防治棉花枯萎病药剂筛选试验研究

通过滤纸条的抑菌法和离体组织抑菌法有机结合对市售农药及有选择性的组织进行药性测定和筛选,找出了一些对棉花枯萎病菌防治有效的药剂和组配,本试验除了注重筛选对病菌等杀抑作用好的药剂,还注重筛选对病菌并无明显的杀抑作用,但通过寄主组织后却能较好的抑制病菌扩展的药剂,同时也注重筛选具有上下传导作用的药剂,并指出药剂复配后对棉花枯萎病杀抑效果更佳.     

新型苯并咪唑类化合物 对棉花枯萎病菌的毒力测定

采用菌落直径法,测定了12种新型苯并咪唑类化合物对棉花枯萎病菌的抑菌活性。结果表明:在测定浓度为200 μg/mL的情况下,12种新型苯并咪唑类化合物对棉花枯萎病菌的抑菌率达32.5%～89.45%。其中,化合物N-(3-甲基苄基)-1H-苯并咪唑、N-(3-氯苄基)-1H-苯并咪唑、N-(3-溴苄基)-1H-苯并咪唑对棉花枯萎病菌的抑菌率较高,分别为80.1%、89.45%、80.3%,它们对棉花枯萎病菌的EC50值分别为66.1 μg/mL、38.1 μg/mL、86.3 μg/mL,具有良好的抑菌活性;其他9种化合物抑菌活性均低于80%。     

2种激发子对西瓜枯萎病的诱抗作用

分别测定了来源于西瓜枯萎病菌和香蕉枯萎病菌的细胞壁来源的水溶性、热稳定激发予对西瓜枯萎病的诱抗作用。结果表明：2种来源的激发子均有明显的诱导西瓜苗细胞壁木质化的作用，但来源于香蕉枯萎病菌的激发子对木质化的诱导活性比来源于西瓜枯萎病菌的要高；西瓜苗分别经2种激发子处理后，体内过氧化物酶、多酚氧化酶和苯丙氨酸解氮酶的活性均有异常的增加，但来源于西瓜枯萎病菌的激发子对这3种防御酶的诱导速度比来源于香蕉枯萎病菌的要快；经激发子诱导处理后瓜苗对枯萎病菌的抗性有了明显的提高，但来源于西瓜枯萎病菌的激发予的诱抗效果相对较好。     

银杏酸对6种蔬菜病原菌物的抑制作用

室内测定了银杏酸对5种蔬菜病原菌物菌丝生长的活性,结果表明:在70mg/mL浓度下,银杏酸对茄子立枯病菌、茄子白绢病菌24h的菌丝生长抑制率分别为65.2%、65.3%,对甘蓝黑斑病菌、白菜炭疽病菌、黄瓜枯萎病菌48h的菌丝生长抑制率在63.6%～77.3%之间;加药后,稀薄菌丝沿培养基表面生长,气生菌丝少,有的菌丝变色;对黄瓜枯萎病菌、甘蓝黑斑病菌、苦瓜枯萎病菌、白菜炭疽病菌等孢子萌发抑制率均在86%以上,其中对黄瓜枯萎病菌的抑制率最好;显微观察说明:银杏酸处理后,菌丝细胞出现不规则膨大、凋亡、黄化、扭曲、液泡变多、节间缩短等异常现象;毒力测定显示:银杏酸对甘蓝黑斑病菌抑制作用较强,EC50为24.80mg/mL。     

玉米、小麦、大豆根系水溶性分泌物对马铃薯枯萎病菌的影响

以玉米、小麦和大豆3种作物为试验材料,利用水培法收集3种作物根系分泌物测定其对马铃薯枯萎病菌生长的影响。结果表明,玉米、小麦和大豆的根系分泌物对马铃薯枯萎病菌菌丝生长、孢子萌发和孢子产量均具有一定的抑制作用,尤其是玉米根系分泌物的抑制作用最为显著,小麦根系分泌物次之,而大豆根系分泌物的抑制效果较差。     

