution. © 2000 Society of Chemical Industry  相似文献   

17.
A non-volatile oil-based spray mix of a low-vapour-pressure insecticide, aminocarb, containing an oil-soluble red dye was applied at a dosage rate of 70 g AI in 1-5 litre ha?1, using a fixed wing aircraft equipped with four ?Micronair’?® AU3000 atomizers, over a 1000 × 500 m spray block selected in Bathurst, New Brunswick, Canada. Spray was applied twice, at an interval of five days, to provide a total dosage rate of 140 g AI in 3.0 litre ha?1. Spray mass recovery was assessed on glass plates and droplets were collected on ?Kromekote’?® cards, both at ground level. The stain sizes were grouped into different categories. The area containing the stains was excised, and the aminocarb present was quantified by gas-liquid chromatography (GLC). The mass of aminocarb per droplet in each stain size category was evaluated. From the mass, the spherical droplet diameter (d), number and volume median diameters (DN.5 and Dv.5 respectively), a new parameter [mass (of aminocarb) median diameter] (DM.5), and the droplet size spectra were calculated. The DM.5 for the first application was 56 μm, which was identical to the Dv.5. whereas the DN.5 was smaller at 45 μm. The corresponding values for the second application were: DM.5 = Dv.5 = 63 μm, but the DN.5 was 53 μm. Because the spray mix was non-volatile, all the droplet size spectra parameters were identical both at spray release height and at ground level. The present study has provided, for the first time in the literature, a novel method to determine directly the spherical diameters of the droplets deposited on artificial samplers, without having to go through the tedious procedures of spread factor measurements under laboratory conditions. In fact, the present study has made it possible to calculate spread factors under field conditions, by using the stain diameters measured and the spherical diameters calculated from the aminocarb concentration levels.  相似文献   

18.
In paired tests on batches of malathion- and dieldrin-resistant Anopheles arabiensis, one of each pair received a continuous exposure to either malathion or dieldrin for 16 h or more, while the other received a non-exposed rest phase in the middle of the exposure period. Among dieldrin-resistant mosquitoes, the mortality rate was decreased in the group that experienced the interrupted, as opposed to the continuous exposures; however, the survival rate of malathion-resistant adults was unaffected by interrupted exposure. There was a significant positive correlation between the mortality rate and the adult age for malathion, but the responses to dieldrin were independent of age. Movement of adult mosquitoes to and from malathion deposits in sprayed houses should not impair the efficacy of this insecticide, whereas prolonged absence from contact with dieldrin would require even longer exposures to achieve the same mortality in the insects.  相似文献   

19.
Direct topical impact of an insecticide spray on a population of a non-target leaf-eating beetle, Gastrophysa polygoni, was studied, and the relative importance of phenology, instar susceptibility and instar specific exposure was evaluated. Two insecticides, cypermethrin and dimethoate, were investigated. In the laboratory, topical toxicity to eggs, second-instar larvae and adults was recorded in dose-response experiments. The spatial distribution of larvae and eggs were measured in the field. Deposition of insecticide onto eggs, second-instar larvae and adult specimens was measured at different positions within the crop canopy by use of a dye tracer technique. A temperature-driven population model was constructed to simulate population development of all life stages in the field. The model was based on laboratory measures of growth and development at various temperatures. Mortality due to direct insecticide exposure was calculated as a function of population demography, spatial distribution of individuals, spatial deposition of the insecticide, and stage-specific susceptibility. Cypermethrin had the greatest impact, reducing population size by 19–32%. The life stages most sensitive to cypermethrin were the larval instars. As the population developed from eggs to larvae and imagines, the impact of one spraying first increased and then decreased according to the proportion of larvae in the population. Dimethoate had less effect on the population, i.e. 1·9–7·6% reduction. Dimethoate was most toxic to the egg stage, and consequently the effect on the population decreased as the proportion of eggs decreased due to hatching. The direct effect of insecticide spraying was significantly affected by all three factors investigated, i.e. phenology, life stage susceptibility and stage-specific exposure. The latter factor is composed of both spray flux at various spatial positions in the canopy and the ability of different life stages to retain spray droplets. © 1998 SCI  相似文献   

20.
The effect of fungicide spray droplet density (droplet cm-2), droplet size, and proximity of the spray droplet deposit to fungal spores was investigated with Mycosphaerella fijiensis ascospores on the banana (Musa AAA) leaf surface for two contact fungicides: chlorothalonil and mancozeb. When droplet size was maintained at a volume median diameter (VMD) of 250 μm while total spray volume per hectare changed, M. fijiensis ascospore germination on the leaf surface fell below 1% for both fungicides at a droplet deposit density of 30 droplet cm-2. At a droplet deposit density of 50 droplet cm-2, no ascospores germinated in either fungicide treatment. When both droplet size and droplet cm-2 varied while spray volume was fixed at 20 litre ha-1, ascospore germination reached 0% at 10 droplet cm-2 (VMD=602 μm) for both fungicides. At lower droplet densities (2–5 droplet cm-2 VMD=989 μm and 804 μm respectively), ascospore germination on the mancozeb-treated leaves was significantly lower than on the chlorothalonil-treated leaves. The zone of inhibition surrounding a fungicide droplet deposit (VMD=250 μm) on the leaf surface was estimated to extend 1·02 mm beyond the visible edge of the spray droplet deposit for chlorothalonil and 1·29 mm for mancozeb. The efficacy of fungicide spray droplet deposit densities which are lower than currently recommended for low-volume, aerial applications of protectant fungicides was confirmed in an analysis of leaf samples recovered after commercial applications in a banana plantation. Calibrating agricultural spray aircraft to deliver fungicide spray droplets with a mean droplet deposit density of 30 droplet cm-2 and a VMD between 300 and 400 μm will probably reduce spray drift, increase deposition efficiency on crop foliage, and enhance disease control compared to aircraft calibrated to spray finer droplets. © 1997 SCI.  相似文献   

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