十种病害可引发茄果类蔬菜烂果

1、绵疫病：绵疫病危害下部老果较多。初期出现水浸状小斑,逐渐扩大产生白色棉絮状菌丝,果实内变黑,极易脱落。病果落地后,遇潮湿全果腐烂产生白霉,最后干缩,成为黑褐色僵果。发病初期,根据病情7-10d喷1次25％百菌清可湿性粉剂500倍液,或65％代森锌可湿性粉剂500倍液,连喷2—3次。     

孟加拉国的水稻有害生物综合治理

一、水稻栽培及有害生物发生情况农业是孟加拉国经济的支柱,为全国人口提供了85%的生活必需品。盂加拉国的水稻按生长季节可分为四季:(1)Aus 季(3月中旬—7月),(2)B.Aman 季(3月—12月中旬),(3)T.Aman 季(7月中旬—12月),(4)Boro 季(11月至翌年5月)。这表明整年可种植水稻。1986—1987年水稻种植情况见表1。     

清除病残体对防治芦笋茎枯病的作用

芦笋茎枯病菌以休眠菌丝和分生孢子器在病残体中越冬,是翌年初侵染源。经对14科43属49种大田作物和其他植物人工接菌,均未发病,该菌只寄生芦笋。因此。彻底清除病残体对减轻芦笋茎枯病有重要意义。从大田调查证明,冬春清除病残体做得彻底的比清残差的发病率下降54.1—79.3％,病情指数下降50.31—59.8,茎秆枯死率下降28.1—29.4％;夏季进行第二次清残的比未清残的发病率下降32.5—56.9％,病情指数下降25.2—52.8,茎秆枯死率下降25.6—32.1％。施用药剂结合清残则能显著提高防治效果,降低茎秆枯死率。     

广州地区豌豆黄顶病和武汉地区蚕豆黄顶病的病原病毒初步鉴定

广州地区豌豆黃顶病每年在11月开始发生,发病率一般很低,但个別田块可达50％以上。病株頂部叶片黄化,縮小,皺縮卷曲,叶质脆,植株矮縮,不开花結莢,最后发生丛枝現象,植株很快枯死。武汉地区蚕豆黄頂病每年在苗期(11月)开始发生,发病率約1—5％,翌年4、5月流行,发病率輕的为5—10％,重的达80—100％。症状和广州地区的豌豆黄頂病基本相同。     

叶枯宁防治小麦细菌性黑颖病研究

1985—1987年,经温室、小区和田间示范试验证明,用15％叶枯宁胶悬剂,以300—1000ppm浓度,从孕穗初期起喷药防治小麦黑颖病,隔7—10天喷1次,连喷2—3次,防效达81—99％,可增产1—2成,经济效益显著;用该药浸种或随灌溉水施药,也有较好的防治效果。该试验结果,可供生产上大面积推广应用参考。     

甘蔗赤斑病的发生与防治

甘蔗赤斑病发病初期在叶上产生圆形或不规则形黄色病斑,边缘为红褐色,病斑多时愈合引起大面积坏死,继后整叶干枯,使植株早衰,危害严重的减产３０％以上。病原菌有甘蔗叶鞘赤斑菌、甘蔗台湾尾孢霉和甘蔗小斑明尾孢霉３种。２５％敌力脱１０００～１５００倍液,每隔１５ｄ喷１次,连续喷３次,防治效果达７０％以上。     

意大利蝗卵越冬期呼吸代谢对季节变化的响应

为明确意大利蝗Calliptamus italicus(L.)卵越冬过程中的呼吸代谢变化,通过定期解剖野外意大利蝗卵观察其胚胎发育进度,并应用多通道昆虫呼吸代谢测量系统逐月测定意大利蝗卵的O_2消耗率、CO_2释放率、代谢率和呼吸商,分析其变化特征,同时对其越冬环境温度进行实时测定。结果表明,意大利蝗卵的呼吸代谢水平随着越冬时间的推进发生季节性波动。越冬前(8—10月),意大利蝗卵的呼吸代谢水平较高,其中在8月间最高,此时胚胎发育较快,且复眼背部边缘在10月出现红色;越冬期间(11月—翌年2月),呼吸代谢水平在11月间最低,在12月—翌年2月之间则无显著差异,复眼颜色逐渐加深,胚胎发育基本停滞;越冬结束后(翌年3—4月),呼吸代谢水平逐渐升高,在翌年4月间显著高于10月—翌年3月,但显著低于8月,此时发生胚胎转动且恢复发育。越冬过程中,意大利蝗卵呼吸商均大于0.94。不同月份意大利蝗卵的O_2消耗率、CO_2释放率、代谢率与5 cm地温之间均呈显著正相关,相关系数分别为0.857、0.831和0.902。在整个越冬过程中,意大利蝗卵的呼吸代谢变化与其胚胎发育进度以及环境温度密切相关,且蝗卵均以糖类为主要能源物质,以最大程度减少物质能量消耗,从而确保蝗卵的正常发育、越冬及来年的顺利孵化。     

