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1.
The acaricidal activity of materials derived from the rhizome of Cnidium officinale Makino against Tyrophagus putrescentiae Schrank adults was examined using direct contact application and fumigation methods, and compared with that of benzyl benzoate and N,N-diethyl-m-toluamide (DEET). The biologically active constituent of the Cnidium rhizome was identified as butylidenephthalide by spectroscopic analyses. On the basis of 24-h LD50 values, acaricidal activity was more pronounced with butylidenephthalide (5.80 microg cm(-2)) than with benzyl benzoate (9.75 microg cm(-2)) and DEET (16.26 microg cm(-2)). In typical poisoning symptoms, butylidenephthalide resulted in lethargy of treated mites, leading to death without knockdown, whereas benzyl benzoate and DEET caused death associated with uncoordinated behaviour. In a fumigation test with T. putrescentiae adults, butylidenephthalide was much more effective in closed containers than in open ones, indicating that the effects of this compound were largely due to action in the vapour phase. Naturally occurring C. officinale rhizome-derived materials merit further study as potential T. putrescentiae control agents or as lead compounds.  相似文献   

2.
BACKGROUND: The toxicity to adult Dermatophagoides farinae of allyl isothiocyanate identified in horseradish, Armoracia rusticana, oil and another 27 organic isothiocyanates was evaluated using contact + fumigant and vapour‐phase mortality bioassays. Results were compared with those of two conventional acaricides, benzyl benzoate and dibutyl phthalate. RESULTS: Horseradish oil (24 h LC50, 1.54 µg cm?2) and allyl isothiocyanate (2.52 µg cm?2) were highly toxic. Benzyl isothiocyanate (LC50, 0.62 µg cm?2) was the most toxic compound, followed by 4‐chlorophenyl, 3‐bromophenyl, 3,5‐bis(trifluoromethyl)phenyl, cyclohexyl, 2‐chlorophenyl, 4‐bromophenyl and 2‐bromophenyl isothiocyanates (0.93–1.41 µg cm?2). All were more effective than either benzyl benzoate (LC50, 4.58 µg cm?2) or dibutyl phthalate (24.49 µg cm?2). The structure‐activity relationship indicates that types of functional group and chemical structure appear to play a role in determining the isothiocyanate toxicities to adult D. farinae. In the vapour‐phase mortality bioassay, these isothiocyanates were consistently more toxic in closed versus open containers, indicating that their mode of delivery was, in part, a result of vapour action. CONCLUSION: In the light of global efforts to reduce the level of highly toxic synthetic acaricides in indoor environments, the horseradish oil‐derived compounds and the isothiocyanates described herein merit further study as potential acaricides for the control of house dust mite populations as fumigants with contact action. Copyright © 2011 Society of Chemical Industry  相似文献   

3.
The toxicity of formulations of oil of cassia, Cinnamomum cassia Blume, (20 and 50 g L(-1) sprays and 100% oil-based fumigant) to adult Dermatophagoides farinae Hughes and D. pteronyssinus Trouessart was examined using contact and vapour-phase toxicity bioassays. Results were compared with the lethal activity of three commercial acaricides: benzyl benzoate, dibutyl phthalate and diethyl-m-toluamide (deet). The contact toxicity of cassia oil to both dust mite species was comparable with that of benzyl benzoate but was higher than that of the other two acaricides. Sprays containing 20 and 50 g L(-1) cassia oil were effective against both mite species when applied to fabric, glass, paper, plastic, tin or wood substrates. Applications of the 50 g L(-1) spray to different space volumes and surface areas determined that 50-60 mg of cassia oil was needed to control dust mites in 3.4 m(3) or in 1 m(2). In tests with fumigant devices, toxicity varied according to the thickness of non-woven fabric covering the device, the exposure time, the number of fumigant devices used and the volume of the space sprayed. Fumigant toxicity to adult D. pteronyssinus was more pronounced with devices enclosed in thinner (40 microm) versus thicker (45 or 50 microm) non-woven fabric covers. A single fumigant device with a 40 microm thick non-woven fabric cover resulted in substantial control in a space of 0.05 m(3) but exhibited only moderate to weak control in spaces >or= 0.097 m(3) at 4 days after application. Two fumigant devices gave 88% mortality in a space of 1.73 m(3). Cassia oil applied as sprays or in fumigant devices appears to provide effective protection of humans from house dust mites.  相似文献   

