苹果锈病防治药剂筛选及施药适期研究

为了筛选防治苹果锈病的有效杀菌剂,明确其最适施药时期,通过先接种后施药和先施药后接种的方法,测试了8种药剂对苹果锈病的内吸治疗效果和7种药剂的保护效果.结果表明,8种内吸治疗剂中,氟硅唑、戊唑醇、苯醚甲环唑3种药剂对苹果锈病的治疗效果为100％;嘧霉胺和吡唑醚菌酯两种药剂的治疗效果分别为81.58％和74.52％;多抗霉素、嘧菌环胺和甲基硫菌灵3种药剂对苹果锈病没有治疗作用.7种保护剂中,代森锰锌、百菌清、吡唑醚菌酯和氟硅唑在接种前12 d内施药,保护效果皆为100％;异菌脲和甲基硫菌灵的保护效果分别为90.58％和90.21％;多抗霉素没有保护作用.上述结果表明,三唑类药剂是防治苹果锈病有效的内吸治疗剂,在病菌侵染后的5d内使用效果较为理想.代森锰锌、百菌清、吡唑醚菌酯等是防治苹果锈病的有效保护剂,持效期可达7～10 d.     

降香黄檀炭疽病的化学防治研究

通过室内测定15种杀菌剂对降香黄檀炭疽病菌的毒力,选出5种效果较好的药剂,即多菌灵、咪鲜?戊唑醇、恶醚?咪鲜胺、苯醚?甲环锉和根太阳,5种药剂在稀释500倍时,对菌丝生长抑制效果均是100%,对孢子萌发抑制率接近或达到100%。将此5种杀菌剂对降香黄檀进行保护和治疗试验,发现所有杀菌剂的保护效果均在50%以上,500倍的恶醚咪鲜胺和咪鲜戊唑醇对降香黄檀治疗效果最好,分别是87.59%和83.10%。进一步选取恶醚咪鲜胺和咪鲜戊唑醇进行田间防治试验,500倍液的咪鲜戊唑醇防治效果较好,达到79.28%。     

吡唑醚菌酯·代森联防治柑桔炭疽病效果评价

利用吡唑醚菌酯·代森联等五种杀菌剂进行防治柑桔炭疽病田间药效试验,结果表明,供试各药剂对柑桔炭疽病均有一定的防效;供试药剂吡唑醚菌酯·代森联有效成分800mg/L五次施药,叶片防效达到(97.88±1.90)%及果实贮藏60d防效为91.18%的效果,表现较好的持效性。     

防治珍珠李叶枯病的药剂筛选

采用菌丝生长速率法测定了12种药剂对珍珠李叶枯病主要病原胶孢炭疽菌(Colletotrichum gloeosporioides)的抑制作用,并进行田间施药防病试验,调查各药剂的实际防效。结果表明,氟硅唑·咪鲜胺、咪鲜胺和苯醚甲环唑·醚菌酯对病原菌的室内毒力较高,EC50均低于0.03μg/mL;50%咪鲜胺可湿性粉剂、5%氨基寡糖素水剂、325 g/L苯醚甲环唑·醚菌酯悬浮剂、10%苯醚甲环唑水分散粒剂和250 g/L吡唑醚菌酯乳油的田间防病效果较好,均在75%以上。     

防治牡丹根腐病的有效药剂筛选

采用菌丝生长速率法和孢子萌发法,分别测定了咪鲜胺、醚菌酯、苯醚甲环唑、百菌清、多菌灵、代森锰锌等6种杀菌剂对牡丹根腐病菌的室内毒力。结果表明,6种药剂对病菌菌丝生长的EC50大小顺序为：咪鲜胺<多菌灵<代森锰锌<苯醚甲环唑<百菌清<醚菌酯,其中以咪鲜胺对牡丹根腐病病菌的菌丝生长抑制作用最强, EC50为0.200 mg/L;多菌灵、代森锰锌、苯醚甲环唑、百菌清依次减弱,醚菌酯的抑制菌丝生长的作用最小,EC50为33.98 mg/L。6种药剂对病菌孢子萌发的EC50大小顺序为：百菌清<咪鲜胺<苯醚甲环唑<多菌灵<代森锰锌<醚菌酯;其中以百菌清对牡丹根腐病菌的孢子萌发抑制作用最强,EC50为0.343 mg/L;咪鲜胺、苯醚甲环唑、多菌灵、代森锰锌依次减弱,醚菌酯抑制孢子萌发的作用最小,EC50为38.4 mg/L。     

