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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.
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

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   

5.
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   

6.
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   

7.
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   

8.
Abstract

A biconical trap is described which incorporates a 5 KV electrocuting grid to stun tsetse flies, which then fall via a funnel into a preservative in a tube segregator capable of separating the catch at intervals of 1–24 hours. The trap was effective in Upper Volta and Ivory Coast against Glossina tachinoides (Westw.) and G palpalis s. 1. respectively. A 12 V 45Ah battery allowed continuous operation for over 20 days.  相似文献   

9.
Chemical and other selective insecticides are annually used as foliar treatments against defoliating Lepidoptera in the southern Spanish open woodland (known as dehesa), one of the largest forest ecosystems in the Mediterranean basin. In order to analyse the negative impact of these treatments on beneficial arthropods, the toxic effect of the three authorised insecticides on Philodromus buxi Simon (Araneae: Philodromidae), the most abundant tree canopy spider in southern Spain, was tested under laboratory conditions. Cypermethrin was the most harmful insecticide 96 hours after application, causing around 90% corrected mortality, while flufenoxuron (an insect growth-regulator) prompted around 45% mortality, and Bacillus thuringiensis caused no mortality at all. In addition, flufenoxuron produced a clear alteration in the predatory capacity of P. buxi, increasing the reaction times of treated specimens, and additional mortality associated with the moulting process. Bacillus thuringiensis caused no effects in reaction times, growth or moulting. The results obtained clearly indicate that B. thuringiensis is the most suitable of the authorised insecticides for conserving populations of P. buxi in dehesa woodland in southern Spain.  相似文献   

10.
An efficient method for rapidly mass-screening insecticides for use against sap-feeding virus vectors is presented with a case study of 30 chemicals. The method permits large numbers of insecticides to be tested simultaneously and relatively inexpensively in a sequence of laboratory bioassays. The sequence is designed to find the most effective pesticide at the lowest concentration giving control without phytotoxicity. The system was derived to test candidate insecticides to control tomato yellow leaf curl virus vectored by the tobacco whitefly, Bemisia tabaci Gennad., the most serious pest of greenhouse and field tomatoes in the Middle East. Although the insecticides were all more efficacious in the laboratory than in the field, bioassay results were highly correlated with results from field trials, giving high confidence that the screening process selected only the most efficacious insecticides. Most of the insecticides accepted by the screening process have since been adopted by vegetable growers in Israel. The method is not intended to eliminate field efficacy trials, but to reduce the number of trials and treatments that need to be performed, thereby reducing costs. The method provides for the optimization of application rates which will contribute to the expected life of insecticides before resistance develops, and will also help to reduce environmental contamination. In addition, the method is suitable for estimating relative efficacy for pesticide benefits assessments, a required part of the (re-)registration process for pesticides in some countries. Although developed for screening insecticides against virus-transmitting sap-feeding insects, the method could be modified to assess the efficacy of insecticides in controlling other insect pests.  相似文献   

11.
The effects of NAA [2‐(1‐naphthyl)acetic acid] concentration and pH on penetration of NAA from aqueous droplets (5 µl) through isolated tomato (Lycopersicon esculentum) fruit cuticles were studied using a finite dose diffusion system. Penetration time‐courses were characterized by a lag phase, which generally extended beyond the time of droplet drying. Initially penetration rates increased, reached a maximum penetration rate, remained constant for several hours, and then decreased with time. Penetration approached a plateau within 120 h after droplet application. Increasing NAA concentration in the donor droplet increased NAA penetration in both the presence and absence of the citric acid buffer (20 mM , pH 3.2). Maximum rates of penetration and the total amount of NAA that penetrated at 120 h were both linearly related to the initial concentration of the donor droplet (ranging from 0.001 to 0.1 mM NAA). The apparent first‐order rate constants for the concentration dependence of NAA penetration rates were greater with buffer than without (0.94 × 10−8 vs 0.50 × 10−8 m s−1, respectively). While pH of the receiver solution (pH 6.2 vs 2.2) did not affect penetration, decreasing donor pH from 6.2 to 2.2 increased NAA penetration at 120 h. © 2000 Society of Chemical Industry  相似文献   

