烟粉虱捕食性天敌淡色斧瓢虫的形态特征及生活习性

对淡色斧瓢虫Axinoscymnuscadilobus的形态特征和生活习性进行了观察。在 ( 2 5± 1 7)℃条件下 ,以烟粉虱为食料 ,淡色斧瓢虫完成 1个世代平均历期为 49 5 9d ,成虫的平均寿命为 64 45d ,平均产卵量为 95 4粒 ;淡色斧瓢虫可捕食烟粉虱的卵、若虫、蛹及成虫 ,是烟粉虱的有效天敌 ,具有很好的保护利用价值。     

益害虫比对沙巴拟刀角瓢虫与越南斧瓢虫捕食烟粉虱行为的影响

在实验室条件下研究了烟粉虱Bemisia tabaci Gennadius若虫不同密度、既定烟粉虱密度不同天敌数量两种条件下,沙巴拟刀角瓢虫Serangiella sababensis Sasaji和越南斧瓢虫Axinoscymnus apioides Kuznetsov & Ren的捕食行为.研究结果表明,但烟粉虱若虫密度从5增加到40头/cm2,沙巴拟刀角瓢虫和越南斧瓢虫搜寻猎物的时间,随着粉虱密度的增加而逐渐减少;取食猎物的时间,随着粉虱密度的增加而逐渐增加;对烟粉虱若虫的取食量也随密度的增加呈上升趋势.两种瓢虫相比,在既定猎物密度的情况下,刀角瓢虫搜寻、取食烟粉虱的时间要显著长于斧瓢虫所用的时间,但对烟粉虱的取食量明显低斧瓢虫的取食量.在固定粉虱数量的情况下,当瓢虫数量从1头增加到3头时,单头刀角瓢虫和斧瓢虫对烟粉虱的取食量逐渐减少,个体间的干扰作用逐渐显现.     

淡色斧瓢虫对烟粉虱的捕食作用

研究了淡色斧瓢虫对烟粉虱的捕食作用.结果表明,淡色斧瓢虫对烟粉虱的功能反应呈Holling Ⅱ型.随着猎物龄期的增加,淡色斧瓢虫成虫的寻找效率(a)逐渐降低,处置时间(T_h)依次延长;随着淡色斧瓢虫幼虫龄期的增加,其对烟粉虱卵的寻找效率逐渐提高,处置时间依次缩短.淡色斧瓢虫成虫对烟粉虱卵的捕食效应随捕食者间干扰作用的增加而下降,捕食作用率(E)与淡色斧瓢虫数量（P）之间呈幂函数关系,即E=0.5205P^-0.6631.温度对淡色斧瓢虫的捕食效应影响显著,寻找效率和处置时间与温度间的函数关系为:a=- 0.0002T³+0.0166T²-0.3492T+3.2329,T_h=4×10^-7T³-3×10^-5T²+0.0006T-0.0009.     

2种瓢虫捕食烟粉虱行为的时间分配策略

【背景】沙巴拟刀角瓢虫和越南斧瓢虫是自东南亚地区引进的粉虱类害虫的优势捕食性天敌,然而其控制烟粉虱的有效性尚未明确。【方法】在室内研究了2种瓢虫幼虫捕食烟粉虱若虫时取食、爬行与休息等行为的时间分配,以及2种瓢虫幼虫和成虫在既定时间内对烟粉虱的取食时间和取食量。【结果】随着瓢虫幼虫龄期的增大,其取食烟粉虱低龄和高龄若虫的时间和休息时间均逐渐减少,而爬行寻找猎物的时间逐渐增多。沙巴拟刀角瓢虫幼虫取食烟粉虱各虫态的时间显著长于越南斧瓢虫幼虫,取食量也显著大于后者;而沙巴拟刀角瓢虫成虫取食烟粉虱的时间长于越南斧瓢虫成虫,但取食量明显低于后者。【结论与意义】2种瓢虫对烟粉虱都有较好的捕食作用,但其时间分配策略有所不同。因此,应根据田间烟粉虱的发生时期,选择合适的瓢虫进行释放。     

