Interspecific interactions between Bemisia tabaci (Hem., Aleyrodidae) and Liriomyza sativae (Dipt., Agromyzidae)

Abstract:  The study examines interspecific interactions between Bemisia tabaci (Hem., Aleyrodidae) and Liriomyza sativae (Dipt., Agromyzidae) feeding on pumpkins and cucumbers. L. sativae density on control pumpkins and cucumbers peaked 3 and 2 weeks after adults were seen, respectively. Compared with controls, L. sativae densities observed for weeks 3–6 and 2–6 in the B. tabaci -pre-infested plants were significantly lower, respectively ( F _2.00 = 22.66, P < 0.01). The survival of L. sativae larvae transplanted to B. tabaci -pre-infested pumpkins and cucumbers was 16.06%, 10.02% and 13.09%, 9.21%, whereas those transplanted to control plants were 52.20%, 36.06% and 48.25%, 28.22% after 5 and 10 days, respectively ( χ ² = 6.9, d.f. = 1, P < 0.01). Pupation rates of L. sativae feeding on control plants were 20.25% and 16.45%, whereas those feeding on the B. tabaci -pre-infested plants only 4.08% and 4.21%, respectively ( χ ² = 7.0, d.f. = 1, P < 0.01). The length and number of mines of L. sativae on the control pumpkins and cucumbers were 54.05%, 54.10% and 89.06%, 76.22% longer or higher than those on B. tabaci -pre-infested plants, respectively. Leaf positions of L. sativae feeding on the plants were also affected by B. tabaci -pre-infested. These results showed that B. tabaci infestations had a significantly negative effect on L. sativae when they were feeding simultaneously on the same host plant.     

Olfactory responses of the leafminer Liriomyza sativae (Dipt., Agromyzidae) to the odours of host and non-host plants

Abstract: Electroantennogram (EAG) responses of male and female leafminer Liriomyza sativae Blanchard to 15 species of host and non-host plant odours were recorded. The most distinct EAG responses of both sexes were obtained in the host plants bean and tomato. EAG responses to other host plants, such as cucumber, celery, chrysanthemum, towel gourd and cotton were reduced. Odours of non-host plants, such as Chinese rose, tobacco and morning glory elicited minimal EAG responses. In a behavioural study, both sexes of L. sativae were more attracted by the odours of host plants than of non-host plants. Thus, olfactory cues are important for host plant location by L. sativae . In addition, the combination of strong EAG and behavioural responses for both males and females to specific plant odours suggests that host plant volatiles can be important as aggregation cues for both sexes.     

Molecular identification of Liriomyza trifolii (Burgess) (Dipt., Agromyzidae) based on real-time PCR

Abstract:  Rapidly identifying juvenile individuals of Liriomyza trifolii (Burgess) from Liriomyza sativae Blanchard is crucial in plant quarantine. We report a molecular method to identify L . trifolii based on real-time polymerase chain reaction (PCR). By comparing partial DNA sequences of mitochondrial COI genes of L . trifolii samples collected from Guangdong and Taiwan provinces in China, Japan, Philippine, Israel, Germany, the USA, Mexico and Honduras sequenced by authors, and those of related species recorded in GenBank, a L . trifolii -specific probe was developed. There was no difference in individuals of different stages tested by this probe. The total time for real-time PCR assay system was 2 h, and it would save 3–7 h compared with conventional PCR.     

温度对美洲斑潜蝇及南美斑潜蝇种群增长的影响

在恒温条件下观察了美洲斑潜蝇和南美斑潜蝇实验种群的发育、存活及繁殖情况,拟合了两种斑潜蝇发育速率与温度之间的关系模型,求出了各发育阶段的发育起点温度及有效积温,组建了不同温度下两种斑潜蝇实验种群的生殖力表,计算了主要的生命表参数.结果表明,温度对两种斑潜蝇的发育、存活、繁殖均有显著的影响,且两种斑潜蝇对温度的适应特性有着明显差异.美洲斑潜蝇适应的温度范围较广,相对较高的温度有利于种群的发育、生存及繁殖;而南美斑潜蝇适应的温度范围相对较窄,且适温范围明显偏低,高温不利于种群的增长;在各自的适温条件下,两种斑潜蝇都有很强的种群增殖能力.     

