中国寄生于林木食叶害虫的短角平腹小蜂属(膜翅目,旋小蜂科)四新种记述

记述了短角平腹小蜂属Mesocomys Cameron(膜翅目,旋小蜂科)4新种:枯叶蛾短角平腹小蜂M.trabalae sp.nov.,短柄短角平腹小蜂M.breviscapis sp.nov.,落叶松短角平腹小蜂M.superansi sp.nov.,中华短角平腹小蜂M.sinensis sp.nov..它们均寄牛于我国重要的食叶害虫的卵.是重要的灭敌昆虫.同时,编制了我国矩角平腹小蜂属种的枪索表.     

林间释放平腹小蜂防治银杏大蚕蛾研究

笔者于1999-2000年在城口银杏大蚕蛾发生区释放用其卵繁育的平腹小蜂防治银杏大蚕蛾,结果表明:放蜂区虫卵寄生率明显提高,其校正寄生率为69.30%,是一种可利用的天敌昆虫.可在银杏大蚕蛾发生区内推广应用.     

松毛虫卵期几种寄生蜂的共寄生现象及其对寄生率的影响

松毛虫赤跟蜂 Trichogramma dendrolimi Matsumura 白跗平腹Pseudanastatusalbitarsis Ashmead松毛虫宽缘金小蜂Pachyneuron olitarium(Harig), 松毛虫黑卵蜂 Telenomus dendrolimusi Chu和大蛾卵跳小蜂Ooenvyrtus Kuwanae(Howard)是松毛虫卵期几种主要寄生蜂。通过对上述几种寄生蜂寄生习性的研究表明：赤眼蜂和平腹小蜂不但能寄生新鲜害虫卵,还可以寄生对方已寄生并巳发育1-3天的寄生卵,但羽化串均不高;松毛虫宽缘金小蜂不寄生新鲜害虫卵,专门寄生赤眼蜂寄生后巳发育1-7,天的寄生卵,其中又以赤眼蜂发育3-5天的卵寄生串和羽化率为最高。除赤眼蜂和平腹小蜂可以混合使用外,其它蜂种混用都不同程度地存在相互排挤的现象。如果先让平腹小蜂寄生尔后再让赤眼蜂寄生或先让赤眼蜂寄生,尔后再让跳小蜂或黑卵蜂寄生,能够提高卵块寄生串和充分发挥各自天敌的作用。     

松毛虫卵期几种寄生蜂的共寄生现象及其对寄生率的影响

松毛虫赤眼蜂Ｔｒｉｃｈｏｇｒａｍｍａｄｅｎｄｒｏｌｉｍ　Ｍａｔｓｕｍｕｒａ,白跗平腹小蜂ＰｓｅｕｄａｎａｓｔａｔｕｓａｌｂｉｔａｒｓｉｓＡｓｈｍｅａｄ,松毛虫宽缘金小蜂Ｐａｃｈｙｎｅｕｒｏｎ　ｓｏｌｉｔａｒｉｕｍ（Ｈａｒｔｉｇ）,松毛虫黑卵蜂Ｔｅｌｅｎｏ－ｍｕｓ　ｄｅｎｄｒｏｌｉｍｕｓｉ　Ｃｈｕ和大蛾卵跳小蜂Ｏｏｅｎｃｙｒｔｕｓｋｕｗａｎａｅ（Ｈｏｗａｒｄ）是松毛虫卵期几种主要寄生蜂。通过对上述几种寄生蜂寄生习性的研究表明：赤眼蜂和平腹小蜂不但能寄生新鲜害虫卵,还可以寄生对方已寄生并已发育１—３天的寄生卵,但羽化率均不高;松毛虫宽缘金小峰不寄生新鲜害虫卵,专门寄生赤眼蜂寄生后已发育１—７天的寄生卵,其中又以赤眼蜂发育３—５天的卵寄生率和羽化率为最高。除赤眼蜂和平腹小蜂可以混合使用外,其它蜂种混用都不同程度地存在相互排挤的现象。如果先让平腹小蜂寄生尔后再让赤眼蜂寄生或先让赤眼蜂寄生,尔后再让跳小蜂或黑卵蜂寄生,能够提高卵块寄生率和充分发挥各自天敌的作用。     

