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11.
P. C. Mercer 《国际虫害防治杂志》2013,59(2):190-192
Abstract Organochlorine, organophosphate (o.p.) and carbamate insecticides have been extensively used in Australia to combat Lucilia cuprina Wied. the main initiator of fly-strike of sheep occurring wherever sheep are run on the continent. The improved mules operation, mid-season crutching and insecticides are important in the management of Merino sheep. Insecticides are particularly valuable against body strike, especially in young sheep, in years with intermittent rain during the warmer months. Resistance to larvicides developed in the blowfly over a period of 10y from 1957. The time between the introduction of various insecticides and development of resistance is considered and a comparison made between the emergence of resistance problems to the newer synthetic insecticides in the housefly in Denmark, and in the blowfly in Australia. To provide a complete history of insecticides against the blowfly reference is made to arsenicals, to which there was no suspicion of resistance until low order cross resistance was diagnosed in o.p.-carbamate resistant strains. Some seven years after their introduction DDT and γ BHC were replaced by cyclodiene insecticides in 1954/1955. Reasons are advanced to explain the non-emergence of resistance to DDT and BHC in that period. Resistance to dieldrin and aldrin developed in late 1957 after which diazinon was introduced. The resistance has a typical BHC/dieldrin resistance spectrum and is due to a semi-dominant gene which has persisted in the field in the absence of pressure from cyclodiene insecticides. Non-specific resistance to o.p. insecticides developed in two steps. Low order resistance, diagnosed in 1965, was supplemented by an additional resistance mechanism in 1966, three alleles on two chromosomes are involved. The carbamate, butacarb, was effective against o.p. resistant strains of the blowfly when introduced in the 1966/67 season. In 1967, resistance to butacarb was diagnosed and rapidly became widespread. For the past three fly seasons larvae have been used to monitor resistance levels to o.p. and carbamate insecticides; resistance factors to both these classes of insecticide are significantly higher in larvae than adult females. Resistance levels to o.p. insecticides have stabilised. By contrast resistance levels to butacarb have doubled. A combined o p.-carbamate resistance generally applies in field samples. Larvae from o.p.-carbamate resistant strains form artificial strikes earlier than susceptible larvae, particularly on sheep treated with butacarb. It is concluded that registered o.p. insecticides, but not butacarb, will still give considerable protection against fly-strike, providing the maximum levels of o.p. resistance, reached in laboratory selection programmes, are not exceeded in the field. Investigation into o.p. resistance in the species suggests that the resistance mechanisms place their carriers at a disadvantage in the absence of selection pressure. Measures to minimise the amount of insecticide used against the blowfly are therefore strongly advocated—these include: the improved mules operation, mid season crutching and good animal husbandry. 相似文献
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The components of the essential oils from seeds of Azadirachta indica, Azadirachta siamensis, and Azadi-rachta excelsa were studied by gas chromatography and gas chromatography-mass spectrometry. The main components of A. indica oil were hexadecanoic acid (34.0%), oleic acid (15.7%), 5,6-dihydro-2,4,6-triethyl-(4H)-1,3,5-dithiazine (11.7%), methyl oleate (3.8%), and eudesm-7(11)-en-4-ol (2.7%). The major components of A. siamensis oil were hexadecanoic acid (52.2%), tricosane (10.5%), tetradecanoic acid (6.8%), oleic acid (4.9%), and pentacosane (4.9%). Azadirachta excelsa oil contained oleic acid (31.3%), hexadecanoic acid (14.2%), octadecanoic acid (13.0%), 4-octylphenol (9.7%), and O-methyloximedecanal (6.8%) as the main constituents. The essential oils from A. indica, A. siamensis, and A. excelsa were found to contain fatty acids (52.6%–72.3%) as major components. The minor components of the oils were n-alkanes, aromatics, esters, sulfur and nitrogen compounds, and terpenoids. Differences in oil composition were observed between the three species. 相似文献
