南方小花蝽对三种蚜虫的捕食能力和喜好性

南方小花蝽Orius similis是我国南方农田生态系统中一种对小型害虫极具控害潜力的重要捕食性天敌昆虫.为了明确天敌南方小花蝽对云南小春作物上常见蚜虫的捕食能力和喜好性,本文在实验室条件下研究了南方小花蝽5龄若虫、雌雄成虫对不同组猎物的捕食喜好性.选取云南小春作物上3种主要蚜虫种类:烟蚜Myzus persicae...     

Transmission of barley yellow dwarf virus by cereal aphids collected from different habitats on cereal farms

Cereal aphids were collected from cereal crops, from Poa annua within cereal fields, from Lolium perenne pastures and from wild grasses in hedge bottoms and around farm buildings. The frequency of barley yellow dwarf virus (BYDV) transmission was assessed by aphid transmission tests. There were differences in transmission rates between aphid species, between host species and between years. The transmission rates of Rhopalosiphum padi from the different host species were broadly similar whereas for Sitobion avenae, P. annua within cereal fields was significantly better than the other host species. Wild grasses other than P. annua were relatively poor sources of virus. A large percentage of aphids frequently transmitted more than one strain, suggesting that host plants are often infected with more than one BYDV strain.     

Identification and characterization of a novel whitefly-transmitted member of the family potyviridae isolated from cucurbits in Florida

ABSTRACT A novel whitefly-transmitted member of the family Potyviridae was isolated from a squash plant (Cucurbita pepo) with vein yellowing symptoms in Florida. The virus, for which the name Squash vein yellowing virus (SqVYV) is proposed, has flexuous rod-shaped particles of approximately 840 nm in length. The experimental host range was limited to species in the family Cucurbitaceae, with the most dramatic symptoms observed in squash and watermelon, but excluded all tested species in the families Amaranthaceae, Apocynaceae, Asteraceae, Chenopodiaceae, Fabaceae, Malvaceae, and Solanaceae. The virus was transmitted by whiteflies (Bemisia tabaci) but was not transmitted by aphids (Myzus persicae). Infection by SqVYV induced inclusion bodies visible by electron and light microscopy that were characteristic of members of the family Potyviridae. Comparison of the SqVYV coat protein gene and protein sequences with those of recognized members of the family Potyviridae indicate that it is a novel member of the genus Ipomovirus. A limited survey revealed that SqVYV also was present in watermelon plants suffering from a vine decline and fruit rot recently observed in Florida and was sufficient to induce these symptoms in greenhouse-grown watermelon, suggesting that SqVYV is the likely cause of this disease.     

毛乌素沙地植物资源调查及开发利用研究

经野外调查统计,毛乌素沙地共有植物731种,分属于117科、400属。其中,藻类植物3科、3属、3种;菌类植物6科、6属、6种;苔藓植物4科、4属、4种;地衣植物1科、1属、1种;蕨类植物3科,3属、5种;裸子植物5科、9属、25种;被子植物95科、374属、692种。被子植物中,双子叶植物80科、310属、583种,单子叶植物15科、64属、109种。在这些植物中,包含有食用植物、饲用植物、药用植物、观赏植物及其他工业原料植物等各种野生种子植物623种,具有较大的开发利用价值。     

陇中长城沿线种子植物区系特征与长城保护

通过对定西地区战国秦长城沿线种子植物调查,共统计到种子植物58科242属444种,其中裸子植物2科3属3种;被子植物56科239属441种。单种属的科共15个,超过10属的科5个,其总属数占调查总属数的45.5%,种数占调查总种数的52.4%,以菊科最多,共38属82种。科的区系分布类型共4个正型和4个变型。属的区系分布类型共13个正型和11个变型,中国特有属2个,分布在菊科（Compositae）和伞形科（Umbelliferae）。调查区域的植物种类相对丰富;地理成分比较复杂,以温带成分占优势,以北温带分布型和旧世界温带分布型为主;发现珍稀濒危植物2种。这为保护长城选择适宜的植物类群和代表性物种提供了理论依据。     

cis-Jasmone treatment induces resistance in wheat plants against the grain aphid,Sitobion avenae (Fabricius) (Homoptera: Aphididae)

