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1.
Thuringiensin produced by Bacillus thuringiensis subsp. darmstadiensis was further subjected to a two-phase aqueous separation system. A modified HPLC method and a test for quantitative pathogenicity using the house fly Musca domestica were used for analysis of thuringiensin. Within a realistic range of dosages, more effect was observed in the pupal stage than in the larval stage. The percentage effective control rate (ECR) was calculated by (100-percentage emergence); malformed and non-reproductive adults were considered as emerged. Pupal mortality, pupal weight, and ECR after feeding the three-day-old larvae were the measured response criteria for bioassay. The EC50 of thuringiensin for pupae mortality was 1·64 μg ml-1 diet, and 0·83 μg ml-1 for mortality of adults. Insecticidal activity of the broth increased with fermentation time-course from 9th to 21st hour. The bioassay curve constructed with three-hour sampling interval during the fermentation course had good correlation to thuringiensin content as determined by the HPLC method. In the two-phase aqueous separation system, a maximum of 96·7% ECR was achieved with the bottom salt layer, compared to a value of 46·7% with the upper PEG layer. These results suggest that thuringiensin, prepared through a fermentation and recovery process, is suitable for pest control. © 1997 SCI.  相似文献   

2.
The activities of the chitin synthesis inhibitors, diflubenzuron and PH 60–38, against Spodoptera littoralis larvae were assayed by feeding treated alfalfa or poisoned wheat bran baits, by allowing the larvae to imbibe sucrose-containing aqueous dispersions of the compounds, and by injection into larvae. PH 60–38 was less active than diflubenzuron. On alfalfa, diflubenzuron had to be fed for at least 2 days to prevent formation of normal pupae and emergence of adults. For very big (480–540 mg) larvae, feeding diflubenzuron at concentrations of 50 mg/litre for 2 days or 2.5 mg/litre for 3 days prevented adult emergence. For 200–250 mg larvae, this was achieved by feeding concentrations of 100 mg/litre for 2 days, 5 mg/litre for 3 days or 3.5 mg/litre for 4 days. In all larvae > 150 mg, mortality in feeding experiments occurred in the prepupal or the pupal stage. Only with 30–50 mg and 100–150 mg larvae was there considerable mortality during moults between larval instars, the larvae being unable to liberate themselves from the old larval skins and head capsules. Diflubenzuron incorporated into wheat bran baits at concentrations of from 2.5 to 10 000 μg/g killed approximately 70–90% of the insects. When imbibed, diflubenzuron was much less toxic as a wettable powder than as a liquid formulation but the two formulations were equitoxic when injected into the larvae.  相似文献   

3.
Laboratory experiments were conducted to evaluate the prey stage preference and the daily consumption of each stage of the coccinellid predatorStethorus punctillum Weise (Coleoptera: Coccinellidae) feeding on the two-spotted spider miteTetranychus urticae (Koch) (Acari: Tetranychidae). Groups of different life stages of the prey were offered (eggs, larvae, nymphs and adults). The prey preference varied with the stage ofS. punctillum. First larval instars had no significant preference among theT. urticae stages offered. Second larval instars consumed significantly more spider mite larvae in comparison with nymphs. In contrast, third larval instars indicated a strong preference for mite eggs. Significantly fewerT. urticae larvae were consumed by the fourth larval instars ofS. punctillum, in comparison with the three other mite stages. Finally, adult predators consumed significantly more mite eggs than the other stages offered. This preferential trend was similar for all adults tested, whether during the pre-oviposition or the oviposition period. http://www.phytoparasitica.org posting Feb. 17, 2004.  相似文献   