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印楝质杀虫剂的生物活性及作用机制研究进展 总被引：12，自引：0，他引：12
印楝质杀虫剂对昆虫有忌避、拒食、干扰生长发育、降低生殖力等多方面的生物活性。印楝质杀虫剂对不同昆虫的取食影响差异较大，鳞翅目昆虫较敏感。对不同昆虫的生长发育、生殖等方面的效应较为一致，但处理方法对效果有影响，注射处理比点滴、口服效果好。印楝质杀虫剂的作用机制包括：（1）影响触角、跗节、产卵器化上化学感受器的功能导致忌避作用；（2）影响口器上厌食及其他化学感器产生初生拒食反应；（3）作用于消化系统形成次生拒食反应；（4）障碍形态发生肽类激素的释放，影响蜕皮激素、保幼激素滴度，抑制生长发育并使生殖力下降；（5）抑制细胞分裂、损害发育中的器官组织。印楝质杀虫剂在细胞、分子生物学水平上的作用机制尚待阐明。 相似文献
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J. Igrc Barčić R. Bažok S. Bezjak T. Gotlin Čuljak J. Barčić 《Journal of pest science》2006,79(4):223-232
The Colorado potato beetle (Leptinotarsa decemlineata Say.) (CPB) is the main potato pest in Croatia. The main problems in CPB control are related to a number of treatments and resistance development. In order to investigate the efficacy of combinations a reduced dose of spinosad (33% of the full doses) with the reduced doses (33% of full doses) of B.t.t., neem and pyrethrin against CPB larvae, 3-year field trials and one laboratory trial were conducted. Joint actions of the insecticides in combinations were analyzed. The CPB attack on experimental fields in all 3 years of investigation was high to moderate. In 2001 the maximum number of larvae on untreated plots was 11.7 larvae per plant, while in 2002 and 2003 it was lower, 5.5 and 6.1 larvae/plant, respectively. The efficacy obtained with a full dose of B.t.t. reached 75% in the field, and 78% in the laboratory trial. The residual efficacy of a full dose of B.t.t. lasted 7–10 days. The application of both, full and reduced doses of B.t.t., did not result in a significant yield increase. The results indicate that only one treatment with B.t.t. insecticide alone is not enough for efficient protection of potato against the attack of CPB larvae. The application of neem resulted in an efficacy of between 54 and 87.9%. The residual activity of neem was too short to ensure significant yield increase in 2 out of 3 years of the investigation. The application of a full dose of pyrethrin ensured an efficacy of between 86 and 89% with residual activity of 7–10 days. Only in the trial in 2003 significant yield increase (40% higher than untreated control) after the application of a full dose of pyrethin was recorded. The application of both, full and reduced doses of spinosad resulted in very high efficacy (over 90%), with residual activity between 10 and 20 days. The application of spinosad resulted in a significant yield increase in 2003, both in full and reduced doses, and in 2001 in the full dose (the reduced dose was not tested alone in 2001). High efficacy of the reduced dose of spinosad indicated its high biological activity and possibility for the reduction of the recommended dose. However, applications of combinations of insecticides in reduced doses (spinosad with B.t.t., neem and pyrethrin) resulted in efficacies of over 97% with residual activity of up to 21 days. Significant yield increase was noted after the application of the combinations of spinosad with B.t.t. and pyrethrin. The results of the laboratory trial confirmed the results of field trials. The joint action of insecticides was mainly described as independent synergism. It can be concluded that applied combinations are suitable in IPM in potato. 相似文献
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Effects of margosan-o™, azatin™ and RD9-repelin® on spiders,and on predacious and phytophagous mites
The effects of Margosan-OTM, AzatinTM and RD9-Repelin on the phytophagous miteTetranychus cinnabarinus (Boisd.), the predacious miteTyphlodromus athiasae, and the predatory spiderChiracanthium mildei were studied and compared in laboratory experimentsr.-No toxic effect of any of these neem formulations was observed onC. mildei. Margosan-O and Azatin were not toxic to eitherT. cinnabarinus orT. athiasae, but RD9-Repelin was highly toxic to both the phytophagous and the predacious mite. 相似文献
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S. Senthil Nathan K. Kalaivani Paul Gene Chung 《Pesticide biochemistry and physiology》2005,81(2):113-122
