陕西不同地区马铃薯腐烂茎线虫的分离鉴定及同源性分析

旨在鉴定陕西不同地区马铃薯腐烂茎线虫生物型,为其防治提供理论依据。对陕西不同地区马铃薯腐烂茎线虫进行分离,对其形态进行观察并测量特征值,通过茎线虫线粒体COⅠ通用引物、ITS区通用引物及A、 B生物型的特异性引物对不同地区采集马铃薯腐烂茎线虫进行PCR检测及序列分析,利用MEGA6.0进行系统发育树构建及种群同源性分析。结果表明,陕北地区腐烂茎线虫的生物型为B型,关中地区为A型。形态特征值数据显示雌成虫体长、体宽均大于雄成虫,A型的体长、体宽均大于B型。系统发育树结果显示,陕北不同地区的B型马铃薯腐烂茎线虫聚为一支,合阳、兴平的A型马铃薯腐烂茎线虫聚为一支,与分子鉴定结果相一致。     

姜瘟病发生规律调查及防治建议

通过对舒城、铜陵、临泉、体宁等主要栽姜区姜瘟病发生规律的调查、病原菌鉴定和防治研究,明确了引起姜瘟病的病原菌为姜青枯假单胞菌,除少数菌株属生物型Ⅲ外都为生物型Ⅳ。新栽姜区的菌原主要来自带病种姜,而老姜区土壤带菌和带病种姜都是主要侵染源。病害发生与轮作、种姜处理、气候、姜田管理、土质、施肥等关系密切。采取轮作、选留无病种姜建立留种田、种姜处理、加强田间管理等,结合大田期药物防治能有效的控制病害。     

Economic injury levels for Bemisia tabaci (Homoptera: Aleyrodidae) in cotton: impact of crop price, control costs, and efficacy of control

Field studies were conducted during 1993 and 1994 in the Imperial Valley, California and Maricopa, Arizona to examine relationships between densities of Bemisia tabaci (Gennadius) populations and cotton (Gossypium hirsutum L.) yields, and to estimate economic injury levels (EILs) for pest management application. Populations of B. tabaci were manipulated by applying different numbers of insecticide applications in replicated plots. Resulting insect populations and cotton lint yields were used to develop damage functions and to estimate EILs for all life stages in relation to variable cotton prices, insecticide costs, and pest control efficacy. Economic injury levels declined with increasing cotton prices and increased as the cost of control increased, however, these changes were relatively small, based on typical ranges in price and control costs. In contrast, the efficacy of control provided by insecticide applications had a large influence on EILs, with lower efficacies being associated with higher injury levels. We developed a multiple regression model that accounted for the dynamic changes in the EIL in relation to crop price, control costs, control efficacy, and potential yield. Based on average prices and reasonable control costs and efficacy, EILs ranged from 5.9–15.2 adults/leaf, 6.1–19.8 eggs cm⁻², and 1.7–4.7 nymphs cm⁻² of leaf area. Additional research is needed to more closely relate the costs of control to the suppression of insect populations, and to define economic thresholds that will enable pest managers to maintain pest populations below EILs.     

Sequence Analysis of mtDNA COIGene and Molecular Phylogeny of Different Geographical Populations of Bemisia tabaci (Gennadius)

Bemisia tabaci(Gennadius) is a serious pest in many cropping systems worldwide and occurs in different biotypes. The mtDNA COI gene of the 12 Bemisia tabaci (Gennadius) populations from different regions and countries were analyzed.Based on mtDNA COI sequences, their biotypes were characterized and phylogenetic relationships among these populations were established with the method of UPGMA. The results indicated the genetic similarity between those populations from Beijing, Zhengzhou, Zaozhuang, Nanjing, Shanghai, Haikou, and the B-biotype populations from California, Texas, Arizona reached 99.8-100%, which meant the nation-wide infested populations of B. tabaci in China in recent years were B-biotypes. Another population collected from Kunming of Yunnan Province showed very high similarity with Q-biotype B. tabaci from Spain and Morocco, which meant the Kunming population was Q-biotype. This is the first report on the invasion of Q-biotype into China.     

陕西菜田2种粉虱数量结构及烟粉虱生物型鉴定

旨在研究陕西菜田烟粉虱和白粉虱的数量结构,为粉虱风险评估和防治策略制定提供理论依据。利用定点调查与普查相结合的方法,对陕西关中、陕南和陕北不同生态区、不同季节、不同蔬菜作物以及不同菜田烟粉虱和温室白粉虱的种群分布和组成进行研究,并结合mtDNA-CO1标记基因实现对陕西菜田烟粉虱的生物型鉴定。结果表明,烟粉虱和温室白粉虱的分布和种群组成因地区、季节、作物种植模式不同而异。其中烟粉虱均呈现优势分布,并占到种群数量的67.2%～100%。采用标记基因技术、序列同源性分析和系统发育研究,明确了陕西菜田烟粉虱生物型为Q型烟粉虱。     