引进天敌越南斧瓢虫的形态特征和生物学特性

引进天敌越南斧瓢虫Axinoscymnus apioides Kuznetsov & Ren原产于东南亚,是烟粉虱Bemisiatabaci(Gennadius)的重要捕食性天敌之一。文章详细描述越南斧瓢虫的形态特征,并研究其基本的生物学特性。越南斧瓢虫可取食烟粉虱的卵、若虫、伪蛹等各虫态,可有效地控制烟粉虱种群,具有很好的利用价值。在(26±1)℃条件下,越南斧瓢虫捕食烟粉虱的世代平均发育历期为20.33d,世代存活率为73.04%,雌成虫寿命为143.17d,平均单雌产卵量为284.33粒。越南斧瓢虫取食烟粉虱的内禀增长率(rm)为0.0457,净增殖率(R0)为103.4050,平均世代历期(T)为99.3626,周限增长率(λ)为1.0478。     

越南斧瓢虫对烟粉虱的捕食作用

【目的】烟粉虱Bemisia tabaci(Gennadius)是一种外来入侵性的重大农业害虫,越南斧瓢虫Axinoscymnus apioides Kuznetsov&Ren是其重要的捕食性天敌之一,本文系统研究了越南斧瓢虫对烟粉虱的捕食作用。【方法】在温度误差为±1℃,相对湿度为75%,光照周期为L︰D=14︰10条件下,测定瓢虫成虫对烟粉虱各虫态的功能反应和不同温度下对烟粉虱4龄若虫的功能反应以及测定瓢虫成虫取食烟粉虱4龄若虫个体间的干扰反应。【结果】结果表明,越南斧瓢虫对烟粉虱的功能反应呈HollingⅡ型,随着猎物龄期的增加,越南斧瓢虫成虫的寻找效率(a)逐渐降低,处置时间(Th)基本依次延长。温度对瓢虫的捕食效应影响显著,试验所设温度为15,20,25,30,35℃,越南斧瓢虫成虫的寻找效率(a)分别为0.3226,0.4496,0.5868,0.5788和0.6235,处置时间(Th)分别为0.2348,0.1451,0.1039,0.0904和0.0976,均与温度(T)则呈二次曲线关系。越南斧瓢虫对烟粉虱4龄若虫的捕食作用率(E)在捕食者密度较低(在1~5头)时,捕食作用率下降较快,而在捕食者>6时,其对捕食作用率的影响效果减小。寻找系数为0.0607,干扰系数为0.5569。【结论】随着猎物龄期的增加,越南斧瓢虫成虫的寻找效率降低,处置时间延长;越南斧瓢虫成虫对烟粉虱4龄若虫的寻找效率随着温度的升高而提高,而在更高的温度条件下,其寻找效率略有下降。瓢虫对烟粉虱的处置时间则随着温度的升高而不断缩短;越南斧瓢虫成虫自身密度对其捕食作用产生干扰反应,捕食作用率随着捕食者密度的增加而降低。     

放蜂密度对桨角蚜小蜂Eretmocerus sp.控制烟粉虱效果的影响

研究了不同放蜂密度对桨角蚜小蜂Eretmocerussp .控制烟粉虱种群效果的影响。结果表明 ,按 1头、2头、3头、5头雌蜂 /株的密度释放桨角蚜小蜂 ,3周后烟粉虱种群的增长趋势指数分别为 2 4 .13、18.5 1、12 .4 1和 8.0 6 ,随着放蜂密度的增加 ,烟粉虱种群增长趋势指数逐渐减小 ,蚜小蜂寄生对烟粉虱种群增长的干扰作用控制指数分别为 0 .80 5 1、0 .6 176、0 .4 14 1和 0 .2 6 89。研究表明在生产中以 3头或 5头雌蜂 /株的密度释放桨角蚜小蜂Eretmocerussp .,对烟粉虱种群的控制效果较好     