香蕉枯萎病菌及其粗毒素对香蕉的致病性比较

从8种培养液中筛选出能诱导香蕉枯萎病菌4号小种(Fusarium oxysporum f.sp.cubense race4)FOCAAA315菌株高产毒素的改良CzapekB培养液,FOCAAA315菌株在该培养液中培养第15d,镰刀菌酸(FA)产量高达669.2mg/L,蔗糖为诱导产毒的最佳碳源。采用伤根浸渍法接种,测定枯萎病菌和病菌发酵粗毒素对香蕉组培苗的致病性。结果表明,粗毒素接种可诱发与病原菌类似的病害症状。受侵染的植物组织在细胞水平上发生一系列形态结构和生理生化代谢的病理变化,包括细胞壁消解、侵填体堵塞气腔、粘胶质减少、淀粉量减少、细胞木质化和黄褐色胶状物堵塞导管等。香蕉枯萎病菌的粗毒素是重要的致病化学物质;利用病菌孢子悬浮液在香蕉苗期接种,可以作为室内快速鉴定香蕉品种抗病性的方法。     

泰国大果番石榴果腐病研究报告：Ⅱ.室内毒力测定和大田药效试验

泰国大果番石榴果腐病严重影响了果实的产量和质量,一直是生产中急待解决的问题之一.为此我们在对病原菌分类鉴定的基础上,进行了室内和大田的药剂筛选工作,经多年试验,我们认为多菌灵对果腐病菌(Ascochyta spp)有明显的抑制作用.一、材料和方法(一)室内毒力测定1、参试药剂:25%苯来特,50%多菌灵,50%退菌特,50%托布津,45%代森铵,92%乙磷铝.2、供试浓度:100、50、5、0.5、0.05(ppm).     

甘蔗赤腐病菌对碳、氮源的利用及其室内毒力测定

选择来自海南岛不同蔗区的4个甘蔗赤腐病菌的有效单孢菌株用于毒力测定,并对其代表菌株的碳、氮利用特性进行了研究。结果表明,综合赤腐病菌生长速度及其长势2个指标而言,其最适碳源是D-木糖,氮源则是硝酸钠。此外,毒力测定结果表明,6种常用药剂对4株赤腐病菌的生长有不同程度的影响。其中,多菌灵、正品甲津托、福美双和丙环唑对甘蔗赤腐病菌毒力较强,相比之下,百菌清和代森锰锌两种药剂效果较差。     

橡胶树枝条内生真菌的分离及其拮抗性的测定

经过严格的表面消毒程序,从橡胶树枝条中分离到18株内生真菌,并对其进行初步鉴定.结果表明,这18株内生真菌分别归属于2个目,2个科,7个属,其优势菌群为无孢菌群(Mycelia Sterilia).通过温度测定,确定橡胶树内生真菌最适生长温度为25～28℃:采用平板对峙培养法,研究内生真菌对香蕉枯萎病菌(Fusarum pxysporum f.sp.cubense)和橡胶炭疽病菌(Colletorichum gloeosporioides Penz.Sace)的抑菌作用.结果表明,ITBB2-2对两种植物病原菌的拮抗作用最好.ITBBBB2-10和ITBB2-15次之,ITBB2-3对香蕉枯萎病菌拮抗作用明显而对橡胶炭疽病菌拮抗作用不明显,其它内生真菌对两种植物病原菌无拮抗作用或不明显.     

棉花黄枯萎病抑菌试验研究方法和技术

为筛选出防治棉花黄、枯萎病和兼治两病的有效药剂 ,试图打破从前只侧重对病菌的杀、抑方面研究而将对菌的杀、抑、防和对寄主的抗、调、促等多种功能的药剂通过复配将其有机地结合在一起 ,在室内试验研究中 ,采用直接抑菌试验法和通过离体组织抑菌试验法相结合 ,研究开发新型高效防治两病的复配药剂。直接抑菌试验法体现病毒与药剂之间的互作关系 ,而通过离体组织抑菌试验法体现病毒、寄主、药剂三者之间的关系 ,更接近于田间实际情况 ,一方面考察药剂对病菌的抑制效果 ,另一方面药剂通过寄主组织表现对病菌的抑制效果。这两种试验研究方法…     

不同杀菌剂对马铃薯晚疫病的防治效果

通过田间试验调查,研究了7种化学药剂对马铃薯植株和薯块晚疫病的防治效果。结果表明:7种药剂对马铃薯晚疫病均可达到显著防治效果。防治效果最好的4种药剂为25%瑞凡、50%福帅得、0.5%苦参碱和30%甲霜.嘧菌酯,防治效果均达到80%以上;其次为45%三苯乙酸锡和68.75%银法利,防治效果达到70%以上;较差为52.5%抑快净,防治效果达到65%。建议在生产上交替使用,避免产生抗药性。     