水稻种植密度和生育期对三化螟卵天敌种群及其效益的影响

研究结果表明,水稻种植密度和生育期对三化螟Scirpophaha incertulas卵的天敌种群及其捕食串和寄生率有显著的影响。捕食性天敌和某些寄生蜂的种群密度随种植密度的增加和生育期的增长而增加,但啮小蜂和赤眼蜂对种植密度的反应不明显。螟卵捕食串随种植密度的增加和生育期的增长而增加。但螟卵寄生率则相反：种植密度低、生育期早,卵寄生率高,且差异显著。种植密度和生育期不仅影响了单种寄生蜂的寄生率,而且也影响了螟卵寄生蜂种类的多少。在种植密度低的地块和水稻生长初期,卵块通常有3种寄生蜂出现,而在密度高的地块和生长末期,卵块通常没有寄生蜂或仅有赤眼蜂出现。虽然卵捕食和卵寄生都是三化螟卵的重要控制因素,但由天敌所造成的卵死亡率则随种植密度的增加或生育期的延长而下降。     

平腹小蜂Anastatus sp.个体发育与马尾松毛虫胚胎发育的相互影响

在28℃恒温下,松毛虫的胚胎发育期为7—8天;平腹小蜂的个体发育周期为19天左右,其中胚胎期约2天。如果松毛虫在产卵后12小时,胚胎发育到盘形成期以后,被平腹小蜂寄生,则胚盘在半小时内解体离散成匀质;产卵后约36小时,胚带形成后被寄生,经约5—12小时,胚带开始破坏而逐渐解体离散成为小颗粒;松毛虫胚胎发育到胚动以后,甚至将近孵化时,仍可被平腹小蜂寄生,并将离散后的寄主胚胎组织吞食殆尽,发育成蜂,破卵壳出来。在松毛虫胚胎发育早期被寄生,卵粒寄生率高,蜂的成活率也高,反之则低。 同一寄主卵可被一头或多头平腹小蜂复寄生。一粒寄主卵内的寄生蜂卵可达9粒,但最后只羽化一头蜂。     

一种寄生梨茎蜂的重要天敌-梨茎蜂啮小蜂(膜翅目,姬小蜂科)新种记述

描述了寄生梨茎蜂Janus piri Okamoto et Muramatsu的一种重要天敌新种--梨茎蜂啮小蜂Tetrastichus janusi sp.nov.,该种属小蜂总科姬小蜂科啮小蜂属.新种群集外寄生于梨茎蜂幼虫,一般1头寄主上寄生4～14头个体,雌雄性比为2.6∶1.0.一年发生两代.在越冬代梨茎蜂幼虫中的寄生率达44.7%.新种在梨茎蜂的生物防治中具有良好的应用前景.这是啮小蜂亚科在国内外首次发现寄生于茎蜂科害虫.新种模式标本保存于中国林业科学研究院昆虫标本馆.     

寄生于红腹缢管蚜的蚜小蜂属二新种（膜翅目：蚜小蜂科）

红腹缢管蚜为陆稻的重要根部害虫,云南文山州发现其有效寄生天敌,经研究为蚜小蜂属２新种：文山蚜小蜂Ａｐｈｅｌｉｎｕｓ ｗｅｎｓａｎｕｓ ｓｐ．ｎｏｖ．及缢管蚜小蜂Ａｐｈｅｌｉｍｕｓ ｒｈｏｐａｄｏｓｉｐｈｉｐｈａｇｕｓ ｓｐ．ｎｏｖ．,本文详加描述、比较、并略论及中国蚜小蜂科概况,新种模式标本存北京农业大学昆虫标本馆。     

舞毒蛾卵平腹小蜂野外寄生柞蚕卵规律的观察

2005年5～9月,在长春市吉林农业大学校园内的杨树林和李树林内进行人工挂放柞蚕Antheraea pernyi Guerin-Meneville卵卡诱集本地平腹小蜂Anastatus spp.寄生试验.结果表明杨树林中的舞毒蛾卵平腹小蜂Anastatus japonicus Ashmead的寄生率最高可达23.1%,李树林中的舞毒蛾卵平腹小蜂的寄生率最高可达33.5%,李树林中舞毒蛾卵平腹小蜂的寄生率明显高于杨树林.全年中,舞毒蛾卵平腹小蜂分别在6月下旬和8月上旬出现2次寄生高峰.     