福建省草莓炭疽病菌对吡唑醚菌酯的敏感性及与其他药剂的交互抗性

为明确吡唑醚菌酯对福建省草莓炭疽病菌Colletotrichum gloeosporioides的防治潜力和应用前景,采用室内生测法测定草莓炭疽病菌对该菌剂的敏感性及其与6种不同杀菌剂之间的交互抗性。结果显示,吡唑醚菌酯对福建省5个地区分离的62株草莓炭疽菌菌株的EC₅₀介于0.086～0.879μg/mL之间,总变异系数为10.24,且符合正态分布,以其平均值0.363μg/mL为敏感基线的菌株抗性比值均低于5;此外,吡唑醚菌酯EC₅₀与多菌灵、戊唑醇、苯醚甲环唑、咪酰胺、咯菌腈、甲基硫菌灵的EC₅₀间不存在显著相关性。表明福建省不同地区草莓炭疽病菌群体对吡唑醚菌酯的敏感性虽存在一定变异,但仍均较敏感;吡唑醚菌酯与其他6种杀菌剂间不存在交互抗性,可用于防控草莓炭疽病。     

7种药剂对杜果炭疽病的田间防治效果

本试验分别使用42.4%吡唑醚菌酯·氟唑菌酰胺SC(健达)、42%肟菌.戊唑醇SC(拿稳敌)、22.5%啶氧菌酯SC(阿砣)、35%氟菌·戊唑醇SC(露娜润)、25%吡唑醚菌酯EC(凯润)、50%咪鲜胺锰盐WP(施保功)、45%咪鲜胺EC(施保克)等7种药剂在百色市和南宁市对杧果炭疽病进行试验。第三次施药后7 d调查结果,百色试验区上述药剂对杧果炭疽病的防治效果为别为70.67%、50.85%、49.66%、51.82%、47.43%、70.21%和69.85%,南宁实验区的防治效果别为73.19%、53.78%、51.40%、51.84%、48.91%、70.86%和70.21%。第三次施药15 d后,百色试验区的防治效果分别为69.89%、44.60%、35.44%、42.70%、41.14%、68.70%和68.61%,南宁试验区的防治效果分别为72.37%、44.47%、36.81%、41.57%、41.22%、70.79%和70.37%。生产上使用42.4%吡唑醚菌酯·氟唑菌酰胺SC(健达)3 000倍液、50%咪鲜胺锰盐WP(施保功)1 500倍液和45%咪鲜胺EC(施保克)1 000倍液喷施果实3次,间隔10 d一次,均能较好的防治杧果炭疽病。     

几种药剂对草莓炭疽病的效果

采用菌丝生长速率法测定了48%波尔多液可湿性粉剂、50%咪鲜胺可湿性粉剂、40%福美锌可湿性粉剂和70%代森联干悬浮剂4种药剂对草莓炭疽病菌的室内毒力。结果表明,4种药剂对菌丝生长的EC50的大小顺序为:50%咪鲜胺40%福美锌70%代森联48%波尔多液,50%咪鲜胺的EC50为6.24 mg/L。并选取毒力较好的50%咪鲜胺可湿性粉剂和40%福美锌可湿性粉剂进行了田间药效测定,48%波尔多液可湿性粉剂作为对照。试验发现:50%咪鲜胺可湿性粉剂在田间的效果最好,其800 mg/L处理在田间2次药后7 d的防效达到了80.26%,与对照药剂48%波尔多液可湿性粉剂间存在显著性差异。     

