江西省毛竹枯梢病发生情况与治理措施

毛竹枯梢病Ceratosphaeriaphyllostavhychs是毛竹毁灭性的重要病害之一,也是全国森林植物检疫对象。其病原菌可侵染当年新竹的嫩枝和侧枝,引起枝枯、梢枯甚至全株枯死。发生严重时,致使竹林大面积枯死,状如火烧,造成毁竹荒山,影响竹林的生长和发展,甚至造成巨大的经济损失。笔者就我省毛竹枯梢病的发生情况及治理措施介绍如下。1毛竹枯梢病发生情况毛竹枯梢病是我省70年代在兴国、分宜、宜春等县（市）调查发现。1982年发病面积达1019．5hm2,分布于6个地（市）18个县（市、区）。由于防治不及时,到1991年发病面积猛增到10041．ghm…     

萍乡市杨歧山毛竹枯梢病调查

毛竹枯梢病 Ceratosphaeria phgllosta-cheyis Zhang 是毛竹的一种毁灭性病害,亦是全国森林植物检疫对象之一。据反映,杨歧山地区毛竹枯梢病发生非常严重,为此,笔者于1989年进行了现场考察,现将结果报道如下:     

南竹北移中的毛竹枯梢病问题的初步研究

毛竹枯梢病 Ceratos phaeria phyllos-tachydis Zhang 是我国南方林木的重要病害之一。1983年林业部保护司在制定国内林木检疫细则时,已拟定将这一病害列入国内检疫对象。七十年代以来,毛竹北移在黄河、淮河流域诸省大规模开展,是北方发展毛竹的重要地区。随着毛竹的北移,枯梢病的传播问题也受人关注了,毛竹枯梢病是否已随着毛竹北移而进入黄淮流域呢?在今后的毛竹北移中是否对这一病害实施检疫措施呢?为此,我们对这些问题作了以下的研究。     

福建省毛竹枯梢病的监测调查及检疫防除

通过研究毛竹枯梢病的生物生态学特性，结合具体情况，加强宣传，运用行政干预手段，采取以疫情监测调查为基础，重点抓好人工和营林技术措施，辅以杀菌药剂保护等检疫防除技术，经过８年的防除，全省毛竹枯梢病面积下降到５３０４．８ｈｍ２，有１０个县（市、区）的疫情基本得到了根除，并总结出一套毛竹枯梢病检疫防除技术的的成功经验。     

浙赣毗邻处毛竹枯梢病的发生与对策

毛竹枯梢病 Ceratosphaeria phyllostachydis Zhang是国内森林植物检疫对象。分布上海、江苏、浙江、安徽、江西等省(市),但我市和江西省广丰县原来未发现此病。80年代初,在两省县(市)的毗邻处——广丰县十都乡毛岩村     

落叶松枯梢病分子检测初步研究

本研究对小兴安岭、长白山和完达山3个区域的落叶松枯梢病病原菌Botryosphaeria laricina(K.Sawada)的ITS序列进行了PCR扩增、序列测定和亲缘关系比对分析.并通过对落叶松梢栖真菌ITS序列的分析,设计出特异引物ITSA1与ITSB1.该特异引物可以将落叶松枯梢病病原菌与其它9种(属)落叶松梢栖真菌分别开,具有较好的特异性和较高的灵敏度,初步建立了落叶松枯梢病的分子检测方法.     

国外松枯梢病发生规律及防治对策

国外松枯梢病是由一种原发性生理病害导致松色二孢菌Diplodiapinea(Desm)Kickx继发性浸染所致。低温冻害是发病的主导因素．适地适树防止冻害是预防枯梢病发生的根本措施。     

铁皮石斛梢枯病病原菌分离鉴定及淀粉酶产色链霉菌代谢产物对其防治效果

梢枯病是浙江省武义县寿仙谷铁皮石斛种植基地一种常见的真菌病害,严重影响铁皮石斛的产量与品质,而鉴定枯梢病的病原菌是有效防治该病害的前提条件。本文通过对铁皮石斛染病组织培养、病原菌分离纯化,柯赫法则验证、形态学观察与基因序列比对分析(Alta1、EF-1α、RPB2、ATP、His 3)等,明确了引起浙产铁皮石斛梢枯病的病原菌为链格孢菌Alternaria alternata。淀粉酶产色链霉菌Streptomyces diastatochromogenes 1628代谢产物对链格孢菌菌丝生长有较强的抑制作用,IC₅₀为0.461%(体积浓度)。田间试验结果表明,在7和14 d的校正防效分别为68.35%和65.97%,均显著高于阳性对照50%多菌灵。本研究明确了铁皮石斛梢枯病病原菌的分类地位,并获得能够有效抑制该病原菌的微生物抑菌物质淀粉酶产色链霉菌代谢产物,为后续浙产铁皮石斛梢枯病的防治提供了实践依据。     