cis-Jasmone is a plant volatile known to have roles as an insect semiochemical and in inducing plant defence. It was evaluated in laboratory and field trials for control of cereal aphids. In an olfactometer bioassay cis-jasmone was repellent to alatae of the grain aphid, Sitobion avenae (Fabricius) (Homoptera: Aphididae). Moreover, wheat, Triticum aestivum (L), seedlings sprayed with formulated cis-jasmone 24 h previously were less susceptible to attack by S. avenae than control plants. In field simulator studies, significantly fewer alate S. avenae settled on cis-jasmone-treated plants over a 24-h period. In addition, the intrinsic rate of population increase, r(m), of S. avenae apterae was reduced on cis-jasmone treated seedlings. In a series of small-plot experiments conducted over four years, cis-jasmone applications reduced cereal aphid populations infesting wheat in the field.     

Effect of azadirachtin applied systemically through roots of plants on the mortality,development and fecundity of the cabbage aphid (<Emphasis Type="Italic">Brevicoryne brassicae</Emphasis>)

The effect of low concentrations of azadirachtin applied systemically through root tissues of rape plants (Brassica napus subsp.napus) on the mortality, period of development, longevity and fecundity of the cabbage aphid (Brevicoryne brassicae L.) (Sternorrhyncha: Aphididae) was studied. The concentrations of azadirachtin A tested were: 0.25, 0.05, 0.005, 0.0005 and 0.00005 mg ml⁻¹. The mortality of cabbage aphid nymphs, particularly during the period of ecdysis, increased significantly with increasing concentrations. Azadirachtin had no effect on the length of the development period of the respective immature stages of cabbage aphids. The average longevity of the cabbage aphids decreased with increasing azadirachtin concentration and time spent feeding. The fecundity of aphids decreased after the application of azadirachtin. http://www.phytoparasitica.org posting May 6, 2004.     

侵染苜蓿的豇豆花叶病毒的研究

 从新疆苜蓿矮缩花叶病株上分离到一种病毒分离物G-14,在测定的9科40种植物中,此分离物可侵染6科19种植物,易由汁液摩擦接种,桃蚜(Myzus persicae)、豆蚜(Aphis craccivora)、棉黑蚜(A.atrata)和苜蓿无网长管蚜(Acyrthosiphon rondoi)等不传毒,可由首蓿叶象岬(Hypera variabilis)传毒;致死温度55~60℃,稀释限点10^-3~10^-4,体外保毒期21天;病毒粒体球状,直径约28nm。电镜观察病组织超薄切片,可见晶格状排列的病毒粒体。经琼脂双扩散血清学测定,该分离物与豇豆花叶病毒(CPMV)抗血清呈阳性反应。由此鉴定G-14为CPMV。提纯病毒经SDS-聚丙烯酰胺凝胶电泳测定有3个蛋白组分。分子量分别为44800,24500,22400道尔顿;琼脂糖电泳测得有二个核酸组分。     

新疆乌鲁木齐南山八一林场地衣生态地理学特征

采用显色反应(CT)、微量结晶 (MCT)和薄层色谱 (TLC)等方法,分析乌鲁木齐南山八一林场地衣的物种组成及生态地理特征。结果表明：乌鲁木齐南山八一林场地衣资源较为丰富,共有7目、23科、51属、114种、9变型、9变种。含5种以上的大科共有7个,占总科数的30.43%,分别包括本地区50.98%的属和68.42%的种。地衣的地理成分可划分为12类, 包括欧亚-北美成分(39.47%) 、北半球广布成分(13.16%) 、中国特有成分(12.28%)和世界广布成分(10.53%)。该地区地衣种类与北美、欧洲等地在地衣区系上有一定的相似性,并具有明显的中国特有种类。     

The dietary toxicity of deltamethrin to the carabid,Nebria brevicollis (F.)

