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1.
The efficacy of 14 selected fungicides against Cylindrocarpon liriodendri and Cylindrocarpon macrodidymum was evaluated in vitro by testing their effect on mycelial growth and conidial germination. Carbendazim, hydroxyquinoline sulphate, imazalil, and prochloraz were the most effective fungicides in reducing mycelial growth in both Cylindrocarpon species. Captan, copper oxicloride, didecyldimethylammonium chloride and thiram were the most effective to inhibit conidial germination of both species. A pot assay was also conducted with captan, carbendazim, copper oxychloride, didecyldimethylammonium chloride, hydroxyquinoline sulphate, imazalil and prochloraz in order to determine their potential to prevent infections caused by C. liriodendri and C. macrodidymum during the rooting phase in the grapevine propagation process. All fungicides significantly decreased the root disease severity values in both species compared with control treatment, with the exception of imazalil in C. macrodidymum. In the case of the percentage of reisolation, all values were lower than those obtained for the control treatment, but only captan, carbendazim and didecyldimethylammonium chloride were significantly different in the case of the cuttings inoculated with C. liriodendri, and prochloraz in the case of those inoculated with C. macrodidymum.  相似文献   

2.
Fungicide resistance in Phaeoacremonium aleophilum, one of the most frequent fungal pathogens associated with grapevine trunk diseases, was investigated and found to exist in some isolates of the pathogen against a commercial formulation, Escudo®. The effect of this compound and its two active substances, carbendazim and flusilazole, was first evaluated on the mycelial growth of P. aleophilum. Escudo®-resistant isolates were estimated at a frequency of 24% in Spanish vineyards. Then, the two active substances were used individually to test their effect on mycelia growth of twelve single-spore cultures originating from six Escudo®-resistant isolates. Flusilazole (DMI-triazole) did not inhibit mycelia growth of any single-spore cultures of P. aleophilum. Carbendazim (benzimidazole) used alone allowed the growth of the same single-spore cultures that were also resistant to Escudo®. AFLP characterization of sensitive and resistant single-spore cultures showed genetic diversity within P. aleophilum isolates but no AFLP markers were associated with resistance. New primers set (L2/R1) were designed to partially amplify the exon 6 of the beta-tubulin gene of P. aleophilum. Two different point mutations resulted in glycine (GGC) or lysine (AAA) replacing the glutamic acid (GAG) at codon 198 of the beta-tubulin gene in some of the resistant single-spore cultures studied. Resistant single-spore cultures of P. aleophilum were shown to have different aggressiveness levels as sensitive single-spore cultures by inoculation of wood segments of Vitis vinifera in the presence and absence of fungicide.  相似文献   

3.
采用含毒介质法分别测定玉米穗腐病菌禾谷镰孢菌和拟轮枝镰孢菌对9种药剂的敏感性,在田间进行防治玉米穗腐病的药效试验,综合评价化学和生物药剂以及不同施药处理对玉米穗腐病的防治效果。室内毒力测定结果表明,9种药剂在一定浓度下对玉米穗腐病均有毒力作用,10%苯醚甲环唑、70%甲基托布津对禾谷镰孢菌毒力较强;70%甲基托布津对轮枝镰刀菌毒力较强,10%苯醚甲环唑次之。田间药效试验结果表明,50%异菌脲可湿性粉剂防效为92.3%,5%井冈霉素为80.64%;且先接菌后喷药的防治效果优于先喷药后接菌处理。  相似文献   