Utilisation of morphological features in life table studies of Liriomyza huidobrensis (Dipt., Agromyzidae) developing in lettuce

Abstract: A method of distinguishing different larval instars of Liriomyza huidobrensis morphologically, using measurements of the cephalopharyngeal skeleton was developed. The growth ratios of cephalopharyngeal skeletons between first and second and second and third instar larvae were 1.80 and 1.47, respectively, enabling clear separation to be achieved for experimental work. Using this method the development rates of the immature stages of L. huidobrensis feeding on Lactuca sativa were determined under constant temperatures of 11, 16, 19, 26 and 28 ± 1°C and were shown to increase linearly with temperature over the range investigated. The theoretical lower threshold temperatures for development from oviposition to the end of each larval instar or pupal stage were 5.35, 6.30, 6.20 and 5.70°C, respectively. The overall threshold temperature for development from oviposition to 50% adult emergence (5.70°C) was used to calculate degree‐day (DD) requirements for development from oviposition to each larval instar or pupal eclosion, which were 84.3, 30.1, 58.9, 143.7 DD, respectively. The use of these data for optimizing the timing of application of control agents which are effective against specific developmental stages is discussed.     

美洲斑潜蝇室内饲养研究

筛选了室内饲养美洲斑潜蝇的适宜寄主植物,进行了饲养密度及成虫补充营养糖的浓度试验。结果表明：初生菜豆PhaseolusvulgarisL.苗是室内饲养的适宜寄主植物,用该种植物饲养,幼虫饲养密度低于1头／cm2,则幼虫成活率大于90％,饲养密度提高,则幼虫成活率降低,每平方厘米初生叶饲养1头幼虫是适宜的饲养密度,成虫补充营养糖或蜜糖的浓度以8％为宜。     

阿维菌素、伊维菌素和芽孢杆菌对美洲斑潜蝇的防治效果

田间试验结果表明 ,阿维菌素对美洲斑潜Liriomyzasativae蝇幼虫防效较好 ,优于伊维菌素对美洲斑潜蝇的防效 ,可较好地控制美洲斑潜蝇幼虫的危害 ,而Btg,Bti,Bs不宜单独用于防治美洲斑潜蝇幼虫。阿维菌素用量为 0 2 7,0 3 6,0 45g (a .i.) 667m2 时 ,对美洲斑潜蝇幼虫防效第 7d校正防效为 65 %左右 ,施药后第 1 1d校正防效为 85 48%～ 99 0 5 % ,施药后第 1 5d校正防效为 90 94%～ 99 89%。伊维菌素 0 5g (a .i.) 667m2 施药后第 3 ,7,1 1d校正防效分别为 61 67% ,90 5 3 % ,90 93 % ,伊维菌素 0 2 5g(a i ) 667m2 相应防效为 5 7.71 % ,84 68% ,85 83 %。Btg ,Bti,Bs施药后第 3 ,7,1 1d校正防效为 3 3 88%～ 5 5 5 4%。     

温度对黄腹潜蝇茧蜂功能反应的影响

在17,21,25,29和33℃下测定了黄腹潜蝇茧蜂OpiuscaricivoraeFischer对美洲斑潜蝇LiriomyzasativaeBlanchard的功能反应。结果表明,在17~33℃范围内的各个温度下的功能反应均能用HollingII型圆盘方程较好地拟合。各温度下的功能反应参数存在着显著差异,33℃下的瞬时攻击率比17~29℃下的显著地高,而17℃低温和33℃高温下的处置时间比21,25和29℃的显著延长,25℃下的处理时间最短,相同寄主密度下寄生率在25℃达到最高。     

Comparative demography of Liriomyza sativae Blanchard （Diptera： Agromyzidae） on cucumber at seven constant temperatures