4.
BACKGROUND: Piperazine derivatives possess pharmacological properties, yet the acaricidal activity of these compounds has not been investigated. This study was conducted to evaluate the colour alteration and acaricidal activity of piperazine derivatives against Dermatophagoides spp. and Tyrophagus putrescentiae (Schrank) using filter paper and fumigant methods. RESULTS: In a fumigant bioassay, 1‐phenylpiperazine (7.83 µg cm?2) against D. farinae (Hughes) was found to be 4.7 times more toxic than DEET (36.84 µg cm?2), followed by benzyl benzoate (9.72 µg cm?2), piperazine (11.41 µg cm?2), 1‐ethoxycarbonylpiperazine (20.14 µg cm?2) and 1‐(2‐methoxyphenyl)piperazine (22.14 µg cm?2). In a filter paper bioassay, 1‐(2‐methoxyphenyl)piperazine (3.65 µg cm?2) was 5.7 times more toxic than DEET (20.64 µg cm?2), followed by 1‐ethoxycarbonylpiperazine (4.02 µg cm?2), 1‐phenylpiperazine (4.75 µg cm?2), benzyl benzoate (7.83 µg cm?2) and piperazine (10.59 µg cm?2). Similar results have been exhibited with piperazine derivatives against D. pteronyssinus (Troussart). However, no activity against T. putrescentiae was observed for piperazine derivatives, except for piperazine. CONCLUSIONS: These results indicate that piperazine derivatives may be suitable as vapour‐phase acaricide fumigants owing to their high volatility, acaricidal activity and safety. 1‐Phenylpiperazine was found to be an excellent mite indicator based on the colour change it induced. Taken together, these findings indicate that piperazine derivatives may be used to replace existing problematical acaricides owing to their activity and ability to act as a mite indicator. Copyright © 2009 Society of Chemical Industry  相似文献   

5.
Patch and skin bioassays were used in laboratory and indoor tests to evaluate the repellency of (E)-cinnamaldehyde, identified in Cinnamomum cassia Blume bark and essential oil, and a cream containing 5% (w/w) cassia oil against Aedes aegypti (L.) females. Results were compared with those of a known C. cassia compound cinnamyl alcohol, N,N-diethyl-m-toluamide (DEET) and two commercial repellents: MeiMei cream containing citronella and geranium oils and Repellan S aerosol containing 19% DEET. In patch bioassay tests with A. aegypti females, (E)-cinnamaldehyde at 0.153 mg cm(-2) and DEET at 0.051 mg cm(-2) provided 93 and 89% protection at 40 min after exposure. In skin bioassay tests, (E)-cinnamaldehyde at 0.051 mg cm(-2) and DEET at 0.025 mg cm(-2) provided 87 and 95% protection at 30 min after application. (E)-Cinnamaldehyde was significantly more effective than cinnamyl alcohol in both bioassays. In indoor tests with four human volunteers, 5% cassia oil cream provided 94, 83 and 61% protection against A. aegypti females exposed for 30, 50 and 70 min after application respectively. Cassia oil cream was a slightly less effective repellent than MeiMei cream. Repellan S aerosol provided 91% repellency at 120 min after application. Products containing cassia oil merit further study as potential repellents for the protection of humans and domestic animals from blood-feeding vectors and the diseases they transmit.  相似文献   

6.
BACKGROUND: Recent studies have focused on materials derived from plant extracts as mite control products against house dust and stored food mites because repeated use of synthetic acaricides had led to resistance and unwanted activities on non‐target organisms. The aim of this study was to evaluate the acaricidal activity of materials derived from Lycopus lucidus against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae. RESULTS: The LD50 values of L. lucidus oil were 2.19, 2.25 and 8.45 µg cm?2 against D. farinae, D. pteronyssinus and T. putrescentiae. The acaricidal constituent of L. lucidus was isolated by chromatographic techniques and identified as 1‐octen‐3‐ol. In a fumigant method against D. farinae, the acaricidal activity of 1‐octen‐3‐ol (0.25 µg cm?2) was more toxic than N,N‐diethyl‐m‐toluamide (DEET) (36.84 µg cm?2), followed by 3,7‐dimethyl‐1‐octen‐3‐ol (0.29 µg cm?2), 1‐octen‐3‐yl butyrate (2.32 µg cm?2), 1‐octen‐3‐yl acetate (2.42 µg cm?2), 3,7‐dimethyl‐1‐octene (9.34 µg cm?2) and benzyl benzoate (10.02 µg cm?2). In a filter paper bioassay against D. farinae, 1‐octen‐3‐ol (0.63 µg cm?2) was more effective than DEET (20.64 µg cm?2), followed by 3,7‐dimethyl‐1‐octen‐3‐ol (1.09 µg cm?2). CONCLUSION: 1‐Octen‐3‐ol and 3,7‐dimethyl‐1‐octen‐3‐ol could be useful as natural agents for the management of three mite species. Copyright © 2011 Society of Chemical Industry  相似文献   

