多异瓢虫对瓜蚜为害后植物挥发物的行为反应及挥发物成分分析

为明确寄主植物挥发物在多异瓢虫Hippodamia variegata (Goeze)搜索猎物过程中的作用, 采用Y型嗅觉仪测定了多异瓢虫成虫对来自瓜蚜Aphis gossypii Glover、 健康植株、 有蚜植株及蚜害植株本身的挥发物的行为反应。结果表明： 高密度蚜虫（≥700头/L）、 有蚜植株以及密度≥400头/盆的蚜虫为害诱导的黄瓜挥发物和密度≥200头/盆的蚜虫为害诱导的搅瓜挥发物对多异瓢虫成虫具有明显的引诱作用, 而低密度蚜虫（≤500头/L）和健康植株挥发物没有引诱作用。应用动态顶空收集法提取健康植株、 有蚜植株及蚜害植株的挥发物, 进行气质联用仪分析鉴定。结果表明, 从黄瓜健康植株、 蚜害植株和有蚜植株中分别鉴定出8, 12和18种挥发物, 主要组分为十八烯、 E-5-二十碳烯、 正十六烷和正十七烷, 诱导出的新组分为对二甲苯、 邻二甲苯、 正十三烷、 α-法呢烯、 雪松醇、 正十八烷、 正二十六烷及7种未知种类; 从搅瓜健康植株、 蚜害植株和有蚜植株分别鉴定出11, 18和20种挥发物, 主要组分为石竹烯、 十八烯、 正十六烷和正十七烷, 诱导出的新组分为苯乙烷、 对二甲苯、 间二甲苯、 α-蒎烯、 正十四烷、 长叶烯、 α-石竹烯及2种未知种类。上述结果为进一步研究挥发物中引诱多异瓢虫的有效组分奠定了必要的基础。     

Reactions of adult female parasitoids, particularly Aphidius rhopalosiphi, to volatile chemical cues from the host plants of their aphid prey

Abstract. In Y-tube olfactometer tests, Aphidius ervi Hal., Trioxys sp., Praon sp., Aphelinus flavus (Nees), Lysiphlebus fabarum (Marsh.) and Aphidius rophalosiphi De Stef. responded positively to the odour of the plant on which aphid mummies containing them had been collected. The response to host plant odour was greater than the response to the odour of host aphids, their honeydew or a combination of the two. The strongest response was to a combination of plant and host aphids. A. rhopalosiphi showed a strong positive response to three wheat volatiles (cis-3-hexenyl acetate, cis-3-hexen-1-ol and trans-2-hexenal) as well as to indole-3-acetaldehyde (a breakdown product of tryptophan in aphid honeydew). In both olfactometer tests with odours and choice trials with whole plants, newly emerged A. rhopalosiphi distinguished and preferred the variety of wheat on which their development had occurred to other wheat varieties.     

The reactions of two cereal aphid parasitoids, Aphidius uzbekistanicus and A. ervi to host aphids and their food-plants

ABSTRACT. A Y-tube olfactometer was used to test the reactions of the hymenopteran cereal aphid parasitoids Aphidius uzbekistanicus Luzhetski and A. ervi Haliday to odours from aphids and their host plants. Only females responded to aphids but both sexes responded to plant odours. A. uzbekistanicus responded to the cereal aphids Sitobion avenae (F.) and Metopolophium dirhodum (Walker) whilst A. ervi , which has a broad host range, responded to M. dirhodum and the pea aphid, Acyrthosiphon pisum. Female A. uzbekistanicus responded to wheat leaves only but males responded to a range of plant material. Both male and female A. ervi responded to wheat and bean leaves. The failure of A. ervi to respond to either nettle aphids, Microlophium carnosum (Bukt.), or nettle leaves, despite its frequent parasitization of this aphid in the field, suggests the existence of more than one race of the parasitoid and casts doubts on the usefulness of alternative hosts as reservoirs for A. ervi in integrated control programmes. Males of both species responded to their respective females suggesting the presence of a sex specific attractant.     

