Characterization of imidacloprid resistance in the housefly Musca domestica (Diptera: Muscidae)

In recent years, imidacloprid was introduced to control the housefly in China and it was documented that the housefly indeed showed signs of resistance to imidacloprid somewhere but not in China. Therefore, a housefly population collected from filed (IFS) was selected continuously with imidacloprid to establish the resistant strain (IRS) and the basic characteristics were investigated in this study. After continuous selection over 21 generations, the resistance ratio increased from 9.01 to 140, and different levels of cross-resistance were developed to beta-cypermethrin, chlorpyrifos, chlorfenapyr, acetamiprid and azamethiphos in the IRS strain. The realized heritability of resistance was 0.10. The synergistic ratios for IRS pretreated with DEF, DEM and PBO were 1.68, 1.52 and 2.53, and the corresponding ones for IFS were 3.17, 1.87 and 2.67, respectively. Synergistic and biochemical assays suggested that the cytochrome P450 may play an important role in the imidacloprid resistance comparing with GSTs- and carboxylesterases-mediated detoxification in the IRS strain, and there might be additional mechanisms (e.g. reduced target-site sensitivity) contributed to imidacloprid resistance in the IRS strain.     

Using synergists to detect multiple insecticide resistance in field populations of rice stem borer

The rice stem borer, Chilo suppressalis (Walker), an important insect pest of rice in China, has developed resistances to several classes of insecticides in field. In order to investigate multiple resistance mechanisms, synergistic tests were conducted with the Ruian (RA) population and Lianyungang (LYG) population, two representative populations to different insecticides. Results showed that diethyl maleate (DEM), S,S,S-tributyl phosphorotrithioate (DEF) and piperonyl butoxide (PBO), had no significant synergistic or inhibitory effect on the high level of resistance to monosultap (313.4-fold) and moderate level to chlorpyrifos (36.9-fold) in Ruian field population from the year 2011 (RA11). DEF significantly synergized the activity of triazophos in RA11 population (536.8-fold), with synergism ratio of 1.92. DEF and PBO significantly suppressed 43.3% and 40.4% of resistance to fipronil in RA11 population (48.4-fold), respectively, with the synergistic ratios of 1.76 and 1.69. When pretreated with PBO, the activity of deltamethrin against RA11 population were significantly synergized, with synergism ratio of 9.57, and with reducing resistance levels from 152.5- to 15.9-fold. The results of this study indicated that resistance to several classes of insecticide among the field populations of C. suppressalis might be provided by the combination of the multiple resistance mechanisms. Metabolic resistance mechanism might be the major reason for the evolution for resistance to deltamethrin and fipronil, while resistance to monosultap, triazophos and chlorpyrifos is not associated with metabolic resistance.     

小麦孢囊线虫病传播扩散途径研究初报

为了明确小麦孢囊线虫病的扩散传播途径,调查病区农用机械、麦田翻耕后田间及其周边流水中小麦孢囊线虫的孢囊数量.结果表明,收割机、旋耕机和播种机上土样的孢囊检出率分别为27.1％、51.6％和44.0％,麦稻轮作的病田中,浪渣的孢囊检出率为58.3％,翻耕后麦田积水、沟渠和小河流中的孢囊检出率分别为33.3％、22.7％和7.7％.说明农业机械的跨区作业和水流是小麦孢囊线虫病传播、扩散的重要途径.     

菜豆普通细菌性疫病菌在土壤和植株残体中的越冬能力

为评估菜豆普通细菌性疫病菌地毯草黄单胞杆菌菜豆致病变种或褐色黄单胞菌褐色亚种在土壤及植物残体中的越冬能力,对采自黑龙江、内蒙古、山西、河北及新疆的18块菜豆生产田的20份土壤及14份植物残体样品进行病原菌分离和鉴定。在MT选择性培养基上有12个土壤样品和13个植株残体样品提取液产生典型的类似黄单胞菌菌落。选取29个分离物进行致病性测定,有27个分离物对菜豆品种"英国红"致病。利用地毯草黄单胞杆菌菜豆致病变种和褐色黄单胞菌褐色亚种的特异性引物X4c/X4e及褐色黄单胞菌褐色亚种特异性引物Xf1/Xf2对29个分离物进行多重PCR检测,其中17个分离物为地毯草黄单胞杆菌菜豆致病变种,10个分离物为褐色黄单胞菌褐色亚种。结果表明,菜豆普通细菌性疫病菌可以在黑龙江、内蒙古、山西、河北的一些菜豆种植区的土壤及植株残体中越冬存活。     