9种杀菌剂对西瓜炭疽病菌的室内毒力测定及配比试验

为筛选防治西瓜炭疽病的高效低毒杀菌剂, 缓解和治理生产中病菌对药剂的抗性, 在室内离体条件下采用生长速率抑制法及孢子萌发抑制法测定了9种杀菌剂对西瓜炭疽病菌( Colletotrichum orbiculare )的毒力。结果表明, 嘧菌酯、咪鲜胺和甲基硫菌灵对病原菌菌丝生长的EC50在0.093 3~0.118 2 mg/L之间, 均小于1 mg/L, 表明西瓜炭疽病菌对上述杀菌剂比较敏感; 百菌清、烯肟菌酯和戊菌唑的EC50在2.310 1~5.925 9 mg/L, 病菌对药剂的敏感程度相对较低; 代森锰锌、恶霉灵和多菌灵的EC50分别为36.876 3、74.466 6和99.898 5 mg/L, 抑菌活性较差。孢子萌发试验中, 嘧菌酯、咪鲜胺和甲基硫菌灵对病菌孢子萌发的抑制活性最高, EC50在0.069 4~0.167 2 mg/L之间; 百菌清、烯肟菌酯、代森锰锌的抑制活性次之, EC50在1.853 0~9.503 9 mg/L之间; 多菌灵的抑制活性相对最低, EC50为99.335 3 mg/L。将两种不同作用机理的杀菌剂嘧菌酯与咪鲜胺按照2∶1的比例混配, 联合毒力测定和评价结果表明两者混配对抑制西瓜炭疽病菌具有增效作用。     

7种杀菌剂对樟树溃疡病菌的室内抑菌效果

采用菌丝生长速率法,测定70%甲基硫菌灵WP、80%代森锰锌WP、250g/L吡唑醚菌酯EC、10%苯醚甲环唑WG、250 g/L咪鲜胺EC、250 g/L嘧菌酯SC和250 g/L丙环唑EC 7种杀菌剂对樟树溃疡病病原菌的菌丝生长抑制效果。结果表明,当有效成分浓度为0.80μg/m L时,供试药剂对樟树溃疡病病原菌的菌丝生长均有抑制作用,其中250 g/L咪鲜胺EC的效果最好,抑制率达100%,显著高于其他药剂的效果。甲基硫菌灵、吡唑醚菌酯、嘧菌酯、丙环唑、苯醚甲环唑和代森锰锌的抑菌效果分别为59.64%、57.22%、46.40%、36.54%、19.27%和2.62%。     

有机硅助剂在苹果炭疽叶枯病化学防控中的减药增效作用评价

有机硅助剂具有低毒、易降解的特性,可提高农药的药液展布性和渗透性。本研究分别采用室内离体叶片法和田间试验评价了2种有机硅助剂对吡唑醚菌酯和代森锰锌防治苹果炭疽叶枯病的减药增效作用。室内离体试验结果表明,杀菌剂浓度减半的处理以及模拟雨水冲刷处理均导致吡唑醚菌酯和代森锰锌的防效显著下降;而添加了有机硅助剂后,2种处理的防效显著提高,并且恢复到与正常施药量相同的水平。田间试验结果表明,正常情况下杀菌剂浓度减半后防效显著下降;而施用有机硅助剂后,浓度减半的吡唑醚菌酯和代森锰锌的防效显著高于不施用有机硅的处理。本研究结果表明,施用有机硅助剂可以在减少化学农药实际用量的情况下,保持较高的防效,这对于化学农药的减施增效具有重要意义。     

嘧菌酯对扁豆纹枯病的物理作用方式及其生物动力学特性

以多菌灵和福美双为对照药剂,测定了嘧菌酯对立枯丝核菌Rhizoctonia solani的抑制活性,并用离体叶片法测定了嘧菌酯对该病原菌引起的扁豆纹枯病的物理作用方式及其生物动力学特性。嘧菌酯、多菌灵和福美双对立枯丝核菌菌丝生长的EC50值分别为0.072 4、1.134 4和1.202 6 μg/mL。施药后立即接种, 250 μg /mL嘧菌酯、500 μg /mL多菌灵和1 000 μg /mL福美双对扁豆纹枯病的保护效果分别为95.61％、99.88％和81.45％;施药3 d后再接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的保护效果分别为92.27％、100％和46.96％;接种36 h后再施药,3种药剂对扁豆纹枯病的治疗效果分别为90.40％、95.75％和61.94％。表明嘧菌酯对扁豆纹枯病具有很好的保护作用、持效性和治疗作用。在叶片基部施药后在顶部接种,嘧菌酯、多菌灵和福美双对扁豆纹枯病的防治效果分别为87.81％、42.09％和7.24％;在叶片背面施药后在正面接种,3种药剂对扁豆纹枯病的保护效果分别为87.30％、37.00％和16.15％。表明嘧菌酯在扁豆叶片中具有很好的木质部输导和跨层转移活性。     