韭菜迟眼蕈蚊雌成虫对其不同虫态气味的行为反应

【目的】明确韭菜迟眼蕈蚊Bradysiaodoriphaga Yang et Zhang雌成虫对不同虫态的行为趋性及起作用的活性物质,为开发高效引诱剂诱杀成虫的绿色防控技术提供基础。【方法】采用Y型嗅觉仪测定未交配或已交配韭菜迟眼蕈蚊雌成虫对2龄幼虫、4龄幼虫、蛹和卵块挥发物的趋性,应用固相微萃取和气-质联用仪对有引诱活性虫态挥发物进行定性和定量分析,然后进一步采用Y型嗅觉仪测定不同化学成分及比例对雌虫的引诱活性。【结果】结果表明,未交配或者已交配韭菜迟眼蕈蚊雌成虫明显嗜好4龄幼虫,而对2龄幼虫、蛹和卵块无明显趋性。韭菜迟眼蕈蚊4龄幼虫体表挥发物主要成分是二丙基二硫醚和2,2-二甲基-1,3-噻烷等二硫化物,前者含量是后者的10倍。50 mg二丙基二硫醚单体对韭菜迟眼蕈蚊交配雌成虫具有明显吸引作用,50 mg和5 mg 2,2-二甲基-1,3-噻烷单体对韭菜迟眼蕈蚊交配雌成虫具有一定吸引作用;二丙基二硫醚与2,2-二甲基-1,3-噻烷以1︰1(50 mg︰50 mg)和10︰1(50 mg︰5 mg)混合物对韭菜迟眼蕈蚊交配雌成虫具有明显吸引作用;而将二丙基二硫醚和2,2-二甲基-1,3-噻烷以10︰1(50 mg︰5 mg)混合后与50 mg二丙基二硫醚单体比较,前者对韭菜迟眼蕈蚊交配雌成虫的吸引作用更明显。【结论】韭菜迟眼蕈蚊雌成虫明显嗜好4龄幼虫,其体表挥发物二丙基二硫醚等二硫化物对韭菜迟眼蕈蚊雌成虫具有吸引作用,2,2-二甲基-1,3-噻烷对二丙基二硫醚单体吸引韭菜迟眼蕈蚊交配雌成虫具有增效作用。     

Effects of aphid herbivory on volatile organic compounds of Artemisia annua and Chrysanthemum morifolium

We showed the effect of aphid infesting on the volatile organic compounds (VOCs) emitted by the infested Artemisia annua and Chrysanthemum morifolium cultivar ‘Nan nong hong feng’ plants by using headspace solid-phase microextraction (HS-SPME) method combined with gas chromatography mass spectrometry (GC–MS). In olfactometer bioassay experiment, aphids showed a preference for the odour of both healthy and infested chrysanthemum, while we found an opposite result in A. annua. Aphids tend to healthy plants compared with the infested, and the phenomenon became obvious with time. Different extracts were tested with the healthy plants and aphid infested plants. Eucalyptol, β-caryophyllene, (E)-β-farnesene, and germacrene D were released as the major constituents in both species. After aphid infesting, we observed a great increase in artemisia ketone and (E)-β-farnesene and a decrease in germacrene D in A. annua; comparatively, eucalyptol, isoborneol and β-caryophyllene increased in chrysanthemum. Combined with the GC–MS data and olfactometer bioassay results we concluded that (E)-β-farnesene and artemisia ketone emitted from A. annua might act as a potential volatile compound to resist aphids, and the two compounds would be useful for future ecological control of aphid in chrysanthemum cultivation.     

Responses to aphid sex pheromones by the pea aphid parasitoids Aphidius ervi and Aphidius eadyi

Aphidius ervi and Aphidius eadyi, two parasitoids of the pea aphid Acyrthosiphon pisum, were attracted to components of the aphid sex pheromone in laboratory bioassays. Pre-test experience with host aphids in the presence of aphid sex pheromone did not affect the response of A. ervi to pheromone in a 4-way olfactometer, compared with that of naive parasitoids. Aphidius ervi females exposed only to the pheromone prior to testing did not respond in the olfactometer, suggesting habituation to the foraging cue by the parasitoid. In a wind tunnel, aphid sex pheromone increased the attraction of A. ervi to the plant-host complex (Vicia faba/A. pisum), suggesting an additive effect when two different foraging cues are present simultaneously.     