12.
BACKGROUND: Typical active ingredient (AI) residue patterns are formed during droplet drying on plant surfaces owing to the interaction of spray solution characteristics and leaf micromorphology. Currently, comparatively little is known about the influence of AI deposit patterns within a spray droplet residue area on the penetration and biological efficacy of glyphosate. A scanning electron microscope with energy dispersive X‐ray microanalysis has been used to characterise residue patterns and to quantify the area ultimately covered by glyphosate within the droplet spread area. RESULTS: The easy‐to‐wet weed species Stellaria media L. and Viola arvensis L., as well as the difficult‐to‐wet Chenopodium album L. and Setaria viridis L., differing in their surface micromorphology, have been used. Rapeseed oil ethoxylates (RSO 5 or RSO 60) were added to glyphosate solutions to provide different droplet spread areas. Addition of RSO 5 enhanced droplet spread area more than RSO 60, and both caused distinct glyphosate residue patterns. The biological efficacy of treatment solutions showed no significant correlation with the area ultimately covered by glyphosate. CONCLUSION: The results have implications on herbicide uptake models. This study shows that droplet spread area does not correspond to the area ultimately covered by glyphosate, and that the latter does not affect glyphosate phytotoxicity. Copyright © 2009 Society of Chemical Industry  相似文献   

13.
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   

14.
本文就继续研究应用呋喃丹、杀虫脒、巴丹类等内吸杀虫剂根区施用的十种不同方式防治水稻三化螟、稻瘿蚊、稻蓟马、稻纵卷叶螟、褐稻虱等主要害虫的药效及对害虫天敌影响的新进展作扼要的报道,进一步阐明根区施药的科学根据、盆栽及田间试验结果、以及指出应用楝科植物(印楝、川楝、苦楝)对稻瘿蚊等害虫防治的可能性和探索呋喃丹根区施用对褐稻虱的杀卵作用。此外,对湖北、江西等地约10万余亩稻田推广根区施药试验示范的情况亦作适当的介绍。  相似文献   

15.
Abstract

Incidence and geographical distribution of downy mildew (Peronosclerospora sorghi) on maize (Zea mays) were determined in a systematic survey of 181 maize fields in the major maize‐growing regions and ecological zones of Nigeria. Downy mildew was observed in the forest and Guinea savanna ecologies, but no disease was detected in other ecologies. Highest levels of disease incidence (63%) were observed in the forest zone, and progressively less disease incidence was found at the southern and northern Guinea savanna zones. Spatial pattern analysis indicated an aggregation and randomness of infected plants in the northern Guinea savanna and the forest zone, respectively. Disease incidence was positively correlated with the presence of downy mildew infected sorghum plants and relative amount of sporulation on infected sorghum (Sorghum bicolor) but negatively correlated with plant age and cropping pattern. Relative sporulation on maize plants was negatively correlated with age of maize plants. Higher levels of disease incidence were observed when the previous crop was either maize or sorghum than when previous crops were cassava, okra, tomatoes, or rice.  相似文献   

16.
Effects of droplet size and carrier volume on foliar uptake and transport of daminozide were investigated. A constant dose of daminozide (100 µg per leaf) was applied to both primary leaves of 10‐day‐old Phaseolus vulgaris (cv Nerina) in droplet sizes of 1–10 µl and carrier volumes of 10 to 200 µl per leaf. Decreasing droplet size or increasing carrier volume decreased daminozide penetration, but increased translocation. Plotting the logarithm of the leaf surface/droplet interface area vs daminozide uptake yielded a negative linear relationship, but for translocation an optimum quadratic type relationship was obtained. Some phytotoxicity occurred at low carrier volumes and large droplet sizes. The degree of phytotoxicity was positively related to the amount of daminozide deposited per unit wetted area above 0.7 µg daminozide mm−2. Below this threshold, there was no visual evidence of phytotoxicity. At the breakpoint, the deposit covered an area of 276 mm2 on both primary bean leaf surfaces. Since the maximum in the relationship of translocation with interface area was in close agreement with the threshold amount of deposit above which phytotoxicity occurred, the inverse relationship between daminozide uptake and translocation at low interface areas was attributed to phytotoxicity. © 2000 Society of Chemical Industry  相似文献   