Batches of adult Nebria brevicollis (F.) (Coleoptera: Carabidae) were provided with freeze-killed aphids, Metopolophium dirhodum (Walk.) (Homoptera: Aphididae), that had been treated topically with 30 ng a.i. deltamethrin. Beetles in different hunger states were found to consume contaminated aphids, but they consumed significantly fewer aphids than control beetles. The mean numbers of contaminated aphids eaten increased with hunger-level, from 2.5 aphids per beetle for those provided with food 24 h before exposure, to 4.5 aphids per beetle for those provided with food 120 h prior to exposure. The highest mortality that occurred over the following six days after consumption of contaminated aphids was 27% for the beetles that had been fed 120 h before exposure and the lowest was 13% for the beetles that had been fed 24 and 48 h prior to exposure. A regurgitation response was observed in 53–80% of the beetles that had consumed deltamethrin-treated aphids. The beetles that survived consumption of treated aphids showed a short-term reduction in mean numbers of untreated aphids consumed relative to the control beetles. Dietary and topical dose-response data for deltamethrin and N. brevicollis were compared by probit analysis and maximum likelihood procedures. The dietary exposure probit line had a significantly steeper slope than the topical exposure probit line but the two lines occupied similar positions along the dose axis. The steepness of the dietary exposure probit line may be partly explained by the regurgitation response shown by the beetles, which causes water loss and may amplify toxic effects. The results indicated that the consumption of deltamethrin-contaminated prey may be an important cause of predator mortality soon after pesticide application.     

New potyvirus isolated from <Emphasis Type="Italic">Cryptotaenia japonica</Emphasis>

 A potyvirus, for which the name Japanese hornwort mosaic virus (JHMV) is proposed, was isolated from Japanese hornwort plants (Cryptotaenia japonica) with mosaic disease symptoms. The virus was used to inoculate mechanically 34 plants belonging to 33 species of 10 families. Of these species seven from two families were infected. Faint chlorotic spots appeared on the inoculated leaves of Chenopodium quinoa and C. amaranticolor, but no systemic infection occurred in these plants. JHMV systemically infected only Umbelliferae plants; they did not infect 26 other species in eight families. JHMV was transmitted in a nonpersistent manner by aphids (Myzus persicae). The virus was a flexuous rod-shaped particle about 750 nm in length. Sequencing the nucleotides in the 3′ terminal region of JHMV revealed that the coat protein contains 280 amino acids with a molecular mass of 32.2 kDa. The nucleotide sequence of the coat protein of JHMV had the highest similarity with that of Zantedeschia mosaic virus (83.3%) compared to those of other potyviruses (57.0%–64.9%). An antiserum against JHMV reacted strongly with JHMV and weakly with Potato virus Y. These results indicate that JHMV is a new potyvirus. Received: September 9, 2002 / Accepted: November 7, 2002 RID="*" ID="*" The nucleotide sequence determined in this work appears in the DDBJ/EMBL/GenBank nucleotide sequence databases with the accession number AB081518     

Application of the consolidated species concept to identify the causal agent of strawberry anthracnose in Iran and initial molecular dating of the <Emphasis Type="Italic">Colletotrichum acutatum</Emphasis> species complex

Anthracnose caused by Colletotrichum spp. is one of main strawberry diseases worldwide. The disease recently arrived in Iran and become epidemic in the Kurdistan province. A combination of morphological, molecular and pathogen-host interaction approaches (referred to the consolidated species concept) were applied to isolates from symptomatic strawberry tissues collected in Iran. Multi-gene phylogenetic analysis based on ITS-rDNA, beta-tubulin (TUB2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) identified the species as the S5 clade of Colletotrichum nymphaeae. No significant intraspecies variation was observed in terms of morphology and pathogenicity. No significant genetic variation was observed among the isolates using inter simple sequence repeat analysis (ISSR) and primer pair combination of ERIC1/BOX and ERIC2/BOX fingerprinting markers. Based on the results of this study, it can be postulated that the C. nymphaeae population in Iran established itself from a single origin due to a founder effect. More generally, molecular dating based on relaxed clocks indicates co-radiation of C. nymphaeae S5 and strawberry plants and suggests high reciprocal specificity between the host and pathogen.     

