棉株上烟粉虱若虫种群的垂直分布与统计方法研究

对烟粉虱Bemisiatabaci在棉花植株上的垂直分布调查发现 ,烟粉虱在棉株各部位均有分布 ,且分布极不均匀 ,统计分析表明棉株各部位间烟粉虱的种群数量存在显著的差异。棉花顶部烟粉虱的若虫数量约占全棉株若虫总量的 1 6%,通过对棉株各部位烟粉虱的若虫数量与整株若虫总量的回归分析 ,建立了相应的回归方程式     

观察球孢白僵菌侵染烟粉虱若虫过程的新方法——荧光显微法

【目的】介绍一种观察白僵菌Beauveria bassiana侵染烟粉虱Bemisia tabaci(Gennadius)若虫的荧光显微方法。【方法】将被白僵菌侵染的烟粉虱若虫用荧光素二乙酸酯(FDA)染色,并于波长为450~490 nm的蓝光下显微观察。【结果】在接种白僵菌12 h和24 h的烟粉虱若虫上分别观察到昆虫表皮上分生孢子的萌发和芽管穿透表皮。结合裸眼和荧光显微观察结果证实了被真菌侵染的烟粉虱若虫体色变红和菌体在虫体内增殖是同时发生的。【结论】应用荧光显微方法能观察到白僵菌在烟粉虱若虫体表和体内的侵染。     

两种蚜小蜂对烟粉虱寄主的产卵选择性(英文)

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明:两种寄生蜂均可寄生烟粉虱的1~4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

观察球孢白僵菌侵染烟粉虱若虫过程的新方法——荧光显微法

【目的】介绍一种观察白僵菌Beauveria bassiana侵染烟粉虱Bemisia tabaci(Gennadius)若虫的荧光显微方法。【方法】将被白僵菌侵染的烟粉虱若虫用荧光素二乙酸酯(FDA)染色,并于波长为450~490 nm的蓝光下显微观察。【结果】在接种白僵菌12 h和24 h的烟粉虱若虫上分别观察到昆虫表皮上分生孢子的萌发和芽管穿透表皮。结合裸眼和荧光显微观察结果证实了被真菌侵染的烟粉虱若虫体色变红和菌体在虫体内增殖是同时发生的。【结论】应用荧光显微方法能观察到白僵菌在烟粉虱若虫体表和体内的侵染。     

两种蚜小蜂对烟粉虱寄主的产卵选择性（英文）

双斑恩蚜小蜂和桨角蚜小蜂是华南地区烟粉虱的两种优势种寄生蜂。本文研究了两种寄生蜂对不同龄期烟粉虱寄主的产卵选择特性。结果表明: 两种寄生蜂均可寄生烟粉虱的1～4龄若虫。当只有1个龄期的烟粉虱若虫存在时,双斑恩蚜小蜂更多地寄生3龄和4龄若虫,较少寄生1龄和2龄若虫;而桨角蚜小蜂则更多地寄生3龄和2龄若虫,较少寄生1龄和4龄若虫。在4个龄期若虫同时存在时,双斑恩蚜小蜂会明显增加对3龄和4龄若虫的产卵寄生,降低对1龄和2龄若虫的寄生;而桨角蚜小蜂则增加对2龄和3龄若虫的寄生,减少对1龄和4龄若虫的寄生。寄主植物的差异不影响这二种蚜小蜂对各龄期烟粉虱若虫的产卵选择倾向。结果提示,烟粉虱若虫3龄和4龄是双斑恩蚜小蜂最适宜的寄主,而桨角蚜小蜂最适宜的寄主是烟粉虱2龄和3龄若虫。     

烟粉虱若虫在甘蓝和花椰菜莲座期不同叶位层上的分布

对烟粉虱Bemisia tabaci(Gennadius)若虫在花椰菜Brassica oleraceavar.italica和甘蓝Brassica oleraceavar.capitata不同叶位层的分布调查结果显示,烟粉虱若虫在菜株各部位均有分布,但各部位间极不均匀。统计分析表明:其若虫的种群数量在同种蔬菜的菜株各部位间均存在极显著的差异。但在2种叶菜寄主间同一部位上烟粉虱若虫的种群数量差异不明显。通过对菜株各部位烟粉虱若虫量与整株总量的回归分析,建立了叶菜植株不同部位烟粉虱虫量与全株总虫量的回归方程及多元回归模型。     