Control of Glomerella cingulata f.sp. camelliae with fungicides

A critical test of fungicidal activity against the wound pathogen Glomerella cingulata f.sp. camelliae on camellias involved the application of a conidial suspension to scratches on detached leaves, treated with fungicide 24 h previously. In this test, prochloraz at 250–500 μg/ml a.i. in both EC and manganese WP formulations was highly effective, inhibiting leaf rotting by 90–100% compared with 55% or less in some tests with benomyl, chlorothalonil and captafol at 500–1000 μg/ml and captan at 1200 μg/ml. Prochloraz gave similar protection to leaves when applied to whole plants. Protection was less, especially on older leaves, when wounding and inoculating were delayed by 7 or more days after treatment. Prochloraz did not prevent all infection through comparatively large wounds, e.g. leaf scars, made on stems 24 h after treatment.
Poor control of the disease in a nursery was not due to resistance of the pathogen to benomyl; in vitro tests failed to detect full resistance at this time. Under nursery conditions a statutory policy of destroying infected plants and spraying the remainder with prochloraz or prochloraz manganese (both at 500 μg/ml), alternating with benomyl (500 μg/ml) on a weekly basis apparently prevented spread of the disease to healthy plants.     

不同新型作用机制杀菌剂对梨树主要病菌毒力及防治流程应用

 为明确多种新型作用机制杀菌剂与引起梨树褐斑病、黑星病、白粉病等病原菌的有效对靶关系及制定梨树主要病害防治流程,采用菌丝生长速率法、离体叶片法与田间药效方法研究新型杀菌剂对靶标病原菌的毒力、对靶标病害的防效及其田间有效应用,建立替代梨树主要病害传统化学杀菌剂的防治流程技术。结果显示,双胍三辛烷基苯磺酸盐在离体叶片法下对褐斑病的防效大于85%,田间药效验证3次用药后7 d防效大于85%、30 d防效大于80%、90 d防效仍大于60%,兼治轮纹病菌其毒力EC₅₀值均小于1 μg·mL^-1。双胍三辛烷基苯磺酸盐、辛菌胺醋酸盐、吩嗪α-2羧酸在离体叶片法下对黑星病防效大于90%且毒力EC₅₀值小于1 μg·mL^-1;田间药效验证1次用药后7 d防效大于80%、30 d防效仍大于75%。噻肟菌酯、硝苯菌酯、丙硫菌唑在离体叶片法下对白粉病的防效大于85%;田间药效验证3次用药后7 d铲除效果大于70%、30 d仍大于60%。丙硫菌唑对黑斑、轮纹病菌毒力EC₅₀值均小于1 μg·mL^-1;吩嗪α-2羧酸同时对褐斑、黑斑、轮纹病菌毒力EC₅₀值小于1 μg·mL^-1。针对梨树主要病害发生期,选用新型杀菌剂替代传统杀菌剂制定防治技术流程,其综合防效达到88.94%。不同新型作用机制杀菌剂在防治梨树主要病害上的应用,能够降低抗药性产生,同时达到有效防治的目的。     