Reproduction and population parameters of vegetable leafminer, Liriomyza sativae Blanchard were measured on cucumber （Cucumis sativus L.） at seven constant temperatures （10, 15, 20, 25, 30, 35 and 40℃）. No eggs were found at 10℃ and flies died after exposure to 40℃. The significantly highest intrinsic rate of natural increase （rm）, net reproductive rate （R0） and finite rate of increase （λ） ofL. sativae were obtained at 25℃ as 0.196, 52.452, and 1.216, respectively. The above-mentioned parameters decreased at 15℃ and 135℃ and this reduction at 35℃ was strong. Doubling time （DT） varied significantly with temperature. The shortest doubling time was obtained at 25℃. Mean generation time （T） decreased significantly with increasing temperature between 15℃ and 35℃. Percentage of immature ages in the stable age distribution was more than 95% at all temperatures. Female longevity was greater than male at all temperatures. Liriomyza sativae lived for a long time at 15℃, whereas at 35℃ had lower survival rates. The effect of temperature on reproduction, especially the intrinsic rate of increase of L. sativae would be useful for predicting its longterm population fluctuation over several generations.     

寄生性天敌对美洲斑潜蝇种群控制作用评价

组建了美洲斑潜蝇自然种群生命表,在此基础上应用排除控制指数分析方法,分析了寄生性天敌对美洲斑潜蝇自然种群的控制作用。结果表明,美洲斑潜蝇在秋季花前期菜豆上种群趋势指数为５．６１;寄生性天敌的寄生是影响美洲斑潜蝇自然种群数量增长的重要因子;若排除寄生性天敌的作用,其种群密度将增长为原来的２．４７６倍。     

Avermectin类农药对美洲斑潜蝇的生物活性

Avermectin类农药对美洲斑潜蝇Liriomyzasattvae Blanchard生物活性的室内研究结果表明： 揭阳霉素对美洲斑潜蝇1、2、3龄幼虫的LC₅₀分别是1.54×10^-4 g/L、3.73×10^-4 g/L、1.99×10^-3g/L;害极灭对上述幼虫的LC₅₀分别是1.48×10^-4g/L、3.68x10^-4 g/L和1.97×10^-3 g/L。美洲斑潜蝇幼虫对Avermectln类农药以1龄最敏感,其中揭阳霉素对3龄幼虫的LC₅₀是1龄的12.9倍。揭阳霉素对雌成虫24 h、48 h的LC₅₀分别是3.12×10^-3 g/L和2.08×10^-3 g/L,其对美 洲斑潜蝇取食、产卵拒避持效期分别是4-8天和10天。使用浓度0.005 g/L揭阳霉素处理6天、8天和10天后接虫,幼虫的存活率分别是0、16.13%和28.07%。田间使用浓度0.005 g/L的揭 阳霉素和0.0045 g/L几的害极灭分别处理,6天后的校正虫口减退率分别为91.0%和90.9%,两者差异不显著,而使用浓度0.0067 g/L揭阳霉素处理,6天后校正虫口减退率为93.6%。     

Entomopathogenic nematodes for biological control of the leafminer,Liriomyza trifolii (Dipt.: Agromyzidae)

In the laboratory, mortality rates of the agromyzid leafminer larvae,Liriomyza trifolii (Burgess), ranged from 48 to 98% by 20 strains and/or species of steinernematid and heterorhabditid nematodes. In the greenhouse, abamectin provided superior control of larval leafminers, killing 100% of them as compared withSteinernema carpocapsae (Weiser) All strain (24 to 43% leafminer mortality) orS. carpocapsae Liriomyza-selected strain (8 to 44% leafminer mortality); the maximum relative humidity (r.h.) ranged between 81 and 91% and the minimum r.h. between 50 and 70%. In the foghouse under high r.h., the commercially available All strain and the Hawaiian isolate ofS. feltiae (Filipjev) MG-14 strain caused 69 and 67% mean mortality, respectively. There was a significant correlation (P<0.01) between nematode mortality of leafminers and r.h., including the mean, standard deviation, and minimum r.h. during the 48 h after treatment. Average r.h. >92% with a standard deviation of <9% r.h. and a minimum of 72% r.h. providedS. carpocapsae All strain mortality rates of leafminers >65%. The major constraint against the use of nematodes against leafminers in the foliar environment is low r.h. The use of nematodes againstL. trifolii can be successful if the r.h. remains high and if nematodes enter leafmines before desiccation, and the nematodes should be integrated with chemical insecticides such as abamectin to manage pesticide resistance inL. trifolii.     