Response of potato aphid (Homoptera: Aphididae) to synthetic potato-derived Colorado potato beetle (Coleoptera: Chrysomelidae) attractant and natural potato odor

A recently synthesized kairomone blend, based on the volatiles produced by potato (Solanum spp.) plants, has been demonstrated to be attractive to both adult and larval stages of the Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae). It was subsequently formulated in a viscous inert carrier for field applications and showed potential for aggregating beetles in treated areas of the field. We investigated effects of this kairomone formulation on the potato aphid, Macrosiphum euphorbiae (Thomas) (Homoptera: Aphididae). The response of both winged and wingless adults to natural potato foliage and synthetic kairomone was tested in a Y-tube olfactometer. Aphid response to untreated potato foliage, foliage treated with the kairomone blend, and foliage treated with blank inert carrier also was tested in petri dishes. In addition, aphid densities on field plots treated with kairomone and blank inert carrier were compared with the control plots. The untreated potato foliage was found to be attractive to wingless, but not winged, potato aphids. In the olfactometer, the foliage treated with synthetic Colorado potato beetle kairomone was not attractive to either winged or wingless aphids. In petri dishes, aphids avoided leaflets treated with both kairomone formulation and its blank carrier. There was no statistical difference between any treatments compared in the field.     

Organosulphur constituents in garlic oil elicit antennal and behavioural responses from the yellow fever mosquito

Garlic (Allium sativum) and its essential oil have long been used for their distinct flavour, therapeutic effects and as a topical and systemic insect repellent. We tested the hypothesis that the yellow fever mosquito, Aedes aegypti L. (Diptera: Culicidae), responds electrophysiologically and behaviourally to specific components of the steam‐distilled essential oil of garlic. In coupled gas chromatographic‐electroantennographic detection analyses of garlic oil, antennae of female Ae. aegypti responded to 14 compounds. Seven of them [diallyl disulphide, diallyl trisulphide, diallyl tetrasulphide, 2‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 3‐(2,3‐dithia‐5‐hexenyl)‐3,4‐dihydro‐2H‐thiopyran, 6‐methyl‐4,5,8,9‐tetrathiadodeca‐1,11‐diene and 4,5,9,10‐tetrathiatrideca‐1,12‐diene] were isolated or synthesized and tested for their ability to repel host‐seeking female Ae. aegypti. A solution of diallyl trisulphide and diallyl tetrasulphide applied to a human forearm provided protection from female mosquitoes significantly longer than the paraffin oil control. All compounds had mean protection times significantly shorter than an equivalent dose of the ‘gold standard’N,N‐diethyl‐3‐methylbenzamide. Understanding the common moiety in organosulfur compounds that causes repellence could lead to the design of analogues that are more effective than their natural counterparts in repelling mosquitoes.     

Diurnal Patterns in Host Finding by Potato Aphids, Macrosiphum euphorbiae (Homoptera: Aphididae)

Potato aphid, Macrosiphum euphorbiae (Homoptera: Aphididae), is an abundant potato pest and vector of potato leaf-roll virus and potato virus Y in Maine and other potato growing areas. We investigated the circadian rhythmicity of its movement towards host plant odor. Effects of daily cycle (day or night) and illumination (light or dark) on the proportion of aphids colonizing potato leaflets were determined in a Petri plate arena and in a Y-tube olfactometer. In Petri dishes, both daily cycle and light had a highly significant effect on plant colonization. Increasing temperature reduced aphid colonization of the leaflets. In the olfactometer, light had a significant effect on the proportion of aphids walking towards the host plant. Interaction between time and light was also statistically significant, with the effect of illumination being smaller during the day than during the night. Our results suggest that circadian rhythm in host-finding behavior of the potato aphid is regulated by both exogenous and endogenous mechanisms.     

Sources of semiochemicals mediating host finding in Callosobruchus chinensis (Coleoptera: Bruchidae)

Bruchid pests such as Callosobruchus chinensis (Linnaeus) endanger stored legume seeds throughout the tropical belt. The chemical composition of the headspace volatiles from healthy and fourth instar larvae-infested cowpea seeds were identified, characterized, and compared using gas chromatography-mass spectrometry. Y-tube olfactometer bioassays were performed to evaluate the effect of these chemicals on the orientation of conspecific adult females. Analysis of volatiles released from healthy and infested seeds revealed qualitative differences for three out of the 17 compounds identified. Dimethyl disulphide, isobutenyl methyl ketone and methyl trisulphide were found only in the blend emitted from infested but not from healthy seeds. Quantitative differences were apparent for tridecane which was released in larger amounts from infested seeds. While volatiles collected from healthy seeds were attractive to female bruchids, volatiles collected from infested seeds were repellent. To test the hypothesis that the qualitative differences in the chemical composition found may be due to insect-derived components, the volatiles from frass and fourth instar larvae combined were analysed. These volatiles contained both of the sulphides emitted from infested seed but not from healthy seeds. Although a limited induction of volatiles from cowpea seeds cannot be excluded, it is postulated that behavioural differences of the female weevils are largely due to insect-derived semiochemicals. The potential use of such semiochemicals as part of an integrated pest management strategy is discussed.     

