解淀粉芽胞杆菌YU-1对水稻纹枯病的防治作用

本文旨在筛选对水稻纹枯病有生防作用的菌株,并初步探索其生防作用机理。收集水稻、甘蓝、黄瓜等不同植物根际土壤,采用稀释分离和对峙培养法筛选对水稻纹枯病菌Rhizoctonia solani Kühn有抑菌作用的菌株;通过离体接种防效、盆栽防效、抑菌谱、对水稻纹枯病菌菌核萌发及形成的抑制作用等方面评价其生防潜力,并对生防菌株进行鉴定。结果表明,从采集的37份根际土壤中共分离获得细菌297株,其中4株对纹枯病菌具有较好的拮抗作用,菌株YU-1对水稻纹枯病菌菌丝生长的抑制率达89.8%;对西瓜枯萎病菌、草莓灰霉病菌、番茄早疫病菌、油菜菌核病菌、小麦赤霉病菌菌丝生长的抑制率均在85%以上;对水稻纹枯病的离体和盆栽防效分别为73.1%和66.3%;对水稻纹枯病菌菌核萌发的抑菌率在92%以上;经生理生化和分子鉴定为解淀粉芽胞杆菌Bacillus amyloliquefaciens。由此可看出,菌株YU-1对水稻纹枯病的防治具有较强的应用价值,具有进一步开发成生物农药的潜力。     

水稻纹枯病菌强拮抗菌B34的分离与鉴定

 从水稻植株上分离到1株对水稻纹枯病菌有强烈拮抗作用编号为B34的菌株,在PDA平板上表现有对水稻纹枯病菌较强作用的抑菌带,其发酵菌液对纹枯病菌丝有强烈的致畸作用,抑菌率达到71.5%,使菌核的菌丝萌发率降低69.0%。离体防效和田间小区防效分别高达81%和48.74%,高于清水和井冈霉素处理。经生理生化检测及细胞壁化学成分分析,确定其为致黄假单胞菌(Pseudomonas aureofaciens)。     

3种药剂防治水稻纹枯病、稻曲病和稻瘟病田间药效试验

采用田间药效试验方法,比较3种药剂对水稻纹枯病、稻曲病、稻瘟病的防治效果。结果表明:3种药剂对水稻纹枯病、稻曲病、稻瘟病都有一定防效。其中75%肟菌戊唑醇水分散粒剂225 g/hm2对水稻纹枯病、稻瘟病防效最好,防效分别为85.74%、85.19%;43%戊唑醇悬浮剂225 mL/hm2对稻曲病的防治效果最好,防效为88.25%。综合防治效果表明,75%肟菌戊唑醇水分散粒剂150～225 g/hm2对水稻纹枯病、稻曲病、稻瘟病的防效最好,43%戊唑醇悬浮剂225 mL/hm2对稻曲病和纹枯病防治效果较好,在实际生产上可广泛应用。     

75%肟菌·戊唑醇水分散粒剂防治水稻穗瘟、纹枯病、稻曲病试验结果初报

75%肟菌·戊唑醇WG防治水稻穗瘟、纹枯病、稻曲病田间药效试验结果表明,水稻全生育期用药3次,每次每亩用药12g和15g 2种处理,对稻穗瘟防效分别达82.11%和84.47%,对纹枯病防效分别达93.86%和96.39%,对稻曲病防效分别达84.05%和91.61%,对水稻穗瘟、纹枯病、稻曲病综合防效较好。     

水稻内生细菌B196的鉴定及其对水稻纹枯病的防治作用

从水稻体内分离得到的细菌菌株B196对水稻纹枯病菌Rhizoctonia solani的生长有较强抑制作用.通过形态学和生理生化鉴定及16S rDNA序列分析,将菌株B196鉴定为巨大芽孢杆菌Bacillus megaterium.采用浸种和喷雾的方法将菌株B196接种到水稻植株后,均能在稻株体内回收到该菌株,表明菌株B196能在水稻体内定殖.菌株B196对水稻纹枯病的盆栽和田间防效分别为64.29%和55.13%.     

