Encarsia (Hymenoptera: Aphelinidae) parasitoids of Bemisia species in Taiwan (Hemiptera: Aleyrodidae)

The whitefly genus Bemisia (Hemiptera: Aleyrodidae) is represented by five species in Taiwan, including the notorious global pest Bemisia tabaci. A catalogue of Encarsia species attacking these whiteflies, based almost entirely on previously unpublished records, is provided. A key for the identification of the 17 Encarsia species known to parasitize Bemisia species in Taiwan is provided. Three new species, E. guangxingana Shih, Ko and Polaszek sp. nov., E. lineolata Shih, Ko and Polaszek sp. nov. and E. magnalata Shih, Ko and Polaszek sp. nov., are described from Taiwan. These new species were all reared from Bemisia giffardi.     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The “B” biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with “B” biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The "B" biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with "B" biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.     

Identification of Chinese populations of Bemisia tabaci (Gennadius) by analyzing ribosomal ITS1 sequence

Spreading of Bemisia tabaci B biotype has had a large impact on the production of vegetables, ornamental and fiber crops in many countries of the world since the 1990s. This study analyzes the ribosomal ITS1 sequence (～520 bp) to distinguish genetic difference of B. tabaci from representative different geographical populations in China. Phylogenetic analysis shows that populations of B.tabaci from Beijing and Shandong Province are of biotype B, and populations of B.tabaci from sweet potato in Fujian Province and pumpkin in Guangxi, China, belong to two different non-B biotypes and have a geographical origin of Asia.     

检测丽蚜小蜂取食寄主银叶粉虱的多重聚合酶链式反应

结合Ｄ２引物和ＢＥＦ引物,优化了一个可以用来检测丽蚜小峰（Ｅｎｃａｒｓｉａ ｆｏｒｍｏｓａ Ｇａｈａｎ）取食寄主银叶粉虱（Ｂｅｍｉｓｉａ ａｒｇｅｎｔｉｆｏｌｉｉ Ｂｅｌｌｏｗｓ＆Ｐｅｒｒｉｎｇ）的重多聚合酶链式反应。特异于银叶粉虱的ＢＥＦ引物（正向５′－ＡＡＴ ＴＣＡ ＣＡＣ ＡＴＡ ＣＧＴ ＴＡＧ ＣＣＣ ＣＴ－３′和反向５′－ＴＡＡ ＣＣＧ ＡＡＣ ＣＡＴ ＣＡＡ ＣＡＧ ＡＴＴ ＡＴＴ－３     

福州大豆非洲伯粉虱Bemisia afer发生为害的初步研究

非洲伯粉虱Bemisia afer(Priesner et Hosny)隶属同翅目粉虱科,是福州大豆上一种发生较为普遍的小型刺吸性害虫。国外报道于1934年在埃及发现,1970年定名,可为害木薯、红柠檬、散沫花等多种植物,并传播植物病毒,国内对该虫研究尚为空白。本文通过田间试验和室内观察,对非洲伯粉虱的形态特征、发生为害习性、田间分布与消长及寄生状况等进行了初步研究。     

粉虱座壳孢对烟粉虱的致病力测定及其时间-浓度效应

本研究用粉虱座壳孢 Aschersonia aleyrodis Webber孢子悬浮液 1× 10 5、5× 10 5、1× 10 6、5× 10 6和 1×10 7孢子 /ml,对烟粉虱 Bemisia tabaci(Gennadius) 2龄若虫进行致病力测定 ,并应用时间 -剂量 -死亡率模型研究了粉虱座壳孢对烟粉虱致死的时间和浓度效应 ,拟合良好。结果表明 ,粉虱座壳孢对烟粉虱的致病力较强 ,接种后第 9d,5× 10 6和 1× 10 7孢子 /ml两个浓度处理累计死亡率达 90 %以上 ;第 10 d的 LC50 和 LC90 分别为 2 .5 8× 10 5和 4 .6 7× 10 6孢子 /ml;在 5× 10 5- 1× 10 7孢子 /ml的浓度范围内 ,L T50 为 2 .6 1- 4.82 d     

攀西桑粉虱的形态研究

桑粉虱Pealius mori(Takahashi)和杨梅粉虱Bemisia myricae Kuwana的一般外形特征非常相似极易混淆,为了弄清攀西地区发生的主要种类究竟是杨梅粉虱还是桑粉虱我们对其形态进行了显微研究.发现该地区危害的种类是桑粉虱,表明除已报道的台湾、江浙外,四川攀西也有桑粉虱的发生.     

Identification of three major Bemisia tabaci biotypes in China based on morphological and DNA polymorphisms

The sweet potato whitefly, Bemisia tabaci, is a complex species, and many of its biotypes are important agricultural pests. The B and Q biotypes are invasive and coexist with the native Cv biotype on vegetable and ornamental crops in China. In this study, these three biotypes were identified based on their morphological characteristics, RAPD–PCR analysis, and DNA sequences of the COI gene. The anterior and posterior wax fringes of the B, Q, and Cv biotypes significantly differed from each other. Based on this morphological characteristic, the three biotypes can easily be distinguished in greenhouses and fields. Genomic DNA RAPD–PCR band patterns also revealed differences between these biotypes using the H16 primer. The B biotype has three bright DNA bands between 250 and 600 bp, the Q biotype only has one bright band at 300 bp, while the Cv biotype has no band between 250 and 500 bp. Both the Cv and Q biotypes have two bright bands at 750 and 1000 bp while the B biotype has only one band at 1000 bp. Based on the COI gene, the genetic identity between B and Cv, B and Q, and Q and CV was 85.8%, 94.7%, and 86.0%, respectively. The MP tree indicated that the phylogenetic relationship between the B and Q biotypes is much closer than that between the B and Cv or the Q and Cv biotypes. The uses of the morphological, RAPD–PCR, and DNA sequencing methods in biotype identification of B. tabaci are discussed.     

基于mtDNA COI序列的福建B型烟粉虱田间种群分析

本研究对福建B型烟粉虱10个田间种群的线粒体DNA COI基因(mtDNA COI)进行测序,并通过与NCBI数据库上埃及、湖北、武汉3个B型烟粉虱地理种群的mtDNA COI的序列进行比对分析,结果表明在核苷酸多样性、单倍型数、单倍型多样度上,不同地理种群都不一样,但是福建种群这些遗传特征数据显著高于其它地理种群.结合近年来我省田间烟粉虱种群抗药性水平迅速提高这一结果分析,可以推测,在不同杀虫剂压力选择下,不同抗性基因得以在我省不同地理群体中流动,种群内呈现比较明显的抗性遗传分化趋势,群体遗传多样性也更为丰富,表现出烟粉虱对不利环境较强的适应能力.