7.
为研制华北大黑鳃金龟Holotrichia oblita的植物源引诱剂,选取7种植物挥发物单体,筛选各单体最佳引诱浓度并据此设计35个三元配方,通过华北大黑鳃金龟成虫触角电位反应试验及进一步的趋势行为反应试验筛选出对华北大黑鳃金龟雌、雄成虫引诱作用较强的配方,并通过笼罩引诱试验测试所筛选配方对成虫的引诱效果。结果表明,趋势行为反应试验中配方5(邻苯二甲酸二丁酯+芳樟醇+苯甲醇)、配方14(肉桂醛+苯甲醇+顺-3-己烯基乙酸酯)、配方27(1-己醇+肉桂醛+苯甲醇)和配方35(1-己醇+顺-3-己烯基乙酸酯+顺-3-己烯基异丁酸酯)对雌成虫引诱效果较好,选择反应率分别为62.09%、62.79%、60.22%和85.13%;配方3(邻苯二甲酸二丁酯+肉桂醛+顺-3-己烯基乙酸酯)、配方6(邻苯二甲酸二丁酯+芳樟醇+顺-3-己烯基乙酸酯)和配方35对雄成虫引诱效果较好,选择反应率分别为69.12%、64.22%和89.05%。笼罩引诱试验结果表明,成虫对配方3、配方6和配方35的选择反应率分别为68.16%、60.24%和70.59%,均高于其它配方;配方3、配方6和配方35引诱的成虫数量分别为61、61和72头,均显著高于其对照引诱的成虫数量(29、40和30头)。表明配方3、配方6和配方35对华北大黑鳃金龟成虫具有显著引诱效果,可作为其引诱剂备选配方应用于生态防控。  相似文献   

8.
BACKGROUND: The contact + fumigant toxicity of 92 plant essential oils and control efficacy of 18 experimental spray formulations containing nine selected essential oils (0.5 and 0.1% sprays) and six commercial insecticides to females from B‐ and Q‐biotypes of Bemisia tabaci were evaluated using vapour‐phase mortality and spray bioassays. RESULTS: Garlic and oregano (LC50, 0.15 mL cm?3) were the most toxic oils against B‐ and Q‐biotype females. Strong fumigant toxicity to both biotype females was also obtained from catnip, cinnamon bark, clove bud, clove leaf, davana, savory and vetiver Haiti oils (LC50, 0.17–0.48 mL cm?3). The 0.5% sprays of these oils (except for thyme red oil) resulted in 90–100% mortality against both biotype females. Only garlic applied as 0.1% spray provided 100% mortality. Spinosad 100 g L?1 suspension concentrate (SC) treatment resulted in 92 and 95% mortality against both biotype females, whereas acetamiprid 80 g L?1 wettable powder (WP), imidacloprid 80 g L?1 SC, thiamethoxam 100 g L?1 water‐dispersible granule (WDG) and pyridaben 200 g L?1 WP treatments resulted in 89–100% mortality against B‐biotype females only. CONCLUSION: In the light of global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment, the essential oils described, particularly garlic, cinnamon bark and vetiver Haiti, merit further study as potential insecticides for the control of B. tabaci populations as fumigants with contact action. Copyright © 2011 Society of Chemical Industry  相似文献   