4.
Blueberry scorch virus (BlScV) is one of the most pervasive pathogens of highbush blueberry. The virus is aphid-vectored and exhibits a latent period between infection and symptom expression in the host plant of up to 5 years. In many cases, we have observed BlScV symptom expression in new fields that appears inconsistent with aphid-vectored introduction and spread. It was, therefore, speculated that the virus may be introduced through infected nursery stock. To examine this possibility, we first surveyed selected nurseries to determine if mother plants, used for propagation by cuttings, were BlScV-infected. Two nurseries were found to harbor symptomless, infected, mother plants (cv. Duke). Cuttings from one nursery were collected from infected and non-infected plants and rooted in propagation beds. The survival and infection of cohorts from each mother plant were determined one year after planting. A significantly greater proportion of cuttings survived from non-infected mother plants (0.7) than from infected mother plants (0.5). Of the cohort from infected mother plants that survived, 40% tested positive for BlScV. We also surveyed the distribution of infected, symptomatic plants in recent ‘Duke’ plantings that originated from nurseries with BlScV-infected mother plants and compared distribution with older plantings with more advanced BlScV outbreaks. In all cases, the distribution of BlScV symptom development in young fields was random, which is consistent with introduction from planting stock. Older plantings showed a strong clustered distribution, which is consistent with aphid transmission. This study identifies infected nursery stock as an important source of BlScV dissemination and underscores the importance of having symptomless mother plants virus tested.  相似文献   

5.
Trunk diseases are important on grapevines (Vitis vinifera L.) in most countries where grapevines are grown. In Chile, Diplodia seriata, Inocutis sp. and Phaeomoniella (Pa.) chlamydospora are the most prevalent pathogens associated with this syndrome. It has been demonstrated that fresh pruning wounds are the main infection route for fungal trunk disease pathogens. The objective of this study was to evaluate the efficacy of paste and spray fungicide applications in protecting pruning wounds against D. seriata, Inocutis sp. and Pa. chlamydospora on ‘Cabernet Sauvignon’ grapevines in two important Chilean grapevine production areas. The fungicides used in this study were benomyl, pyraclostrobin, tebuconazole, and thiophanate-methyl, which were applied as paste and liquid fungicide on fresh pruning wounds pre- and post-inoculation with mycelium plugs of the different fungal pathogens used in this study. The efficacy of the fungicides was assessed by measuring the length of the discoloration of the vascular system and percent re-isolation obtained on fresh pruning wounds. The results obtained demonstrate that infections caused by D. seriata, Inocutis sp. and Pa. chlamydospora can be significantly reduced using both paste and spray applications of benomyl, pyraclostrobin, tebuconazole and thiophanate-methyl and that the paste formulations provided a better control than spray applications. Regardless of the fungicide and application method used, the pre-inoculation treatments (performed 24 h before inoculation) resulted in better control than the 24 h post-inoculation treatments. The current study showed that Inocutis sp. can induce vascular discoloration on grapevine spurs. This study supports a broader use of benzimidazole fungicides for the control of the devastating trunk diseases in all grape productions worldwide.  相似文献   

6.
Biological control agents offer one of the best alternatives to reduce the use of pesticides. This investigation studied the tolerance to fungicides and integrated use of the potential biocontrol agent Streptomyces sp. A6 for control of Fusarium wilt of pigeon pea, Cajanus cajan. Streptomyces sp. A6 exhibited strong tolerance towards most of the fungicides used in the study at concentrations higher than those recommended for field applications. The isolate showed enhanced growth and mycolytic enzyme production in the presence of sulphur, mancozeb, carbendazim, fosetyl aluminium and triadimefon. The fungicides mancozeb, sulphur and carbendazim were selected for further studies. Effective concentrations (EC50 values) of the test fungicides that reduced Fusarium spore germination and fungal biomass by 50% were determined. Similarly, the EC50 for inhibiting fungal spore germination and reducing fungal biomass to 50% by Streptomyces sp. A6 and culture filtrate (CF) were also determined. Combining the EC50 dose of the culture and CF with test fungicides was found to be more effective for controlling Fusarium infection in C. cajan compared to the sum of the effects of the individual treatments. Such combined use of biocontrol agent with fungicides can reduce the dosage of toxic fungicides in agricultural fields, thereby reducing environmental risks. Tolerance and synergistic interaction of Streptomyces sp. A6 with frequently used fungicides suggested its potential in integrated pest management. To the best our knowledge, this is the first extensive study on integrated use of Streptomyces species with fungicides.  相似文献   

