Effects of the fungus <Emphasis Type="Italic">Lecanicillium lecanii</Emphasis> on survival and reproduction of the aphid <Emphasis Type="Italic">Schizaphis graminum</Emphasis>

This study investigated the effects of a strain of the fungus Lecanicillium lecanii (Zimm.) Zare and Gams (Hypocreales: Ascomycota) on the aphid Schizaphis graminum (Rondani) (Hemiptera: Aphididae). The fungus was administered to fourth instar nymphs and to alate and apterous adult morphs as a ground rice-kernel formulation. This study showed that L. lecanii formulation affected the survival of the aphids and interacted differently with the studied morphs, the Lethal Time values being lower for alate compared to apterous morphs and nymphs. The treatment also caused a significant reduction in the fecundity of the three treated aphid groups. Histological analysis revealed that the hyphae invaded the host hemocoel of a limited number of alate and apterous morphs: the fungus only entered through the spiracles. Scanning Electron Microscope observations revealed that L. lecanii adhered to the body surface of both adults and nymphs without differentiation. In conclusion, the present study suggests that this strain might be a good candidate for a programme of biological control of S. graminum and other aphid species.     

Life-history strategies affect aphid preference for yellowing leaves

According to the nutrient-translocation hypothesis, yellowing tree leaves are colonized by aphids at the end of the growing season owing to improved availability of nutrients in the phloem sap after chlorophyll degradation. We measured aphid densities on potted Betula pendula seedlings in a field site where a small proportion of foliage rapidly turned yellow before normal autumn coloration as a consequence of root anoxia. The number of adults and nymphs of the birch-feeding specialist aphids Euceraphis betulae, Betulaphis brevipilosa and Callipterinella tuberculata were counted from leaves on each of the 222 plants. Aphids were detected on 19 per cent of green leaves and on 41 per cent of yellow leaves. There was no indication of aphid avoidance of yellow leaves, and the number of winged (alate) viviparous E. betulae adults and their nymphs were significantly higher on yellow leaves than on green leaves, while the numbers of apterous B. brevipilosa and C. tuberculata did not differ between the leaf colour types. Our result suggests that only aphid species with alate generation during colour change can take advantage of yellowing leaves. This may explain the exceptional abundance of E. betulae compared with other aphid species on birches.     

田间不同品种蔬菜对萝卜蚜种群的影响(英文)

本试验通过利用５个品种蔬菜（萝卜,芥蓝,芥菜,菜芯和白菜）研究萝卜蚜（Ｌｉｐａｐｈｉｓ ｅｒｙｓｉｍｉ）在不同蔬菜上的种群动态以及对寄生于萝卜蚜的菜蚜茧蜂（Ｄｉａｅｒｅｔｉｅｌｌａ　ｒａｐａｅ）种群的影响。研究结果显示,在３０天研究期间,有翅萝卜蚜的平均虫口（蚜虫数／苗）在萝卜、芥蓝、芥菜、菜芯和白菜苗上分别为３．９１８、０．８３１、１．１４９、１．７４３和５．２３头,表明降落在萝卜苗上的有翅蚜数量显著地比在其它蔬菜苗上的高;而无翅萝卜蚜的中均虫口分别为６３．４２１、１０．０４１、２４．９２８、２３．３２３和１１４．３０８头,说明萝卜蚜无翅蚜在白菜上的种群显著地高于其它品种蔬菜上的。由于萝卜蚜在不同品种蔬菜上的种群不同,导致菜蚜茧峰种群在不同品种蔬菜上也不同,其僵蚜虫口分别为１．０５６、０．２５１、０．２７７、０．６５１和１．４４头,显示了在萝卜和白菜上的僵蚜数量显著地比其它蔬菜上的高。分析结果表明,萝卜蚜的种群（ｘ）与菜蚜茧峰的种群（ｙ）呈显著的相关关系：ｙ＝０．１１８８＋０．０１４３ｘ（ｒ＝０．９７３９）。本研究还利用试验结果提出了萝卜蚜无翅蚜种群从蔬菜在田间种植后达到防治指标（５０头／苗）的临界天数（ｃ     

