华北地区十字花科芸薹属蔬菜上立枯丝核菌的病原生物学研究

 由丝核菌引起的十字花科蔬菜叶腐和茎基腐病在中国华北地区普遍发生,其中以河北、内蒙以及北京较为严重。2011~2018年,从华北地区不同省份具有典型叶腐和茎基腐症状的芸苔属蔬菜上分离获得95个丝核菌(Rhizoctonia spp.)分离物,大多数分离自发病植株的叶部,少数分离自茎基部。通过细胞核染色,87株菌属于多核丝核菌,另外8株属于双核丝核菌;经菌丝融合鉴定、rDNA-ITS区及TEF-1α(translation elongation factor 1-alpha, TEF-1α)序列分析,大多数多核丝核菌属于立枯丝核菌(Rhizoctonia solani)AG-2-1(74％),其他少数分别属于AG-1-IB(16％)、AG-4-HG II(2％)和双核丝核菌AG-A(8％)。温室条件下进行寄主范围致病力测定,各分离物对原寄主都表现出致病力,呈现典型叶腐或茎基腐症状;对其他作物的致病力差异较大。不同融合群(Anastomosis group,AG)的菌株对寄主致病力大小存在差异,AG-2-1致病力最强,只有AG-A对叶部没有致病力。AG-2-1对寄主叶部的致病力和对茎基部的致病力呈显著正相关,AG-1-IB对寄主叶部的致病力和对茎基部的致病力无显著相关性。     

Genetic diversity of the pine pathogen Lecanosticta acicola in Slovenia and Croatia

Brown spot needle blight (BSNB), a disease of pine trees caused by the fungus Lecanosticta acicola, has been known in Slovenia since 2008 and in Croatia since 1975. Recent outbreaks in Slovenia prompted this study to compare L. acicola populations in these two neighbouring European countries. Sixty-nine isolates collected from three pine species (Pinus mugo, P. halepensis and P. nigra) were used to determine the phylogenetic relationships, genetic structure, and reproductive strategy of the pathogen. EF1-α sequences showed that Slovenian and Croatian isolates share a common ancestry with individuals from central and northern Europe. Population structure analysis revealed four distinct population clusters of L. acicola in these two countries, generally corresponding to their respective geographic location and host. An unequal ratio of mating types and a low overall genetic diversity in the population indicated a strong influence of asexual reproduction. Although some of the oldest recorded European occurrences of BSNB are from Croatia, this study provided no evidence that the population studied in Croatia was the source of the sampled outbreaks in Slovenia. Recent outbreaks of L. acicola in Slovenia are most likely due to introductions from other, yet to be identified, sources.     

寄生不同龄期草地贪夜蛾的斑痣悬茧蜂生长发育表现

草地贪夜蛾Spodoptera frugiperda(J. E. Smith),又称秋黏虫,是新入侵我国的外来物种。为探究本土天敌斑痣悬茧蜂寄生不同龄期草地贪夜蛾幼虫后的生长发育表现,本研究检测了斑痣悬茧蜂寄生2龄、3龄和4龄草地贪夜蛾幼虫后子代蜂幼虫发育历期、茧历期、羽化率、茧重、成蜂个体大小和成蜂寿命。结果表明,寄主龄期对子代蜂的幼虫发育历期、茧历期和成蜂寿命存在显著影响。与寄生4龄幼虫的子代蜂相比,寄生2龄和3龄幼虫的子代蜂幼虫发育历期分别平均延长了2.08 d(z=5.42,P0.05)和1.64 d(z=4.23,P0.05);寄生2龄幼虫的子代蜂茧历期平均延长了0.46 d(z=3.51,P0.05),但寄生4龄幼虫的子代蜂茧历期与寄生3龄幼虫的子代蜂茧历期无显著差异。4龄幼虫体内羽化的子代蜂成蜂寿命比在2龄和3龄幼虫体内羽化的子代蜂成蜂寿命分别平均延长了1.46 d(z=-2.60,P0.05)和1.68 d(z=-2.98,P0.05)。寄主龄期对子代蜂羽化率、茧重和成蜂个体大小无显著影响。随寄主龄期增大,子代蜂的发育速度加快,但寿命缩短。研究结果将为揭示斑痣悬茧蜂与寄主草地贪夜蛾的互作关系提供参考。     

中华卵索线虫人工室内培养技术

为室内大量繁殖中华卵索线虫Ovomermis sinensis,采用个体由大到小的斜纹夜蛾Spodoptera litura、棉铃虫Helicoverpa armigera和黏虫Mythimna separata作为宿主,测定被中华卵索线虫寄生后3种宿主的体长和体重,研究宿主种类对中华卵索线虫有效率、雌雄比和体长的影响以及寄生强度对线虫雌雄比的影响。结果显示,被中华卵索线虫寄生后,斜纹夜蛾、棉铃虫和黏虫生长减缓。在相同感染比例下（除宿主与线虫比为1∶15外）,3种宿主的线虫有效率之间差异不显著。当寄生强度为5时,3种宿主体内脱出的中华卵索线虫均为雌线虫;当寄生强度从10增到40时,斜纹夜蛾、棉铃虫和黏虫所脱出的雌性比分别由100.0%、90.0%、83.9%降为0;相同寄生强度下,从斜纹夜蛾体内脱出的雌性比显著高于从棉铃虫与黏虫体内脱出的雌性比。斜纹夜蛾、棉铃虫和黏虫体内脱出雌线虫和雄线虫平均体长分别为14.8、13.8、12.8 cm和8.0、7.5和7.5 cm。当中华卵索线虫与宿主按照比例20∶1～25∶1侵染斜纹夜蛾、按照15∶1侵染棉铃虫和黏虫时,能获得线虫最适雌雄比（1∶1...     

寄主植物对舞毒蛾生长发育的影响

该文选择了青杨Populus cathayanaRehd.、华北落叶松Larix principis-rupprechtiiMayr.和山杏Aarmeniaca sibiricaLinn.,研究植物对舞毒蛾Lymantria disparL.生长发育历期、蛹重、产卵量的影响。结果表明舞毒蛾发育历期、蛹重及产卵量与所取食的寄主植物有明显的相关性,取食华北落叶松的舞毒蛾个体发育历期最短,平均为38.22±0.56 d,蛹最重,平均为1.48±0.09g,产卵量最多,平均每雌560.65±41.67粒;取食青杨的舞毒蛾发育历期最长,平均为46.68±0.65 d,蛹最轻,平均为1.17±0.08 g,产卵量最少,平均每雌315.47±49.07粒;取食山杏的舞毒蛾间于二者之间,平均历期为39.53±0.58 d,平均蛹重为1.24±0.08 g,每雌产卵量394.50±58.65粒。可以认为,在供试范围内华北落叶松最适宜舞毒蛾生长发育,山杏次之,青杨最不适宜。