7.
The results of long term virus surveys in intensively cultivated vanilla plots in the Society Islands (French Polynesia), between 1999 and 2007 are reported here. The data confirmed a potential for high incidence of aphid borne viruses in particular Cucumber mosaic virus (CMV) and Watermelon mosaic virus (WMV) as well as the non vectored Cymbidium mosaic virus (CymMV). CMV had a particularly high prevalence (over 30% of the plots) and could severely damage up to 50% of the vines before blossom. Severe outbreaks of CMV were correlated to the presence of the weed Commelina diffusa as a reservoir of virus and aphid vectors. The application in 2003 of simple prophylactic measures resulted in a sharp reduction of virus incidence in new plantations, compared to levels of virus diseases recorded in the previous decade. Indeed, at the beginning of fruiting, the incidence of aphid borne viruses did not exceeded 1.6% of vines for the 29 shade houses which adopted the virus prophylaxis. The three remaining shade houses were severely (20–50%) infected by WMV or CymMV because of the planting of virus-infected cuttings. These results demonstrate the benefit of implementing prophylaxis at the scale of an archipelago, and widen the possibilities of developing intensive cultivation of vanilla in other areas confronted with similar virus constraints.  相似文献   

8.
In the years 2006–2008, clusters of Vitis vinifera (cv. Riesling) were inoculated with a conidia suspension of Guignardia bidwellii, the causal agent of grape black rot, at weekly intervals from one week before until eight weeks after bloom. Berries’ susceptibility turned out to be strongly linked to the speed of the phenological development in the respective season. In view of this, a degree day-based model simulating the relative susceptibility as a function of the phenological development was established. Infections on inflorescences were already possible prior to bloom. The period of highest susceptibility for direct infection on berries lasted from fruit set to the beginning of bunch closure. Successful infections took place until the end of bunch closure. Ontogenic resistance occurred clearly before veraison. Consequently, control measures should focus on the period between directly prior to bloom and bunch closure. Thus, the time span of black rot control coincides with the period in which vineyards need to be protected against the two major grape pathogens, Erysiphe necator and Plasmopara viticola. Applications of fungicides aimed at powdery and downy mildew control, also effective against G. bidwellii (e.g. strobilurins, triazoles and dithiocarbamates), offer a simultaneous control strategy for these three fungal diseases.  相似文献   

9.
通过形态学和分子生物学方法对2016年采自吉林省36个村镇的玉米根腐病样品进行镰孢菌分离和鉴定,并通过田间试验筛选有效药剂。结果发现,共分离获得84株镰孢菌,主要包括尖孢镰孢、禾谷镰孢、拟轮枝镰孢、层出镰孢、三线镰孢等11种镰孢菌,其中尖孢镰孢平均分离频率最高,为45.2%;其次是禾谷镰孢,平均分离频率为20.2%。从分布区域看,尖孢镰孢是白城、吉林、辽源和通化地区玉米根腐病的主要致病菌,分离频率分别为75%、54.5%、85.7%和45.5%;禾谷镰孢是松原和四平地区玉米根腐病的主要致病菌,分离频率分别为41.7%和41.7%。田间试验表明,5种药剂的防治效果为16.35%～81.26%,药种比为10 g/kg的10%咯菌腈悬浮种衣剂对玉米根腐病防治效果最好,防效达81.26%。吉林省玉米根腐病的主要病原菌为尖孢镰孢,药种比为10 g/kg的10%咯菌腈悬浮种衣剂可用于玉米根腐病的田间防治。  相似文献   

