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101.
采用Munger cell法,就室内测定多杀菌素对西花蓟马 Frankliniella occidentalis 生物活性实验中需要控制的温度、相对湿度、滴水量、光周期、光照度和叶片6个环境条件对测定结果的影响进行了研究。发现:在25 ~30 ℃、相对湿度50% ~70%、光周期(L:D)为16 h:8 h~24 h:0 h、光照度6 500~13 000 lx这一测定条件范围内,采用月季、西葫芦、萝卜、芸豆、苹果、芹菜、菠菜叶片进行生物测定时结果较稳定;叶片纤毛数量与多杀菌素对西花蓟马的LC50值成负相关,相关系数为0.919;叶片纤毛的长度则与测定结果无相关性。  相似文献   
102.
BACKGROUND: Thrips tabaci Lindeman (Thysanoptera: Thripidae) is a major pest on onion, Allium cepa L., worldwide. In 2010, research was conducted in a commercial onion field in north‐western Italy in order (i) to evaluate the efficacy of different insecticides and of the SAR activator acibenzolar‐S‐methyl, (ii) to correlate thrips infestation levels with bulb size and weight at harvest and (iii) to implement a reliable thrips sampling method. Efficacy of the three active ingredients spinosad, lambda‐cyhalothrin and acibenzolar‐S‐methyl on local thrips populations were also evaluated in laboratory bioassays. RESULTS: During field surveys, the highest and the lowest thrips infestations were observed in plots treated with lambda‐cyhalothrin and with spinosad and acibenzolar‐S‐methyl respectively. The effectiveness of spinosad was also confirmed in laboratory bioassays. At harvest, bulb size and weight did not significantly differ between treatments. A high correlation with visual inspection made plant beating a suitable sampling method for routine practice, enabling a good estimate of thrips infestation. CONCLUSION: Damage caused by thrips is often not severe enough to warrant the frequent pesticide applications the crops receive in north‐western Italy. The use of spinosad and acibenzolar‐S‐methyl is suggested as an alternative to conventional insecticides for the preservation of natural enemies. Copyright © 2011 Society of Chemical Industry  相似文献   
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104.
The pine processionary moth Thaumetopoea wilkinsoni Tams is a serious pest on pine trees in southwestern Turkey. The efficacy of a naturally derived insecticide, spinosad, on fourth-fifth instar larvae of T. wilkinsoni was studied under laboratory conditions. The product exhibited strong larvicidal activity and at doses above 5 mg litre(-1) caused > 90% mortality in the fourth-fifth larval stages of the species after 72 h. At 72 h the LD50 and LD90 values were 3.26 and 5.69 mg litre(-1) respectively. The results showed that spinosad is highly effective on T. wilkinsoni larvae.  相似文献   
105.
The development of resistance to an insecticide under various types of application method has yet to be reported in the literature. Five fall armyworm Spodoptera armigera (JE Smith) colonies were reared in a chamber for ten generations before starting topical application bioassays. From each colony, 200-500 third-fourth-instar larvae were fed for 72 h on corn plants sprayed with cypermethrin or spinosad at minimum application rate (20 g ha(-1)) using a small droplet size nozzle XR8001VS (volume median diameter D(v0.5) = 163 microm) or a large droplet size nozzle XR8008VS (D(v0.5) = 519 microm). Surviving larvae were transferred to untreated corn leaves to complete their life cycle. Next-generation third-instar larvae of each colony were topically dosed with technical cypermethrin or spinosad at 1 microL per larva, and mortality was recorded 24 h post-treatment. The results indicated that cypermethrin demonstrated an insecticidal activity greater than that of spinosad, and the cypermethrin regression lines moved to the right faster than those for spinosad, indicating an increased tolerance of cypermethrin. Generally, larvae from all generations (F1-F7) under the XR8008VS treatments were less susceptible to cypermethrin and developed resistance faster and to higher levels than larvae from the XR8001VS treatments. The confidence limits (95%) of LD(50) for all spinosad treatments indicated that there was no significant difference from the LD(50) value of the susceptible reference strain. The results are a first indication that application technology/insecticide reaction may affect the rapidity of resistance development in certain pest/plant scenarios, but field studies are needed to confirm this conclusion.  相似文献   
106.