蚜小蜂和粉虱座壳孢对烟粉虱的控制作用研究

研究了烟粉虱两种寄生性天敌桨角蚜小蜂(Eretmocerus sp．)和粉虱座壳孢(Aschersonia aley-rodis)单独使用和联合使用时对烟粉虱种群的控制作用。结果表明,在单独进行控制时,在一个世代内按5×10^6个孢子·ml^-1喷施粉虱座壳孢2次,对烟粉虱种群的控制作用达95．74％,按每株植株3头雌蜂的密度释放桨角蚜小蜂2次,对烟粉虱种群的控制作用达57.58％。在两者联合控制时,一个世代内喷施粉虱座壳孢2次,再释放桨角蚜小蜂1次或2次,对烟粉虱种群的控制作用达97．02％～97．91％,烟粉虱种群增长趋势指数低于1,种群数量逐渐下降,联合使用时,桨角蚜小蜂和粉虱座壳孢间无消极影响。     

国内烟粉虱B生物型的分布及其控制措施研究

收集了国内 15个省 2 6个不同地区的烟粉虱种群 ,根据有关报道合成了一个随即引物H16 ,对不同地区的烟粉虱DNA进行了RAPD -PCR扩增 ,根据扩增结果分析了不同烟粉虱种群的生物型。结果表明 ,在以上不同省市和地区中 ,北京、山东等 11个省 19个地区都有烟粉虱B型的分布。以烟粉虱B型为防治对象 ,比较了使用高效氯氰菊酯、高效大功臣 2种化学农药 ,和应用桨角蚜小蜂、粉虱座壳孢 2种寄生性天敌 ,对黄瓜上烟粉虱种群的控制效果 ,结果表明在一个世代内 ,喷施高效大功臣 (10 0 0× ,1次 ) ,喷施粉虱座壳孢 (5× 10 6 个孢子 /ml,2次 ) ,和释放桨角蚜小蜂 (3头雌蜂 /株 ,2次 ) ,对烟粉虱种群的控制作用分别达到 78.2 1%、95 .74 %和 5 7.5 8% ,三者都可以对烟粉虱起到较好的防治效果。     

Research on the application of Typhlodromips swirskii for the control of Bemisia tabaci

评价斯氏小盲绥螨Typhlodromips swirskii(Athias-Henriort)在我国日光大棚中对黄瓜上的烟粉虱Bemisia tabaci(Gennadius)控制作用.在不同温度条件下研究斯氏小盲绥螨以烟粉虱为猎物的试验种群生命表,以及在日光大棚中释放斯氏小盲绥螨控制黄瓜上的烟粉虱所取的防治效果.斯氏小盲绥螨取食烟粉虱的卵、成虫、若虫、伪蛹能完成世代并能正常产卵.在19～35℃范围内总产卵量25～41粒／雌,产雌率60％～62.68％.在(20±1)℃.(25±1)℃,(30±1)℃,(34±1)℃温度条件下斯氏小盲绥螨净增殖率(R0)分别为12.6160、22.1021、17.4500、16.7463;内禀增长率(rm)分别为0.0865、0.1528、0.1535、0.1690.在大棚黄瓜上应用结果表明:释放斯氏小盲绥螨与目前大棚中的常规化学防治比较,生防区能有效地控制烟粉虱成虫、卵、若虫的种群数量增长.根据斯氏小盲绥螨和烟粉虱的生物学特性,结合大棚黄瓜栽培过程中的环境条件,笔者提出了在日光大棚中应用斯氏小盲绥螨控制黄瓜上烟粉虱的策略:在黄瓜生长的整个期间释放2～3次斯氏小盲绥螨,每20～25d释放1次,苗期每株释放20～25只,后期每株释放25～50只,才能达到预期效果.生防园每季减少农药使用次数5次.     