10.
Summary Soil in a potato field naturally infested with black dot (Colletotrichum coccodes) was fumigated with methyl bromide at 126 g m−2 or left unfumigated. Potato seed tubers (cv. BP1) uninfected, lightly infected (1–25% surface affected), severely infected (26–100% surface affected) and severely infected withC. coccodes but dusted with prochloraz manganese chloride as Octave 2.5% DP at 750 g per 100 kg seed were planted in fumigated and unfumigated soil. When harvested, the incidence of black dot on the progeny of infected seed planted in unfumigated soil was twice that of progeny in fumigated soil, with progeny of uninfected seed having a 68.5 times higher disease incidence in unfumigated soil. Black dot on progeny tubers was reduced by pre-treatment of seed with prochloraz in fumigated soil only. With black dot infested fields, planting disease-free seed or treating seed with fungicides would not decrease disease on progeny tubers.  相似文献   

11.
Botrytis bunch rot of grapes is mainly controlled by applying fungicides at three crop growth stages: the end of flowering (BBCH 68), bunch closure (BBCH 77) and the beginning of veraison (BBCH 81). The hydroxyanilide derivative fenhexamid is among the most effective fungicides registered to control Botrytis cinerea. Its effectiveness was examined in relation to spray timing, fungicide resistance and defense responses of grapevine. Overall, the earlier fenhexamid was applied, the more effective it was at controlling B. cinerea. Frequencies of B. cinerea strains which were resistant to fungicides were evaluated at harvest. The frequencies of resistant phenotypes were similar among treatments and years with the exception of a class of multidrug resistant strain (MDR 2) whose frequency appeared to increase after fenhexamid applications. If current spray programs including fenhexamid appear to control bunch rot at the current MDR frequency, a propagation of MDR 2 strains might lead to a decline in disease control. Finally, defense responses were studied in grapevine flowers/berries following fenhexamid application. None of the defense processes tested was induced in flowers/berries at stages 68 and 77. Only an increase in chitinase activity was observed in treated-berries at stage 81, suggesting that fenhexamid effectiveness was not related to a stimulation of defense responses.  相似文献   

12.
The objective of this work was to investigate the efficacy of a prepackaged combined formulation, Companion (carbendazim 12% + mancozeb 63% WP), sole application of carbendazim 50% WP, manozeb 75% WP and methyl jasmonate (MeJA), an inducer of systemic acquired resistance on disease severity and their role in post-infectional defense responses in chilli seedlings against Sclerotium rolfsii. Seeds were treated for 8 h with MeJA (2.5 mM and 5.0 mM) and each of fungicides (500 ppm), and were sown in pots containing soil and fungal inocula (95:5 w/w). At 15 days after sowing maximum defense against fungal infection was exhibited by Companion comparably followed by the sole application of carbendazim and mancozeb. MeJA reduced percent mortality of S. rolfsii-infected chilli seedlings significantly as compared to the inoculated control. Assessment of peroxidase (POX) and esterase (EST) at 15 days after sowing revealed the increased activity under inoculated condition. Highest POX activity in MeJA treatments (5 mM > 2.5 mM) was followed by the Companion treatment. Highest EST activity was registered in Companion treatment. The zymogram of POX isozymes showed over-expression of POX 2 and POX 4 isoforms, and induction of POX 1 isoform in inoculated treatments. On the other hand, that of EST isozymes showed induction of EST 1 isoform in Companion, carbendazim and MeJA treatments. All EST isoforms were over-expressed in Companion-treated seedlings. Both fungicides and MeJA showed significant effects on disease severity, induction of defense enzymes and isozyme pattern in S. rolfsii-infected chilli seedlings. Contact and systemic fungicides under the experiment demonstrated differential responses. The combination formulation was superior in disease control to application of the fungicide components individually. They compared favourably with MeJA in induction of defense-related enzyme activities. All these findings are new with respect to the chilli-S. rolfsii host–pathogen interaction system, S. rolfsii representing the sclerotial basidiomycetes in particular.  相似文献   