4.
The spider mites Tetranychus urticae Koch and Panonychus ulmi (Koch) (Tetranychidae) cause severe economic losses to vegetable farms and deciduous fruit orchards in Turkey. One of their predators, the ladybird beetle Stethorus gilvifrons (Muls.) (Col., Coccinellidae), aggregates on mite-infested patches of plants. The present study assessed whether there is a role for herbivore-induced plant volatiles (HIPVs) and/or odors emitted directly from these two mite species in the aggregative response of ladybird beetles. The olfactory responses of the predator females to volatiles from T. urticae- and/or P. ulmi-infested sweet pepper (four cultivars, viz. ‘Demre’, ‘Yalova Carliston’, ‘Kandil Dolma’ and ‘Yag Biberi’), kidney bean (cv. ‘Barbunya’) and apple (M9 rootstock) were investigated using a two-choice olfactometer. Our results showed that HIPVs emitted from both T. urticae- and P. ulmi-infested plants significantly attracted S. gilvifrons adults for all plants except the sweet pepper cv. Yag Biberi. In addition, it was found that volatiles from apple plants infested by T. urticae and, especially, P. ulmi are more attractive for S. gilvifrons females than those emitted by other infested plants. The results also suggest that the odors of T. urticae adults and their products might influence the attraction of S. gilvifrons females.  相似文献   

5.
为有效防控重要害虫柑橘木虱Diaphorina citri,在实验室条件下测定取食柑橘木虱后六斑月瓢虫Cheilomenes sexmaculata和龟纹瓢虫Propylea japonica各虫态的发育历期,利用构建的年龄-阶段两性生命表对取食柑橘木虱后六斑月瓢虫、龟纹瓢虫生长发育及其种群参数进行研究。结果显示,取食柑橘木虱后六斑月瓢虫羽化前的发育历期为14.80 d,显著长于取食柑橘木虱后龟纹瓢虫的14.41 d;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫产卵期分别为15.88 d和10.23 d,前者显著长于后者;取食柑橘木虱后六斑月瓢虫净增殖率、内禀增长率和周限增长率分别为25.48、0.10 d-1和1.10 d-1,取食柑橘木虱后龟纹瓢虫净增殖率、内禀增长率和周限增长率分别为14.13、0.06 d-1和1.06 d-1,均低于取食柑橘木虱后六斑月瓢虫;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫的平均世代周期分别为33.87 d和44.95 d,前者显著短于后者。表明取食柑橘木虱后六斑月瓢虫和龟纹瓢虫均能完成整个世代,且六斑月瓢虫种群增长优于龟纹瓢虫,可大规模繁殖六斑月瓢虫,可用于柑橘木虱...  相似文献   

6.
Studies were conducted on maturation feeding and oviposition of Anoplophora chinensis (Forster) (Coleoptera: Cerambycidae), a recently introduced quarantine pest in Europe on different plant species of great importance for urban and forest environments in Italy. The tested plant species were Aesculus hippocastanum, Acer negundo, A. campestris, Castanea sativa, Corylus avellana, Platanus x acerifolia, Quercus petrea, Q. pubescens, Q. rubra, Tilia platyphyllos, Ulmus minor and U. pumila. Tested adults of A. chinensis originated from a population of a recently infested site in Italy (Rome) and all experiments were conducted in a walk-in insect cage under quarantine conditions. Adults of A. chinensis showed a maturation feeding preference for twigs of Acer species (A. negundo and A. campestris) and for C. avellana. In the oviposition experiments conducted on bolts of tested plant species, A. chinensis females did not show clear preferences and some data did not reflect the preferences shown during the feeding experiments. Nevertheless, A. negundo and A. campestris were well accepted plant species for oviposition besides A. hippocastanum and T. platyphyllos.  相似文献   

7.
BACKGROUND: The efficacy of seed dressing and soil application formulations from the isolates of Trichoderma viride (IARI P1; MTCC 5369), T. virens (IARI P3; MTCC 5370) and T. harzianum (IARI P4; MTCC 5371) were evaluated individually and in combination in pot and field experiments during the rainy seasons of 2005, 2006 and 2007 for the management of wet root rot (Rhizoctonia solani) and improvement in the yield of mungbean. RESULTS: A seed dressing formulation, Pusa 5SD, and soil application formulations, Pusa Biogranule 6 (PBG 6) and Pusa Biopellet 16G (PBP 16G), based on Trichoderma virens, were found to be superior to other formulations in reducing disease incidence and increasing seed germination and shoot and root lengths in mungbean. In field experiments, a combination of soil application with PBP 16G (T. virens) and seed treatment with Pusa 5SD (T. virens) + carboxin was superior to any of these formulations individually in increasing seed germination, shoot and root lengths and grain yield and reducing wet root rot incidence in mungbean. Seed treatment was more effective than soil application for all the evaluated parameters. The combined application of Pusa 5SD and carboxin was also superior to individual treatment. CONCLUSION: The efficacy of the evaluated formulations against wet root rot of mungbean proved that the integration of soil application of PBP 16G and seed treatment with Pusa 5SD + carboxin is highly effective for the management of wet root rot, increasing plant growth and grain yield of mungbean Copyright © 2011 Society of Chemical Industry  相似文献   

