砂梨黑斑病的发生规律与无公害防治技术

经3年调查表明,在淮北地区,日韩梨品种(砂梨系统)栽培面积扩大,梨黑斑病的发生蔓延逐渐加重。叶片于4月中下旬开始发病,初侵染发生率与当年3-4月份降雨量密切相关,5-7月份为发病高峰,5-7月份高温多雨是病情严重的主要因素。生产防治应于发芽前(3月上中旬)喷布3～5波美度石硫合剂1次。在发病初期每隔7d喷10%(宝丽安(多抗霉素)WP或50%扑海因(异菌脲)WP1000～5000倍液1次,以后与进口代森锰锌、腐霉剂(速克灵)等交替使用,连续喷三四次,防效显著。     

陕西省苹果树斑点落叶病发生及化学防治的研究

本文通过对苹果斑点落叶病在叶片上发病状况的田间调查，结果表明该病从5月上旬开始发病一直持续到9月上旬，其中6月下旬和8月下旬至9月初为该病害发病的两个高峰期，对果树的中后期生长发育影响极大。化学杀菌剂防治苹果斑点落叶病的田间试验表明，无论是保护性杀菌剂，还是治疗性杀菌剂，在5月上旬“月上旬，喷药34次，7月下旬—8月上旬为补充防治时期，化学防治期应持续到8月中旬，间隔10—15d左右喷1次药。     

7种杀菌剂防治马铃薯晚疫病田间试验初报

本研究测定了7种杀菌剂对马铃薯晚疫病的田间防治效果。结果表明,2次药后7d,68. 75%氟吡菌胺·霜霉威悬浮剂和50%氟啶胺悬浮剂防效最好,分别达到81. 02%和80. 24%;其次为60%霜脲·嘧菌酯水分散粒剂防效达75. 26%;防效在60%～70%之间的有60%锰锌·氟吗啉可湿性粉剂、80%烯酰吗啉水分散粒剂、10%氰霜唑悬浮剂; 75%代森锰锌水分散粒剂防效相对最低。上述药剂对马铃薯晚疫病均有一定防效,建议在生产上轮换使用,其中代森锰锌为保护性杀菌剂,应在发病前或发病初期使用,其他药剂兼具保护和治疗效果。     

农抗120防治西瓜枯萎病的试验研究

1987～1989年进行了农抗120与常用化学杀菌剂防治西瓜枯萎病的药效对比,及不同使用期农抗120的防病效果试验,结果表明,全省多点用300倍农抗120,施药2次,防治西瓜枯萎病的效果平均为83.91±11.86％,比常用化学杀菌剂高23～43％,农抗120的防效与施药时期关系密切,两次灌根时间都应在发病之前,第一次施药时间:直播西瓜在4～5片真叶期,移栽西瓜在苗床期,右,据河南省120个县市,11万亩西瓜的防治示范结果,隔7～10天,进行第二次施药,病株率已控制在0～8％左平均防效为70～95％,每亩挽回西瓜损失200～400公斤。     

不同浓度代森锌对梨黑斑病的防治试验

黑斑病是南方梨园三大病害之一 ,发病率通常在 65～ 85%之间 ,严重影响丰产。本试验通过不同浓度的代森锌对黄花梨黑斑病的防治试验 ,找出防治效果较好的浓度 ,为生产提供参考。1　材料与方法以树龄为 7～ 1 0年的黄花梨为试材 ,试验于2 0 0 0年在孝感市果园场进行。在园中选择发病的黄花梨 ,于 5月 2 4日用有机杀菌剂代森锌 (成都化工厂生产 ) 60 0倍、 1 0 0 0倍、 2 0 0 0对倍整个树冠进行喷药 ,单株小区、重复 3次 ,清水为对照 ,6月 7日调查病情指数和防效。病情指数的计算方法 ,每棵树在树冠上部、下部、内膛、外围各取 1 0 0片叶 ,根…     

福泉市马铃薯晚疫病控制技术研究及推广应用

2008—2011年采取品种抗性、田间自动气象站、栽培方式、种薯处理、土壤处理、化学防治等方法．对福泉市马铃薯晚疫病的发生规律与控制技术进行应用研究。结果表明,马铃薯晚疫病的发生早迟及为害程度与品种抗性和4—6月份的气温、降雨量密切相关,采取控制措施,综合防治效果达到85．5％。     