三峡库区柑橘溃疡病发生规律及综合防治方法

正柑橘溃疡病[Xanthomonas axonopodispv.cirri(Hasse)Vaut]是为害柑橘的一种细菌性病害,被列为柑橘检疫性病害。该病主要为害柑橘叶片、枝梢和果实。苗木和幼树受害,造成落叶、枯梢,影响树势;果实受害,易落果,轻者有病疤不耐贮藏,重者发生腐烂,大大降低果实商品价值。三峡库区是全国重要的柑橘生产优势区,为有效做好溃疡病的预测预报和防控工作,2016—2017年在湖北宜昌秭归     

桉树梢枯原因及防治的研究

观察、试验的结果表明,发生在桉树幼林的梢枯病,是由于缺乏微量元素硼而引起的一种生理性病害。它造成桉树枝梢顶端枯死。影响植株的生长与干形。在广西已有多处桉树种植区发生这种情况,是桉树生产上值得重视的问题,通过施用加硼的配方肥料,可以有效地控制梢枯病的发生。     

A patch—clamp study of the action of a nitromethylene heterocycle insecticide on cockroach neurones growing in vitro

The mode of action of a nitromethylene heterocycle (NMH) insecticide was studied by patch–clamp techniques using cockroach embryonic cultures as an experimental model. Under whole-cell recordings, this compound elicited inward currents resembling those induced by O-acetylcholine (ACh). The reversal potentials for both ACh and the NMH were similar, suggesting that the inward currents induced by both were carried by the same species of ion. Pharmacological investigations of NMH-induced responses revealed that the insecticidal action of this compound is exerted through agonistic action at the nicotinic acetylcholine receptor. Single-channel studies were also performed to study the interaction of NMH with the nicotinic-receptor-coupled ion channel.     

Titanium dioxide photoinduced degradation of some pesticide/fungicide precursors

Five-membered nitrogen heterocycles (pyrrole, imidazole and 1,2,4-triazole) have been degraded using titanium dioxide and simulated solar radiation at pH = 8. The degradations followed a simple Langmuir-Hinshelwood mechanism. Accordingly, the adsorption equilibrium constants K of the heterocycles on the titanium dioxide surface and the rate constants k of degradation of the heterocycle-catalyst adduct have been obtained experimentally. While the K values decrease with heterocycle pKa, the k values increase with increasing pKa. Therefore, apparently, the rate constant depends on the availability of the electron pair on nitrogen, but at the same time the electron pair repulsion induced by the negatively charged titanium dioxide surface at pH = 8 causes a reverse effect in the adsorption equilibrium constant. Only in the case of imidazole, where the adsorption equilibrium constant is low enough (K = 0.013 M(-1)), can the rate constant be approximated to a pseudo-first-order rate expression: k(obs) = Kk. In all other cases, k(obs) = Kk/(1 + K(heterocycle)).     

Prediction and Mapping of the Impact of Winter Temperature on the Development of Phytophthora cinnamomi-Induced Cankers on Red and Pedunculate Oak in France

ABSTRACT Phytophthora cinnamomi is the causal agent of a perennial canker that develops on the lower bole on northern red oak and pedunculate oak. The disease has a limited range in Europe, being reported only in southwest France. This limited distribution is probably linked to the susceptibility of P. cinnamomi to frost. A model was developed in previous work to estimate the impact of temperatures of <0 degrees C on the winter survival of P. cinnamomi in trunk cortical tissues and on the subsequent development of cankers. In this article, we report the use of this model to simulate canker development in 503 locations across France during a 30-year period. The predicted canker extension decreased sharply when the median P. cinnamomi winter survival index decreased from 0.95 to 0.65, with cankers that poorly developed when the median survival index was lower than 0.5 to 0.6. The actual incidence of the disease in 192 stands located across southwest France was compared with that of the model outputs. Both presence of disease in stands and frequency of cankered trees in infected stands, but not canker size on infected trees, were strongly related to the median P. cinnamomi survival index. No disease was present in stands with median survival index lower than 0.65, and the frequency of cankered trees in infected stands remained very low in stands with a median survival index between 0.65 and 0.70. Aspect was an additional factor explaining disease incidence, while the effect of elevation was likely due to its effect on winter temperatures. Maps of winter suitability to P. cinnamomi-induced cankers on oaks in France are presented.     