8.
Large‐scale virulence tests using trees or saplings are expensive, time‐consuming and require a considerable amount of space. The suitability of using ‘Golden Delicious’ apples as a rapid screen for identifying Ophiostoma novo‐ulmi transformants with reduced virulence was thus evaluated. When a collection of O. novo‐ulmi field isolates belonging to subspecies novo‐ulmi or americana was inoculated to apples, members of subsp. novo‐ulmi induced, on average, larger necrotic lesions than subsp. americana isolates. The size of the lesions on apples was not correlated with mycelial growth rate of isolates on nutrient agar. Insertional mutants from O. novo‐ulmi subsp. novo‐ulmi isolate H327 were inoculated to ‘Golden Delicious’ apples and Ulmus parvifolia × U. americana saplings in parallel experiments. Results clearly indicated that the O. novo‐ulmi transformants included several exhibiting significantly altered levels of virulence. Variability among replicates within a treatment was reduced in apple inoculation data compared to elm sapling data. Overall, the ‘Golden Delicious’ apple assay was found to be an excellent means for rapidly assessing the virulence level of O. novo‐ulmi isolates.  相似文献   

9.
Diflubenzuron, 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl)urea, possesses larvicidal and ovicidal activities. On larvae it acts mainly as a stomach poison, yet it sometimes exhibits important contact activity. Though all instars can be controlled, older instars are generally less susceptible than younger ones. Histological inspections of Leptinotarsa decemlineata larvae revealed that after ending exposure to the compound, distortions in newly deposited cuticular layers decreased gradually. Ovicidal effects resulted from direct contact of diflubenzuron with eggs or from contamination of females by contact or feeding. Electron microscopic observations of embryos of Leptinotarsa decemlineata, contaminated via the female, also showed disturbed cuticule formation, suggesting a similar activity of the compound in larvae and in eggs. Spraying the eggs of Leucoptera scitella shows the compound to be mainly ovidical at a rate of 100 mg litre?1, whilst with lower concentrations (10 and 1 mg litre?1) the young larval instar will be killed. The levels of cross-resistance to diflubenzuron as a larvicide are low and the compound can be used effectively in the field against populations that are highly resistant to conventional insecticides. Laboratory and field results, based on larvicidal and ovicidal activities of diflubenzuron, are discussed in respect of species belonging to the Diptera, Lepidoptera, Coleoptera, Acarina (Phyllocoptruta oleivora) and Hemiptera (Eurydema oleraceum and Psylla piri).  相似文献   

10.
丽蚜小蜂寄生对Q型烟粉虱生长发育的影响   总被引:1,自引:1,他引:1  
为明确丽蚜小蜂寄生对Q型烟粉虱的影响,通过室内饲养观察不同龄期Q型烟粉虱被丽蚜小蜂寄生后的生长发育,并比较了被寄生后烟粉虱若虫的个体大小及死亡率。结果表明,2龄、3龄和4龄烟粉虱若虫被寄生后均能继续发育,2龄若虫蜕皮进入3龄和3龄若虫蜕皮进入4龄的时间与对照间无显著差异,而被寄生若虫的4龄期显著延长。对于同一龄期的烟粉虱若虫,丽蚜小蜂偏向于选择较大的个体寄生,2龄和3龄被寄生若虫发育后期个体比未被寄生个体大,但4龄时被寄生的个体在发育后期略小于未被寄生个体,显示丽蚜小蜂对不同龄期若虫的生长发育影响不同。2龄若虫死亡率为61.64%,显著高于3龄和4龄若虫;4龄若虫褐蛹率最高,为48.84%。表明无论寄生哪一发育阶段的烟粉虱若虫,丽蚜小蜂的寄生均为容性寄生,田间应用丽蚜小蜂防治Q型烟粉虱时在其若虫3~4龄时释放更适宜。  相似文献   