莱阳地区梨锈病防治适期研究

在山东莱阳地区,梨锈病菌冬孢子角自梨花现蕾期开始陆续成熟,成熟的冬孢子角遇1.5 mm/d以上的降雨,萌发产生担孢子。经2～3次降雨后,冬孢全部萌发,以后不再产生担孢子。梨树初花后35 d内对锈病最敏感,即为防治期。若该期内降雨量大于1.5 mm/次、叶面结露时间长于7 h/次,担孢子即可侵染。其侵染量与梨园周围越冬菌原的数量、降雨持续时间和品种抗病性等因子有关。田间试验表明:担孢子侵染后至病斑显症前(约7 d)是内吸性杀菌剂防治的有效时期。病斑显症后只有少数杀菌剂能抑制病斑扩展,20.67%氟硅唑乳油、10%苯醚甲环唑水分散粒剂和15%三唑酮可湿性粉剂3种药剂在病原菌侵入前喷施能有效地抑制担孢子侵染,持效期约7 d;担孢子侵染后喷药能有效抑制病斑显症,因此,要特别关注梨树初花时第1次降雨后梨锈病的防治。     

5种杀菌剂对马铃薯晚疫病田间防效比较

为筛选防治马铃薯晚疫病经济有效的药剂,测定了5种杀菌剂对马铃薯晚疫病的防治效果。结果表明,5种杀菌剂对马铃薯晚疫病均有不同程度的防效。其中,烯酰·唑嘧菌和氰霜唑对马铃薯晚疫病防控效果最佳,第5次施药后7d的防效分别为94.5%和94.1%;其次为丁子香酚和唑醚·代森联,防效分别为88.7%和76.1%;苦参碱防效较差,仅为23.7%。供试的5种杀菌剂中,氰霜唑和烯酰·唑嘧菌处理的防效和增产率均较高,建议可在生产上大面积推广使用。     

上海柑橘黑点病田间流行与降雨关系研究

自2009年起柑橘黑点病逐渐成为上海地区影响柑橘果实商品价值的最主要病害,严重制约上海市柑橘产业的效益。为了解该病的田间流行动态以及病害发生与降雨量的关系,2010年—2018年连续9年进行了病害发生动态调查和分析。结果表明,上海地区6月上旬至8月下旬是果实感病期,其中,6月中旬至7月中旬为发病高峰期;雨水是黑点病发生的必要条件,果实生长期不同阶段的降雨参数,尤其是6月下旬的降雨量与病情指数密切相关。本文以病情发展的3个时间节点(7月15日、8月15日和9月10日)的病情指数为因变量,以这3个时间点之前各旬的降雨量、降雨日为自变量筛选变量建立了多元线性回归方程,根据分析结果,采用6月下旬的降雨量等气象因子建立的多元线性回归方程,可以比较准确地预测7、8月中旬和9月10日即病害发展稳定期的田间病情。     

菊花煤烟病及其防治的研究

菊花煤烟病,又叫煤病、煤烟病、煤霉病。发病植株叶片形成象煤状黑色霉层,为菌丝体组成,被害叶片变薄无光泽。发病严重时叶柄及嫩头均有黑色霉层显现,叶背面一般无症状。受害菊花叶片光合作用减弱,影响菊花整体造型及观赏价值,致使经济效益降低。1998年7～8月病害流行期调查当地发病情况,发病普遍率为34.3%;病叶率一般40%～50%,严重的达80%以上;病情指数一般在80左右,严重的在90以上。该病属半知菌丛梗孢目,暗色孢科,枝孢属芽枝霉菌。在菊花生长季节7～9月份可多次侵染,连续发生。其发生与病原、寄主、气候、人为活动密切相关。连续阴雨、空…     

Sensitivity of Venturia inaequalis to trifloxystrobin

The sensitivity of Venturia inaequalis to trifloxystrobin was monitored by both in vitro (spore germination) and in vivo tests (on apple seedlings). There was good correlation between the in vitro and in vivo results. Baseline sensitivity was established with 95 bulk isolates from Europe between 1995 and 1998 which showed a narrow sensitivity range-factor of up to 17 between the least and most sensitive isolates. Monitoring of populations originating from trifloxystrobin-treated and untreated orchards between 1995 and 1999 showed only sensitive isolates and no performance deficiencies were reported. Data also show that trifloxystrobin is not cross-resistant to anilinopyrimidines and triazoles, but is cross-resistant to kresoxim-methyl, another strobilurin which also inhibits the cytochrome bc1 enzyme complex at the Qo-site in the respiration chain of fungal mitochondria (QoI inhibitors). Under experimental conditions from a specific trial site in Switzerland, where trifloxystrobin has been tested since 1994, isolates containing conidia resistant to Qo inhibitors were detected in 1997 and 1999. However no obvious performance deficiencies were reported. Nevertheless these results demonstrate a risk for the development of practical resistance in V inaequalis to Qo inhibitors and therefore a need to apply resistance management principles strictly.     