山楂喀木虱的初步研究

山楂喀木虱(Cacopsylla idiocrataegi Li.)为喀木虱属一新种(李法圣 1990),主要为害山里红和山楂,使叶、花早落,影响果实产量。该虫在辽宁清原一年发生1代,以成虫越冬,翌年3月下旬出蛰活动。用40％乐果乳油500-1000倍液喷杀产卵前成虫,效果最佳。     

河北坝上亚麻复合苗病发生规律及防治

随着亚麻播种面积的扩大,亚麻复合苗病在坝上地区发生日趋严重。据1983—1984年抽样调查,一般田的病苗率为15—30％,枯苗率为5—10％,发病严重地块的枯苗率达到50％以上,平均减产9.4—10.4％,少数地块甚至毁种绝收。1985年坝上各县发病总面积达10万公顷,占播种面积的80％以上。其中严重减产或绝收面积5千公顷,损失     

松阳县发生水稻细菌性条斑病后采取的防治措施

1989年8月我县新兴乡发现水稻细条病,随即全县范围进行普查,共波及8个乡、2600多亩晚稻,101亩杂交稻制种田。我县采取的综合防治措施;(1)烧掉病稻草。(2)发病田用20％叶青双100g兑水50kg,喷雾防治,用高锰酸钾加食盐冲水防治。(3)集中处理田边各种杂草、稻桩。(4)有病种子由县种子公司收购,翌年一律选用无病稻种,并用     

关中地区温室越冬茬番茄黄化曲叶病毒病分子鉴定及流行规律

为了明确关中地区越冬茬番茄黄化曲叶病毒病发生和流行规律,通过分析该病发生与番茄品种、定植期及传播介体烟粉虱之间的关系,并采用PCR技术对田间病原进行分子鉴定。结果表明,番茄黄化曲叶病毒病在8月中下旬至11月上中旬开始侵染,翌年3月中下旬发生再侵染,秋季病情减轻;烟粉虱种群数量与病害发生程度呈线性正相关;不同番茄品种对番茄黄化曲叶病毒(Tomato yellow leaf curl virus,TYLCV)的抗性差异显著,其中大番茄品种布鲁尼1288和DRW7728,小番茄品种千禧和美红对该病表现为免疫;分子检测结果表明,4个样品中均扩增出543 bp的特异片段,与NCBI数据库Gen Bank的TYLCV序列(登录号为GU084381、KC138544.1、KC138543.1和JX456642.1)的相似性达99%。研究表明,关中地区番茄病毒病为番茄黄化曲叶病毒病,番茄品种、定植期及烟粉虱发生动态是影响该病发生的主要因素。     

New Leaf Spot Disease of Cymbidium Species Caused by Fusarium subglutinans and Fusarium proliferatum

Fusarium species were consistently isolated from yellow, swollen spots with reddishbrown centers and small black spots on leaves of Cymbidium plants in the greenhouse. Fusarium subglutinans caused the yellow spots and Fusarium proliferatum caused either the yellow or the black spots. We propose the name “yellow spot” for the new disease. To denote differences in their pathogenicity to orchid plants, we designate the population causing yellow spot as race Y and that causing black spot as race B of F. proliferatum. Received 29 October 1999/ Accepted in revised form 10 March 2000     

Comparative analyses of spot blotch and tan spot epidemics on wheat under optimum and late sowing period in South Asia

In South Asia, foliar blight of wheat (Triticum aestivum L.) is a disease complex caused by Cochliobolus sativus (the spot blotch pathogen) and Pyrenophora tritici-repentis (the tan spot pathogen) which can reduce yields by >30?%. Little is known about the effects of wheat genotypes and their planting time on foliar blight epidemics. Field experiments were conducted to determine the infection potential and epidemic development of C. sativus and P. tritici-repentis on two susceptible (Sonalika and BL1473) and two tolerant (NL750 and Milan/Shanghai-7) wheat genotypes under optimum (November 26) and late (December 11 and December 26) planting conditions. The dynamics of airborne conidia were studied using air samplers. The highest aerial concentrations of conidia and disease incidence of both pathogens on all four wheat genotypes were detected during the first 3?weeks of March under both optimum and late seeding conditions in both years. Compared to optimum sowing time (i.e. November 26), wheat genotypes had higher disease severity when planted late on December 11 and 26. The disease complex reduced grain yield by 20.5, 27.2 and 37.3?% for November 26, December 11 and December 26 plantings, respectively in 2004. The corresponding differences were 17.7, 23.6 and 30.2?% in 2005. The findings of this study provide valuable information on the epidemiology of spot blotch and tan spot, which could help in developing strategies for managing these diseases in South Asian region through the selection of suitable genotypes and planting dates.     