11.
Callosobruchus maculatus (F.), a major pest of grain legumes, causes considerable losses worldwide. C. maculatus management relies on synthetic insecticides with their adverse environmental and health concerns. The current study investigated the use of Artocarpus altilis (breadfruit) extracts on contact and fumigant toxicity, repellency and oviposition deterrency of C. maculatus as a management strategy. Fumigant mortality (LC50) of the dry inflorescence extract of A. altilis was 126.65 µL L?1 air at 53.4 h. Fruit extract gave 73.3% repellency at 1000 ppm after 24 h. Percent repellency was dose and time dependent. Green inflorescence extract of A. altilis reduced egg laying with 50% oviposition occurring after 37.78 h at 1000 ppm. We conclude that extracts of leaf, fruit, green and dried inflorescence of A. altilis displayed contact mortality, repellency, deterred oviposition and had fumigant activity toward C. maculatus.  相似文献   

12.
为明确L-阿拉伯糖对B型和Q型烟粉虱毒性及其取食行为的影响,调查了饲喂含有L-阿拉伯糖人工饲料后烟粉虱的死亡率,利用刺吸电位技术(EPG)记录其取食行为,并观察了饲喂后其在人工饲料膜上的刺孔数量及直径。结果表明,B型和Q型烟粉虱的校正死亡率均随L-阿拉伯糖浓度及饲喂时间的增加而升高;在3种浓度下,B型烟粉虱校正死亡率均显著高于Q型烟粉虱;在5%、10%浓度下,Q型烟粉虱校正死亡率分别在第5天和第3天达100%,B型烟粉虱分别在第3天和第2天达到100%;5%L-阿拉伯糖对B型烟粉虱取食行为影响比Q型大;在5%浓度下,B型和Q型烟粉虱在膜上的刺孔数量总体少于对照组。研究表明,L-阿拉伯糖对烟粉虱具有杀虫活性,且对B型和Q型烟粉虱的毒性效果不同。  相似文献   

13.
BACKGROUND: Developmental resistance, i.e. reduced virulence and speed of kill of late instars, is a limiting factor in the use of baculoviruses for caterpillar control. Agrotis ipsilon multicapsid nucleopolyhedrovirus (AgipMNPV) is highly infective to young black cutworms, Agrotis ipsilon, but too slow‐acting against late instars for effective curative control on golf courses or sports fields. Chitin‐synthesis‐inhibiting fungicides containing the active ingredient polyoxin‐d are used to control fungal diseases in turfgrass, and similar compounds have been shown in the laboratory to synergize baculoviruses by disrupting peritrophic membrane function. This study tested whether applying the virus together with such a fungicide can synergize AgipMNPV activity against A. ipsilon in turfgrass. RESULTS: The addition of a chitin synthesis inhibitor failed to increase AgipMNPV infectivity to A. ipsilon in the field. Rather, delayed and slightly reduced mortality from viral infection was seen when larvae fed on fungicide/virus‐treated grasses as opposed to virus‐only treatments. Choice tests revealed the fungicide residues to be a mild feeding deterrent. CONCLUSION: Because polyoxin‐d does not deactivate AgipMNPV, the two substances are compatible. However, combination applications of polyoxin‐d and Agip MNPV on turfgrass might interfere with larval ingestion of a lethal virus dose, resulting in prolonged larval feeding in the field. Copyright © 2011 Society of Chemical Industry  相似文献   