9.
Pan W  Luo P  Fu R  Gao P  Long Z  Xu F  Xiao H  Liu S 《Pest management science》2006,62(3):283-287
An acaricidal substance extracted from the external seed coat of Ginkgo biloba L. was identified by UV (ultraviolet), IR (infrared), EI-MS (electron impact ion source mass spectrometry), (1)H NMR (nuclear magnetic resonance) and (13)C NMR as 6-[(Z)-10-heptadecenyl]-2-hydroxybenzoic acid (compound 1). Laboratory bioassay on citrus red mite, Panonychus citri (Mcg), showed that compound 1 possessed the following properties. (i) Powerful contact toxicity with an LC(50) of 5.2 mg litre(-1) after 24 h that was similar to that of pyridaben (LC(50) = 3.4 mg litre(-1)) and significantly superior to that of omethoate (LC(50) = 122 mg litre(-1)). Furthermore, its LC(90) was 13.4 mg litre(-1) after 24 h, which is significantly superior to both pyridaben (LC(90) = 69.6 mg litre(-1)) and omethoate (LC(90) = 453 mg litre(-1)). (ii) Quick-acting acaricidal activity. At identical concentrations, compound 1 was much faster-acting than pyridaben or omethoate. (iii) Compound 1 had strong corrosive action on the cuticle of P. citri but no phytotoxicity to plants.  相似文献   

10.
Five esters, butyl acetate, allyl acetate, ethyl acetoacetate, isopropyl acetate and propyl acetate, were screened as fumigants in the laboratory for 24 h at 27 (+/-2) degrees C against the adults of Rhyzopertha dominica (F), Sitophilus oryzae (L) and Tribolium castaneum (Herbst). Of the compounds tested, allyl acetate was the most toxic, with LD(99) values of 7.56, 12.81 and 11.42 mg litre(-1) against R dominica, S oryzae and T castaneum, respectively. Tests with allyl acetate against mixed-age cultures of Cryptolestes ferrugineus (Stephens), Oryzaephilus surinamensis (L), R dominica, S oryzae and T castaneum revealed that doses of 50-150 mg litre(-1) with 24-120-h exposures were necessary to achieve 100% mortality of all life stages. Cryptolestes ferrugineus was the most tolerant insect tested, whilst R dominica was highly susceptible. The insect toxicity data indicates that allyl acetate has potential as a fumigant of stored food grains.  相似文献   

11.
BACKGROUND: Because methyl bromide has been phased out as a soil sterilant, new nematicides are urgently needed. Four different chemical classes of organic acids acting as anion transport (AT) blockers were tested against a free-living nematode, Caenorhabditis elegans Maupas, a plant-parasitic nematode, Meloidogyne incognita (Kofoid and White) Chitwood, and an entomopathogenic nematode, Heterorhabditis bacteriophora Poinar, in toxicity bioassays. The materials tested were DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid), 9-AC (anthracene-9-carboxylic acid), NPPB [5-nitro-2-(3-phenylpropylamino)benzoic acid] and IAA-94 (indanyloxyacetic acid). RESULTS: All the compounds showed slowly developing nematicidal activity against second-stage juveniles of M. incognita and adults of C. elegans, but not against H. bacteriophora infective-stage juveniles. The LC(50) values of these compounds were < 50 mg L(-1) after 48 and 72 h incubation, while at 168 h incubation the LC(50) values were < 10 mg L(-1) for both sensitive species. Across both species and time, the LC(50) values generally differed no more than twofold among the four compounds tested in this study. In contrast, none of the compounds (200 mg L(-1)) caused more than control mortality to H. bacteriophora, even after 168 h of incubation. CONCLUSION: These compounds are potential leads for commercial nematicides. The insensitivity to H. bacteriophora is consistent with the natural exposure of this nematode to DST (3,5-dihydroxy-4-isopropylstilbene), a stilbene produced by its symbiotic bacterium. Based on the known activity of the compounds used in this study, it is suggested that anion transporters form the probable target sites for DIDS, 9-AC, NPPB and IAA-94 in nematodes.  相似文献   