Host plant-related parasitism and host feeding activities of Diglyphus isaea (Hymenoptera: Eulophidae) on Liriomyza huidobrensis, Liriomyza sativae, and Liriomyza trifolii (Diptera: Agromyzidae)

Host plant species can affect the behavior and attributes of parasitoids, such as host searching, oviposition, and offspring fitness. In this study, parasitism, host feeding, and sex ratios of Diglyphus isaea (Walker) (Hymenoptera: Eulophidae) on Liriomyza huidobrensis (Blanchard), Liriomyza sativae Blanchard, and Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) larvae reared on Phaseolus vulgaris L., Pisum sativum L., Solanum lycopersicum L., and Vicia faba L. were determined. In no-choice tests, L. huidobrensis had the highest rate of parasitism when reared on P. vulgaris (46%), L. sativae when reared on V. faba (59%) and P. vulgaris (59%), and L. trifolii when reared on S. lycopersicum (68%). Host feeding in no-choice tests ranged between 2% and 36% and was highest on L. trifolii reared on V. faba. Results of choice tests showed a significant interaction effect for host plant and Liriomyza species on parasitism and host feeding. Within plant mixtures, L. sativae reared on P. vulgaris had the highest rate of parasitism (31%), followed by L. trifolii on S. lycopersicum (29%) and L. huidobrensis on V. faba (28%). Host feeding was highest on L. trifolii reared on S. lycopersicum (14%) and lowest on L. huidobrensis reared on P. sativum and S. lycopersicum (1%). In some instances, plant mixtures resulted in a higher proportion of females of D. isaea than single plant species. The highest proportion of females was obtained in plant mixtures on L. huidobrensis and L. trifolii on V. faba (71 and 72%, respectively). This study suggests that planting crop mixtures can potentially lead to higher proportions of females, thus improving parasitism and host feeding, depending on Liriomyza and host plant species.     

美洲斑潜蝇成虫的卵巢结构观察及营养影响卵子发生的试验

卵育型(Synovigenic)植食性昆虫的雌成虫需要取食寄主植物组织或非寄主食物(如花蜜、花粉等)以延长寿命和促进产卵。为了明确寄主食物和非寄主食物对美洲斑潜蝇Liriomyza sativae卵子发生的功能差异,本实验在明确美洲斑潜蝇成虫卵巢发育动态和结构的基础上,比较了清水(饥饿,对照)、菜豆叶片、20%葡萄糖溶液、菜豆叶片+20%葡萄糖溶液四种处理下的雌成虫卵子发生动态。结果显示:美洲斑潜蝇为强卵育型昆虫,初羽化成虫体内无卵子;两侧卵巢管数之和为11-18根,大多数情况下,左右两侧卵巢管数目不等。成虫在饥饿条件下,几乎不能形成成熟卵子;继续取食寄主叶片、20%葡萄糖溶液和寄主叶片+20%葡萄糖溶液,均可显著促进卵子发生和卵成熟,但补充葡萄糖溶液起到极显著促进作用;成虫不具备卵子重吸收功能。本文重点从卵育型角度,对美洲斑潜蝇取食寄主食物和非寄主食物的营养功能进行了讨论。研究结果为美洲斑潜蝇以及该类植食性害虫的室内饲养和田间生态调控提供了依据。     