EFFECTS OF HOST PLANTS ON POPULATION DYNAMICS OF LIPAPHIS ERYSIMI (KALT.) IN THE FIELD

Abstract The population dynamics of alates and apterous of turnip aphid (TA) Lipaphis erysimi (Kalt.) together with the incidence of parasitism by Diaeretiella rapae (M'Intosh) on five host vegetable varieties in the field were evaluated. The results showed that the average populations of TA apterous on host vegetable varieties turnip, Chinese kale, leaf mustard, flowering cabbage and Chinese cabbage were 63. 425, 10. 041, 24. 928, 23. 323 and 114. 308 aphids/plant, respectively. The 'critical day' was used to estimate the date when TA population density on host vegetable varieties reaches its economic threshold. The relationship between TA apterous population ( x ) and mummy aphids parasitized by parasitoid D. rapae was significant, and the regression formula is y = 0. 1211 + 0. 01431 (r=0. 9739**).     

Evaluation of green lacewings, Chrysoperla plorabunda (Fitch) (Neurop., Chrysopidae), for augmentative release against Toxoptera citricida (Hom., Aphididae) in citrus

Larvae of the lacewing Chrysoperla plorabunda (Fitch) were evaluated in laboratory and field tests for potential to control the brown citrus aphid, Toxoptera citricida (Kirkaldy) in inundative releases. Larvae surviving to pupation consumed an average of 1676, 1297, 392, 165 and 130 1st–4th instar T. citricida nymphs and apterous adults, respectively, and the mean developmental time was 27.0, 23.0, 16.5, 13.8 and 18.3 days, respectively. The average pupation rate was 37.5%, but only 6.3% of pupae yielded adults. Developmental time and survival to pupation varied with the life stage of aphids fed to larvae, 4th instars yielding the highest survival and shortest developmental time. Development of C. plorabunda was compared on diets of T. citricida and Aphis spiraecola . Only 6.3% of larvae completed development on T. citricida , whereas 37.5% yielded adults on A. spiraecola . Larvae consumed more of the brown T. citricida than the green A. spiraecola in a choice test on a white background, but no preference was evident when aphids were offered on a black background. Two separate field trials were performed in citrus groves with T. citricida infestations in which an average of 275 and 116 C. plorabunda larvae/tree were released, respectively. The rate of T. citricida colony maturation (= survival to alate production) was very low in the first trial, and relatively high in the second trial, but did not differ between control and release trees in either trial. The most apparent cause of aphid colony mortality was predation by the coccinellids Cycloneda sanguinea L. and Harmonia axyridis Pallas. Despite acceptance of T. citricida in the laboratory, very few C. plorabunda larvae were observed feeding on aphid colonies on release trees.     

麦长管蚜的低温适应性及陕西杨凌小麦田春季虫源分析

【目的】本研究旨在探明低温条件下麦长管蚜Sitobion avenae的存活率和快速冷驯化反应,以期为该虫耐寒性的研究和准确预测预报提供依据。【方法】测定麦长管蚜实验室种群各发育阶段的过冷却点和结冰点;测定1龄若蚜和未产仔成蚜分别在-7.0～-11.0℃极端低温下暴露3 h和在0℃冷驯化1～5 h后暴露于致死温度3 h,再转移至15℃72 h后的存活率;调查自然条件下陕西杨凌小麦整个生育期麦长管蚜的种群动态。【结果】麦长管蚜1龄和2龄若蚜的过冷却点波动范围较小,分别为-27.4～-19.2℃和-27.3～-18.3℃;3龄若蚜、4龄若蚜和成蚜的过冷却点波动范围较大,分别为-27.4～-10.7℃,-26.7～-12.5℃和-26.7～-11.2℃。麦长管蚜的过冷却点和结冰点随龄期增加均显著升高,其中成蚜的过冷却点显著高于1龄和2龄若蚜。3龄若蚜、4龄若蚜和成蚜的过冷却点在不同翅型之间不存在显著性差异。低温存活率分析表明,麦长管蚜1龄若蚜和无翅成蚜的致死温度(80%死亡率)分别在-10.5℃和-8.1℃左右。0℃快速冷驯化显著提高了麦长管蚜1龄若蚜和无翅成蚜在极端低温下的存活率,其中冷驯...     