17.
Three previously reported methanesulfonate insecticides, 6-isobutylthio-2-pyridyl methanesulfonate ( I ) and its sulfoxide ( II ) and sulfone ( III )analogues were examined in two insect species Lucilia cuprina and Blattella germanica and in tissues from vertebrates. The results of B. germanica tests and cholinesterase assays confirmed the insecticidal activity of the compounds, with cholinesterase inhibition being the most likely mode of insecticidal action. The inactivity of the sulfide I and sulfoxide II in vertebrate in-vitro studies may indicate that conversion, in vivo, of the sulfide and sulfoxide methanesulfonates to the sulfone ( III ) is a requirement for activity. In mouse toxicity tests, matching high toxicity was observed for the alkylthio-, alkylsulfoxy- and alkylsulfone analogues indicating fast metabolic oxidation of the injected alkylthio- and alkylsulfoxy-compounds. However, in in-vitro tissue tests, the sulfone, although active, did not exhibit the characteristic pharmacological profile of the standard acetylcholinesterase inhibitor, physostigmine. The sulfone demonstrated a mixed action, with indications that it acts as an inhibitor of specific cholinesterase isozymes, or that it may modify responses at cholinoceptors.  相似文献   

18.
用点滴法测定了 13种杀虫剂对中华草蛉 (Chrysopa sinia (Jieder) )幼虫的毒力 ,按敏感性由高至低依次为 :久效磷、氯氟氰菊酯、灭多威、丙溴磷、辛硫磷 >氧乐果、甲基对硫磷、甲基毒死蜱 >硫丙磷 >抑太保 >氰戊菊酯 >阿维菌素及硫丹。同时测定了多种药剂对棉铃虫 (H elicoverp a armigera Hübner)、棉蚜 (Aphis gossyp ii Glover)的毒力 ,证明多数有机磷杀虫剂及灭多威为非选择性药剂 ;具有选择性的药剂中 ,硫丹选择性最高 ,其次为氰戊菊酯。氯氟氰菊酯对中华草蛉与棉铃虫表现出一定程度的选择性 ,但对中华草蛉与棉蚜则表现为非选择性 ;随棉蚜抗药性提高 ,各药剂选择性降低。  相似文献   

19.
Effects of droplet size and carrier volume on foliar uptake and translocation of gibberellic acid (GA3) and 2,4-D were investigated. Simulated spray droplets were applied to primary leaves of 10-day-old Phaseolus vulgaris (cv Nerina) in droplet sizes and carrier volumes ranging from 0.5 to 10 μl and 10 to 200 μl per leaf, respectively. Doses of GA3 (2 μg per leaf) and 2,4-D (100 μg per leaf) were held constant. Total uptake of GA3 approached a penetration equilibrium within 24 h after application, but uptake of 2,4-D continued to increase. Decreasing droplet size and/or increasing carrier volume increased GA3 and 2,4-D uptake. Translocation to stem and roots was positively related to total uptake. A positive linear relationship between the logarithm of the total droplet/leaf surface interface area and 2,4-D uptake or translocation was found, but for GA3 this relationship was quadratic. Potential mechanisms of the effects of spray application factors on foliar uptake are discussed. © 1999 Society of Chemical Industry  相似文献   

20.
Abstract

Laboratory studies were carried out to determine the course of poisoning and toxicity of some synthetic pyrethroid insecticides (bioresmethrin, cismethrin, cypermethrin, deltamethrin, fenpropathrin, fenvalerate and permethrin) against the desert locust. From doses in excess of the LD99 all the insecticides were quick acting; from doses of about the LD99 or less the insects are rapidly knocked down or show symptoms of poisoning, but may recover. The symptoms which follow treatment by the various insecticides are described. Although these insecticides are all highly toxic to locusts there are many other insecticides which are similarly toxic, can be sprayed at high concentrations and are much cheaper.  相似文献   

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