寄生蜂对美洲斑潜蝇自然种群控制作用的评价

应用作用因子生命表方法以及在此基础上提出的排除作用控制指数法评价了寄生蜂对美洲班潜蝇自然种群的控制作用,结果表明,底比斯釉姬小蜂,丽潜蝇姬小蜂,冈崎釉姬小蜂,异角姬小蜂,黄潜蝇姬小蜂,甘蓝潜潜蝇茧蜂和离潜蝇的种群数量将比原各群增长1．23,2．73,5．98,5．92和5．71倍,在春季菜豆,豇豆,丝瓜和黄瓜上第2代美洲斑潜蝇中,若排除寄生蜂作用因子后,美洲斑潜蝇在上述4种蔬菜上的种群数量将分别多增长2．73,2．87,2．24和1．89倍,寄生蜂对美洲班潜蝇3龄幼虫的控制作用大于1龄,2龄幼虫和蛹的控制作用;春季美洲斑潜连续世代中,第1,2代寄生蜂的控制作用较第3,4,5代低,寄生蜂有菜豆和豇豆上的控制作用比在丝瓜和黄瓜上高。     

Role of plant volatiles in host plant location of the leafminer, Liriomyza sativae (Diptera: Agromyzidae)

Abstract The role of plant volatiles in host plant location of the leafminer Liriomyza sativae Blanchard was studied. Four types of antennal sensilla were identified on the funiculus by scanning electron microscopy: trichoid, basiconic, clavate and grooved sensilla. An olfactory pit, containing groups of sensilla, was present on the ventral side of the funiculus. No sexual difference was detected in sensilla diversity and distribution. In behavioural assays, both males and females were attracted by the odour of the bean Phaseolus vulgaris L. They had distinct EAG responses to the bean odour. No significant sexual difference was found in behaviour or EAG responses.
Electroantennograms were recorded from female L. sativae to 14 plant volatile compounds. The most distinct EAG responses were obtained for: (1) the general green leaf volatiles 1-hexanol (E)-2-hexen-1-ol, (E)-3-hexen-1-ol and its isomers, (Z)-3-hexen-1-ol, the acetate (E)-3-hexenylacetate and the aldehyde hexanal; and (2) limonene, a compound associated with tomato, which is a key host plant of this insect. Other volatile compounds associated with host plants, such as α-pinene, myrcene, β-caryophyllene, and eugenol did not elicit responses. The ability of this insect to locate a host plant appears to be augmented by the perception of a combination of host-specific and general green leaf volatiles. A modification of the EAG recording method of Dipteran species was provided.     

Substrate-borne vibrational signals and stridulatory organs for sexual communication in leafminer,Liriomyza sativae (Diptera: Agromyzidae)

The vegetable leafminer (Liriomyza sativae [Burgess]) is a highly polyphagous pest that threatens vegetables and horticultural plants. Although sexual communication is a key component of the animal behavioral repertoire, the mechanism underlying sexual communication in L. sativae remains to be elucidated. Here, we used laser vibrometry to characterize the vibrational signals emitted by L. sativae during pair formation. By emitting trains of vibrational pulses (male calling) the male initiated communication on the host plant. The female then became immobile and responded to the male calling by emitting replies (female replies), which in turn triggered male replies consisting of a rapid series of chirps and trills. If the female replied, a continuous exchange of male and female replies ensued, representing a duet. In playback trials, a playback signal caused responses from the opposite sex. Moreover, scanning electron microscopy revealed vibration-producing stridulatory organs in both male and female individuals. The files in males were more developed than those in females, and older male specimens had more signs of abrasion. The results provide new insight into the mating biology of L. sativae.     

Application of molecular techniques to distinguish Liriomyza trifolii from L. sativae (Diptera: Agromyzidae) on tomato cultivation in Japan

A molecular method is applied for differentiating the morphologically related leafminers Liriomyza trifolli and L. sativae on tomato cultivation. The method requires multiplex polymerase chain reaction (PCR) amplification of a region of mitochondrial cytochrome oxidase DNA using multiprimer sets. The method divides the mitochondrial fragment of L. trifolli into two fragments and L. sativae into three fragments. It is faster, less costly, and easier than random amplified polymorphic DNA-PCR, PCR-restriction fragment-length polymorphism, and DNA sequencing and more sensitive than the enzyme electrophoresis method, which are other ways to differentiate these two species. We applied the method to samples from populations of another place, sex, and stage and obtained the same results.