中国林木害虫寄生蜂研究概况

本文从林木害虫寄生蜂资源调查、主要种类生物学、生态学、生理生化、人工繁殖及利用等方面综述了我国林木害虫寄生蜂的研究进展.并介绍了松毛虫赤眼蜂、管氏肿腿蜂、花角蚜小蜂、平腹小蜂及白蛾周氏啮小蜂等的利用情况.     

Sentinel eggs underestimate rates of parasitism of the exotic brown marmorated stink bug,Halyomorpha halys

Native to eastern Asia, the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), has become a serious invasive pest in North America. Consequently, accurate assessment of parasitism rates under field conditions is critical for determining baseline parasitism rates of native egg parasitoids on BMSB, and for future evaluations of native or exotic parasitoid biological control release strategies and impacts. BMSB sentinel (laboratory-laid) egg masses have typically been used for this purpose, even though they could be providing misleading estimates of parasitoid activity. Accordingly, we compared the use of BMSB sentinel (laboratory-laid) and wild (naturally field-laid) egg masses in 2012 and 2013 to examine rates of parasitism and the parasitoid community composition of indigenous egg parasitoids in outdoor ornamental nurseries. Wild egg masses consistently had higher rates of parasitism than sentinel egg masses. In 2012, wild egg masses had a mean percent parasitism of 28.4% compared to 4.6% in sentinel egg masses, while in 2013 the difference between the two methods increased even further with a mean percent parasitism of 55.3% in wild egg masses compared to 0.8% in sentinel eggs. Furthermore, we found greater total numbers of parasitoids (889, 42) and greater species richness (seven, five), when using wild egg masses compared to sentinel egg masses, respectively. While sentinel egg masses provide a rapid and convenient way to assess the presence of natural enemies, our findings indicate that using sentinel egg masses could dramatically underestimate actual rates of parasitism and provide inaccurate estimates of parasitoid community composition. Future studies should address potential mechanisms underlying these patterns such as lack of certain host cues required by parasitoids in sentinel compared to wild egg masses.     

Responses of native egg parasitoids to the invasive seed bug Leptoglossus occidentalis

1. The Western conifer seed bug Leptoglossus occidentalis, a native insect of North America, was accidentally introduced in Europe in the late 1990s. Since then, it has spread rapidly. Biological control could provide an efficient management option but natural enemies of the pest have been poorly examined in Europe.
2. In this study, we exposed sentinel egg masses and collected naturally laid egg masses in southern France in 2016 and 2017, to identify the egg parasitoids of L. occidentalis and investigate their potentials.
3. Three egg parasitoids were detected: Anastatus bifasciatus, Ooencyrtus pityocampae and Ooencyrtus telenomicida. The overall parasitism was low compared to that observed in the native range with 6.4% of all eggs being parasitized, while 17.1% of egg masses carried at least one parasitized egg. The total number of parasitized egg masses was similar between parasitoid species, but the mean number of parasitized eggs per egg mass was highest for A. bifasciatus (5.57 vs. 1.25 for Ooencyrtus spp.).
4. Sentinel egg masses underestimated the parasitism compared to natural egg masses (respectively, 1.42% and 7.71%).
5. Our results suggested that the three generalist parasitoids detected can respond in a Leptoglossus egg density-dependent manner, but this requires further investigations.

