南方根结线虫寄生真菌的分离和鉴定

 1992年和1993年,在广东和广西采集南方根结线虫样品44个,分离129个菌株,它们分属9属18种.     

利用微生物防除根寄生杂草列当

根寄生杂草列当(Orobanche spp.)已经严重制约全球许多地区的农业发展,寻找有效防除措施迫在眉睫。由于列当具有特殊生活史且与寄主关系密切,常规防除杂草措施难以达到理想防效。目前,尚无既能有效防除列当又不对寄主造成危害且便于大规模推广应用的列当防除措施。在众多列当防除措施中,微生物防除越来越引起关注和重视。本文对微生物防除列当的国内外研究进展及防除机理进行了综述。目前,列当生防微生物的研究主要集中在镰刀菌(Fusarium spp.)等列当病原菌和根瘤菌(Rhizobium spp.)等列当寄主植物共生菌上。微生物防除列当的机制主要包括两方面:一是通过产生代谢产物直接影响列当的萌发和生长,或通过降解列当种子萌发诱导物质间接影响列当的萌发;二是通过提高寄主植物自身对列当的抗性间接影响列当的寄生和生长。此外,本文还重点介绍了植物土传病害的土壤拮抗微生物防除列当杂草的可行性及研究进展。植物土传病害病原菌和列当均首先通过在地下侵染作物的根系进而危害作物正常生长,而作物抗土传病害的机理也与抗列当的机理类似。因此,存在于土壤中具有防治植物土传病害能力的微生物可能也具有防除根寄生杂草列当的功能。本团队前期试验从植物土传病害的土壤拮抗微生物中筛选到在盆栽试验中能够有效防除向日葵列当(O.cumana Wallr.)和瓜列当(O.aegyptiaca Pers.)的放线菌各1株,分别为淡紫褐链霉菌(Streptomyces enissocaesilis Sveshnikova)和密旋链霉菌(Streptomyces pactum Bhuyan B.K)。其中,密旋链霉菌的菌剂在田间试验中既降低了瓜列当的出土数量又增加了番茄的产量。总之,微生物是防除根寄生杂草列当的一条有效途径。     

不同生境下泽兰实蝇的寄生状况及其影响因素分析

[目的]研究不同生境下泽兰实蝇的寄生状况及其影响因素。[方法]通过对云南大中山地区紫茎泽兰入侵生境中泽兰实蝇的寄生状况抽样调查,分别从环境因素和紫茎泽兰生长状况两方面,分析了影响泽兰实蝇寄生的因素。[结果]不同生境泽兰实蝇的寄生状况有显著差异,其中林区公路和林区空旷地寄生率、虫瘿数和虫瘿内幼虫数最高,显著大于华山松林和落叶阔叶林。乔木层盖度与泽兰实蝇的寄生率、虫瘿数、虫瘿重呈显著负相关,而灌木层盖度与泽兰实蝇的寄生率呈显著正相关。泽兰实蝇寄生率与紫茎泽兰均高和开花率均呈极显著的正相关。[结论]开阔的生境有助于泽兰实蝇的寄生和扩散,林下的光照条件对泽兰实蝇的寄生亦有影响。泽兰实蝇偏好寄生林区公路边和林区空旷地植株较大、分枝较多的植株,泽兰实蝇对花期的植株可能更具有趋性。     