梨黑星病菌寄生部位及致病作用研究

 组织透明及扫描电镜研究结果表明:梨黑星病菌在叶片上主要寄生于表皮细胞和叶脉薄壁组织细胞的表面,沿细胞表面扩展。病原菌并非只在角质层与表皮细胞间生长,而且在表皮细胞和叶脉薄壁组织细胞的细胞间寄生。在大量的观察中,没有发现侵入到细胞内菌丝或菌丝变态结构。梨黑星病菌不寄生叶肉细胞,但能导致叶肉细胞病变。由于黑星病菌的寄生性既不同于专性寄生,也不同于杀生寄生,才使梨黑星病的潜育期和产孢期都长于这两类真菌病害。这是认识和研究梨黑星病发病特点和流行规律的基础。     

苹果黑星病菌中国菌株生物学特性研究

 苹果黑星病菌(Venturia inaequalis(Cooke) Wint.)适合生长的培养基有苹果叶汁、苹果果汁、麦芽浸渍物、PSA、PDA、V8和马铃薯麦芽糖;适合产孢的培养基有苹果叶汁、V8和PSA。菌落生长和产孢适宜的pH值为5.0~6.5,温度为15~20℃。在碳源和氮源中,蔗糖、葡萄糖、果糖、麦芽糖、酵母提取物、硝酸钠和牛肉膏有利于病菌生长和产孢,硫酸铵抑制产孢,草酸铵抑制菌落的生长和产孢。20℃时,光周期为12 h,光照强度为600 lx条件下有利于病菌在PSA培养基上生长和产孢,其产孢量约为黑暗条件下的13倍。病菌分生孢子在水滴中萌发的适宜温度为20~25℃,最适pH值为5.0~6.5     

梨黑星病菌被哈茨木霉感染后抗氧化系统的变化

测定被哈茨木霉感染后梨黑星病菌抗氧化系统变化的结果表明,被哈茨木霉感染后梨黑星病菌过氧化氢酶、过氧化物酶和超氧化物歧化酶的活性逐渐下降;丙二醛含量和超氧阴离子产生速率上升;还原型谷胱甘肽和抗坏血酸含量降低。初步明确,梨黑星病菌被哈茨木霉感染后,活性氧清除系统等被破坏,膜脂过氧化作用加强,是最终导致菌体受害的原因之一。     

Sensitivity of mitochondrial respiration to different inhibitors in Venturia inaequalis

The sensitivity of Venturia inaequalis field isolates to inhibitors of the cytochrome bc1 complex at the Qo site (QoIs) was characterised at the molecular, biochemical and physiological level, and compared to other respiration inhibitors. Comparison of a sensitive and a QoI-resistant isolate revealed very high resistance factors both in mycelium growth and spore germination assays. Cross-resistance was observed among QoIs such as trifloxystrobin, azoxystrobin, famoxadone, strobilurin B and myxothiazol. In the mycelium growth assay, antimycin A, an inhibitor of the cytochrome bc1 complex at the Qi site, was less active against the QoI-resistant than against the sensitive isolate. The mixture of QoIs with salicylhydroxamic acid (SHAM), an inhibitor of the alternative oxidase, exerted synergistic effects in the spore germination but not in the mycelium growth assay. Thus, the cytochrome and the alternative respiration pathways are assumed to play different roles, depending on the developmental stage of the fungus. Induction of alternative oxidase (AOX) by trifloxystrobin was observed in mycelium cells at the molecular level for the sensitive but not the resistant isolate. Following QoI treatment, respiration parameters such as oxygen consumption, ATP level, membrane potential and succinate dehydrogenase activity were only slightly reduced in Qo-resistant mycelium cells, and remained at much higher levels than in sensitive cells. In contrast, no difference was observed between sensitive and resistant isolates when NADH consumption was measured. Comparison of the cytochrome b (cyt b) gene of the sensitive and resistant isolates did not reveal any point mutations as is known to occur in resistant isolates of other plant pathogens. It is assumed that QoI resistance in V inaequalis may be based on a compensation of the energy deficiency following QoI application upstream of the NADH dehydrogenase of the respiratory chain.     

薄壳山核桃疮痂病菌TaqMan荧光定量PCR检测方法的建立及应用

疮痂病是薄壳山核桃上最具毁灭性的病害,带菌植物材料是传播疮痂病的重要来源。准确、灵敏、快速的检测方法可为该病害流行规律调查和防控提供有力的依据。本文通过比较薄壳山核桃疮痂病菌Venturia effusa及其近似种之间的ITS序列差异,设计了特异性引物和TaqMan探针,建立了薄壳山核桃疮痂病菌的荧光定量PCR检测方法。特异性检测结果表明,该方法可以检测不同地区的薄壳山核桃疮痂病菌菌株,而对其近似种以及薄壳山核桃上的其他真菌均没有信号。本研究建立的检测方法对薄壳山核桃疮痂病菌DNA的最低检测限可达0.5 pg/μL。该方法用于田间样品检测时,检测时间仅需1 h,远快于常规的分离培养法。本研究建立的基于TaqMan探针的荧光定量PCR检测方法为薄壳山核桃疮痂病菌的快速检测和监测提供了有力工具。     