Impact of wheat-mung bean intercropping on English grain aphid (Hemiptera: Aphididae) populations and its natural enemy

The effects of intercropping wheat, Triticum aestivum L., with mung bean, Vigna radiate L., on the populations of English grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae), and its natural enemies were evaluated by field and laboratory experiments. The population densities of aphids and their natural enemies were evaluated in the intercropped field against different row ratio combinations of wheat-mung bean. Results showed that wheat-mung bean intercropping caused a drop in aphid densities, and the ratio 12 wheat: 4 mung bean brought about the largest drop (> 8%). In addition, the population densities of coccinellids (ladybirds) and parasitoids and the species diversity of all the natural enemies of aphid were higher in the intercropped field than in the field planted only with wheat. However, intercropping did not influence the community indices (evenness and index of dominance concentration) of the natural enemies. Y-tube olfactometer bioassays were carried out in the laboratory to test whether odor blends of host and nonhost plants affect the host selection of S. avenae. Bioassays indicated that both apterous and alate aphids significantly preferred host plant odor over odor blends of host and intercropped species. Hence, the olfactory-based host location of aphids in the field might be affected by intercropping. The intercropping experiment clearly showed that increased crop species diversity suppresses aphid population growth and preserves the population of natural enemies of aphids. Our results also provide support for the "resource concentration hypothesis" and the "enemies hypothesis".     

蚜虫化学生态学研究进展及展望

昆虫化学生态学主要以化学手段研究昆虫种内、种间以及与其它生物之间的化学信息联系,昆虫对化学因素的适应等,是昆虫的神经生理和感觉生理、生物化学及生态学的交叉学科,也是当前国际昆虫学界最活跃的研究领域之一。蚜虫属于同翅目（Ｈｏｍｏｐｔｅｒａ）蚜总科（Ａｐ...     

红火蚁工蚁对棉蚜诱导的棉花挥发物的嗅觉和行为反应

【目的】红火蚁 Solenopsis invicta 与棉蚜 Aphis gossypii 存在兼性共生关系,红火蚁可能利用棉蚜危害诱导棉花释放的挥发物定位棉蚜。本研究将测试红火蚁工蚁对棉花挥发物的嗅觉和行为反应。【方法】使用Y型管实验测试红火蚁工蚁对棉花气味的行为反应;以红火蚁告警信息素2-乙基-3,5(6)-二甲基吡嗪为阳性对照,测试红火蚁工蚁对不同剂量(100, 10, 1 和0.1 μg)的9种棉花挥发物组分[α-蒎烯、β-蒎烯、β-石竹烯、( E, E )-4,8,12-三甲基-1,3,7,11-十三碳四烯(TMTT)、( E )-4,8-二甲基-1,3,7-壬三烯(DMNT)、辛醛、6-甲基-5-庚烯-2-酮、顺-3-己烯基乙酸酯和水杨酸甲酯]的触角电位反应;再利用Y型嗅觉仪测试这些挥发物对红火蚁工蚁的行为选择影响。【结果】结果表明,受棉蚜为害的棉花较健康棉花对红火蚁工蚁具有极显著的引诱效果。红火蚁对9种挥发物组分的EAG反应随着剂量升高而升高。各化合物在100 μg剂量时EAG反应值最大,其中,工蚁对水杨酸甲酯和6-甲基-5-庚烯-2-酮这两个化合物反应最强。在行为选择实验中,化合物水杨酸甲酯、6-甲基-5-庚烯-2-酮和DMNT对红火蚁工蚁均具有显著的引诱效果。【结论】棉蚜诱导的棉花挥发物中水杨酸甲酯和6-甲基-5-庚烯-2-酮对红火蚁有显著的引诱效果,这2种化合物可能在红火蚁定位棉蚜、建立共生关系中起着关键的作用。     

Volatile emission in wheat and parasitism by Aphidius avenae after exogenous application of salivary enzymes of Sitobion avenae