Antibiosis and antixenosis of six commonly produced potato cultivars to the green peach aphid, Myzus persicae Sulzer (Hemiptera: Aphididae)

The antibiotic and antixenotic resistance of six commonly produced potato cultivars in Iran including Aozonia, Agria, Cosima, Cosmos, Kondor and Savalan to the green peach aphid, Myzus persicae Sulzer, were investigated under laboratory conditions at 20 ± 2oC, 65 ± 5% RH and 16:8h (L:D) in 2009. Antibiosis experiments showed significant differences in the developmental time, nymphal survivorship, fecundity, adult longevity of the green peach aphid among the potato cultivars. Intrinsic rate of natural increase (r m) for apterous aphids varied significantly with the potato cultivars on which the aphids were reared. This value ranged from 0.225 to 0.293 females/female/day, which was lowest on Cosmos and highest on Aozonia. Additionally, the estimated net reproductive rate (R0) and finite rate of increase (λ) for apterous aphids were the lowest on Cosmos. For the antixenosis experiment, no significant difference was found in aphid's preference to the potato cultivars. However, Aozonia was preferred more than the other five cultivars by the apterous aphids. Therefore, our results demonstrated that among the investigated cultivars the Cosmos cultivar is moderately resistant to the green peach aphid.     

Vertical and Temporal Distribution of Aphis gossypii Glover and Coccinellid Populations on Different Chilli (Capsicum annuum) Varieties

The vertical and temporal distribution of an aphid, Aphis gossypii Glover, and the coccinellid populations on six chilli varieties were studied. The total number of apterous aphid per plant stratum was significantly different among plant strata of a particular variety (treatment) as well as among the treatments. Generally, the total number of aphids was significantly greater in the lower stratum than in the middle and upper strata. However, the varieties with erect and open plant architecture (Kulai and MC 11) had significantly less number of apterous aphids at all strata as compared to varieties with compact or prostrate plant architectures. There was a significant difference in the total number of coccinellids per plant strata among the treatments but not within a treatment. The distribution of apterous aphid populations varied significantly among sampling periods and treatments. The temporal distribution of coccinellids showed a similar trend as that of apterous aphids. The total number of alate aphids caught per week was significantly different among the sampling periods. However, its population was significantly greater during the early season and gradually declined as the season progressed except during June 18 to 24. The importance of recording the most observed coccinellids species, which limit the aphid populations at each particular plant stratum per variety, and the conditions that favor natural enemies are also discussed.     

Alarm pheromone eliciting attack and escape responses in the sugar cane woolly aphid,Ceratovacuna lanigera (Homoptera,Pemphigidae)

All nymphal stages and apterous adults ofCeratovacuna lanigera secreted droplets containing an alarm pheromone from their abdominal cornicles when stimulated with a pin. When fresh droplets on piece of filter paper were put near the aphids, 1st-instar nymphs originating from apterous adults attacked it, but the advanced instar nymphs and adults escaped from the spot. Nymphs and adults originating from alate adults showed escaping behavior only. These different responses strongly correlated with morphological differences, such as relative lengths of the frontal horns and legs. When a syrphid larva,Allograpta javana, was placed on a colony of aphids, many 1st-instar nymphs attacked it using their frontal horns. During the attack, these nymphs spontaneously secreted droplets and adhered them to the syrphid body. When these droplets were placed on the body, the syrphid larva was agressively attacked by additional 1st-instar nymphs.     