不同新型作用机制杀菌剂对梨树主要病菌毒力及防治流程应用

 为明确多种新型作用机制杀菌剂与引起梨树褐斑病、黑星病、白粉病等病原菌的有效对靶关系及制定梨树主要病害防治流程,采用菌丝生长速率法、离体叶片法与田间药效方法研究新型杀菌剂对靶标病原菌的毒力、对靶标病害的防效及其田间有效应用,建立替代梨树主要病害传统化学杀菌剂的防治流程技术。结果显示,双胍三辛烷基苯磺酸盐在离体叶片法下对褐斑病的防效大于85%,田间药效验证3次用药后7 d防效大于85%、30 d防效大于80%、90 d防效仍大于60%,兼治轮纹病菌其毒力EC₅₀值均小于1 μg·mL^-1。双胍三辛烷基苯磺酸盐、辛菌胺醋酸盐、吩嗪α-2羧酸在离体叶片法下对黑星病防效大于90%且毒力EC₅₀值小于1 μg·mL^-1;田间药效验证1次用药后7 d防效大于80%、30 d防效仍大于75%。噻肟菌酯、硝苯菌酯、丙硫菌唑在离体叶片法下对白粉病的防效大于85%;田间药效验证3次用药后7 d铲除效果大于70%、30 d仍大于60%。丙硫菌唑对黑斑、轮纹病菌毒力EC₅₀值均小于1 μg·mL^-1;吩嗪α-2羧酸同时对褐斑、黑斑、轮纹病菌毒力EC₅₀值小于1 μg·mL^-1。针对梨树主要病害发生期,选用新型杀菌剂替代传统杀菌剂制定防治技术流程,其综合防效达到88.94%。不同新型作用机制杀菌剂在防治梨树主要病害上的应用,能够降低抗药性产生,同时达到有效防治的目的。     

防治玉米叶斑病高效药剂筛选及药剂减施增效技术

为有效防治玉米小斑病和弯孢叶斑病并减少化学农药使用量,本研究采用菌丝生长速率法从11种杀菌剂中选取抑菌效果较好的8种药剂进行田间小区药效试验。同时选取对两种叶部病害兼具防效的最佳药剂再与中量元素水溶肥、腐植酸、氨基寡糖素、芸苔素内酯等产品混配开展田间药效试验,确定该药剂田间施用浓度和增效组合。结果显示,各供试药剂对2种病菌菌丝生长具有不同的抑制作用,其中25%丙环唑EC、25%戊唑醇WP、40%氟硅唑EC、30%氟菌唑WP、12.5%烯唑醇WP在供试各浓度下对2种病菌抑制率均为100%,田间小区药效筛选测定中,25%戊唑醇WP防治效果最好,对玉米小斑病和弯孢叶斑病两种叶部病害防效分别为81.07%和72.22%。田间试验中,25%戊唑醇WP防治玉米小斑病和弯孢叶斑病的最佳施用浓度为2 000倍液,防效分别为59.48%和53.96%。在减量50%情况下防效有所下降,配施氨基寡糖素后,防效可提高37.40百分点和22.98百分点,与最佳施用浓度防效相当,达到了减药增效的作用。     

Bioassays using detached tobacco leaves to determine the sensitivity of Peronospora tabacina to fungicides

Two bioassay methods are described which use detached tobacco leaves to measure the sensitivity of Peronospora tabacina to systemic fungicides. Tobacco leaves (13–15 cm²), treated with fungicides before or after detachment from the plant, were inoculated with sporangia in water drops and, after incubation in beakers and Petri plates, the disease severity and/or production of sporangia was determined 4–7 days after treatment with the fungicides. Of 15 systemic fungicides applied to detached leaves, eight N-phenylamides at 0.066?1.0 μg ml^?1 controlled blue mould; metalaxyl was the most effective fungicide. Isolates of P. tabacina, collected in the field from tobacco plants grown in soil treated with metalaxyl, were not resistant to the fungicide applied to detached leaves prior to inoculation. The fungicide, applied to leaves before detachment, was used to measure the efficacy of five systemic N-phenylamide fungicides sprayed on the basal and unsprayed distal portions of the leaves. Blue mould was controlled on the basal portion of the leaf by all the fungicides at 0.66?1.0 μg ml^?1, but it required the application of 3–30 times more chemical on the basal portion to achieve comparable blue mould control on the distal part of the leaf.     