Enzymes in the saliva of the English green aphid, Sitobion avenae (F.) (Homoptera: Aphididae), may be responsible for inducing indirect defence in wheat. In this study, we examined the effects of exogenous application of three salivary enzymes of S. avenae , namely, polyphenol oxidase, pectinase, and cellulase, on the release of volatiles from wheat and the attractiveness of these volatiles to the parasitoid Aphidius avenae Haliday (Hymenoptera: Aphidiidae). In greenhouse experiments, parasitism of S. avenae on plants surrounded by pectinase-treated plants and aphid-damaged plants was significantly higher than parasitism of aphids on plants surrounded by cellulase- and polyphenol oxidase-treated plants. In Y-tube olfactometer tests, female A. avenae significantly preferred the volatiles collected from pectinase-treated plants and aphid-damaged plants. Gas chromatography-mass spectrometry analysis showed that two kinds of semiochemicals, sulcatol and sulcatone, were identified only in pectinase-treated plants and aphid-damaged plants. In field experiments, parasitism of S. avenae by A. avenae was significantly higher on plants sprayed with a mixture of sulcatol and sulcatone than parasitism on plants sprayed with volatiles collected from cellulase- and polyphenol oxidase-treated plants. These results show that pectinase in S. avenae watery saliva can trigger wheat plant indirect defence, and play a crucial role in interaction between wheat, wheat aphid, and A. avenae .     

Infection of potato plants with potato leafroll virus changes attraction and feeding behaviour of Myzus persicae

Potato leafroll virus (PLRV; genus Polerovirus, family Luteoviridae) is a persistently transmitted circulative virus that depends on aphids for spreading. The primary vector of PLRV is the aphid Myzus persicae (Sulzer) (Homoptera: Aphididae). Solanum tuberosum L. potato cv. Kardal (Solanaceae) has a certain degree of resistance to M. persicae: young leaves seem to be resistant, whereas senescent leaves are susceptible. In this study, we investigated whether PLRV‐infection of potato plants affected aphid behaviour. We found that M. persicae's ability to differentiate headspace volatiles emitted from PLRV‐infected and non‐infected potato plants depends on the age of the leaf. In young apical leaves, no difference in aphid attraction was found between PLRV‐infected and non‐infected leaves. In fact, hardly any aphids were attracted. On the contrary, in mature leaves, headspace volatiles from virus infected leaves attracted the aphids. We also studied the effect of PLRV‐infection on probing and feeding behaviour (plant penetration) of M. persicae using the electrical penetration graph technique (DC system). Several differences were observed between plant penetration in PLRV‐infected and non‐infected plants, but only after infected plants showed visual symptoms of PLRV infection. The effects of PLRV‐infection in plants on the behaviour of M. persicae, the vector of the virus, and the implications of these effects on the transmission of the virus are thoroughly discussed.     

Semiochemicals associated to spacing behaviour of the bird cherry-oat aphid Rhopalosiphum padi L. (Hem., Aphididae) do not affect the olfactometric behaviour of the cereal aphid parasitoid Aphidius rhopalosiphi De Stephani-Pérez (Hym., Braconidae)

Volatiles produced by the interaction of Rhopalosiphum padi and wheat, and semiochemicals which elicit the spacing behaviour of R. padi on wheat and oat, were evaluated in an olfactometer against the cereal aphid parasitoid Aphidius rhopalosiphi . The parasitoid was attracted by volatiles produced by the R. padi -wheat interaction at high density of aphids, but not by the R. padi -wheat interaction at low density. Compounds produced by the interaction of wheat or oat that was infested with a high density of aphids (approximately 9 aphids/cm²), 6-methyl-5-hepten-2-one (MHO), 6-methyl-5-hepten-2-ol (MHOH), 2-tridecanone (2-T), and methyl salicylate (MS), neither attracted nor repelled A. rhopalosiphi as pure compounds or in the naturally occurring mixture. The results are discussed in terms of the use of semiochemicals and parasitoids in the integrated management of aphid pests.     

Effective concentrations of garlic distillate (Allium sativum) for the control of Tetranychus urticae (Tetranychidae)