12.
BACKGROUND: 1,3 Dichloropropene (1,3-D) is a preplanting soil fumigant for the control of cyst and free-living nematodes and is currently undergoing a resubmission under Annex 1 listing of Directive 91/414/EEC. The characteristics of 1,3-D are such that the risk of it or its soil metabolites leaching through the soil profile cannot be excluded. As such, groundwater monitoring programmes were established in five EU countries representing a wide range of agricultural, climatic and hydrogeological situations, covering a range of groundwater vulnerability scenarios. All monitoring was conducted in areas where there has been historical use of 1,3-D. RESULTS: Over 5000 groundwater samples were analysed for the presence of 1,3-D and its metabolites over a 2 year period. Almost all analyses (for parent and metabolites) yielded concentrations of <0.1 microg L(-1). There were just two detections of >0.1 microg L(-1) (0.12 microg L(-1) and 0.4 microg L(-1)) for the 3-chloroacrylic acid metabolite in shallow groundwater samples of the alluvial gravels of the River Tiétar in the Caceres region of Spain. CONCLUSION: Groundwater monitoring programmes have been conducted in the EU in five countries. These have demonstrated that there is negligible contamination of groundwater with 1,3-D or its metabolites across a range of agroclimatic regions where 1,3-D is known to have been used for a number of years. Local scientific knowledge of geological features, hydrology, agricultural practice and specific local issues was essential to the conduct of the study.  相似文献   

13.
BACKGROUND: Various attempts to control the populations of house‐dust and stored‐food mites have been implemented using synthetic chemicals. Although effective, the repeated use of these chemicals has led to resistance owing to the mite's high reproductive potential and short life cycle. Therefore, this study aimed to develop natural acaricides using oils derived from Leptospermum scoparium JR & G Forst., which may affect the overall biological activity of a mite without adverse effects. Results were compared with those from using benzyl benzoate and N,N‐diethyl‐3‐methylbenzamide (DEET). RESULTS: The LD50 values of L. scoparium oil were 0.54, 0.67 and 1.12 µg cm?2 against Dermatophagoides farinae (Hughes), D. pteronyssinus (Troussart) and Tyrophagus putrescentiae (Schrank) respectively. The active constituent isolated from L. scoparium was identified as leptospermone (6‐isovaleryl‐2,2,4,4‐tetramethyl‐1,3,5‐cyclohexanetrione) by spectroscopic analysis. Based on the LD50 values of leptospermone and its derivatives, the most toxic compound against D. farinae was leptospermone (0.07 µg cm?2), followed by 2,2,4,4,6,6‐hexamethyl‐1,3,5‐cyclohexanetrione (1.21 µg cm?2), benzyl benzoate (10.03 µg cm?2) and DEET (37.12 µg cm?2). Furthermore, similar results were observed when the leptospermone and its derivatives were tested against D. pteronyssinus and T. putrescentiae. CONCLUSIONS: These results indicate that L. scoparium oil‐derived materials, particularly leptospermone and 2,2,4,4,6,6‐hexamethyl‐1,3,5‐cyclohexanetrione, have potential for development as new agents for the control of three species of mite. Copyright © 2008 Society of Chemical Industry  相似文献   

14.
为有效防控新入侵迁飞性害虫草地贪夜蛾,指导科学用药,本研究按照农业农村部推荐用药,在室内采用浸叶法测定了8种杀虫剂对滇西南、滇南、滇中、滇东北4个区域5个草地贪夜蛾种群3龄幼虫的毒力。测定结果表明,8种杀虫剂对上述草地贪夜蛾种群的毒力大小顺序依次为:5%甲氨基阿维菌素苯甲酸盐WG(0.05～0.09 mg/L)≥25%乙基多杀菌素WG(0.16～0.26 mg/L)5%虱螨脲SC(0.84～7.07 mg/L)20%氯虫苯甲酰胺SC(3.31～10.50 mg/L)10%虫螨腈SC(4.82～11.47 mg/L)30%茚虫威SC(23.79～40.41 mg/L)2.5%高效氯氟氰菊酯EC(102.85～147.60 mg/L)32 000 IU/mg Bt WP(141.09～352.61 mg/L),其中,甲氨基阿维菌素苯甲酸盐、乙基多杀菌素、茚虫威和Bt对4个区域种群的LD_(50)无显著性差异,虱螨脲、氯虫苯甲酰胺、虫螨腈和高效氯氟氰菊酯对4个区域种群的LD_(50)存在区域性差异,其中区域间差异显著的是5%虱螨脲SC,最大相对毒力指数为8.42倍。甲氨基阿维菌素苯甲酸盐、乙基多杀菌素、虱螨脲、氯虫苯甲酰胺和虫螨腈对草地贪夜蛾的LD_(90)均低于各药剂的田间推荐剂量,是防治草地贪夜蛾的最佳杀虫剂;茚虫威对草地贪夜蛾的LD_(90)超过了推荐剂量,选用时注意防效,高效氯氟氰菊酯和Bt不推荐作为防治药剂。研究结果为云南地区草地贪夜蛾的有效防治提供了参考。  相似文献   