不同杀菌剂对马铃薯晚疫病的田间防效试验

马铃薯晚疫病是马铃薯生产中一种普遍发生、危害严重的病害,杀菌剂防治该病仍是生产中采用的主要措施。本试验采用氟吡菌胺和霜霉威、噁霜·锰锌、烯酰吗啉和多菌灵4种农药,从发病初期开始连续进行2次施药防治晚疫病。结果表明,4种杀菌剂均有较好的防治效果,68.75%氟吡菌胺和霜霉威SC 1000倍、64%噁霜·锰锌WP 300倍、50%烯酰吗啉WP 1500倍和50%多菌灵WP 500倍施用2次后,平均防治效果分别为76.8%、70.0%、71.0%和62.0%,前3种杀菌剂的防效明显好于后者。     

12个马铃薯品种对晚疫病抗性比较与药剂防治

通过田间试验,探讨常用马铃薯晚疫病防治药剂对不同马铃薯品种晚疫病防治效果,对产量影响及筛选出对马铃薯晚疫病有抗性的品种。结果表明,田间晚疫病发病初期,银法利单用或与其他药剂混用均可以有效控制马铃薯晚疫病,并且增加田间产量;‘荷兰7’,‘黄麻子’、‘荷兰15’和‘尤金’为马铃薯晚疫病易感品种,因此田间管理要提前预防马铃薯晚疫病的发生;‘克新18号’、‘麦肯’、‘延薯4号’和‘克新13号’对晚疫病有较高的抗性;‘中兴202’、‘Lt-5’、‘夏波蒂’和‘克新1号’对晚疫病表现中抗,病害发生初期施药可以有效的控制病害扩展。     

几种杀菌剂防治马铃薯晚疫病试验

由于长期使用几种广谱性杀菌剂防治马铃薯晚疫病,导致该病病原菌抗药性增强,防效降低。为筛选高效、经济、安全的杀菌剂在生产上推广使用,试验选取了18.7%烯酰.吡唑酯WG、68.75%氟吡菌胺.霜霉威SC、72%甲霜灵锰锌WP、75%代森锰锌WG 4种药剂,设置高、中、低不同浓度,高浓度施药2次,中低浓度施药3次进行防治马铃薯晚疫病的田间药效试验。试验结果表明:18.7%烯酰.吡唑酯WG高、中、低浓底的防效分别为71.08%、73.03%、69.04%;其次为68.75%氟吡菌胺.霜霉威SC防效分别为62.09%、74.53%、64.65%,72%甲霜灵锰锌WP的防效分别为56.91%、71.71%、66.87%;75%代森锰锌WG的防效分别为46.52%、70.38%、68.85%。其中18.7%烯酰.吡唑酯WG和68.75%氟吡菌胺.霜霉威SC防效较好,其余2种药剂对马铃薯晚疫病均有一定的防效,建议生产上轮换使用。     

Potassium phosphite combined with reduced doses of fungicides provides efficient protection against potato late blight in large-scale field trials

Potato late blight caused by the oomycete Phytophthora infestans is a devastating disease of potato worldwide. Most of the potato cultivars grown in conventional agriculture are susceptible, or at best moderately resistant, and require frequent applications of fungicides to avoid heavy yield losses.In field trials spanning four years, we have investigated the effect of potassium phosphite, an inorganic salt on potato late blight. Potassium phosphite is known to induce defence responses in potato and to also have direct toxic effects on oomycetes, which in turn counteract late blight and tuber blight development. However, the use of this salt is not yet implemented and approved in European potato cultivation. We compared the effect of phosphite alone with fungicides currently used in Swedish potato cultivation. We also investigated the combined use of potassium phosphite and reduced doses of fungicides. Table potato cultivars and starch potato cultivars with different levels of resistance were used.We found that potassium phosphite in combination with reduced doses of fungicides results in the same level of protection as treatments with the recommended full dose of fungicides. These combined treatments reduce the need of traditional fungicides and may also decrease the selection pressure for fungicide resistance development in the pathogen. In relatively resistant starch potato cultivars using phosphite alone gave sufficient protection against late blight. Furthermore, in starch potato a combination of phosphite and fungicides at two-week intervals provided similar protection to weekly applications of fungicide at the recommended dose. Foliar treatment with phosphite also gave protection against tuber blight at similar levels to that of the best-performing fungicide. Our data suggests that potassium phosphite could be used in potato cultivation in temperate regions such as in Sweden, at least in combinations with reduced rates of fungicides. The implementation of the use of phosphite in practical potato crop protection as part of an IPM strategy is discussed. Doses, intervals and combinations could be adjusted to the level of cultivar resistance.     