Effect of parasitism on flight behavior of the soybean aphid, Aphis glycines

Many aphid species possess wingless (apterous) and winged (alate) stages, both of which can harbor parasitoids at various developmental stages. Alates can either be parasitized directly or can bear parasitoids eggs or larvae resulting from prior parasitism of alatoid nymphs. Winged aphids bearing parasitoid eggs or young larvae eventually still engage in long-distance flights, thereby facilitating parasitoid dispersal. This may have a number of important implications for biological control of aphids by parasitoids. In this study, we determined the effect of parasitism by Aphelinus varipes (Hymenoptera: Aphelinidae) on wing development and flight of the soybean aphid, Aphis glycines (Hemiptera: Aphididae). We also quantified the influence of aphid flight distance on subsequent A. varipes development. Parasitism by A. varipes was allowed at different A. glycines developmental stages (i.e., alatoid 3rd and 4th-instar nymphs, alates) and subsequent aphid flight was measured using a computer-monitored flight mill. Only 35% of aphids parasitized as L3 alatoid nymphs produced normal winged adults compared to 100% of L4 alatoids. Flight performance of aphids parasitized as 4th-instar alatoid nymphs 24 or 48 h prior to testing was similar to that of un-parasitized alates of identical age, but declined sharply for alates that had been parasitized as 4th-instar alatoid nymphs 72 and 96 h prior to testing. Flight performance of aphids parasitized as alate adults for 24 h was not significantly different from un-parasitized alates of comparable ages. Flight distance did not affect parasitoid larval or pupal development times, or the percent mummification of parasitized aphids. Our results have implications for natural biological control of A. glycines in Asia and classical biological control of the soybean aphid in North America.     

The effect of starvation and subsequent feeding on the reproductive potential of the grain aphid,Sitobion avenae

The short‐term starvation tolerance of alate and apterous morphs and the effect of periods of starvation on the longevity and fecundity of alate adults were evaluated in the grain aphid, Sitobion avenae (Fabricius) (Hemiptera: Aphididae). Alate adults exhibited a proportionally larger length of survival compared with apterous adults under continuous starvation conditions. Newly molted pre‐reproductive adults were starved for 0–96 h and their survival rate on the 1st day after recovering with food was not significantly different from that of control aphids. Starvation reduced lifetime fecundity, but increased the reproductive rate immediately after nutrition being improved. Fecundity and longevity after 24, 48, 72, and 96 h of starvation were significantly higher than after 120 or 144 h of starvation. However, no significant differences were observed for alate adults after 24, 48, 72, or 96 h of starvation. This study suggests that the ability of alatae to adapt to brief periods of starvation could be one of the important factors affecting the reproductive success of aphids during delays in locating host plants.     

桃蚜不同蚜型DNA多态性的RAPD研究

采用RAPD方法,对全周期桃蚜的有翅产雌性母蚜、无翅性母蚜、雄蚜、卵、干母、干雌、有翅迁移蚜等蚜型的DNA遗传多态性进行了分析。结果表明：卵的DNA多态性最大,性蚜次之,孤雌生殖蚜最小;卵与其它蚜型之间在遗传上具最大差异,其中与孤雌生蚜的差异大于与性蚜的;干母、干雌和迁移蚜之间的遗传关系最近。     