Life history of Axinoscymnus cardilobus (Col., Coccinellidae), a predator of Bemisia tabaci (Hom., Aleyrodidae)

Abstract:  Axinoscymnus cardilobus is an indigenous coccinellid predator in South China, which feeds on many whitefly species. Its development, consumption rate, survivorship, longevity and fecundity on a diet of eggs and nymphs of Bemisia tabaci were evaluated. Larval consumption decreased sharply as instars of B. tabaci become bigger, and development time of beetle larvae was significantly different when fed on different stages of B. tabaci . The sex ratio was 0.44. The performances were better after feeding on whitefly eggs than nymphs. Axinoscymnus cardilobus showed good potential for biological control of B. tabaci , especially in greenhouse situations.     

Sublethal effects of imidacloprid on Bemisia tabaci (Hemiptera: Aleyrodidae) under laboratory conditions

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pests in tropical and subtropical agriculture and is a key pest in greenhouse production worldwide. Current management of B. tabaci relies upon frequent applications of insecticides. Insecticide use not only directly affects pest populations through acute toxicity but also has indirect (sublethal) effects on pest physiology or behavior. In this study, we described sublethal effects of imidacloprid on adult feeding, immature development, adult fecundity, and F1 development of B. tabaci. Honeydew excretion of adults feeding on leaves treated with LC20 and LC40 concentration was significantly lower than that on untreated leaf discs. Egg production of B. tabaci adults subject to LC20 and LC40 concentrations also was less than untreated individuals. Upon transfer to untreated leaves, honeydew excretion and egg production recovered well within 24 and 48 h, respectively. Exposure to LC20 and LC40 concentrations significantly affected developmental time of B. tabaci eggs and nymphs, whereas it did not affect adult molting rate. We did not find sublethal effects on longevity and fecundity of B. tabaci adults when exposed to LC90 and LC40 concentrations for 24 h, and on egg hatching rate, nymphal mortality, and molting rate of the subsequent F1 generation. Exposure to imidacloprid at LC40 concentration significantly decreased the number of females in the F1 generation. Imidacloprid negatively affects development and reproduction of exposed individuals, and sex ratio of subsequent (F1) generation of B. tabaci, which probably disrupts B. tabaci population dynamics, slows population increase, and reduces infestation levels. Therefore, it is necessary to consider potential impact from imidacloprid for integrated management of the pest.     

Interspecific interactions between Bemisia tabaci biotype B and Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)

Bemisia tabaci (Gennadius) biotype B and Trialeurodes vaporariorum (Westwood) are invasive whitefly species that often co-occur on greenhouse-grown vegetables in northern China. Although B. tabaci biotype B has been present in China for a relatively short period of time, it has become dominant over T. vaporariorum. We studied the interspecific competitive interactions between the two species in single or mixed cultures at 24 ± 1 °C, 40 ± 5% RH, and L14:D10 h photoperiod. Female longevity on tomato was not significantly different between species, but B. tabaci reproduced 4.3 to 4.9 fold more progeny. The ratio of female to male progeny in both instances was greater for B. tabaci. When cultured on tomato, cotton, and tobacco, B. tabaci developed 0.8, 3.3, and 4.7 d earlier in single culture, and 1.8, 3.9, and 4.3 d earlier in mixed culture. B. tabaci displaced T. vaporariorum in four, five and six generations when the initial ratios of B. tabaci to T. vaporariorum were 15:15, 20:10, or 10:20 on tomato. Populations of B. tabaci were 2.3 fold higher than that of T. vaporariorum on tomato plants for seven consecutive generations in single culture. B. tabaci performed better in development, survival, fecundity, and female ratio. We conclude that B. tabaci could displace T. vaporariorum in as short as four generations in a controlled greenhouse environment when they start at equal proportions. Warmer greenhouse conditions and an increase in total greenhouse area could be contributing factors in the recent dominance of B. tabaci.     