Identification and characterization of a potyvirus causing chlorotic spots on <Emphasis Type="Italic">Phalaenopsis</Emphasis> orchids

A putative virus-induced disease showing chlorotic spots on leaves of Phalaenopsis orchids was observed in central Taiwan. A virus culture, phalaenopsis isolate 7-2, was isolated from a diseased Phalaenopsis orchid and established in Chenopodium quinoa and Nicotiana benthamiana. The virus reacted with the monoclonal antibody (POTY) against the potyvirus group. Potyvirus-like long flexuous filament particles around 12–15 × 750–800 nm were observed in the crude sap and purified virus preparations, and pinwheel inclusion bodies were observed in the infected cells. The conserved region of the viral RNA was amplified using the degenerate primers for the potyviruses and sequence analysis of the virus isolate 7-2 showed 56.6–63.1% nucleotide and 44.8–65.1% amino acid identities with those of Bean yellow mosaic virus (BYMV), Beet mosaic virus (BtMV), Turnip mosaic virus (TuMV) and Bean common mosaic virus (BCMV). The coat protein (CP) gene of isolate 7-2 was amplified, sequenced and found to have 280 amino acids. A homology search in GenBank indicated that the virus is a potyvirus but no highly homologous sequence was found. The virus was designated as Phalaenopsis chlorotic spot virus (PhCSV) in early 2006. Subsequently, a potyvirus, named Basella rugose mosaic virus isolated from malabar spinach was reported in December 2006. It was found to share 96.8% amino acid identity with the CP of PhCSV. Back-inoculation with the isolated virus was conducted to confirm that PhCSV is the causal agent of chlorotic spot disease of Phalaenopsis orchids in Taiwan. This is the first report of a potyvirus causing a disease on Phalaenopsis orchids.     

甘肃省红豆草病原真菌鉴定及病害发生动态调查

为明确甘肃省红豆草的病害种类、发生动态和危害状况,采用病原物分离与培养、形态学及分子生物学鉴定和致病性测定确定红豆草病害种类,于2012—2013年在通渭、渭源、榆中和碌曲4县调查各病害的发病率以确定发生动态,观察病害田间发生特点并结合调查数据评价其重要性。结果表明,4县共发生真菌性病害12种,分别为大茎点霉叶斑病(病原为大茎点霉属真菌Macrophoma sp.)、壳针孢叶斑病(病原为歪头菜壳针孢Septoria orobina)、炭疽病(病原为白蜡树刺盘孢Colletotrichum spaethianum)、黑秆病(病原为红豆草壳二孢Ascochyta onobrychis、菠菜刺盘孢C.spinaciae和链格孢Alternaria alternata混合侵染)、壳二孢叶斑病、茎点霉叶斑病、尾孢叶斑病、柱格孢白斑病、匍柄霉叶斑病、链格孢黑斑病、锈病和白粉病,其中大茎点霉属真菌、白蜡树刺盘孢和菠菜刺盘孢在红豆草上首次发现;尾孢叶斑病和壳针孢叶斑病为甘肃新记录病害;大茎点霉叶斑病为世界新病害,仅于碌曲县发现。白粉病、锈病、链格孢黑斑病发生于红豆草生长后期,其它病害则始于6月;6—9月危害加重的为黑秆病和柱格孢白斑病,发病率最高达89.7%和96.0%;危害渐轻的为茎点霉叶斑病、壳二孢叶斑病和壳针孢叶斑病,发病率最高达88.7%、57.4%和45.1%。黑秆病和茎点霉叶斑病在甘肃省目前危害最重。     

梨叶枯病发生规律与诱病因子研究

梨叶枯病 (Mycovellosiella pyricola Guo,Chen&;Zhang)是梨树新病害 ,分布于甘肃临夏、兰州、定西等地。病菌以子座在病落叶上越冬 ,翌年 6月初显症 ,8月中、下旬发病达高峰期。降雨量、湿度是主要诱病因子 ,立地条件和各种栽培措施对病害也有一定影响     