微波辐射对桃蚜生长发育和繁殖的影响

【目的】研究筛选对桃蚜Myzus persicae有致死作用的安全微波频率和照射时长,以为探究新型物理防蚜技术,弥补化学防治上的缺陷提供参考依据。【方法】在暗箱中,应用微波发射仪分别发射1375, 2 750, 5 500和11 000 MHz 4个不同频率的微波照射桃蚜1日龄无翅成蚜,每个频率的照射时长分别为15, 30, 60和120 s;照射后在人工气候箱中饲养,分别于照射后8, 24, 48和72 h观察其生长发育及繁殖状况,统计桃蚜死亡率、繁殖力(累计产蚜量)及子代有翅蚜率。【结果】4个不同频率的微波分别在4个不同照射时长下,对桃蚜1日龄无翅成蚜的死亡率、繁殖力和子代翅型分化都有不同程度的影响。照射后72 h, 5 500 MHz微波照射时间为15 s时对桃蚜1日龄无翅成蚜的致死作用最强,死亡率达到55.00%,在照射时间为30和120 s时可抑制子代桃蚜向有翅蚜的分化。2 750 MHz微波照射30和60 s时促进桃蚜1日龄成蚜繁殖,照射30 s时繁殖力最强,而照射15和120 s时却表现为抑制繁殖,且2 750 MHz微波照射30 s能抑制子代桃蚜向有翅蚜分化。【结论】微波辐射能够影响桃蚜1日龄成蚜的存活、繁殖和子代翅型分化。本研究初步筛选出了对桃蚜1日龄无翅成蚜有致死作用的微波频率和照射时长。     

Transgenic Bt maize and Rhopalosiphum padi (Hom., Aphididae) performance

Abstract.  1. The population abundance and age structure of Rhopalosiphum padi , one of the most common maize aphid species, on transgenic Bt (expressing the Cry1Ab protein) and non-Bt isogenic maize was studied in commercial plots during three crop seasons.
2. A higher density of aphids, particularly alates and young nymphs, occurred in Bt plots at very young maize development stages, corresponding to the settlement period, in the 3 years studied. Possible causes are discussed. After this period, there were no differences between Bt and non-Bt maize.
3. Mortality, development, and reproduction of the offspring of alate forms of R. padi and the offspring of different generations of apterous forms fed with Bt maize were evaluated in the laboratory under controlled conditions.
4. The developmental and pre-reproductive times of the offspring of the first generation of alatae were shorter and the intrinsic rate of natural increase ( r _m ) higher when aphids fed on Bt maize. The opposite occurs with the offspring of the first generation of apterous mothers, which have lower nymphal and adult mortality, shorter developmental and pre-reproductive times, a higher effective fecundity rate, and greater r _m , when fed on non-Bt maize. The differences in aphid development on the two cultivars may be linked to changes in host-plant quality due to pleiotropic effects of the genetic modification.
5. No differences on aphid mortality, developmental and pre-reproductive times, fecundity, and r _m were found between the offspring of apterous aphids maintained on Bt or non-Bt maize for several generations.     

Differential inter- and intra-specific defense induction in Lupinus by Myzus persicae feeding

Experiments were conducted to investigate the potential induction of plant defenses by Myzus persicae Sulzer (Homoptera: Aphididae) feeding on five lupin, Lupinus spp. (Leguminosae), varieties with well‐characterized levels of aphid resistance. Myzus persicae feeding on L. angustifolius and L. luteus varieties induced genotype‐specific changes in their host that were not consistent with the level of aphid resistance or the plant species. The plant responses were systemically detected by apterous and alate forms of the aphids. Chemical assays revealed no induction of oxidizing enzyme (catalase, peroxidase, or polyphenol oxidase) activity, serine or cystein proteinase inhibitors, or soluble phenolics in any of the five varieties tested following 3 days of feeding by 10 or 30 aphids. However, there were significant differences among the five lupin varieties in the levels of peroxidase and polyphenol oxidase activity, proteinase inhibitors, and soluble phenolics.     

两种品系油菜植株成分与蚜虫种群消长及成蚜翅型的关系

本文研究两种品系油菜植株成分与桃蚜(Myzus persicae(Sulzer))、萝卜蚜(Lipaphis erysimi(Kaltenbach))的种群消长及成蚜翅型的关系。经分析得出如下结果:1.桃蚜种群消长与苏氨酸、赖氨酸、组氨酸、丙氨酸、硬脂酸等含量有关;桃蚜成蚜无翅率与精氨酸、谷氨酸、酪氨酸、异亮氨酸等含量有关。2.萝卜蚜种群消长与苏氨酸、蛋氨酸、异亮氨酸、苯丙氨酸、酪氨酸、含水量有关;萝卜蚜成蚜无翅率与含水量。亚麻酸。苏氨酸、油酸,天门冬氨酸、丝氯酸、亚油酸等含量有关。     