The two‐spotted spider mite, Tetranychus urticae Koch, is a worldwide pest that feeds on a large variety of plant families. Because its resistance to acaricides is spreading rapidly, the development of new biological control tactics for population management is crucial. Plant extracts, such as garlic extract (Allium sativum Linn.), may represent viable alternatives, because they are currently considered to be minimum‐risk pesticides. Although garlic is known for its acaricidal properties, the extract concentration that provides the most efficient control has not yet been precisely determined. In this study, we conducted a series of laboratory experiments to determine the susceptibility of adult females to different concentrations of garlic extract. Fresh garlic cloves were steam‐distilled and sprayed using a Potter spray tower. Mortality and fecundity were measured upon treatment with garlic extract concentrations ranging from 0.46 to 14.4 mg/l. Female mortality increased with concentration, with LD₅₀ and LD₉₀ values of 7.49 and 13.5 mg/l, respectively. Reduced fecundity was previously observed at concentrations of 0.36 and 0.74 mg/l. The chemical composition of the Allium sativum distillate was characterized by reversed‐phase high‐performance liquid chromatography coupled with photodiode array detection, GC/MS and Fast GC‐FID against an authentic standard (Standard, Bioextract).Vinyl dithiin, diallyl disulphide, diallyl trisulphide and methyl allyl trisulphide were identified based on their mass spectra. Sesquiterpenoids were identified by their retention index.     

Influence of Experience on the Response of Bathyplectes curculionis (Hymenoptera: Ichneumonidae), a Nonaphidophagous Parasitoid, to Aphid Odor

Bathyplectes curculionis (Thomson) is an introduced natural enemy of the alfalfa weevil in North America. The wasp requires carbohydrate foods as an adult. Adult wasps have increased longevity and fecundity when provided access to pea aphid, Acyrthosiphon pisum (Harris), honeydew in the laboratory, and adults respond positively to the presence of pea aphids in alfalfa fields. However, it is unknown how these wasps find aphid honeydew in the field. In a series of Y-tube olfactometer experiments, we evaluated the response of naïve and experienced adult female B. curculionis to odors from pea aphids, alfalfa, and pea aphids on alfalfa. Naïve adult females did not respond positively to pea aphid odor even when hungry. But adult females were able to learn aphid odor, and the mechanism of learning appears to be associative rather than by sensitization. Naïve females also showed no preference for alfalfa odor but learned alfalfa odor through sensitization. The wasps did not distinguish between alfalfa with aphids and alfalfa without aphids, even after exposure to aphids or alfalfa with aphids. However, they preferred pea aphid odor to alfalfa odor after a feeding experience in the presence of pea aphid odors. But after exposure to mixed odors of aphids and alfalfa while feeding, B. curculionis females preferred the odor of alfalfa to the odor of pea aphids. These results suggest that alfalfa odors mask or override aphid odors when aphids are associated with alfalfa (as happens naturally), thus interfering with the wasp's ability to respond to learned aphid odors. Therefore, although the wasps are capable of learning to find pea aphids and their honeydew in a simplified laboratory setting, it appears unlikely that they do so in the field.     

麦长管蚜对E-β-法尼烯的嗅觉行为反应

【目的】测定麦长管蚜Sitobion avenae Fabricius对E-β-法尼烯(E-β-farnesene,EβF)矿物油溶液反应的最低阈值浓度,为EβF的田间应用提供依据。【方法】观察麦长管蚜3龄若蚜对不同浓度EβF的逃逸行为和"Y"型管嗅觉行为反应。每天定时分5次(9:00,11:30,14:00,16:30和19:00)滴加10μL EβF于滤纸上,滤纸用牙签固定于麦苗盆中心,持续处理5 d。每盆麦苗处理前接1龄若蚜15头。记录成蚜翅型及2周后蚜虫总数量。【结果】随着EβF浓度升高,麦长管蚜3龄若蚜3 min内逃离数显著增加,有翅蚜比例显著增加,种群个体数量显著下降,驱避效果明显增强。EβF浓度为200 ng/μL和≥600 ng/μL使蚜虫逃离数显著增加(P0.05)。"Y"型管选择行为测试结果表明,EβF≥600 ng/μL对3龄若蚜具有极显著的驱避作用(P0.01)。与对照相比,EβF≥600 ng/μL处理极显著提高了有翅蚜比例(P0.01);EβF≥400 ng/μL极显著抑制蚜虫种群个体数量增长(P0.01),但与600 ng/μL处理差异不显著。【结论】600 ng/μL EβF矿物油溶液为麦长管蚜驱避剂的最低阈值浓度。     

Alliin in the garlicky taxon Adenocalymma alliaceum (Bignoniaceaei)

Dried leaves of Adenocalymma alliaceum (Bignoniaceae) contain alliin [(S)-S-allyl-l- cysteine S-oxide], previously known only from Allium species, and an endogeneous enzyme catalyzing the degradation of alliin to give diallyl disulphide, diallyl trisulphide and diallyl tetrasulphide as stable end products.