13.
Summary The effect of fungicides and the antagonistic fungusTrichoderma harzianum (Th) on the potato leak pathogenPythium aphanidermatum (Pa) was investigated in vitro. Rot was reduced by 73% to 89% when tubers inoculated withPa were treated by immersion in solutions (0.5% w/v) of the fungicides Ridomil MZ58. Dithane M45. Manebe 80 and Tachigaren 360. Complete protection was achieved by dusting inoculated tubers with Ridomil MZ58 diluted in kaolin at a final concentration of 0.1% (w/w). The biological treatments of dipping inoculated tubers in a conidial water suspension ofTh at 108 conidia/ml or of dusting with a mixture of a barley culture ofTh and kaolin to a final concentration of 2×109 conidia/g were as effective as the chemical treatments. Control was still effective when inoculated tubers were treated with Ridomil MZ58. Tachigaren 360 or the conidial suspension ofTh after 24h incubation at 25°C.  相似文献   

14.
以禾谷镰孢菌为研究对象，在室内测定不同浓度可溶性硅和不同杀菌剂及其互配对禾谷镰孢菌生长的影响。结果表明，可溶性硅浓度越大，对禾谷镰孢菌的抑制率越高，1 666.7 mg/L硅处理后对禾谷镰孢菌的抑制率达30.3%。40%咯菌腈·氟唑菌酰羟胺(0.008 mg/L)对禾谷镰孢菌的毒力最强(EC50=0.008 mg/L)，可溶性硅与40%咯菌腈·氟唑菌酰羟胺混配可明显降低对禾谷镰孢菌的抑制率，降幅为8.7%～12.87%；可溶性硅与5%香芹酚按不同比例混配对禾谷镰孢菌互作效应不同；可溶性硅与其他四种杀菌剂混配都能促进对禾谷镰孢菌的抑制。田间药效试验表明，除40%咯菌腈·氟唑菌酰羟胺外，其他5种杀菌剂与硅肥混合喷施防效和产量都高于单喷，其中，混合喷施2 000 mg/L可溶性硅肥+25%吡唑醚菌酯防效最好，增产最高。  相似文献   

15.
亚粘团镰孢霉引起的玉米顶腐病是我国玉米生产上的一种新病害。在室内采用菌丝生长速率法测定8种杀菌剂对亚粘团镰孢霉的抑菌效果。结果表明,25 g/L咯菌腈悬浮种衣剂的EC50最小,病原菌对其敏感性最高,抑菌效果最好;60 g/L戊唑醇悬浮种衣剂和80%多菌灵可湿性粉剂的EC50较小,病菌对其敏感性也较高,抑菌效果也较好;97%烯酰吗啉可湿性粉剂的EC50 最大,病菌对其敏感性最低,抑菌效果最差。通过温室种子包衣效果,生产上可使用25 g/L咯菌腈悬浮种衣剂和60 g/L戊唑醇悬浮种衣剂来防治玉米顶腐病。同时通过室内毒素平皿培养进一步明确了经咯菌腈、戊唑醇和多菌灵对玉米种子包衣处理后,不同浓度的亚粘团镰孢霉毒素滤液对玉米胚根和胚芽生长的影响。  相似文献   

16.
先玉335、郑单958和京科968抗虫能力的比较研究   总被引：1，自引：0，他引：1  
以先玉335、郑单958、京科968为材料,以玉米螟(Ostrinia furnacalis)、黏虫(Mythimna separata)和禾谷缢管蚜(Rhopalosiphum padi)为供试昆虫,探究玉米品系大喇叭口期对玉米螟和黏虫及抽雄期对禾谷缢管蚜抗性差异,测定其主要抗虫化合物丁布类物质的含量。结果发现,京科968对玉米螟及禾谷缢管蚜抗性均高于另外两个品系;对黏虫的抗性,郑单958和京科968高于先玉335。大喇叭口期京科968中丁布类物质含量最高,抽雄期郑单958和京科968中主要丁布成分含量均高于先玉335,上述组织中丁布合成相关基因在郑单958及京科968中的表达量也均高于先玉335。本研究揭示杂交玉米抗虫性与抗性相关化合物含量及其相关基因表达间存在正向相关关系,为抗虫玉米分子育种提供理论参考。  相似文献   