Prey Preference of Aphidoletes Aphidimyza on Acyrthosiphon Pisum: Effect of Prey Color and Size

Color polymorphism in insects as well as factors contributing to its occurrence and maintenance have been of a great interest. Pea aphid (A. pisum) exhibits a noteworthy color polymorphism which occurs as red and green. The preference of the predatory gall midge Aphidoletes aphidimyza (Rondani) for the two color morphs of pea aphid at two life stages (adult and second instar) was investigated. Red adults, red nymphs, green adults, and green nymphs were offered to the larvae of the predator in different sets. The larvae attacked red aphids more than green ones of a same size. But whenever adults were offered along with nymphs, the nymphs experienced significantly more attacks. Although visual cues could result in more predation on red aphids, our findings showed that the size of aphids was the more important factor. The results showed that previous findings, suggesting more predation on the red morph, are valid when the same size of aphids is used. The ovipositing females exhibited no differences in oviposition choice between stalks infested with either of two colors.     

Bottom‐up effects mediated by an organic soil amendment on the cabbage aphid pests Myzus persicae and Brevicoryne brassicae

Earthworm‐produced compost or vermicompost has been shown to increase resistance of plants to a variety of insect pests, but it is still unclear whether this resistance is dose dependent and whether the mechanisms responsible are the same for insect species with differing feeding habits and preferences. Therefore, we tested the effects of plants grown in various vermicompost concentrations (0, 20, 40, and 60%) on the preference and performance of generalist, Myzus persicae L., and specialist, Brevicoryne brassicae L. (both Hemiptera: Aphididae), aphid pests. Preference was evaluated with leaf disk (apterous) and whole plant (alate) choice assays. After 24 h of feeding, there was no significant negative effect on the feeding preference noted for apterae of either species of any of the treatments tested. To the contrary, apterae B. brassicae showed a significant preference for vermicompost treatments over control leaf disks. Alate M. persicae preferred alighting on control plants over vermicompost‐grown plants, but B. brassicae showed no preference toward any of the treatments tested. Both aphid species deposited significantly more nymphs on control plants than on those grown in 20% vermicompost. Furthermore, plants grown in soil amended with 20% vermicompost significantly suppressed mass accumulation, as well as numbers of adults and nymphs of both aphid species compared to controls. These data clearly show that vermicompost soil amendments can significantly influence pest aphid preference and performance on plants and that these effects are not dose dependent, but rather species and morph dependent.     

Reproductive rate of the Indian mustard aphid (Lipaphis erysimi pseudobrassicae) on different Brassica oilseeds: colmparisons with Swedish strains of mustard (Lipaphis erysimi erysimf) and cabbage aphid (Brevicoryne brassicae)

The reproductive rate of the Indian mustard aphid (Lipaphis erysimi pseudobrassicae), a serious pest on Brassica oilseeds in India, was compared with that of Swedish strains of mustard aphid (L. e. erysimi) and cabbage aphid (Brevicoryne brassicae) on six common Indian and Swedish Brassica oilseed cultivars. There were clear differences between L. e. erysimi and L. e. pseudobrassicae in the relative suitability of the cultivars, emphasisipg the biological differences between these aphids. B. brassicae had similar reproductive rates on all cultivars.
In addition, the reproductive rate of L. e. pseudobrassicae was measured on both young and old plants of the six Brassica oilseed cultivars and 14 Indian rai (B. juncea) cultivars. Among the six Brassica cultivars, the reproductive rates were highest on turnip rape and toria (B. campestris), and lowest on yellow sarson (B. campestris) and rai (B. juncea). The ranking of the cultivars was similar for young and old plants. There were no significant differences between the rai (B. juncea) cultivars tested, neither among young nor among old plants. These results from laboratory studies are compared with field data from India on the relative susceptibility of different Brassica oilseed cultivars to L. e. pseudobrassicae.