广西白背飞虱携带南方水稻黑条矮缩病病毒监测情况简报

利用双重RT-PCR和DIBA快速检测法,对近年广西南方水稻黑条矮缩病传毒介体白背飞虱带毒率进行监测,结果表明:2010～2012年白背飞虱平均带毒率分别为8.18%、0.93%和4.41%,早春白背飞虱带毒率较低,随着外地虫源不断迁入及本地虫源积累、繁殖,后期白背飞虱带毒率明显上升。前期白背飞虱带毒率监测预警,对指导南方水稻黑条矮缩病科学防控意义重大。     

温度、水稻生育期和白背飞虱若虫龄期对南方水稻黑条矮缩病毒介体获毒率的影响

南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)是由白背飞虱(Sogatella furcifera)传播的一种新病毒。为明确白背飞虱获毒的影响因子及南方水稻黑条矮缩病的流行规律,本文采用三因素试验,研究温度(22、27和32℃)、水稻生育期(三叶期、分蘖期和孕穗期)和白背飞虱若虫龄期(3龄和5龄)对白背飞虱获毒效率的影响。结果表明,白背飞虱在27℃和32℃下的获毒率显著高于22℃下的获毒率;在不同生育期水稻上,白背飞虱在分蘖期水稻上的获毒率高于三叶期和孕穗期;白背飞虱若虫龄期也显著影响获毒率,3龄若虫获毒率高于5龄若虫;但这些因素的交互作用对白背飞虱的获毒率无显著影响。     

不同插秧方式对南方水稻黑条矮缩病发生程度的影响

大量的田间调查结果表明,直播、人工移栽及机插3种插秧方式对南方水稻黑条矮缩病的发生程度及其传播介体白背飞虱的发生量均有不同程度的影响。机插方式下白背飞虱发生量最低,分蘖期成虫为4头/百丛,若虫为12头/百丛,抽穗期发病轻、病株率最低,轻病株率为3%,重病株率仅1.8%;人工移栽方式次之;直播白背飞虱和南方水稻黑条矮缩病的发生都较前两种方式重。调查结果还表明,分蘖期白背飞虱虫量直接影响抽穗期病株率的高低。     

不同水稻品种对南方水稻黑条矮缩病的田间抗性试验

近年来,南方水稻黑条矮缩病在贵州省黔南、黔东南的部分县流行为害,以南部的荔波、三都、平塘、罗甸、从江等与广西交界的县发生普遍,坝子田、高坡田、寨脚田、夹沟田等几乎所有类型稻田均有发生,发病程度较重,局部地区出现绝收田块。南方水稻黑条矮缩病的发生主要是白背飞虱取食染毒病株获毒,然后在取食健康水稻的过程中将病毒传播给健康植株。     

2009年湖南省南方水稻黑条矮缩病暴发原因初步分析

2009年,南方水稻黑条矮缩病在湖南省大面积暴发,造成严重的经济损失。根据2008-2009年湖南省道县、汉寿县两地区的田间发病率、传毒介体的种群消长动态、药剂防治情况调查,结合2009年两地区稻飞虱带毒率测定,初步分析结果表明,水稻苗期至分蘖期传毒介体量大、品种感病是2009年湖南省南方水稻黑条矮缩病暴发的部分原因;同时,值得注意的是需要防范该病害在来年扩展危害。     

南方水稻黑条矮缩病毒的快速检测

南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus,SRBSDV)病原鉴定和介体带毒率检测是病害防治的前提条件。本研究分别建立了病株dsRNA基因组鉴定法和介体带毒率测定的斑点杂交法。结果显示:dsRNA基因组鉴定法可以从0.5 g水稻病株组织中快速检测到SRBSDV,不需要经过RT-PCR过程,具有快速简便等特点;斑点杂交法检测介体昆虫白背飞虱带毒率的灵敏度较高,单头带毒介体的总RNA稀释1 000倍后依然可以检测到病毒,并且可以大批量处理样品,用于病害流行研究和测报。     

2010年我国南方水稻黑条矮缩病发生原因及趋势初析

受毒源广泛、传毒介体发生量大、水稻感病生育期与传毒介体发生期吻合、水稻种植制度等因素共同影响,2010年南方水稻黑条矮缩病发生范围显著扩大、为害程度明显加重、发生形势日趋严峻.加快病害发生流行规律及监测、防治技术的研究对保障水稻生产安全意义重大.     