我国主要农作物蚜虫生物防治的研究进展、应用与展望

蚜虫是农业生产上的重大害虫,不仅通过取食韧皮部直接为害植物,还会传播很多植物病毒病,严重影响农作物产量和品质。目前防治蚜虫仍以化学农药为主,然而生物防治作为绿色环保、可持续的防治策略在这几十年中也得到了长足发展。该文对我国近60年关于主要农作物蚜虫生物防治的研究进展进行概述,包括主要农作物蚜虫的天敌资源（主要寄生性天敌196种,主要捕食性天敌16种,主要病原微生物6种）、蚜虫主要天敌生物学和生态学研究、人工扩繁及应用技术及植物抗蚜机制和抗蚜种质资源挖掘,并对目前蚜虫生物防治中存在的问题及未来的研究方向进行展望,以期为蚜虫生物防治技术的发展和推广应用提供参考。     

Diversity and occurrence of chickpea chlorotic dwarf virus on legumes from Iran

Chickpea chlorotic dwarf virus (CpCDV; genus Mastrevirus, family Geminiviridae) is one of the most important legume-infecting viruses with a wide host range and geographic distribution in Africa and Asia. In Iran, CpCDV is common in chickpea (Cicer arietinum), but there is limited information about diversity and infections in plants of other legume species. In the current study, a total of 1671 leaf samples from different pulse crops with symptoms were collected in nine provinces of Iran, and the CpCDV infection status was tested by PCR and/or rolling circle amplification (RCA), resulting in the detection of CpCDV in samples of chickpea, lentil (Lens culinaris) and faba bean (Vicia faba) from different regions. Sequence analysis of complete genomes of 18 isolates recovered by digestion of RCA products revealed infection with isolates of the strains CpCDV-A and CpCDV-F in chickpea, lentil and faba bean. Phylogenetic analysis showed that the Iranian isolates of CpCDV were closely related to previously sequenced isolates of CpCDV-A and CpCDV-F. To the authors' knowledge, this is the first report of CpCDV-F in Iran. Using agroinoculation with infectious clones for one isolate each of CpCDV-A and CpCDV-F, infectivity was confirmed in both faba bean and chickpea, with plants developing leaf curling and/or yellowing. Both infectious clones also successfully infected Nicotiana benthamiana resulting in mild yellowing and intensive leaf curling for CpCDV-A, and dark-green mosaic, dwarfing and mild leaf curling for CpCDV-F.     

Variation in transmission of two BYDV-MAV isolates by multiple clones of Rhopalosiphum padi L.

Vector efficiency of up to 17 Rhopalosiphum padi L. clones originating from Europe, North America and North Africa, was evaluated by transmitting two isolates of the serotype MAV for which this species is normally an inefficient vector. When test plants were inoculated by batches of 3 aphids, both isolates were rather well transmitted by one clone (Rp5), isolate MAV2 was poorly transmitted by all other clones tested and isolate MAV11 was not transmitted by eight clones and poorly transmitted by two clones. When eight aphids were used by test plants, all clones transmitted both isolates. The epidemiological consequences of MAV transmission by some R. padi clones are discussed, as well as the interest of these clones for studying aphid-derived components of luteovirus transmission.     

Identification of chickpea stunt viruses in Algeria

Chickpea samples showing viral-like symptoms of stunting and yellowing were collected from different parts of Algeria. Transmission trials on three species of aphids ( Acyrthosiphon pisum, Aphis craccivora and Aphis fabae ) to a limited range of hosts, and ELISA tests, led to the identification of bean leaf roll luteovirus. Field sampling also allowed identification, by ELISA and TBIA tests, of two other viruses: a luteovirus closely related to beet western yellows luteovirus, and faba bean necrotic yellows nanavirus. Ten species of aphids were identified by trapping in affected fields, most being previously known vectors of the three viruses concerned.     

Species composition and abundance of aphids in Australian hop gardens and their impact on spatiotemporal patterns of Carlavirus epidemics

The species composition and abundance of aphids in commercial cv. Agate and cv. Super Pride hop gardens in Tasmania, Australia, were characterized over three seasons (1999–2001). Gunns Plains recorded 14 aphid species and Bushy Park 11 species, with nine of these common to both sites. The majority of aphids were trapped in the first 2 months (October and November) of active hop growth in all three seasons. Cultivar and geographical location had significant effects on the abundance of total aphids (species pooled) trapped and several individual aphid species in the three seasons. In general, significantly more aphids (total and individual species) were trapped in cv. Agate than cv. Super Pride gardens, and higher numbers were trapped at Bushy Park than at Gunns Plains. This coincided with a higher incidence of plants infected by carlaviruses in cv. Agate gardens at both locations. Differences in the spatiotemporal dynamics of Carlavirus epidemics were described by fitting a stochastic model to the data, with parameters for local spread within the garden (contagion) and background infection (disease increase unrelated to infected plants within the gardens). Local spread of Hop latent virus (HpLV) and Hop mosaic virus (HpMV) was indicated within all gardens. For HpMV in cv. Agate at Gunns Plains, however, infections caused by immigrant viruliferous aphids were also apparent. Using join-count statistics, spatial aggregation of both virus diseases was found for all years, except for the initial year (1999) when incidence was low. Clusters of diseased plants extended to greater distances for HpLV than for HpMV. Based on spatial and spatiotemporal analyses, local spread (mechanical transmission and/or aphid movement within the garden) appears to be the dominant factor in the epidemics of HpLV. Aphid immigration from outside the crop over time may play a more significant role for HpMV epidemics, at least for one location.     