     

Trichogramma pretiosum parasitism and dispersal capacity: a basis for developing biological control programs for soybean caterpillars

In order to succeed in biological control programs, not only is it crucial to understand the number of natural enemies to be released but also on how many sites per area this releasing must be performed. These variables might differ deeply among egg parasitoid species and crops worked. Therefore, these trials were carried out to evaluate the parasitism (%) in eggs of Anticarsia gemmatalis and Pseudoplusia includens after the release of different densities of the egg parasitoid Trichogramma pretiosum. Field dispersal was also studied, in order to determine appropriate recommendations for the release of this parasitoid in soybean fields. The regression analysis between parasitism (%) and densities of the parasitoid indicated a quadratic effect for both A. gemmatalis and P. includens. The maximum parasitism within 24 h after the release was reached with densities of 25.6 and 51.2 parasitoids per host egg, respectively, for the two pests. Parasitism of T. pretiosum in eggs of P. includens decreased linearly as the distance of the pest eggs from the parasitoid release sites increased. For P. includens, the mean radius of T. pretiosum action and the area of parasitoid dispersal in the soybean crop were 8.01 m and 85.18 m2, respectively. We conclude that for a successful biological control program of lepidopteran pests using T. pretiosum in soybean fields, a density of 25.6 parasitoids per host egg, divided into 117 sites per hectare, should be used.     

Natural enemies of the maize cob borer,Mussidia nigrivenella (Lepidoptera: Pyralidae) in Benin,West Africa

Mussidia nigrivenella Ragonot is a pest of maize cobs in West Africa. It significantly reduces maize yields and grain quality, with quantitative losses of 2-25%at harvest, and up to 10-15% indirect losses due to an increase in storage pest infestation levels. Infestation by M. nigrivenella also significantly increased the susceptibility of maize to Aspergillus flavus infection and subsequent aflatoxin contamination. Surveys conducted in different agro-ecological zones of Benin on cultivated and wild host plants during 1994-1997 revealed one egg parasitoid, three larval parasitoids and one pupal parasitoid attacking M. nigrivenella. Egg parasitism was scarce on all host plants sampled and in all four agro-ecological zones. Parasitism by larval and pupal parasitoids was usually less than 10%, and varied with host plant species. Both larval and pupal parasitoids were rare or absent in cultivated maize fields. The solitary chalcidid pupal parasitoid, Antrocephalus crassipes Masi, was the predominant species, contributing approximately 53% of the observed mortality. Logistic regression analysis indicated that this parasitoid was more prevalent on fruits of Gardenia spp. (Rubiaceae) than on the other host plant species including maize used by M. nigrivenella, and was most abundant between February and September. The differences in parasitoid diversity and parasitism between Benin and other regions suggest that there are opportunities for biological control through introduction of exotic parasitoids or using the 'new association' approach, which uses natural enemies of closely related host species that occupy similar ecological niches to the target pest.     

Differences in egg parasitism of Chrysophtharta agricola (Chapuis) (Coleoptera: Chrysomelidae) by Enoggera nassaui Girault (Hymenoptera: Pteromalidae) in relation to host and parasitoid origin

Abstract The first instances of egg parasitism of Chrysophtharta agricola , a pest of eucalypt plantations, are recorded. Enoggera nassaui was found parasitising C. agricola egg batches in Tasmania, the Australian Capital Territory (ACT), New South Wales and Victoria: this is the first record of this parasitoid species from Victoria. One instance of Neopolycystus sp. parasitising C. agricola eggs in Victoria was also recorded. Parasitism of egg batches by E. nassaui ranged from 0 to 55% between five geographical populations collected in mainland Australia ( n  = 45), and from 0 to 2% between two populations collected in Tasmania ( n  = 300). For mainland sites at which parasitism was recorded, parasitism rates within sites differed significantly from either population in Tasmania. Reciprocal exposure experiments using one Tasmanian (Florentine Valley) and one parasitised mainland (Picadilly Circus, ACT) population were conducted in the laboratory to examine whether these different parasitism rates were attributable to egg or parasitoid origin. Parasitoids from the ACT parasitised C. agricola eggs of both origins more successfully than parasitoids from Tasmania, with up to 65% wasp emergence compared with 33% from Tasmania. Parasitoid origin significantly affected the number of wasps that emerged from exposed batches, but not the total loss from parasitism.     