15.
The cardiac glycoside, digitoxin, from Digitalis purpurea L (Scrophulariaceae), a cardiac glycosidal (cardenolide) extract from Calotropis procera (Ait) R Br (Asclepiadaceae), azadirachtin and neem oil from Azadirachta indica A Juss (Meliaceae) were tested for their effects against larvae and adult stages of the camel tick, Hyalomma dromedarii Koch (Acari: Ixodidae). The contact LC50 values of the first three materials against adults were 4.08, 9.63 and >40.7 microg cm(-2), respectively, whereas the dipping LC50 values of the four materials were 409.9, 1096, >5000 and >5000 mg litre(-1), respectively. Contact and dipping LC50 values of the extract and azadirachtin against larvae were 6.16, >20.3 microg cm(-2) and 587.7 and >2500 mg litre(-1), respectively. Azadirachtin had no effects on egg production or feeding of adults up to 5000 mg litre(-1); however at 2500 mg litre(-1), it caused significant reduction in feeding activity of larve, prolonged the period for moulting to nymphal stage, and caused 60% reduction in moultability. Results of the two cardiac glycoside materials are comparable with those of several commercial acaricides. The risks and benefits associated with the use of cardiac glycosides are considered.  相似文献   

16.
Resistance to fumigants has been frequently reported in insect pests of stored products and is one of the obstacles in controlling these pests. The authors studied phosphine resistance and its physiological basis in adult insects of 12 populations of Tribolium castaneum (Herbst) (Tenebrionidae), ten populations of Rhyzopertha dominica (F.) (Bostrichidae) and eight populations of Oryzaephilus surinamensis L. (Silvanidae) from Brazil, and the possible existence of fitness costs associated with phosphine resistance in the absence of this fumigant. The bioassays for the detection of phosphine resistance followed the FAO standard method. The production of carbon dioxide and the instantaneous rate of population increase (r(i)) of each population of each species were correlated with their resistance ratios at the LC(50). The resistance ratio at LC(50) in T. castaneum ranged from 1.0- to 186.2-fold, in R. dominica from 2.0- to 71.0-fold and in O. surinamensis from 1.9- to 32.2-fold. Ten populations of T. castaneum, nine populations of R. dominica and seven populations of O. surinamensis were resistant to phosphine. In all three species there was significant association (P < 0.05) between respiration rate and phosphine resistance. The populations with lower carbon dioxide production showed a higher resistance ratio, suggesting that the lower respiration rate is the physiological basis of phosphine resistance by reducing the fumigant uptake in the resistant insects. Conversely, populations with higher r(i) showed lower resistance ratios, which could indicate a lower rate of reproduction of the resistant populations compared with susceptible populations. Thus, management strategies based on the interruption of phosphine fumigation may result in reestablishment of susceptibility, and shows good potential for more effective management of phosphine-resistant populations.  相似文献   

17.
A wide range of pesticides (insecticides, acaricides and fungicides) is used in the hydroponic cultivation of gerbera. The fate and behaviour of some of these commonly used pesticides (organochlorine and pyrethroid insecticides/acaricides) in a greenhouse installation was investigated. The concentrations of endosulfan, dicofol, tetradifon, permethrin, bifenthrin, cypermethrin and deltamethrin in the air of the greenhouse were related to their physicochemical properties and respective application rates. Of these compounds, endosulfan exhibited the highest concentration in the greenhouse air 2 h after application (10 microg m(-3)), due to its highest volatility; afterwards, up to 12 h post-application, a rapid decrease was recorded which finally led to a concentration of 0.41 microg m(-3) at 6 days post-application. Dicofol exhibited the same trend of dissipation in the greenhouse air; its concentration decreased from 0.27 microg m(-3) immediately after the application to 0.12 microg m(-3) at 6 days post-application. Tetradifon, bifenthrin and permethrin were found at concentrations lower than 0.1 microg m(-3) at 2 h post-application, and cypermethrin and deltamethrin could not be detected. The concentrations of all the above pesticides in the drain water of the open hydroponic system were relatively high immediately after application and decreased rapidly during the following 3 days. In the closed hydroponic system, all the pesticides accumulated in the nutrient solution during the first 24 h after application and slowly decreased in concentration over the following 3 days. The spray operators applying these pesticides were exposed to rather high concentrations and the spray deposits were monitored on the chest and forehead of the operator. Endosulfan exhibited the highest concentrations of the seven pesticides. The organochlorine pesticides (endosulfan, dicofol and tetradifon) were usually detected at higher concentrations on the chest than on the forehead of the operator; pyrethroids were detected at higher concentrations on the forehead than on the chest of the operator.  相似文献   