The <Emphasis Type="Italic">Foc</Emphasis> gene governs resistance to race 3 of <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">cucumerinum</Emphasis> in the cucumber cv. SMR-18

Bois noir (BN) is the most widespread European grapevine yellows disease caused by ‘Candidatus Phytoplasma solani’. Although our knowledge of the mechanisms of interactions of this pathogenic bacteria with host is largely unknown, the plant-pathogen system of BN is commonly used as a model system for studying grapevine yellows diseases. We applied here a conceptual model of general plant pathology – a disease triangle for describing interactions among the host plant, the pathogen and the environment. We generated a proof-of-concept statistical model for disease triangle using original experimental data and different statistical and data mining approaches for a selected system of ‘Ca. P. solani’ infection of cv. ‘Chardonnay’ grapevine plants. We monitored individual plants from a single vineyard over a period of six years. Phytoplasma content, the expression of 21 selected grapevine genes and environmental conditions were recorded and related to disease severity. Our model predicts that in described conditions BN is a function of the expression of grapevine gene VvDMR6, summer rainfall and abundance of ‘Ca. P. solani’. The greatest impact among elements of the disease triangle is attributed to the pathogen, and is independent of the pathogen titer. We showed that this first de facto representation of the disease triangle is useful for showing disease dynamics over several years and could be applied to other plant-pathogen systems. The overall results of this study will contribute to understanding of ‘Ca. P. solani’ biology and its interactions with grapevine host.     

Epidemiology and population ecology of kiwifruit blossom blight

A study of the ecology and epidemiology of kiwifruit blossom blight, believed to be caused by the bacterium Pseudomonas viridiflava , was made at the Horticulture and Food Research Institute's Kumeu Research Orchard during spring 1991. Populations of Pseudomonas species, progression of disease symptoms, and micrometeorological conditions were monitored during flowering. No correlations were found between disease progress and the climate variables measured. The rate of increase in disease incidence changed with the transition of buds to flowers. Changes in the rate of increase, logit transformed, were compared with climate variables using cross-correlation. Populations of P. viridiflava were related to the number of diseased blossoms remaining on the vine. The population of a saprophytic bacterium, P. fluorescens , increased as flowering progressed and as dead flower parts became available for colonization. Other Pseudomonas species were only present in low numbers. The population of P. viridiflava and the rate of disease progress decreased at fruit set. A comparison of simulated disease progress curves (calculated using disease model formulae) with disease progress curves from real data suggested that the epidemic was polycyclic, and observations suggested that disease was spreading to unopened buds.     

The effects of postplanting environment on the incidence of soilborne viral diseases in winter cereals

ABSTRACT Soilborne wheat mosaic virus (SBWMV) and Wheat spindle streak mosaic virus (WSSMV) are putatively transmitted to small grains by the obligate parasite Polymyxa graminis, but little is known about environmental requirements for transmission and the resulting disease incidence. We planted susceptible wheat and triticale cultivars in field nurseries on different autumn dates in 3 years and observed the incidence of symptomatic plants in each following spring. Autumn postplanting environment explained most of the variation in disease caused by both viruses. Little apparent transmission, based on eventual symptom development, of either virus occurred after the average soil temperature dropped below 7 degrees C for the remainder of the winter. To forecast disease, we tested an SBWMV transmission model in the field, based on laboratory results, that predicts opportunities for transmission based on soil temperature and soil moisture being simultaneously conducive. This model was predictive of soilborne wheat mosaic in 2 of 3 years. Zoospores of P. graminis have optimal activity at temperatures similar to those in the SBWMV transmission model. Furthermore, the matric potential threshold (as it relates to waterfilled pore sizes) in the SBWMV transmission model fits well with P. graminis as vector given the size restrictions of P. graminis zoospores. Conditions optimal for SBWMV transmission in the laboratory were not conducive for WSSMV transmission in the laboratory or for wheat spindle streak mosaic development in the field. This differential response to environment after emergence, as indicated by disease symptoms, may be due to virus-specific environmental conditions required to establish systemic infection via the same vector. Alternatively, the differential response may have been due to the involvement of a different vector in our WSSMV nursery than in our SBWMV nursery. Our results suggest that, as a control tactic for SBWMV or WSSMV, earliness or lateness of planting is less important in determining virus transmission and disease than the specific postplanting environment. Improved models based on the postplanting environment might predict virus-induced losses of yield potential, and in some cases, growers might avoid purchase of spring inputs such as pesticides and fertilizer for fields with greatly reduced yield potential.     