苹果黑星病菌遗传多样性的SSR分析

 Apple scab caused by Venturia inaequalis has a tendency to spread and threatens the development of apple production in recent years in China. The genetic diversity and population structure were investigated by using simple sequence repeat (SSR) markers. 51 strains were classified into 3 groups by UPGMA method as Xunyi, Xingping and U. K. population, each of them mainly including strains from its original place. A relatively high level of genetic diversity was revealed:H=0.425 3, I=0.675 8, PPL=66.67% (at species level); H=0.149 1, I=0.228 0, PPL=44.44% (at population level). A high level of genetic differentia-tion was detected among/within populations with Nei's Gst analysis and AMOVA. Molecular genetic variance within populations was greater than that among populations. Genetic variance among populations might result from barriers to gene flow (Nm=0.675 8). Genetic variance within populations might result from sexual propagation of V. inaequalis.     

A new scab‐like disease on apple caused by the formerly saprotrophic fungus Venturia asperata

Atypical scab‐like symptoms were reported for the first time in 2007 in the south of France on fruits of apple cultivars carrying the Rvi6 (=Vf) major resistance gene to Venturia inaequalis. With microscopic observations, nucleotide sequence data and pathological tests, it was shown that the causal agent was Venturia asperata. Scanning electron microscopy was used to compare its infection process and conidiogenesis to those of Venturia inaequalis on apple and Venturia pirina on pear. Venturia asperata produced fewer hyphae and fewer spores than the two other Venturia species, and resulted in weaker symptoms. This fungal species was previously described as a saprotroph on apple leaf litter. This is the first report of damage on apple fruits caused by V. asperata. Changes in host and cultural practices may have created a new context favourable for the emergence of this pathogen. It was also detected on symptomless leaves and on overwintered leaves on the ground. Pseudothecia developed on overwintered leaves and released ascospores over a 2‐month period from the end of March until the end of May, suggesting that the fungus is able to survive from season to season. However, it is not yet known if this new disease will establish over coming years and become an emergent disease.     

Sensitivity to strobilurin fungicides of Italian Venturia inaequalis populations with different origin and scab control

BACKGROUND: Venturia inaequalis (Cooke) Winter with reduced sensitivity to strobilurins has been reported in several countries, including Italy. This study aimed to characterise the sensitivity to strobilurins of three different types of V. inaequalis population: (a) wild types; (b) from commercial orchards satisfactorily managed with strobilurins; (c) from an experimental orchard with control failures by trifloxystrobin and kresoxim‐methyl. In vitro sensitivity tests included antigerminative activity on population conidia and mycelial growth inhibition on monoconidial isolates. Cleaved amplified polymorphic sequence (CAPS) analysis was used for the detection of G143A substitution. RESULTS: Wild‐type populations showed EC₅₀ values lower than 0.031 mg L^?1, while those of orchards with good performance by strobilurins presented EC₅₀ values never higher than 0.063 mg L^?1. Samples with scab control failures showed a strongly reduced population sensitivity. Similar differences were confirmed in monoconidial isolates. The G143A substitution was always detected in low‐sensitivity populations, only sometimes in well‐controlled populations and generally not in wild types. CONCLUSIONS: In vitro sensitivity assays were able to discriminate the three population types with different scab management, while the qualitative PCR analysis (CAPS) was only partially reliable. High sensitivity differences among V. inaequalis populations with good and poor field control by strobilurins were observed. Copyright © 2011 Society of Chemical Industry     

Monitoring of Venturia inaequalis harbouring the QoI resistance G143A mutation in French orchards as revealed by PCR assays

BACKGROUND: Genetic resistance to QoI fungicides may account for recent failures to control Venturia inaequalis (Cooke) Winter in French orchards. Two PCR-based assays were developed to detect the G143A point mutation in the fungal mitochondrial cytochrome b gene. The mutation is known to confer a high level of resistance to QoI fungicides. Occurrence of the G143A mutation in French field isolates collected from 2004 to 2007 was monitored. RESULTS: The QoI-resistant cytochrome b allele was specifically detected either following the cleavage of the amplified marker by a restriction endonuclease (CAPS assay) or its amplification using an allele-specific PCR primer. Using either method, the G143A mutation was found in 42% of the 291 field samples originating from French orchards in which apple scab proved difficult to be controlled. Monitoring of the G143A mutation in orchards located in 15 French administrative regions indicated that the mutation was detected at least once in nine of the regions, and its presence ranged from 33% to 64% of the orchards analysed in 2004 and in 2007 respectively. CONCLUSION: The PCR-based methods developed in this study efficiently reveal the presence of the G143A mutation in French V. inaequalis field populations.