The effect of neem (Azadirachta indica) limonoids azadirachtin, salannin, deacetylgedunin, gedunin, 17-hydroxyazadiradione, and deaceytlnimbin on gut enzyme activity of the rice leaffolder larvae was investigated. When fed a diet of rice leaves treated with limonoids in bioassays, gut tissue enzymes—acid phosphatases (ACP), alkaline phosphatases (ALP), and adenosine triphosphatases (ATPase) activities of rice leaffolder (Cnaphalocrocis medinalis) larvae are affected. Azadirachtin was most potent in all experiments. Larvae that were chronically exposed to limonoids showed a reduction in weight (59-89%) and exhibited a significant reduction in ACP, ALP, and ATPase activities. These results indicate neem limonoids affects gut enzyme activities. These effects are most pronounced in early instars. 相似文献
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Neem-based products including traditional preparations and formulations have been used extensively for the control of insect pests attacking agricultural crops. Content of phytochemicals extracted from different parts of the neem plant varies considerably due to abiotic and biotic factors from collection of the raw material to extract preparation and product formulation. Likewise, effectiveness of crude or synthesized material used in the field or laboratory may be influenced by storage conditions, content of active ingredient (especially azadirachtin), insect species and its growth stage, type of formulation and synergism of products with other control measures. In this paper, the direct and indirect actions of neem phytochemicals on insect pests are described and practical implications for future pest control strategies are discussed. 相似文献
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Summary Field experiments were conducted on transplanted rice (Oryza sativa L., var. Ratna) in a submerged soil, in order to study the distribution of N applied at 100 kg/ha. N was introduced as prilled urea or neem cake coated urea broadcast on the soil, and as urea supergranules, 1 or 2.5 g in size, point-placed at 5 cm depth. The surface-broadcast N was found mostly in the top 0–5 cm layer of soil and there was only a small vertical movement of applied N to 5–10 cm depth. With point placement of 1-g urea granules, the fertilizer N was found mostly at 5–10 cm depth and within 2.5 cm horizontal distance from the point of placement, compared with 5–10 cm depth and within 5 cm horizontal distance from the point of placement for the 2.5-g granules. With the two broadcast applications, the NH4
+-N content reached peaks of 40–68 mg/kg soil in the top 0–5 cm of soil within the first 3–6 days, decreased at a faster rate from the 6th to 12th day and then at a slower rate up to the 32nd day. In contrast, the NH4
+-N content around the points of placement of the urea supergranules reached peaks of 570–900 mg/kg soil during the first 3–12 days after placement, then decreased rapidly during the next 6–9 days, after which the values remained more or less unchanged but were still higher than the untreated control value. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(3-4):524-537
Abstract The mineralization of nutrients from deoiled neem seed (neem seed cake), the residue left after oil extraction, was examined in a typical savanna soil with a view to determining its potential for fertility improvement. The neem seed cake (NSC) application rates were 0, 2.5, and 5.0 g kg?1 soil (0, 5, and 10 tons ha?1). The concentrations of ammonium‐nitrogen (NH4‐N) and nitrate (NO3)‐N mineralized from the neem‐amended soil were two to three times greater than the control. Similarly, exchangeable potassium (K), magnesium (Mg), and cation exchange capacity were significantly greater than the control. The neem‐amended soil maintained organic carbon (OC) at the pre‐incubation level, whereas OC in the control soil declined to significantly less than the pre‐incubation concentration. The electrolytic conductivity of the soil saturation extract with neem application was 8–10 times greater than the control soil. However, the NSC increased exchange acidity markedly and decreased the soil pH significantly. Thus, the benefits of NSC in increasing the concentrations of N, K, and Mg and maintaining OC of the soil must be weighed against the consequences of soil acidity, though it is unlikely that NSC can acidify the soil to the same extent under field conditions as it did in this closed‐system incubation study. 相似文献