Long-term seasonal fluctuations of lepidopteran cereal stemborers and their natural enemies on maize and wild host plants in southern Benin

Abstract  The seasonal fluctuation of lepidopteran cereal stemborers on maize and wild host plants (i.e., grasses and a few sedges) was investigated in southern Benin from 1988 to 1998 by time series analysis and repeated-measures analysis of variance (ANOVA). In addition, a walk-in light trap was used to study the flight behavior of adult moths. On both cereals and grasses, the noctuid Sesamia calamistis was the predominant species, followed by the pyralid Eldana saccharina . The noctuid Busseola fusca was rare on both maize and wild host plants. In general, pest populations increased during the course of the year to reach peak densities during the second short rainy season, and then crashed to close to zero during the dry season. On wild host plants, egg masses and other immature stages were collected throughout the year but they were higher on wild grasses than maize during the off-season. Thus wild host plants can be considered as refuge for both borers and natural enemies during the off-season, when maize is not available. However, only four out of the eleven wild host species played a discernable role. S. calamistis egg densities appeared to be influenced by density-dependent factors, suggesting an effect of natural enemies. Temperature and rainfall had a negative effect on egg abundance. Larval parasitism by a Kenyan strain of the braconid Cotesia sesamiae , which was released in southern Benin in the early 1990s, and by the tachinid Sturmiopsis parasitica varied between seasons and years but there were no discernable patterns. For both parasitoids and borer host species, parasitism was positively correlated with trap catches of adult moths. The recovery of C. sesamiae during a 2-year period suggests that the parasitoid has established its population in southern Benin.     

茶翅蝽沟卵蜂和黄足沟卵蜂对茶翅蝽的寄生潜能研究

茶翅蝽Halyomorpha halys(Stl)是水果和蔬菜生产中的重要害虫。为了寻找优势卵寄生蜂用于其生物防治,本文进行了相关的野外调查和室内试验。通过定期野外采集茶翅蝽卵块,培育、收集和鉴定寄生蜂,发现在自然环境中茶翅蝽卵粒的寄生率为56.29%,其中茶翅蝽沟卵蜂比例最高,占77.66%;其次是黄足沟卵蜂占20.44%。Y型嗅觉仪测定结果显示,茶翅蝽沟卵蜂和黄足沟卵蜂对茶翅蝽卵均具有明显的选择趋性。室内寄生能力试验结果表明,茶翅蝽沟卵蜂与黄足沟卵蜂单独作用的寄生率分别为94.06%和84.21%,与两种寄生蜂混合寄生茶翅蝽卵的寄生率91.65%均无显著性差异。两种寄生蜂混合寄生时,茶翅蝽沟卵蜂与黄足沟卵蜂的寄生比例分别为58.95%和41.05%,二者之间无显著差异。     

The relationship among host plant species,egg clutch size,and level of parasitism for the sharpshooter Tapajosa rubromarginata

The sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae, Proconiini), a vector of the bacterium Xylella fastidiosa Wells et al. (Xanthomonadaceae) that causes citrus variegated chlorosis, has more than 30 reported host plant species. The fitness of a phytophagous insect is determined by the host plant suitability, plant resistance, and the natural enemies. The aim of this study was to: (1) identify plant species utilized as oviposition substrate by T. rubromarginata in the field; (2) establish the relationship between plants and clutch size; (3) establish the relationship among host plants, clutch size, and level of parasitism; and (4) establish variations in parasitoid composition and abundance in the various host plants. Egg masses of the sharpshooter were surveyed on plants reported as hosts, or those that were abundant in the study site. The number of eggs of the sharpshooter and emerged parasitoids were recorded for all the collected masses. We found egg masses of T. rubromarginata on 12 out of 21 plant species sampled. The size of the egg masses was greatly influenced by the type of leaf venation and to a lesser extent by the plant species. Parasitism rates were influenced by both leaf venation and host plant. Trichogrammatidae species were mostly associated with egg masses in plants with parallel-veined leaves, whereas Mymaridae attacked masses laid in reticular-veined leaves. The choice between a good host plant, but heavily attacked by parasitoids, and the host plants that are less suitable for nymphs but less frequently attacked by natural enemies, was a trade-off for T. rubromarginata females to increase their fitness. We conclude that the host plant utilization by T. rubromarginata females in the field could be influenced by leaf structure and the strategy to avoid parasitism by selecting plants that were less attractive for parasitoids.