植物挥发物在寄生蜂寄主定位中的作用

植物挥发物在寄生蜂的寄主栖息地定位中起着重要作用。在自然状态下,某些健康植物能释放对寄生蜂有吸引作用的挥发物。当植物受到植食性昆虫为害后,可引起植物的间接防御,即产生对一定种类寄生蜂具引诱作用的挥发物来保护自己。此外,害虫的产卵也能诱导部分植物产生引诱天敌的物质。对于植食性昆虫取食植物诱导的挥发物研究较深入,而其产卵对植物挥发物的影响研究较少。本文主要综述近年国内外有关植物挥发物对寄生蜂寄主定位影响的研究概况,可望为害虫综合治理研究提供参考。     

新疆额敏县野果林苹果巢蛾主要寄生蜂调查

近年来,新疆塔城地区额敏县野果林遭受苹果巢蛾Yponomeuta padella Linnaeus的严重危害,造成重大经济损失.为寻找其有效天敌,保护这些珍贵的果树资源,2008-2009年,对额敏县野果林苹果巢蛾的寄生性天敌资源展开了调查.通过野外采集及室内饲养,发现了寄生于该害虫卵、幼虫及蛹的3种寄生蜂,即:卵-幼虫跨期寄生蜂--巢蛾多胚跳小蜂Ageniaspis fuscicollis(Dalman),蛹期寄生蜂-黄柄齿腿长尾小蜂Monodontomerusdentipes(Dalman)和幼虫-蛹跨期寄生蜂--全北群瘤姬蜂指名亚种Iseropus stercorator stercorator(Fabricius);其中巢蛾多胚跳小蜂为优势种,寄生率可达95.98%.本研究为苹果巢蛾的生物防治奠定了基础.     

山西省蚜茧蜂自然分布中心及生态地理特征

对山西省境内已知蚜茧蜂种类，按植被划分的五个特定自然分布中心，如雁北干草草区、晋西北灌丛草原区等进行了分析。还归纳了蚜草蜂分布的生态地理特征。     

转基因棉和寄生蜂对棉铃虫生长发育的互作效应

通过比较棉铃虫的体重和发育历期,并运用SPSS软件分析,研究了转基因棉和寄生蜂对棉铃虫生长发育的影响。结果显示:转基因棉中抗310与对照常规棉泗棉3号相比能明显地抑制棉铃虫的生长发育,棉铃虫幼虫的寄生蜂中红侧沟茧蜂和棉铃虫齿唇姬蜂均能有效的控制棉铃虫,且当转基因棉和寄生蜂共同作用时,对棉铃虫的控制效果明显优于任一单因子的效果。     

Parasitoids of the grapeleaf skeletonizer, Harrisina brillians Barnes and McDunnough (Lepidoptera: Zygaenidae) in northwestern Mexico

Nine species of parasitoids were collected from pupae of the grapeleaf skeletonizer, Harrisina brillians Barnes and McDunnough (Lepidoptera: Zygaenidae) in Caborca, Sonora in northwestern Mexico. The parasitoids detected and the percentage parasitization observed were: Ametadoria misella (Wulp), (Diptera: Tachinidae) 29.3%; Hockeria rubra (Ash.), and a species from the genus Euchalcidia (Hymenoptera: Chalcididae), plus five suspected species, all from the family Eulophidae, and a species from the genus Arachnophaga (Hymenoptera: Eupelmidae), 21.6%. Mortality due to unknown causes was 13.7%. In all, 64.6% parasitization and mortality was observed. The most abundant parasitoids were the five unidentified suspected species of Eulophidae, which corresponded to 46% of the total collected; the species from the genus Euchalcidia made up 31% of the total; the tachinid fly, Ametadoria misella comprised 15%; Hockeria rubra comprised 8%, and the species from the genus Arachnophaga comprised < 1%.     

两株虫生真菌对草地贪夜蛾的致病力及高毒力菌株与卵寄生蜂的相容性

为有效防控新入侵我国的重大农业害虫草地贪夜蛾 Spodoptera frugiperda,采用浸叶法测定球孢白僵菌 Beauveria bassiana菌株Bb1237、 Bb201017、 Bb20091317及金龟子绿僵菌 Metarhiziumanisopliae菌株Ma189和莱氏绿僵菌 M. rileyi菌株MrCDTLJ1对草地贪夜蛾3龄幼虫的致病力,筛选对草地贪夜蛾3龄幼虫有较强致病力的菌株,并测定该菌株对草地贪夜蛾3龄幼虫的致病力和对其天敌的致死率。结果显示,球孢白僵菌Bb20091317和莱氏绿僵菌MrCDTLJ1对草地贪夜蛾3龄幼虫的累计校正死亡率显著高于其他菌株,分别为95.59%和97.06%,致死中时LT₅₀分别为3.42 d和5.72 d, LC₅₀分别为7.05×10⁶个/mL和2.25×10⁵个/mL。2种菌在高浓度1×10⁸个/mL下对草地贪夜蛾天敌夜蛾黑卵蜂 Telenomus remus和玉米螟赤眼蜂 Trichogramma ostriniae成蜂的致死率也仅介于15%~20%之间。表明球孢白僵菌Bb20091317和莱氏绿僵菌MrCDTLJ1不仅对草地贪夜蛾有高致病力,同时与夜蛾黑卵蜂和玉米螟赤眼蜂有较好的相容性。     