Feeding preference of Macrolophus caliginosus (Heteroptera: Miridae) on Bemisia tabaci and Trialeurodes vaporariorum (Homoptera: Aleyrodidae)

A study of predation choices of Macrolophus caliginosus Wagner (Heteroptera: Miridae) late instars and adults, when offered various developmental stages (eggs and nymphs) of the recently established whitefly Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), was made based on two preference indices. In addition, prey choices of late instars when presented with three ratios of Trialeurodes vaporariorum (Westwood) (Homoptera: Aleyrodidae) and B. tabaci at a similar developmental stage (eggs, young or late instars) were assessed. M. caliginosus preferred older nymphs of B. tabaci than any other stage. It also chose T. vaporariorum over B. tabaci, unless the latter consisted of > 75% of the available prey. These results suggested that M. caliginosus might interfere with parasitoids such as Encarsia, Eretmocerus, or Amitus spp. because all three species emerge from the host pupal case. Furthermore, in mixed infestations, M. caliginosus preference for T. vaporariorum might either negatively affect the control of B. tabaci, or, contrarily, enhance the predator population, before a B. tabaci outbreak occurs in the greenhouse.     

烟粉虱对四种蔬菜寄主的选择性

为探讨利用趋避作用防治烟粉虱的可能性,进行了3方面试验：1）烟粉虱Bemisia tabaci (Gennadius) 对黄瓜、花椰菜、油菜和莴苣等4种蔬菜的寄主选择性; 2）互喷烟粉虱不同嗜好的寄主植物汁液对其寄主选择性的影响; 3）不同间作方式对黄瓜叶上烟粉虱成虫密度的影响。结果表明,烟粉虱对供试植物有明显的选择性,其嗜好程度为花椰菜>黄瓜>油菜>莴苣。喷施莴苣和花椰菜汁液对烟粉虱的寄主选择性均有显著影响,喷施莴苣原液后,花椰菜和黄瓜上的成虫数分别减少79.6%和87.4%,花椰菜上的着卵量减少84.3%;喷施花椰菜原液后,莴苣上的成虫数和着卵量分别增加82.4%和79.2%,表明不同蔬菜中的内含物是引起烟粉虱对寄主选择性的重要原因。在黄瓜中间作莴苣可使黄瓜叶上烟粉虱成虫数平均减少76.5%;间作花椰菜时,通过诱集作用,也可使黄瓜叶上的成虫数平均降低69.7%。这些结果为利用喷施蔬菜汁液和间作方式控制烟粉虱危害提供了理论依据。     

湿度对烟粉虱实验种群的影响

本研究了不同湿度条件对烟粉虱实验种群的影响,结果表明低湿利于烟粉虱种群的发生和增长,在小黑飘虫人工繁殖中,作为小黑飘虫猎物寄主的烟粉虱的室内繁育,相对湿度控制在60％左右利于温室内烟粉虱种群的增长。     

小黑瓢虫与两种猎物作用系统研究:选择捕食作用

研究了小黑瓢虫与烟粉虱及红蜘蛛两种猎物作用系统中 ,小黑瓢虫雌成虫对两种猎物卵的选择捕食作用。结果表明 :当两种猎物共存时 ,小黑瓢虫雌成虫对烟粉虱卵在低密度下不表现喜好性 ,而在中等密度和高密度下表现正喜好性 ,对红蜘蛛卵在各密度下均不表现喜好性。对烟粉虱卵的转换效应会由于总猎物密度的不同而呈现不同的效应 ,即在低密度 (15 0粒 )时无转换行为 ,在中等密度 (30 0粒 )时有负转换行为 ,在高密度 (6 0 0粒 )时有正转换行为。而对红蜘蛛卵则在各总猎物密度下均呈现负转换效应。同时组建了两种猎物共存时 ,小黑瓢虫雌成虫对猎物的总捕食作用方程及对每一种猎物类型的捕食作用方程 ,分析了两种猎物共存时 ,小黑瓢虫雌成虫对各猎物寻找效应的变化情况。