Effects of leaf blast on photosynthesis of rice 2. Canopy photosynthesis

The effect ofPyricularia oryzae, the causal organism of leaf blast in rice, on photosynthetic rate of a rice crop was determined with mobile equipment in the field. Canopy CO₂ exchanges rate (CER) was significantly reduced in plots inoculated withP. oryzae. The experimentally obtained data were used to evaluate the performance of a model for the effects of leaf blast on canopy photosynthesis. The model comprised photosynthesis and respiration routines of a mechanistic crop growth model, extended with submodels for effects of leaf blast on both processes. Canopy photosynthesis and the effect of leaf blast on CER were accurately simulated with the model.Analysis showed that the reduction in canopy photosynthesis was mainly due to an adverse effect of lesions on leaf photosynthetic rate and to shading by dead leaf are resulting from disease induced senescence. A sensitivity analysis demonstrated the importance of the vertical distribution of the disease in the canopy. This implies that disease monitoring for crop loss assessment should consider vertical disease distribution.     

Suppression of clubroot (Plasmodiophora brassicae) development in Arabidopsis thaliana by the endophytic fungus Acremonium alternatum

This study investigated the ability of an endophytic fungus Acremonium alternatum to reduce clubroot formation in the model plant Arabidopsis thaliana, which is highly susceptible to Plasmodiophora brassicae . Quantitative PCR demonstrated that A. alternatum colonized the P. brassicae -infected roots and shoots of the host plant. When Arabidopsis plants were co-inoculated with P. brassicae and A. alternatum , gall formation was reduced as shown by the reduction of the disease index (DI) by up to 50% compared to plants only infected with P. brassicae, whereas the infection rate was lowered by about 20% only in several, but not all, experiments. Clubroot was similarly suppressed when plants were inoculated with autoclaved A. alternatum spores or spore extracts, showing that viable spores were not needed. However, A. alternatum spores did not inhibit P. brassicae resting spore germination. Compared to the normal root galls, the smaller root galls on A. alternatum -inoculated plants contained fewer resting spores of the clubroot pathogen. It was thus hypothesized that inoculation with A. alternatum delayed the development of P. brassicae . Using quantitative RT-PCR to monitor the expression of P. brassicae genes differentially expressed during the development of the disease, a delayed pathogen development was corroborated. Furthermore, greenhouse experiments identified a time window in which the endophyte had to be administered, where the latest effective time point was 5 days before inoculation with P. brassicae and the optimum treatment was to administer A. alternatum and P. brassicae at the same time. These results indicate that A. alternatum and perhaps similar endophytes could be useful for the management of clubroot disease.     

5-甲基异噁唑-4-甲酸肟酯衍生物的合成及抑菌活性

异噁唑是具有较好活性的五元杂环,本文设计并合成了15个5-甲基异噁唑-4-甲酸肟酯类新化合物,利用核磁氢谱、核磁碳谱和高分辨质谱对其结构进行确证,并测试了其对番茄灰霉病菌Botrytis cinerea、水稻纹枯病菌Rhizoctonia solani、苹果树腐烂病菌Valsa mali和小麦全蚀病菌Gaeumannomyces graminis的离体抑菌活性。结果表明,在50μg/mL下,目标化合物对供试病原菌均有一定的抑菌活性,其中化合物5g对番茄灰霉病菌的抑制活性优于先导化合物L1和肟菌酯,EC₅₀值为1.95μg/mL。     

Assessment of the inheritance of resistance and tolerance in cherry (Prunus sp.) to Blumeriella jaapii,the causal agent of cherry leaf spot

Cherry leaf spot (CLS), caused by Blumeriella jaapii, is a serious fungal disease of sour cherry (Prunus cerasus). Cultivar Montmorency, the major cultivar grown in the United States, is highly susceptible to CLS. As many as 10 fungicide sprays can be required each growing season to combat this disease; therefore, developing CLS‐resistant cultivars is a top breeding priority. Germplasm previously reported to be resistant or tolerant to CLS was acquired and incorporated into the sour cherry breeding programme at Michigan State University (MSU) and included three cherry species: sour cherry, sweet cherry (P. avium), and the wild species P. canescens. This study aimed to: (i) compare the CLS disease progression profile of the susceptible cultivar Montmorency with those of the resistant and tolerant germplasm; and (ii) gain an understanding of the inheritance of these resistance and tolerance traits by evaluating the host response of progeny individuals belonging to families derived from this germplasm. Significant differences were observed between the susceptible Montmorency and the tolerant and resistant accessions in their response to CLS and its progression during the growing season. Evaluation of the CLS host responses of progeny individuals derived from this germplasm supported a dominant two‐gene model for P. canescens‐derived resistance and a recessive gene model for sweet cherry‐derived tolerance. These insights into disease progression and trait inheritance improve the efficiency and potential success of breeding sour cherry cultivars with durable resistance to CLS.