海氏桨角蚜小蜂对不同龄期“Q”烟粉虱的取食和寄生反应

【背景】近年来＂Q＂烟粉虱在我国快速扩张,已成为农业生产上的一种重要入侵害虫。由于化学农药的大量使用,＂Q＂烟粉虱已对多种农药产生高抗药性,保护和利用天敌昆虫对其进行控制具有重要意义。【方法】本文在室内研究了近年引入我国的海氏桨角蚜小蜂对不同龄期＂Q＂烟粉虱若虫的取食和寄生能力。【结果】各龄期的＂Q＂烟粉虱若虫均可被海氏桨角蚜小蜂取食和寄生。在48h内,寄生蜂取食1、2、3、4龄烟粉虱若虫的数量分别为10.7、6.4、6.7、5.0头,呈现随龄期增大取食数量下降的趋势;海氏桨角蚜小蜂对不同龄期烟粉虱若虫的寄生能力存在明显差异,其更偏好寄生2、3龄若虫（25.4和27.5头）,其次是1龄若虫（22.1头）,而寄生4龄粉虱的数量最低（16.5头）。【结论与意义】寄主龄期对海氏桨角蚜小蜂的取食和寄生能力具有显著影响。综合来看,该寄生蜂表现出对＂Q＂烟粉虱较好的生物防治潜能,是防治烟粉虱的理想寄生性天敌昆虫。     

海氏桨角蚜小蜂对不同龄期 “Q”烟粉虱的取食和寄生反应

【背景】近年来 “Q”烟粉虱在我国快速扩张,已成为农业生产上的一种重要入侵害虫。由于化学农药的大量使用,“Q”烟粉虱已对多种农药产生高抗药性,保护和利用天敌昆虫对其进行控制具有重要意义。【方法】本文在室内研究了近年引入我国的海氏桨角蚜小蜂对不同龄期 “Q”烟粉虱若虫的取食和寄生能力。【结果】各龄期的 “Q”烟粉虱若虫均可被海氏桨角蚜小蜂取食和寄生。在48 h内,寄生蜂取食1、2、3、4龄烟粉虱若虫的数量分别为10.〖KG-*8〗7、6.[KG-*8]4、6.[KG-*8]7、5.[KG-*8]0头,呈现随龄期增大取食数量下降的趋势;海氏桨角蚜小蜂对不同龄期烟粉虱若虫的寄生能力存在明显差异,其更偏好寄生2、3龄若虫（25.[KG-*8]4和27.[KG-*8]5头）,其次是1龄若虫（22.[KG-*8]1头）,而寄生4龄粉虱的数量最低（16.[KG-*8]5头）。【结论与意义】寄主龄期对海氏桨角蚜小蜂的取食和寄生能力具有显著影响。综合来看,该寄生蜂表现出对 “Q”烟粉虱较好的生物防治潜能,是防治烟粉虱的理想寄生性天敌昆虫。     

飞虱若虫龄期的鉴别

<正> 以往鉴别飞虱若虫的龄期,主要根据翅芽发育程度和体长来区分,但由于若虫的体长、头宽及胸部各节背板的长度等,在个体间存在一定的变异幅度,很难以量度划清前、后龄期的界限,而翅芽的发育程度虽在3、4、5龄可较准确地区分龄期(图1),然而用于识别1、2龄若虫     

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。     

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.     

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.     

Body‐color and behavioral responses by the mid‐instar nymphs of the desert locust,Schistocerca gregaria (Orthoptera: Acrididae) to crowding and visual stimuli

The effects of crowding and isolation on body color and behavior were observed for the mid‐instar nymphs of the desert locust, Schistocerca gregaria. Some of the solitarious (isolation‐reared) nymphs that were crowded for 1 or 4 h during the third instar developed black patterns at the fourth instar, but most individuals remained unaffected. Black patterns appeared in all individuals that were crowded for 1 day or longer, but even after 4 days of crowding the black patterning for some individuals was not as intense as that for the gregarious (crowd‐reared) controls. Isolation of gregarious nymphs caused the black patterns to recede or disappear at the last (fifth) nymphal instar, but it was necessary to isolate the nymphs from the beginning of the first instar to obtain body coloration looking like solitarious nymphs in most individuals. Solitarious nymphs that were allowed to see gregarious nymphs developed different intensities of black patterns depending on the body size and number of nymphs shown. The behavioral phase shift from one phase to another was observed when the nymphs were crowded or isolated for 2 days or longer, as previously reported for the last nymphal instars of the same strain. Behavioral gregarization was induced for isolated nymphs that were allowed to see a group of nymphs through a transparent double wall. These results suggested that body‐color phase shift occurred more rapidly for mid‐instar nymphs than for late instar nymphs but the rate of behavioral phase shift was similar for the two instars.     