5种药剂对马铃薯晚疫病的防治效果分析

试脸在田间测定了克露、迭克宁、银法利、瑞凡和中药杀菌剂5种药剂对马铃薯晚疫病的防治效果。结果表明：5种药剂对马铃薯晚疫病均具有明显的防治效果和增产效果,防治效果最好的是银法利,其次为瑞凡、达克宁、克露和中药杀菌剂,增产62%-155％,晚疫病烂薯率为1．20％-8．09％。根据病害发展曲线,病害发展前期使用5种药剂。均可达到显著防治效果。病害发展后期,建议选择银法利和瑞凡药剂。注意每种药剂交替使用,避免产生抗药性。     

8种药剂对马铃薯晚疫病的防治效果试验

为减轻马铃薯晚疫病对马铃薯生产造成的损失,本研究选择了8种药剂,在马铃薯地上垄体栽培模式下进行晚疫病防治的药效比较试验。结果表明,不同处理均对地上垄体栽培模式下马铃薯晚疫病具有防治和保产的效果。其中,在马铃薯晚疫病发病前期喷施的保护性杀菌剂种中,60%百泰的防治和保产效果最好,防效达79%以上,增产43.54%;其次是银法利,防效达70%以上,增产42.55%。在发病中期喷施的治疗性杀菌剂中,防效和保产效果最好的药剂为50%安克,防效达73%以上,增产36.71%。     

河北省一季作区马铃薯病虫害发生及综合防控

河北省一季作区马铃薯主要病虫害有晚疫病、早疫病、黑痣病和二十八星瓢虫,此外,病毒引起的品种退化比较普遍,造成不同程度的损失。本文根据河北省一季作区马铃薯病虫害发生特点总结出一套综合防控技术体系,包括将马铃薯与玉米、大白菜等非茄科作物轮作3年减轻黑痣病危害;采用脱毒薯克服病毒引起的品种退化问题;种薯和(或)土壤消毒控制黑痣病和晚疫病;待马铃薯生长至封垄后,遇到适宜晚疫病发生的天气,喷施1～3次保护性杀菌剂预防晚疫病和早疫病;一旦监测到晚疫病中心病株后即拔除并装入塑料袋带出田外,并交替喷施有治疗效果、能兼治早疫病且作用机制不同的内吸性杀菌剂及混剂;田间出现马铃薯二十八星瓢虫成虫,在杀菌剂中混入高效氯氰菊酯或高效氯氟氰菊酯等高效杀虫剂防虫;马铃薯成熟前1～2周将地上部分割掉并运出田外后收获块茎。     

Alternative treatments for late blight control in organic potato: Antagonistic micro-organisms and compost extracts for activity againstPhytophthora infestans

Summary The effects of various fungi, bacteria and different compost extracts on foliar infection of potato (Solatium tuberosum) withPhytophthora infestans were tested in detached leaf bioassays in 2001–2003. Application of microorganism inocula and compost extracts as well as copper oxychloride to excised leaves resulted in different degrees of blight control. In general, suppression of blight lesion growth was not improved by applying the antagonists before the leaves were inoculated withPhytophthora spores. There was some evidence that extracts made from different compost feed stocks of different ages suppressed leaflet infection with blight. However, results were very limited and inconsistent. Moreover, the effects were much smaller than where copper oxychloride was used. Improved efficacy of acceptable alternatives to copper fungicides especially in organic farming is required. No promising effective alternative to the use of copper fungicides to reduce late blight infection in organic potato production systems was identified in the experiments.     

Effects of differential rates of nitrogen and phosphorus on early blight in potatoes

The Kennebec variety of potato was exposed toAlternana solani inoculum during the 1970 and 1971 seasons to determine the effects of differential rates of nitrogen and phosphorus on the incidence of early blight. Both high nitrogen and low phosphorus treatments significantly reduced the incidence of early blight and the combination of high nitrogen and low phosphorus consistently gave the lowest incidence of the disease during both years. The data suggest that this combination of nutrients may be related to early blight resistance in the plant by extending the period of meristematic activity permitting the plant to wall off infection. Yield data indicated that there was too great a yield difference between fertilization for optimum early blight control and fertilization for optimum yield. Therefore, in Maine, potatoes should be fertilized for optimum yield with a reasonable specific gravity, and early blight should be controlled by the application of fungicides and sanitation measures.