广东省国兰病毒病害调查及CymMV和ORSV基于cp基因的系统进化分析

为调查广东省国兰病毒病发生情况,采用双抗体夹心-酶联免疫吸附测定(double sandwich enzyme-linked immunosorbent assay,DAS-ELISA)法对采集自广州市、汕头市和韶关市兰花主产区的53份具有典型病毒病症状的国兰叶片进行检测,选取35份病叶应用RT-PCR技术对检测结果进行验证,并基于cp基因序列对检测到的病毒进行系统进化分析。DAS-ELISA检测结果显示,53份病叶中有44份检出病毒,总检出率为83.02%;其中,有14份仅检出建兰花叶病毒(Cymbidium mosaic virus,CymMV),有19份仅检出齿兰环斑病毒(Odontolossum ring spot virus,ORSV),有11份检出CymMV和ORSV复合侵染,检出率分别为26.42%、35.85%和20.75%。RT-PCR检测结果显示,35份病叶中有30份检出病毒,总检出率为85.71%;其中,有21份仅检出CymMV,有6份仅检出ORSV,有4份检出CymMV和ORSV复合侵染,检出率分别为60.00%、17.14%和11.43%,但未检测到其它病毒。表明广东省国兰病毒病害主要由CymMV和ORSV侵染引起。序列和系统进化分析显示,来源于不同地区和寄主的CymMV和ORSV分离物的cp基因序列极为保守,CP氨基酸序列相似性分别大于97.31%和93.67%,且CymMV和ORSV多样性种群的分化与寄主种属和地理隔离关系不大。     

Bacterial black spot caused by <Emphasis Type="Italic">Burkholderia andropogonis</Emphasis> on <Emphasis Type="Italic">Odontoglossum</Emphasis> and intergeneric hybrid orchids

A new bacterial black spot disease was observed on Odontoglossum, Odontioda, Odontocidium, and Vuylstekeara orchids in Japan. Typical symptoms on the leaves were dark or black spots (or both) with a yellow halo. The causal agent was identified as Burkholderia andropogonis (Smith 1911) Gillis, Van Van, Bardin, Goor, Hebbar, Willems, Segers, Kersters, Heulin and Fernandez 1995. The isolates were pathogenic on four original host orchids, Phalaenopsis orchid, and tulip; they were not pathogenic on white clover or corn after needle stab inoculation. An antibiotic bactericide (oxytetracycline/streptomycin mixture WP) was most effective for controlling the disease.     

Yield Reduction in Wheat in Relation to Leaf Disease From Yellow (tan) Spot and Septoria Nodorum Blotch

Yellow or tan spot (caused by Pyrenophora tritici-repentis) and septoria nodorum blotch (caused by Phaeosphaeria nodorum) occur together and are a constraint to wheat yields in Australia. Recently, higher crop yields and lower fungicide costs have made fungicides an attractive management tool against these diseases. Yield-loss under different rates of progress of yellow spot and septoria nodorum blotch was examined in four experiments over three years to define the relationship between disease severity and yield. In these experiments, differences in disease were first promoted by inoculations either with P. tritici-repentis-infected stubble or aqueous spore suspensions of P. nodorum. Disease progress was further manipulated with foliar application of fungicide. The pattern of disease development varied in each year under the influence of different rainfall patterns. The inoculation and fungicide treatments produced differences in disease levels after flag leaf emergence. The infection of yellow spot or septoria nodorum blotch caused similar losses in grain yield, ranging from 18% to 31%. The infection by either disease on the flag or penultimate leaf provided a good indication of yield-loss. Disease severity on flag leaves during the milk stage of the crop or an integration of disease as area under the disease progress curve on the flag leaves based on thermal time explained more than 80% variance in yield in a simple regression model. The data provided information towards the development of disease management strategies for the control of septoria nodorum blotch and yellow spot.     

Tracking Phytophthora infestans with SSR markers within and between seasons – a field study in Sweden

The dynamics of a late blight epidemic and sexual reproduction in Phytophthora infestans were studied in an experimental field in mid‐Sweden. The field was inoculated with six isolates of P. infestans taken from another potato field where sexual reproduction of the pathogen was suspected. Three weeks after inoculation single‐lesion leaflets were sampled and the resulting isolates characterized using microsatellites (SSRs) and mating type as markers. Among the 151 isolates analysed, the inoculum genotypes constituted more than 80% of the genotypes found, with three other genotypes making up the remainder. The following year, P. infestans obtained from soil samples taken from this field were analysed, and six novel genotypes were identified. Genotypes from the previous summer’s population were not detected. Analysis of the genotypes recovered was consistent with them being recombinants, with the previous summer’s population acting as parents. These findings are consistent with the hypothesis that oospores produced during a summer epidemic in Sweden can overwinter and cause infection the next year.