浙江省水稻病毒病的发生规律和防治

 本文总结了1965-1977年水稻病毒病主要是黑条矮缩病、普通矮缩病的发生规律和传毒昆虫传病特点等方面的调查研究工作。
水稻黑条矮缩病由灰稻虱传播。灰稻虱能把病毒自水稻传到水稻、大小麦、玉米,但难以把病毒从玉米传到其它寄主上。已证实田间早熟禾可以作为黑条矮缩病无症带毒寄主。     

水稻黑条矮缩病发病规律研究

通过室内对水稻不同品种、不同生育期接种带毒灰稻虱成虫 ,观察其传毒发病过程和调查田间自然发病结果表明 ,水稻黑条矮缩病在早、晚稻不同品种上的抗性表现和在不同生育期的感染敏感性有差异。分析了秧苗期与本田期的侵染机率 ,提出了秧苗期是水稻黑条矮缩病治虫防病的关键时期     

2012年元江早稻南方水稻黑条矮缩病及介体昆虫白背飞虱的发生动态研究

对2012年云南元江地区早稻田南方水稻黑条矮缩病与传毒介体白背飞虱的发生动态的调查研究表明,白背飞虱的虫口数量与南方水稻黑条矮缩病的发病率呈正相关关系(r＞0.9),即当白背飞虱数量较大时,南方水稻黑条矮缩病发病率也处于较高水平.     

Insecticidal activity of N,N-diethyl-, N,N-dipropyl-, N,n-di-isopropyl-, and n,n-di-isobutylalkanamides against mosquito larvae

N,N-Diethyl-, N,N-dipropyl-, N,N-di-isopropyl, and N,N-di-isobutylalkanamides in which the acyl moiety ranged from C₈ to C₂₁ were synthesised, and their larvicidal activity was determined against the first-instar larvae of the southern house mosquito Culex quinquefasciatus Say. The four homologous series of amides generally showed an increase in their larvicidal activity as the carbon number in the acyl moiety of the amides increased, until the activity reached a maximum. Subsequently, an increment of carbon number resulted in declining activity in the higher homologues, until the activity disappeared. N,N-Diethyltetradecanamide, N,N-dipropylundecanamide, N,N-di-isopropylundecanamide, and N,N-di-isobutlynonanamide or -dodecanamide were the most active compounds in their respective homologous series of amides; however, they were less active than their analogous N,N-dimethylalkanamides previously studied.     

Dieldrin residues in soybeans in Illinois, 1965, 1966, 1967, 1971, and 1974

The Illinois soybean crop was monitored in 1965, 1966, 1967, 1971, and 1974 for dieldrin residues resulting from aldrin applied to corn in the years before soybean cultivation. Residue levels of dieldrin in soybeans increased between 1965 and 1974. The percent of fields which had soybeans with a dieldrin level above 0.03 ppm increased between 1965 and 1974. Dieldrin residue levels in soybeans grown in Illinois are expected to decline now that the use of aldrin has diminished and will soon cease. No significant correlation was evident between the dieldrin levels in soybeans and the area of the State where they had grown, the date of planting, or the variety.     

Mercury, arsenic, and cadmium in fish, water, and sediment of American Falls Reservoir, Idaho, 1974.

Mercury and cadmium were found in fish, water, and sediment of American Falls Reservoir (AFR), Idaho. Mercury and cadmium levels in some fish exceeded human health standards set by the Food and Drug Administration, U.S. Department of Health, Education and Welfare, and the World Health Organization. Analyses performed on the flesh of rainbow trout showed mercury residues of up to 1.20 mg/kg, which were higher than residues previously reported in trout collected in 1970 and 1971 from AFR. Cadmium residue levels were as high as 0.80 mg/kg. Although arsenic was found in reservoir sediment at levels of 1.36-2.40 mg/kg, it was not detected in fish.     

应用酶联免疫吸附试验法鉴定几种主要马铃薯病毒

制备了PVX,PVY_o,PVY~n,PVA,PVS,PVM,PLRV和TRV等8种主要马铃薯病毒抗体的辣根过氧化物酶结合物,在检测黑龙江省马铃薯主栽品种克新一、二、三、四号等品种的植株样品1155份和800余份正在脱毒中的试管苗样品中,发现上述8种马铃薯病毒在几个主栽品种中的侵染率较高,而且大多数感病植株是由3至7种病毒复合侵染,并首次查明本省存在PVY~n和PVM病毒。对不带上述8种病毒的样品又用双向反向聚丙烯酰胺凝胶电泳鉴定带马铃薯纺锤块茎类病毒(Potato spindle Tuber Viroid)状况,现已获得无上述8种病毒和类病毒的种植材料。     