18.
Spinosad, a reduced-risk commercial insecticide derived from a bacterial fermentation product, possesses both contact and oral toxicities against insects. Contact toxicity of spinosad to adults of Rhyzopertha dominica (F), Sitophilus oryzae (L), and Tribolium castaneum (Herbst) was evaluated by exposure for 24 or 48 h to treated glass Petri dishes. Adults were exposed to different deposits (0.001-0.79 mg cm(-2)) of spinosad in 24-h tests and to deposits of 0, 0.0016 and 0.016mg cm(-2) in 48-h tests. Rhyzopertha dominica was most susceptible to spinosad in 24- and 48-h tests, followed by S. oryzae, and T. castaneum. The 24-h LD50 values were 0.0004, 0.077 and 0.189mg cm(-2) for R. dominica, S. oryzae, and T. castaneum, respectively. All R. dominica adults were dead following 48 h exposure to both spinosad deposits, whereas mortality of S. oryzae and T. castaneum ranged from 10 to 85% and 12 to 48%, respectively. Rhyzopertha dominica, T. castaneum, and O. surinamensis adults were exposed for 14 days to whole wheat, cracked wheat and wheat flour treated with 0, 0.1 and 1.0 mg kg(-1) of spinosad. Rhyzopertha dominica adults were highly susceptible to spinosad, followed by O. surinamensis and T. castaneum. Immatures (eggs and larvae) of T. castaneum and O. surinamensis exposed for 14 days were more susceptible on spinosad-treated whole wheat than on treated cracked wheat and wheat flour. This is the first report documenting contact activity of spinosad, and the effect of grain condition on spinosad toxicity, to stored-product insects.  相似文献   

19.
通过整株盆栽法研究黑龙江省佳木斯市汤原县(种群R1)、856农场(种群R2)、密山市(种群R3)3个水稻田野慈姑种群对丙嗪嘧磺隆的抗性水平,采用分子生物学技术分析3个野慈姑种群在靶标酶基因上的差异,确定3个野慈姑种群对丙嗪嘧磺隆和苄嘧磺隆是否存在交互抗性。结果显示,黑龙江R1、R2、R3种群抗性指数(RI)分别为11.92、22.68、35.99。与敏感的七台河种群S相比,R1、R2、R3的ALS基因均在Pro_(197)位发生不同突变。R1种群为Thr_(197)取代了Pro_(197);R2、R3种群为Ser_(197)取代了Pro_(197),ALS基因的突变是其产生抗性的主要原因。3个野慈姑种群对丙嗪嘧磺隆和苄嘧磺隆存在交互抗性。  相似文献   

20.
Han J  Kim SI  Choi BR  Lee SG  Ahn YJ 《Pest management science》2011,67(12):1583-1588
BACKGROUND: This study was aimed at assessing the fumigant toxicity of 14 essential oil constituents from lemon eucalyptus, Eucalyptus citriodora Hook, and another ten known compounds to females of acaricide‐susceptible, chlorfenapyr‐resistant, fenpropathrin‐resistant, pyridaben‐resistant and abamectin‐resistant strains of Tetranychus urticae Koch. RESULTS: Menthol (LC50, 12.9 µg cm?3) was the most toxic compound, followed by citronellyl acetate (16.8 µg cm?3), against the susceptible females. High toxicity was also produced by β‐citronellol, citral, geranyl acetate and eugenol (LC50, 21.7–24.6 µg cm?3). The fumigant toxicity of these compounds was almost identical against females from either of the susceptible and resistant strains, indicating that the compounds and acaricides do not share a common mode of action or elicit cross‐resistance. CONCLUSION: Global efforts to reduce the level of highly toxic synthetic acaricides in the agricultural environment justify further studies on materials derived from lemon eucalyptus oil, particularly menthol and citronellyl acetate, as potential acaricides for the control of acaricide‐resistant T. urticae as fumigants with contact action. Copyright © 2011 Society of Chemical Industry  相似文献   

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