Protective and curative efficacy of prothioconazole against isolates of Mycosphaerella graminicola differing in their in vitro sensitivity to DMI fungicides

BACKGROUND: Septoria leaf blotch is the most important disease of wheat in Europe. To control this disease, fungicides of the 14α‐demethylase inhibitor group (DMIs) have been widely used for more than 20 years. However, resistance towards DMIs has increased rather quickly in recent years. The objective of this study was to evaluate, on plants and under controlled conditions, the protective and curative efficacy of the DMI fungicide prothioconazole against three current isolates of M. graminicola, chosen to belong to different DMI‐resistant phenotypes. Fungicide efficacy was assessed by visual symptoms and by quantitative real‐time polymerase chain reaction (PCR). RESULTS: With a protective fungicide application, prothioconazole was always effective against each isolate. This was in accordance with the EC₅₀ results. However, curative efficacy differed between the isolates. It remained at a good level, between 60 and 70% against one isolate, whereas it was strongly affected by late applications from 7 days post‐inoculation with the two other isolates. CONCLUSION: A protective application of prothioconazole in wheat crops could be the best strategy to keep a high efficacy against Septoria leaf blotch. Copyright © 2011 Society of Chemical Industry     

Effect of the new pyrazole carboxamide fungicide penthiopyrad on late leaf spot and stem rot of peanut

BACKGROUND: Management of early leaf spot (Cercospora arachidicola Hori.), late leaf spot [Cercosporidium personatum (Berk. & MA Curtis) Deighton] and stem rot (Sclerotium rolfsii Sacc.) of peanut (Arachis hypogaea L.) in the southeastern USA is heavily dependent upon sterol biosynthesis inhibitor (SBI) and quinone outside inhibitor (QoI) fungicides. Effective new fungicides with different modes of action could improve overall disease control and extend the utility of the current fungicides. Penthiopryad is a pyrazole carboxamide fungicide being evaluated for use on peanut. Field experiments were conducted from 2004 to 2007 to determine the effect of a range of rates (0–0.36 kg AI ha^?1) of penthiopyrad on leaf spot and stem rot and the relative efficacy of penthiopyrad and current fungicide standards chlorothalonil, tebuconazole and azoxystrobin. RESULTS: Leaf spot control in plots treated with penthiopyrad at 0.20 kg AI ha^?1 or higher was similar to or better than that for the chlorothalonil standard. The incidence of stem rot for all penthiopyrad treatments was usually less than that for the tebuconazole or azoxystrobin standard treatments. Pod yields for all penthiopyrad treatments were similar to or higher than those for the respective standards. CONCLUSION: Penthiopyrad has excellent potential for management of late leaf spot and stem rot of peanut, and may complement current SBI and QoI fungicides. Copyright © 2008 Society of Chemical Industry     

A test method based on microscopic assessments to determine curative and protectant fungicide properties against Septoria tritici

Glasshouse experiments to test the activity of commercial fungicides against Septoria tritici were carried out under controlled conditions. In addition to the parameter, % necrotic leaf area (NEC), used to estimate the pathogen-induced leaf damage, the number of pycnidia per leaf (PYC) was determined to quantify the pathogen itself. Curative fungicide treatments were applied 100–210 day degrees after inoculation. A high curative activity was achieved up to 170 day degrees after inoculation, whereas the treatments at 200–205 day degrees were less effective. The best curative activity was observed for epoxiconazole-based treatments, followed by slightly less active azoles in the ranking tebuconazole, cyproconazole, prochloraz and flusilazole. Greater differences between the fungicides were observed for the protectant fungicide properties, which were tested 50–350 day degrees prior to inoculation. The best persistency was observed for epoxiconazole, whereas tebuconazole, cyprocoazole, prochloraz and flusilazole showed declining activity with this ranking. Combinations of triazoles with the active ingredients kresoxim-methyl and chlorothalonil, which are known to inhibit spore germination, significantly improved the longevity of the remaining green leaf area in comparison with disease-free treatments with triazoles alone. The results obtained under glasshous conditions were compared with field studies on S. tritici development after treatments with tebuconazole to place the results in context. The comparison of the assessment parameter PYC and NEC between glasshouse and field trial showed that curative and protectant fungicide properties based on microscopic assessments of PYC in the glasshouse correlated well with results from field trials.