17.
大田环境下利用无人机施药,筛选防治双斑长跗萤叶甲有效药剂,探讨玉米中后期害虫一体化防治的可行性。结果表明, 5%高效氯氟氰菊酯 EW、 5%甲维盐 WG、 30%噻虫嗪 SC、 30%噻虫嗪 SC减量 20%+CQMa421施药2 d后对双斑长跗萤叶甲防效均在 97.90%以上。5%高效氯氟氰菊酯 EW和 30%噻虫嗪 SC对蚜虫防效好,且持效期长。5%高效氯氟氰菊酯 EW、 200 g/L氯虫苯甲酰胺 SC、 200 g/L氯虫苯甲酰胺 SC减量 20%+CQMa421施用后玉米螟活虫数为 0～1.67头/百株。研究表明,玉米吐丝初期利用无人机喷施 5%高效氯氟氰菊酯 EW、 5%甲维盐 WG或 30%噻虫嗪 SC能有效控制双斑长跗萤叶甲,其中, 5%高效氯氟氰菊酯 EW能兼防蚜虫和玉米螟,可实现玉米中后期害虫一体化防控。  相似文献   

18.
Carbendazim, iprodione, prochloraz-Mn, thiabendazole and thiophanate-methyl were tested in vitro and in vivo for their effect on Mycogone perniciosa, the mycoparasite that causes wet bubble disease of white button mushroom. In vitro experiments showed that prochloraz-Mn (ED50 = 0.006–0.064 μg ml−1) and carbendazim (ED50 = 0.031–0.097 μg ml−1) were the most effective fungicides for inhibiting the mycelial growth of M. perniciosa, while iprodione (ED50 = 1.90–3.80 μg ml−1) was the least effective. The resistance factors calculated for the five fungicides were between 1.4 and 2. The results obtained suggest that there is very little risk that M. perniciosa will develop resistance to the fungicides assayed. The in vivo efficacy of fungicides for control of wet bubble was studied in two mushroom cropping experiments, which were artificially infected with two doses of M. perniciosa, 106 and 107 spores m−2, respectively. There was, in the low dose inoculum experiment, a very high degree of effectiveness (96.5–100.0%) with all the fungicides assayed. However, iprodione performed poorly (20.5–24.4%) compared with the other fungicides (88.7–100.0%) in the high concentration inoculum experiment. The most effective treatments for controlling wet bubble did not improve the biological efficiency of Agaricus bisporus.  相似文献   

19.
采用ZmCol3基因RNAi载体构建、农杆菌介导玉米遗传转化、转基因材料开花期表型鉴定等研究方法,评估抑制ZmCol3基因表达对玉米开花期的影响。转基因玉米基因组PCR结果证实,人工合成RNAi片段已成功整合到玉米基因组中。qRT-PCR结果表明,在不同转基因玉米株系中ZmCol3基因表达受到不同程度的抑制。温室转基因玉米开花期相关性状调查结果表明,抑制ZmCol3表达,可以将玉米抽雄、散粉和吐丝时间提前2~3 d。研究结果证实,ZmCol3具有调控开花期的生物学功能,抑制该基因表达进而缩短玉米开花期可以作为行之有效的方法应用到玉米熟期改良研究中。  相似文献   

20.
Summary Thirty three fungicides were evaluatedin vitro andin vivo for the control of anthracnose, caused byColletotrichum coccodes (Wallr.) Hughes. Three promising fungicides, thiram, captafol wp and sc and prochloraz, were identified by a filter paper-disc plate method, but only prochloraz had an effect when using a fungicide plate method. None of the fungicides adequately controlled anthracnosein vivo.  相似文献   

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