安徽省姜瘟病菌鉴定

从安徽省舒城、临泉、全椒、铜陵和桐城等县取得十个分离菌,以南京农大提供的姜瘟茵(Pseudomonas solanacearum,ZO 12)菌株为对照,进行致病性、生理生化试验和血清学测验,鉴定结果均属于青枯假单孢菌Pseudomonas solanacearum生物型Ⅳ。姜瘟是我省姜区生产上的严重病害。据1984—1986年对我省主要栽姜区舒城、铜陵、临泉等县市调查,由于姜瘟病为害,常年减产达20—30%,重病年达50—70%,个别区块受害率甚至更高。姜瘟为害,不仅引起减产,且降低品质,影响加工外销,严重挫伤姜农生产积极性。本试验目的为明确我省姜瘟病病原,以期为今后制订防治措施提供参考。故对从舒城、铜陵、临泉、全椒、桐城等五县市分得的菌株进行了鉴定。因任欣正等(1981),吕庆凤等(1983),夏德鑫等(1984),分别对江苏、山东、浙江等地姜瘟病菌进行鉴定,证明均为青枯假单孢菌Pseudomonas Solanacearum (Smith) Smith。故本试验亦为明确我省姜瘟病菌是否和上述三者相同。     

烟粉虱的识别与鉴定技术

本文对烟粉虱的形态特征进行了详细描述,并对A、B两种生物型的超微结构特征进行了研究,提出鉴定这两种生物型的形态特征。此外,文中还就烟粉虱与温室白粉虱的区别特征进行了描述,并提出了烟粉虱的田间识别特征。     

杨陵地区麦二叉蚜在小麦品种Amigo上的抗性鉴定

根据麦三叉蚜种下生物型分化特性，设计了小麦品种Amigo的抗蚜性和麦二叉蚜生物型鉴定试验。分析了自然条件下小麦品种Amigo对麦二叉蚜的出生率、死亡率和内秉增长度的影响，组建了自然条件下麦二叉蚜在小麦品种Amigo上的生命表。以生命表中的内秉增长度和稳定年龄组配为指标进行生物型鉴定分析。结果表明：①麦二叉蚜在Amigo上的生存曲线、繁殖曲线同麦二叉蚜在其它品种上的表现一致，分别为B型和偏峰曲线；②平均世代时间为11.7670d，周限增长率为1.1453；③种群的瞬时出生率为0.3220，瞬时死亡率为0.1846；④内秉增长率为0.1357；⑤稳定年龄期组配成蚜比例为37.64%，若蚜为62.37%，与二叉蚜在其它小麦品种上的参数差异不显著。参数分析表明，在Amigo品种上的麦二叉蚜种群发展趋势是上升的，种群数量是增长的，可见杨陵地区麦二叉蚜既非A、B，也非C生物型，品种Amigo不抗本地区麦二叉蚜。     

葡萄根瘤蚜生物型和遗传多样性研究进展

葡萄根瘤蚜(Daktulosphaira vitifoliae Fitch.)是世界检疫性葡萄专性寄生害虫,19世纪末20世纪初根瘤蚜的大发生给世界葡萄产业造成了灭顶之灾,选育和利用抗性砧木成为葡萄生产的唯一选择。然而随着害虫的协同进化,一些强致病性类型不断出现,致使一些砧木的抗性正在丧失,如加州所使用的砧木AXR#1的抗性被强致病生物型B所克服;SO4、5C、104-14 Mgt等强抗性砧木在一些地区也受到了根瘤蚜的侵染。根瘤蚜新生物型和强致病基因型的出现,推动了对根瘤蚜遗传多样性的研究。我们对葡萄根瘤蚜生物型及其鉴定方法、根瘤蚜的遗传变异研究进展进行了介绍,并讨论了根瘤蚜生物型研究的意义。     

畜禽腹泻与空肠弯曲菌感染的相关性分析

对465只（头）健康和腹泻畜禽的直肠和泄殖腔拭子及108份腹泻死亡畜禽的脏器材料进行空肠弯曲菌培养,并分析畜禽腹泻与该菌感染的关系,腹泻死亡后备蛋鸡的带菌率（93．3％）明显高于腹泻后备蛋鸡（53．3％）（P＜0．005）,腹泻后备收鸡的带菌率又明显高于健康后备收鸡（22．0％）（P＜0．001）,表明后备蛋主其腹泻死亡与该菌感染相关,腹泻仔猪的带菌率很高（88．0％）也提示该菌感染与仔猪腹泻存在一定关系。在腹泻死亡畜禽肠道内,腔弯曲菌在大肠和小肠的检测出率分别为91．7％和39．0％,检出率差异极显著（P＜0．001）,即显示该菌主要感染部位可能为腹泻畜禽的大肠。351株不同动物来源空肠弯曲菌的生物学分型结果表明,分布在各种动物体的主为主（90．4％）,或其比例升高（48．1％）,健康鸡与腹泻鸡的生物型分布有差异（P＜0．05）,提示生物型Ⅱ在致畜腹泻中起一定作用,另外,同一动物体内可有该菌的2个生物型分布。