刺桐姬小蜂在南宁市的发生危害现状及防治对策

报道刺桐姬小蜂在南宁的发生危害情况,介绍刺桐姬小蜂的生物学特性,对刺桐姬小蜂侵入南宁市的途径及扩散原因进行分析,并提出防治对策。     

重庆地区栗瘿蜂寄生蜂种类及其控制作用的研究

通过野外调查和室内饲养,研究重庆市栗瘿蜂寄生蜂的种类及其对寄主种群消长的调控作用,结果表明,在重庆地区栗瘿蜂的主要寄生蜂有9种,分别隶属于膜翅目长尾小蜂科[中华长尾小蜂Torymus sinensis Kamijo、葛氏长尾小蜂Torymus geranial（Walker）、日本大痣长尾小蜂Megastigmus nipponicus Kamijo、斑翅大痣长尾小蜂Megastigmus maculipennis Kamijo、姬黄色长尾小蜂Megastigmus koebelei Ashmead]、旋小蜂科（栗瘿旋小蜂Eupelmus urozonus Dalman）、跳小蜂科（跳小蜂Encyrtidae sp.）、刻腹小蜂科（栗瘿刻腹小蜂Ormyrus sp.）、广肩小蜂科（广肩小蜂Eurytoma sp.）,全部为幼虫期体外寄生性小蜂,中华长尾小蜂Torymus sinensis Kamijo为优势种。个体数量较多的中华长尾小蜂Torymus sinensis Kamijo、栗瘿旋小蜂Eupelmus urozonus Dalman和栗瘿刻腹小蜂Ormyrus sp.分别占寄生蜂总个体数量的30.77%,20.98%,18.88%。在重庆地区寄生蜂是控制栗瘿蜂种群数量变动的主要因子。     

国内斑潜蝇寄生蜂的研究进展

为了进一步了解我国斑潜蝇寄生蜂的研究情况,对国内斑潜蝇寄生蜂的种类、生物学、生态学的研究和应用现状进行了综述,旨在为解决生产上斑潜蝇的危害以及我国斑潜蝇的持续控制打下基础。     

Organic matter and seed survival of Striga hermonthica – Mechanisms for seed depletion in the soil

Seed survival of Striga hermonthica is influenced by amendments of organic matter; however, the role of organic matter quality (C:N ratio) and mechanisms for enhanced seed decay are inadequately understood. In a field experiment, plots received a single dose of 6 t organic matter per hectare but with large differences in quality in terms of C:N ratio. Soil moisture, soil temperature and soil ethylene concentrations were measured, while buried nylon seed bags were periodically withdrawn from the soil and assayed for seed viability and germination. Organic matter amendments incorporated in the soil significantly depressed S. hermonthica seed survival. The effect was strongest with organic matter of high quality. Organic matter of low-quality enhanced soil water content during the first five days after a rainfall event and resulted in a 0.5 °C lower soil temperature. The highest observed ethylene concentrations in the soil were between 2 and 3 ppm, high enough to stimulate S. hermonthica seed germination. Maximal seed germination in vitro was obtained after 48 h of exposure to 1 ppm ethylene. However, observed changes in seed germination and viability of retrieved seed batches (seed survival) did not correlate with soil ethylene concentrations. The latter in turn did not differ between qualities of the applied organic matter. Seed survival decreased with increasing time of burial, especially after 4–8 weeks. As S. hermonthica attachment mainly occurs during the first four weeks of the cropping season the observed effect of seed decay may hardly be beneficial for the on-going cropping season. Nutrient release through decomposition of organic matter, enhancing decay of S. hermonthica seeds, is proposed as the probable cause of seed depletion in the soil.     

大陆漂移与云南胡蜂的扩散分布

云南高原位于北纬21°9′～29°15′和东经97°39′～106°12′之间,总面积394000km2,地质和气候、植被非常复杂.大陆漂移和冰期的进退是影响昆虫起源和演替的一个重要原因.昆虫的祖先是起源于一个统一大陆,在这个大陆上共同起源.共同进化,随着原始大陆的分离和漂移,把这些类群运载到各地,形成现今昆虫分布格局.昆虫的扩散是以中心分布方式成环状向周围扩散的.云南胡蜂的祖先是来自冈瓦那古陆.有两支昆虫进入云南,其中一支来自喜马拉雅山,另一支来自缅甸.冰期是导致南北生物互相混合和渗入的重要因素.胡蜂的特有类群是在冈瓦那古陆分裂之后才发展起来的.其祖先最早是分布在原始古陆较狭窄的区域内.     

Field response of Lathyrus cicera germplasm to crenate broomrape (Orobanche crenata)

Crenate broomrape (Orobanche crenata Forks.) is a major constraint for grain and forage legume cultivation in Mediterranean agriculture, to which little resistance is available. We studied the response to O. crenata of a germplasm collection of chickling pea (Lathyrus cicera L.) in field trials over two seasons showing that resistance although scarce and masked by confounding factors, is available and can be used in breeding. The level of infection was highly influenced by environmental factors and plant growth cycle. Earlier accessions were less infected due to competition of the earlier settled pods with O. crenata tubercles. O. crenata infection strongly reduced host biomass and grain yield. Deviations from the polynomic regression gave an improved approximation of the true genetic resistance levels present in the germplasm.