14.
M. Sobala 《EPPO Bulletin》2000,30(1):99-102
Panonychus ulmi is a serious pest of apple orchards, especially in hot dry years. To improve quantitative insight into its population dynamics, and as a tool for forecasting optimal dates for visual assessment of abundance and of integrated pest management strategies, an age‐ and stage‐structured temperature‐dependent predator–prey model for P. ulmi and two of its natural enemies, Typhlodromus pyri and Amblyseius potentillae, has been developed.  相似文献   

15.
为探明桃蛀螟Conogethes punctiferalis偏好于在青霉菌Penicillium侵染的苹果上产卵的特点与机理,从苹果、玉米和柑橘上分离、纯化获得15株青霉菌,通过形态学和rDNA-ITS序列分析鉴定后,以健康苹果为对照,测试不同青霉菌菌株侵染的苹果对桃蛀螟产卵选择的影响,并利用四臂嗅觉仪测试桃蛀螟对青霉菌诱导的苹果挥发物的行为趋向反应。结果表明,15株青霉菌分别属于皮落青霉P. crustosum、橘青霉P. citrinum、苏门答腊青霉P. sumatrense和指状青霉P. digitatum的不同株型;桃蛀螟对其中的12株青霉菌侵染的苹果的产卵选择率均极显著高于健康苹果,尤其对皮落青霉CO5菌株、苏门答腊青霉OR3菌株和指状青霉OR5菌株侵染的苹果的产卵选择率最高,分别达到67.73%、61.50%和68.39%;桃蛀螟对感染皮落青霉CO5菌株和指状青霉OR5菌株的苹果挥发物的选择率分别为31.37%和29.19%,均显著高于对感染橘青霉OR1菌株和苏门答腊青霉OR3菌株的苹果挥发物的选择率18.14%和21.31%,且前二者之间、后二者之间均无显著差异。表明青霉菌可通过影响寄主植物挥发物释放,从而影响桃蛀螟对寄主植物的产卵选择和行为趋向反应。  相似文献   

16.
The toxicity of pirimicarb, imidacloprid, dimethoate, lambda-cyhalothrin, flonicamid and spinosad to the two-spot ladybird, Adalia bipunctata, was evaluated in a laboratory study. Susceptibility of fourth instars and female adults was assessed by measuring toxicity via residual contact and ingestion through feeding on contaminated green peach aphids (Myzus persicae). Flonicamid and spinosad had no lethal effects on larvae and female adults. Pirimicarb was harmless to the predator by ingestion exposure but showed some residual toxicity at high concentrations to both larval and adult stages. Imidacloprid was highly toxic to the larval stage by residual and ingestion exposure but caused very low adult mortality when ingested through contaminated prey. Dimethoate and lambda-cyhalothrin were highly toxic to both the larval and adult stages of the ladybird. Our findings indicate that pest management programs in agricultural crops using dimethoate, lambda-cyhalothrin and, to a lesser degree, imidacloprid, are detrimental to A. bipunctata, whereas pirimicarb, flonicamid and spinosad are more compatible with the use of this predator.  相似文献   

17.
The toxicities of eight structurally different acaricidal compounds to six‐legged larvae (first motile stage) of three laboratory strains of the two‐spotted spider mite, Tetranychus urticae, and the European red mite, Panonychus ulmi, were evaluated following spray application. The larvae of five field‐derived strains of T urticae originating from France, Italy, Brazil, California and Florida were also tested for their susceptibilities to discriminating concentrations of several acaricides resulting in 95% mortality when applied to the organophosphate‐resistant laboratory reference strain WI. The spray bioassay used was robust and gave repeatable results with a wide range of acaricidal compounds, irrespective of their mode of action (ovo‐larvicides or primarily acting on motile life stages). Compounds tested were abamectin, azocyclotin, chlorpyrifos, clofentezine, deltamethrin, fenpyroximate, hexythiazox and pyridaben. Larvae of one of the laboratory strains of T urticae, AK, originally collected in Japan in 1996 and maintained without further selection pressure, exhibited 2000‐ and >4000‐fold resistance to the mitochondrial electron transport inhibitors pyridaben and fenpyroximate, respectively. Another strain of T urticae, AU, obtained from Australia and maintained in the laboratory under selection with hexythiazox and clofentezine since 1987 showed >770‐ and >1000‐fold resistance to clofentezine and hexythiazox, respectively. The same resistance pattern was observed against larvae of a laboratory strain of P ulmi, CE, also selected with hexythiazox. Larvae of one of the field‐derived strains of T urticae, BR, showed a lower susceptibility to a number of compounds, whilst the others were susceptible to all compounds except the organophosphates. © 2001 Society of Chemical Industry  相似文献   