Wheat Disease Situation in Madhya Pradesh,India

Leafminter of the genus Liriomyza are important pests of agricultural crops. In the mid-1990s three polyphagous new world species have been accidently introduced into South-East Asia. Different aspects of the biology of one species, Liriomyza sativae Blanchard, were studied during the period May 2000?–?July 2001 in Hanoi province in northern Vietnam on longbean, soybean, tomato, potato and cucumber. Trapping of adults and counting of larvae in mines showed that in May?–?June the generation time was approximately 15 days. This was supported by laboratory studies at constant temperature. The generation time was about 25?–?30 days in October?–?November and about 20 days in the spring season (February?–?May), based on adult trapping. In an unsprayed field, more than 50% of all mines contained parasitized larvae about 2 months after transplanting. Use of insecticides had little effect, indicating resistance in the leafminers.     

Establishment and dispersal of the parasitoids Ageniaspis citricola Logvinovskaya (Hymenoptera: Encyrtidae) and Semielacher petiolatus Girault (Hymenoptera: Eulophidae), introduced into Tunisia for the biological control of Phyllocnistis citrella (Lepidoptera: Gracillariidae)

Abstract

A programme for the biological control of the citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera, Gracillariidae) was carried out in Tunisia between 1996 and 1998. Two exotic parasitoids, Ageniaspis citricola (Logvinovskaya) (Hymenoptera, Encyrtidae) and Semielacher petiolatus Girault (Hymenoptera, Eulophidae), were introduced from Australia, mass-reared in a greenhouse on Citrus aurantium L. seedlings infested with P. citrella, and released in different orchards located in the major citrus-growing area of Tunisia. In 1996, A. citricola was recovered in 39.13% of release sites, reaching a maximum percentage of parasitism of 28%. In 1997, the parasitoid was recovered in a third of all release points, with an average percentage of parasitism of 5%. However, the wasp was unable to survive the winter 1998, and has become extinct. The non-establishment of A. citricola may have been due to the more arid climatic conditions present during the rainless summer and most of the autumn in Tunisia. By contrast, the establishment, dispersal, and reduction in citrus leafminer population observed with S. petiolatus between 1997 and 1998 shows this species to be well-adapted to the Tunisian climate. The average percentage parasitism of P. citrella by S. petiolatus increased from 6.6% in 1997 to 15% in 1998. Moreover, S. petiolatus was established in 76% of release points in 1997 and in 82% in 1998. It spread as much as 30 km from some release points, with no apparent decline in parasitism levels with distance. Semielacher petiolatus is considered to be an effective biological control of the leafminer in Tunisia. Its biological control action would supplement the action of the native parasitoids Pnigalio sp. and Cirrospilus pictus Nees (Hymenoptera, Eulophidae).     

Past Studies on and Present Status of Lethal Yellowing Disease of Coconuts

Abstract

The symptoms and extent of lethal yellowing disease of coconuts are described. In research into the cause of the disease nutrient deficiencies, fungi, bacteria, nematodes and, more recently, viruses have been investigated without implicating any causal agent. Mechanical and insect transmissions were attempted by a number of methods. The incubation period was shown to be 3–9 months for young palms and 7–15 months for bearing palms. Experiments to control the disease have been unsuccessful.

Local and introduced coconut varieties and hybrids are being tested for resistance by field exposure. The Malayan Dwarf variety has been shown to have high resistance and is being used to replant the industry. No other variety or hybrid is deemed as yet to be sufficiently resistant for farm planting.

Mycoplasms were recently found associated with the disease. Future research must include confirmation of mycoplasm-lethal yellowing association, continuation of the search for the vector, experimental chemotherapy, and attempts to culture mycoplasms to develop an inoculation technique. Palms showing resistance will be used in the breeding programme. Promising hybrids will be produced in greater numbers for more extensive testing and further introductions will be made.     

Effect of Weeding Regime and Plant Spacings on Weed Growth and Performance of Transplanted Rice

Abstract

Effect of weeding regime (unweeded control, hand weeding once, 4 weeks after transplanting (w.a.t.) and hand weeding twice, 4 and 7 w.a.t.) and different plant spacings (20 × 2.5 cm, 20 × 5 cm, 20 × 10 cm, 20 × 15 cm and 20 × 20 cm) on weed growth and performance of transplanted rice were tested in a split-plot design. Grain yield and number of panicles were not significantly different in both weeding treatments from the unweeded control at 20 × 2.5 to 20 × 10 cm spacings, showing that, at closer spacings weed control may not be necessary to increase grain yield. The number of weeds at harvest was significantly lower in the weeded plots than the unweeded control at all spacings used. Weed weight at harvest was significantly affected by weeding regime at all spacings except at 20 × 2.5 cm, where no significant difference was observed between the weeded and the unweeded plots. Plant spacings significantly affected the grain yield and weed weight, but did not affect the panicle number and weed counts of transplanted rice. At 20 × 2.5 cm, grain yield was significantly better than that at 20 × 15 cm or 20 × 20 cm. A simple trend of increase in grain yield along with the decrease in spacing between plants was observed in terms of actual grain yield.