Salvinia in the State of Kerala,India

Abstract

The mites attacking Important plants in the North Eastern Hill region of India were surveyed for 3 years from 1984. The mites recorded belonged to three families: Tetranychidae, Tenuipalpidae and Eriophidae. The most common and widely distributed species were Eutetranychus orientalis, Tetranychus telarius, Tetranychus cucurbitae and Brevipalpus phoenicis which attacked a number of vegetables and fruit trees. The total number of mite species recorded in Meghalaya were 10 on 28 plants, in Tripura 6 on 17 plants, in Manipur 5 on 14 plants, in Nagaland 3 on 7 plants, in Arunachal Pradesh 3 on 5 plants and Mizoram 3 on 6 plant species.     

Insecticidal activity of 23 essential oils and their major compounds against adult Lipaphis pseudobrassicae (Davis) (Aphididae: Homoptera)

Essential oils from 23 species of plants comprising 14 genera and 4 plant families were obtained by Clevenger-type water distillation. The major compounds in these essential oils were identified with GC-MS and their insecticidal activity against adult turnip aphids, Lipaphis pseudobrassicae (Davis), tested with dosage-mortality bioassays. We examined mortality only for viviparous adults because sizeable aphid populations on crucifer (Brassicaceae) hosts are largely produced by these wingless, parthenogenic females. Twenty-two of the oils were directly applied to aphid females in randomized blocks at concentrations of 0.0, 1.0, 2.5, 5.0 and 10.0 mg ml(-1). Essential oils mixed with a non-toxic emulsifying agent, dimethyl sulfoxide (DMSO), more easily penetrated the waxy insect cuticle. Probit analysis and LC(50) at three different exposures showed aphids were quickly incapacitated and killed by aliphatic aldehydes, phenols and monocyclic terpenes contained in Bifora and Satureja oils and at applied concentrations as low as 0.3 to 1.0 mg ml(-1). Only enough Pimpinella isaurica oil and its three phenylpropanoid fractions were available for testing at a single concentration of 10 mg ml(-1). We could not spare any additional P. isaurica oil for testing at other concentrations. Phenylpropanoids isolated from P. isaurica oil when recombined or left naturally blended in the oil were highly bioactive against L. pseudobrassicae at 10 mg ml(-1).     

Virus transmission by aphids in potato crops

This paper reviews the contribution of vector activity and plant age to virus spread in potato crops. Determining which aphid species are vectors is particularly important for timing haulm destruction to minimize tuber infection by potato virus Y (PVY). Alate aphids of more than 30 species transmit PVY, and aphids such asRhopalosiphum padi, that migrate in large numbers before flights of the more efficient vector,Myzus persicae, appear to be important vectors. Differences in methodology, aphid biotypes and virus strains prevent direct comparisons between estimates of vector efficiencies obtained for aphids in different countries in north western Europe. M. persicae is also the most efficient vector of potato leafroll virus (PLRV), but some clones ofMacrosiphum euphorbiae transmit PLRV efficiently toNicotiana clevelandii and potato test plants. The removal of infected plants early in the season prevents the spread of PLRV in cool regions with limited vector activity. The proportion of aphids acquiring PLRV from infected potato plants decreases with plant age, and healthy potato plants are more resistant to infection later in the season. Severe symptoms of secondary leafroll developed on progeny plants of cv. Maris Piper derived from mother plants inoculated with PLRV in June or July of the previous year. Progeny plants derived from mother plants inoculated in August showed only mild symptoms, but the concentration of PLRV in these plants was as high as that in the plants with severe symptoms.