18.
Experiments on larvicide and ovicide activity of 13 insecticides in semi‐natural conditions showed a medium to low efficacy of bio‐insecticides on all instars of Tuta absoluta (Meyrick) except for Bacillus thuringiensis Berliner var. kurstaki which was distinguished by an average mortality of 72.5%. Spinosad and Spinetoram based insecticides showed high efficiency in controlling all instars of larvae with respectively an average mortality of 66.5% and 85.6%. However, this study revealed a unique ovicide effect of azadirachtin‐neem oil based insecticide with 43.8% egg mortality.  相似文献   

19.

Background

Cimex lectularius L. (bed bug) (Hemiptera: Cimicidae) is a serious indoor pest worldwide, and this nuisance needs to be controlled using different methods in integrated pest management (IPM). Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) kills bed bugs, and insect pathogenic fungi may be utilized to control bed bugs in IPM. To increase knowledge of this methodology, forced exposure experiments were conducted with different formulations, doses, and substrates, using bed bugs in variable physiological states.

Results

Both oil- and water-formulated fungal products showed significant improvement when conidial concentrations were raised in five steps from 0.02 to 2.0%. At low concentrations (0.02% in water) effects from substrate and application strategy were observed. Application on soft substrates (cotton and polyester) yielded significantly higher bed bug mortality rates than on harder substrates (paper, wood, and linoleum) with a final mortality of 35–63% against 8–10%. Multiple applications over time also improved B. bassiana's ability to kill bed bugs, and at low concentrations only a triple application on cotton showed 100% final mortality. Bed bug age and reproductive status significantly affected survival. Older and reproducing individuals showed higher mortality compared to newly emerged adults. Differences in feeding status also yielded differences in mortality timing, but only minor differences in final mortality rates. Egg production and hatching success were significantly reduced by some treatments.

Conclusion

B. bassiana appears to be an asset in the fight against bed bugs. Substrate, dosage, application strategy, and bed bug physiology are important factors to consider for optimal efficacy and safe indoor control with insect pathogenic fungi. © 2023 Society of Chemical Industry.  相似文献   

20.
为寻找有效防控外来入侵物种草地贪夜蛾Spodoptera frugiperda的技术,以烟芽夜蛾囊泡病毒3h株(Heliothis virescens ascovirus 3h,HvAV-3h)为研究对象,通过测定不同龄期草地贪夜蛾幼虫口服或针刺感染HvAV-3h后的死亡率、存活时间、取食量及体重,分析该毒株对草地贪夜蛾幼虫的感染特性及对其生长发育的影响。结果显示,草地贪夜蛾1、2龄幼虫口服HvAV-3h后的校正死亡率分别为9.22%和0,3~6龄幼虫针刺感染HvAV-3h后的校正死亡率则高达100.00%,感染HvAV-3h的幼虫均在幼虫期或蛹期死亡。3~5龄幼虫针刺感染HvAV-3h后的存活时间明显长于健康幼虫;3~6龄幼虫针刺感染HvAV-3h后其体重和取食量均受到不同程度的抑制作用,体重抑制率分别为67.79%、41.68%、16.31%和10.30%,总取食量抑制率分别为57.80%、33.90%、17.42%和41.82%;其中3龄幼虫针刺感染HvAV-3h后的体重和取食量被显著抑制,且蜕皮困难,最终在幼虫期死亡;部分4~6龄感染HvAV-3h幼虫能够完成化蛹,但是均无法羽化。表明HvAV-3h感染能够有效控制草地贪夜蛾幼虫,有望开发为草地贪夜蛾的生防制剂。  相似文献   

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