Developmental response of the brown-winged green bug, Plautia stali (Heteroptera: Pentatomidae), to food shortage

To study developmental response of the brown-winged green bug, Plautia stali Scott, to food shortage we reared nymphs under restricted feeding conditions produced by shortening the feeding period after molt or withholding food from second to fifth instars. For second instars, molting rates were significantly reduced as the feeding period was shortened. Shortening the feeding periods for third to fifth instars also reduced molting rates, but less so; some nymphs were able to complete their developments even if no food was given to any of the instars. Compared with controls for which feeding was not restricted, nymphs that successfully reached the next instar had reduced postmolt body size as a result of restricted feeding for all instars except the fifth (2-day feeding for second instar, and 1-day feeding for third and fourth instars), whereas instar duration was unchanged or only slightly prolonged for all instars. These results suggest that only nymphs with nutritional accumulation over a specific threshold in each instar can progress to the next instar, and that, particularly for second to fourth instars, nymphs develop on schedule without prolonging instar durations to compensate for reduced growth under conditions of food shortage.     

Biology of a thelyotokous biotype of Eretmocerus mundus (Hymenoptera: Aphelinidae) on Bemisia tabaci (Homoptera: Aleyrodidae)

Abstract Thelyotokous biotype of Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae), a parasitoid of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae), was recently recorded in northern Iran. Reproductive biology of this biotype was studied as part of an evaluation of its potential for biological control of B. tabaci. The parasitoid deposited more eggs under 2nd and 3rd nymphal instars than 1st or 4th instars. Adult females fed honey, with no access to whitefly nymphs, lived significantly longer (13.6 ± 4.7 d) than those given access to nymphs, but not fed honey (7.6 ± 2.21 d). Lifetime fecundity averaged 81.7 ± 26.9 female progeny per female parasitoid, ranging from 11–132. Daily fecundity, measured as the number of whitefly nymphs parasitized by per female each day for 10 d, averaged 18.06 ± 3.95 for the first 6 d of life, and then declined to < 11. Developmental time from oviposition to parasitoid emergence was significantly shorter in the 3rd instar of the host (15.9 ± 1.06 d) than in the 1st instar (18.7 ± 2.3 d), but not in the 2nd instar (16.4 ± 1.3 d).     

麦长管蚜虫龄鉴别特征

【目的】为明确麦长管蚜Sitobion avenae (Fabricius)虫龄鉴别特征, 达到快速鉴别的目的。【方法】在成像观察的基础上, 测定无翅型和有翅型个体不同虫龄的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长6项指标。【结果】麦长管蚜不同翅型个体的体长、 体宽、 头壳宽、 触角长、 腹管长和后足胫节长在虫龄间均存在显著差异, 其中体长、 体宽、 头壳宽和触角长在相邻虫龄之间重叠程度大, 后足胫节长的重叠百分比极小或无重叠; 除有翅型个体4龄若蚜和成蚜之间存在13.93%的重叠外, 腹管长在不同翅型的其他相邻虫龄之间重叠百分比均极小或无重叠, 说明后足胫节长和腹管长可作为虫龄鉴定的主要特征。翅、 触角和尾片的其他外部形态特征在虫龄间也存在一定差异： 3-4龄有翅型若蚜和成蚜虫个体前胸的膨大程度及其翅的长度明显大于同一龄期的无翅型个体, 可用于蚜虫翅型的分辨以及3-4龄有翅若蚜和成蚜的鉴别; 麦长管蚜1和2龄若蚜触角均为5节, 3-4龄若蚜和成蚜的触角均为6节; 同时, 除了成蚜具有完整的尾片外, 1-4龄若蚜尾片均不发达, 说明触角的节数和尾片的发达程度可作为麦长管蚜不同龄期形态鉴别的辅助特征。【结论】以腹管和后足胫节作为麦长管蚜虫龄鉴别的主要特征, 配合其他辅助特征, 如翅的大小、 触角的节数以及尾片的发达程度等, 可达到快速鉴别不同翅型不同龄期蚜虫的目的。