多杀菌素B具有很好的杀虫活性,但其天然含量很低,不易获得。作者以单质碘、乙酸钠和氢氧化钠为反应试剂,甲醇为溶剂,通过对反应条件优化,成功地将多杀菌素A中福乐糖胺氮原子上的1个甲基脱去,建立了一条以来源丰富的多杀菌素A为原料,简便、高效合成多杀菌素B的方法,多杀菌素B收率高达81%,为其开发应用及衍生研究奠定了基础。多杀菌素B的结构经1H NMR、13C NMR和HRESI-MS表征。  相似文献   
107.
108.
【目的】研究多杀菌素的最佳提取和萃取条件。【方法】采用单因素试验,分别研究发酵液不同pH(6,7,8,9,10,11)、放置时间(2,4,8,16,24,32,48,72 h)和温度(20,30,40,50,60,70℃)对发酵液中多杀菌素提取效果及稳定性的影响,同时,从乙酸乙酯、石油醚、二氯甲烷和乙醚中筛选最适萃取试剂,并在此基础上研究萃取次数(1,2,3次)和萃取试剂体积对多杀菌素萃取效果的影响。【结果】单因素试验结果显示,在发酵液pH为10时,多杀菌素提取效果较好;放置2~72 h,多杀菌素质量浓度不会发生显著变化;在20~70℃多杀菌素能稳定存在;乙酸乙酯为最适萃取试剂,最佳萃取次数为3次,其与多杀菌素提取液的最适体积比为1∶1。【结论】得到了多杀菌素提取和萃取的最佳条件,在该条件下多杀菌素的质量浓度和萃取率分别为74.50μg/mL和98.18%。  相似文献   
109.
BACKGROUND: Neoseiulus fallacis (Garman) is a key predator of tetranychid mites in integrated pest management (IPM) programs across Canada. This study identified compounds that would be recommended for tier‐II field evaluations in an IPM program. RESULTS: The overall egg mortality caused by the six insecticides was negligible as it extended from 0 to 12.1%. Imidacloprid was classified as toxic to adults. The label rate was 7.73‐fold the LC50. Thiamethoxam was classified as moderately toxic to adults, and its label rate was 2.87‐fold the LC50. Acetamiprid and spinosad were classified as marginally toxic, and their label rates were respectively 0.99‐ and 0.45‐fold the LC50 for adults. Thiacloprid and methoxyfenozide were virtually innocuous to adults. CONCLUSION: Methoxyfenozide was totally harmless to all stages of N. fallacis, and it would be included in IPM programs immediately. Acetamiprid, spinosad and thiacloprid had varying degrees of mild toxicity to at least one growth stage of the predator. Therefore, they were recommended for tier‐II field testing according to their label claims. Imidacloprid and thiamethoxam were toxic to moderately toxic to adults and had significant adverse effects on fecundity. Therefore, they would be field evaluated only if alternatives were unavailable. Copyright 2010 Crown in the right of Canada. Published by JohnWiley & Sons, Ltd  相似文献   
110.
Insecticides which were environmentally friendly and the least toxic, were screened against a laboratory strain ofBracon hebetor (Say) (Hymenoptera: Braconidae) for their suitability for release in IPM of cotton. Concentrations ranging from 1 to 1000 ppm of the formulated insecticides in acetone were applied in glass vials and also by a leaf method, whereby cotton leaves were dipped in aqueous solutions of the same concentrations of insecticides. Adult parasitoids were exposed in both methods. According to the LC50 at 24 h exposure, Λ-cyhalothrin and spinosad were the most (7 and 5 ppm) and least (263 and 225 ppm) toxic in the vial and the leaf method, respectively, toB. hebetor. The possible use of the parasitoid for IPM of cotton is discussed. http://www.phytoparasitica.org posting July 20, 2006.  相似文献   
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