长武旱塬不同麦玉轮作系统产量效应模拟研究

利用EPIC模型对不同麦玉轮作系统进行模拟,通过对其输出结果的分析,综合考虑产量、经济效益、干旱胁迫和氮肥生产率等因素,对不同麦玉轮作系统进行综合评价,从而比较不同麦玉轮作系统的优劣。结果表明:(1)在模拟研究期间,8种麦玉轮作系统的产量均呈波动性下降趋势,其平均值分别为4.61、4.40、4.16、4.48、4.28、4.29、4.714、.55 t/hm2。所有的麦玉轮作系统中,麦玉轮作系统"春玉米→冬小麦"的经济效益最好。(2)在模拟研究期间,麦玉轮作系统"春玉米→冬小麦→冬小麦"的冬小麦和春玉米所遭受的年均干旱胁迫日数最少(29.51d)。在干旱年份麦玉轮作系统中的冬小麦较春玉米更容易遭受干旱威胁。综合产量、经济效益、作物所遭受的干旱胁迫天数和麦玉轮作系统的氮肥生产率等因素,在长武地区适宜采用的麦玉轮作系统为春玉米→冬小麦。     

施肥对小麦、玉米和大豆连作土壤微生物群落功能多样性的影响

为了明确长期施肥和不施肥条件下作物连作对土壤微生物群落功能多样性的影响,以典型黑土为研究对象,选取长期定位实验站长期施肥和不施肥条件下的小麦、玉米和大豆连作处理,通过稀释平板法和Biolog Eco微平板法,测定土壤细菌、真菌、放线菌数量、碳源代谢活性等指标,为建立合理的农田管理措施提供数据支撑和理论依据。结果表明:长期施肥条件下大豆、小麦和玉米连作土壤细菌、真菌和放线菌数量均高于不施肥处理,且均以大豆连作处理细菌和真菌数量最高。不施肥条件下小麦和玉米连作土壤细菌总数较大豆连作处理分别下降了24.8%和31.0%,真菌总数分别下降了64.0%和51.2%;施肥条件下小麦和玉米连作土壤细菌总数则较大豆连作处理分别下降了29.0%和45.5%,真菌总数分别下降了26.7%和31.5%。Biolog结果表明,不施肥条件下小麦连作处理的平均颜色变化率(AWCD)高于玉米和大豆连作处理,施肥条件下则是大豆连作处理的AWCD值高于小麦和玉米连作处理。不施肥条件下大豆、玉米和小麦连作处理利用最多的碳源是碳水化合物类,施肥后不同连作处理利用最多的是碳水化合物类和多聚物类。大豆和小麦连作不施肥条件下土壤微生物利用率最高的碳源均是α-D-乳糖,施肥条件下利用率最高的碳源均是D,L-α-甘油,而不论施肥与否,玉米连作条件下土壤微生物利用率最高的碳源均是D-半乳糖醛酸;葡萄糖-1-磷酸盐和γ-羟基丁酸是农田黑土微生物群落特异利用的关键碳源。主成分分析得出,施肥对土壤微生物碳源代谢能力的影响大于作物的影响。     

Comparison of trifluralin,oryzalin, pronamide,propham, and colchicine treatments on microtubules

The mode of action of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), oryzalin (3,5-dinitro-N⁴,N⁴-dipropylsulfanilamide), pronamide(N-(1,1-dimethylpropynyl) 3,5-dichlorobenzamide), and propham (isopropyl carbanilate) on purified microtubules from pig brains and on the ultrastructure of wheat (Triticum aestivum L. “Mediterranean,” C. I. 5303) and corn (Zea mays L. “yellow dent, U. S. 13”) roots was compared with that known for colchicine. Colchicine disrupts the in vivo cortical and spindle microtubules of root cells. Like colchicine, the herbicides trifluralin, oryzalin, and pronamide caused the loss of both cortical and spindle microtubules of root cells. The rate of microtubule disappearance depended on the type of herbicide and length of exposure of roots to the herbicide. Unlike colchicine, cortical microtubules were present in propham-treated roots but they were disoriented within the cell.In vitro polymerization studies with pig brain microtubules (Sus scrofa) showed that the herbicides failed to inhibit the assembly of purified microtubular protein into microtubules and that radioactively labeled herbicides did not bind to the microtubular protein. Colchicine inhibited the polymerization of microtubular protein and readily bound to the microtubular subunits. These results indicate that the mode of action of the herbicides is not similar to that of colchicine and that the loss of microtubules from root tip cells treated with trifluralin, oryzalin, and pronamide may be caused by these herbicides interfering with synthesis of microtubular protein or metabolism of endoplasmic reticulum membranes involved in microtubule assembly. The mode of action of propham appears to be on the microtubular organizing centers rather than on microtubules per se.