干旱胁迫对文冠果树苗某些生理特征的影响

盆栽条件下设置不同土壤水分含量(土壤绝对含水量为13%、18%和25%),分析了干旱胁迫对文冠果叶片水势、细胞膜透性、渗透调节物质及超氧化物歧化酶(SOD)酶活性等的影响。结果表明:13%和18%土壤含水量条件下文冠果枝条分别达到中度水分胁迫和轻度胁迫程度,文冠果叶片细胞膜透性分别高出对照(土壤绝对含水量为25%)16%和4%;文冠果叶片积累的可溶性糖分别是对照的2.3和1.2倍,积累的脯氨酸分别比对照增加了21%和8%;叶片SOD活性分别下降了5%和3%,过氧化氢酶(CAT)活性下降幅度较大,分别比对照下降83%和68%;MDA积累量分别比对照增加了44%和1%;干旱胁迫主要影响了文冠果地上部干物质的累积,与对照相比,13%和18%水分条件下地上干重分别降低了31%和16%,但根系干重分别是对照的95%和109%。文冠果是一种较为耐旱的树种,但是文冠果栽培过程中要及时补水才能保证树体正常生长。     

Screening of common bean (Phaseolus vulgaris) for resistance against temperate root-knot nematodes (Meloidogyne spp.)

BACKGROUND: An important part of the production area of common bean (Phaseolus vulgaris L.) in Belgium is located on the sandy soils of the provinces of Antwerp and Limburg where Meloidogyne chitwoodi (Golden), M. fallax (Karssen) and M. hapla (Chitwood) are present. The host plant status of ten bean cultivars for root‐knot nematodes was determined by evaluating penetration, development and egg mass formation after inoculation with second‐stage juveniles. RESULTS: The tested cultivars were poor to good hosts for M. chitwoodi, non‐hosts or bad hosts for M. fallax and excellent hosts for M. hapla. Significantly fewer M. fallax were found in the roots, and their development was delayed. Penetration of M. hapla took place over a longer period than that of M. chitwoodi and M. fallax. The number of mature females of M. chitwoodi in cv. Polder 6 weeks after inoculation was no different from that in other cultivars, although fewer egg masses were found on this cultivar in the screening test. There was no influence of M. chitwoodi on vegetative growth of cv. Polder. CONCLUSION: The differences found in host plant status of bean cultivars stress the importance of a correct diagnosis of the Meloidogyne species in agricultural fields. Cultivar Polder showed potential as a trap crop for M. chitwoodi. Copyright © 2011 Society of Chemical Industry     

复合生物保鲜剂对腐败希瓦氏菌的抑菌机理

为了研究复合生物保鲜剂对冷藏带鱼优势腐败菌(腐败希瓦氏菌)的抑菌作用机理,通过牛津杯法测定了复合生物保鲜剂对腐败希瓦氏菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),并测定了复合生物保鲜剂对腐败希瓦氏菌的抑菌活力、细菌生长曲线、细胞膜完整性和细胞的稳定性,对细菌超微结构进行了观察。结果显示:复合生物保鲜剂对腐败希瓦氏菌的MIC与MBC分别为1.6 mg/ml与3.3 mg/ml,且随着作用时间的延长,复合生物保鲜剂对腐败希瓦氏菌的生长有明显抑制作用;尤其经2倍最小杀菌浓度的复合生物保鲜剂处理后,细菌未出现对数生长期;菌液在260 nm处的吸光值明显升高,菌体细胞膜完整性受到破坏;菌体细胞中的碱性磷酸酶升高,菌体细胞壁通透性增大;菌悬液的电导率值明显增大,细胞膜稳定性受损。细菌超微结构观察发现,复合生物保鲜剂作用于菌体细胞后,菌体细胞开始出现皱缩、扭曲变形、表面粗糙和布满泡状物及细胞壁塌陷等现象。表明复合生物保鲜剂可以破坏细菌的细胞内环境和细胞膜稳定性,影响了细菌的正常生长;并且通过影响细菌对营养物质的吸收和代谢物的排出,最终导致菌体死亡。     

基于Simulink船用智能柴油机共轨喷射系统视景仿真

选择合适的建模工具搭建船用智能柴油机燃油共轨喷射系统三维视景模型,在Matlah／Simulink开发环境中设计该系统的数学模型,在此基础上,开发数据交互与通信模块,将上述两种模型进行有机融合,在网络化三维场景中实现燃油喷射过程的高逼真度可视化仿真．     

当前种子企业发展和创新

笔者提出国内种子企业发展中存在的问题,分析企业发展中存在的具体原因,论述只有企业通过自主发展创新才能得到更好的发展。     

宁夏石嘴山市林业有害生物发生现状及防控对策

对石嘴山市林业有害生物发生现状进行了阐述,对防控中存在的主要问题进行了分析,有针对性地提出了加强检疫、监测工作,建立林业有害生物合同制管理,实施无公害防治等防治对策。