水稻细菌性条斑病和纹枯病生防细菌的复筛、室内防效及应用评价

采用活体生测法对前期工作中离体初筛出的5株水稻细菌性条斑病生防菌和5株水稻纹枯病生防菌分别进行复筛、温室防效测定和应用评价。结果表明,菌株GN233、GN222和GN223的菌悬液对水稻苗期细菌性条斑病有一定的防治效果,其中菌株GN233对细菌性条斑病的温室防效最好,达到28.90%,而药剂"稻丰TM多·福"可湿性粉剂的温室防效为34.20%;5株生防菌对水稻纹枯病均有不同防治效果,其中菌株GN222和GN211菌悬液的防治效果较好,分别达到44.4%和27.8%,而药剂"稻丰"可湿性粉剂的防效为33.3%;此外,筛选出的生防菌株GN222、GN233和GN211均对水稻生长具有促生作用。本研究结果可为水稻细菌性条斑病和水稻纹枯病的生物防治奠定基础。     

多旋翼无人飞机在水稻病害防治中的应用效果

通过在稻田开展飞防试验,研究了多旋翼植保无人飞机在水稻纹枯病、稻瘟病全程防治中的应用效果,以及喷雾助剂在无人飞机低容量喷雾中的作用。结果表明:添加飞防助剂可以显著提高水稻冠层上部雾滴覆盖度;两种无人飞机结合不同施药配方,对水稻纹枯病的防效为80.03%～91.85%,对穗颈瘟的防效为80.93%～94.01%,增产率为1.73%～8.97%,试验全程无药害发生。供试的5种制剂250 g/L嘧菌酯悬浮剂、2%春雷霉素水剂、40%嘧菌·戊唑醇悬浮剂、30%肟菌·戊唑醇悬浮剂、9%吡唑醚菌酯微囊悬浮剂均可用作水稻纹枯病和穗瘟病的飞防药剂。     

防治水稻纹枯病药剂田间筛选试验

为筛选生产上防治水稻纹枯病的高效、安全药剂,于2014年8月在田间进行了防治纹枯病10种药利筛选试验。结果表明,嘧菌酯类和噻呋酰胺类复配剂防效突出。24%密菌酯·己唑醇悬浮剂20 mL/667m~2、24%噻呋·咪鲜胺悬浮剂30 mL/667m~2处理对水稻纹枯病的株防效超过或接近85%,病指防效均达90%以上,值得进一步示范推广。     

高产栽培模式水稻纹枯病的防治效果试验

针对高产栽培水稻纹枯病发生发展快、常用药剂防效差的特点,于2009年6—7月在思南塘头667hm2高产示范区,采用30%爱苗乳油、55%生势可湿性粉剂等农药进行了水稻纹枯病的防效试验。结果表明,30%爱苗乳油、55%生势可湿性粉剂等对水稻纹枯病防效较好,第二次药后7d和15d的防效均与20%井冈霉素的防效差异极显著,且对水稻生长无不良影响,可作为高产栽培水稻纹枯病防治的有效药剂推广使用。     

丙环·嘧菌酯防治水稻纹枯病效果初探

研究新型杀菌剂18.7%丙环·嘧菌酯悬乳剂对水稻纹枯病的防治效果和对水稻产量的影响。结果表明,该药剂对水稻纹枯病具有良好防效,30~50 m L/667m2的制剂用量防效可达70%以上,并有利于水稻生长,药剂处理较空白对照增产7.28%~14.56%。     

Localization of metabolic sites of action of herbicides

Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate ¹⁴C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides.     

福寿螺配偶个体大小选择性初步观察

通过野外观察与实验研究,掌握了福寿螺的婚配体制及其配偶选择性规律。福寿螺与多数低等动物一样,其婚配属于乱交制,无固定配偶;雌螺对与其交配的雄螺个体大小没有选择性,而雄螺对雌螺的个体大小有选择性,倾向于与较大个的雌螺交配。     

青稞种子带菌检测及杀菌剂消毒处理效果

为了研究青稞种子外部和内部携带真菌情况,比较不同杀菌剂对青稞种子的带菌消毒效果和对幼苗生长的影响,为青稞种子播前包衣处理和种传真菌病害防控提供依据,采用离体平皿法对云南迪庆‘云青1号’、‘云青2号’和‘短白青稞’3个主栽品种进行带菌检测,并对种子进行拌种或浸种处理测定6种杀菌剂对种子消毒效果,分析杀菌剂对种子发芽和幼苗生长的影响。结果表明:供试青稞种子表面携带的优势菌群为青霉(Penicilliumspp.)、镰刀菌(Fusariumspp.);种子内部寄藏的真菌主要为镰刀菌、核腔菌(Pyrenophoraspp.)、附球菌(Epicoccumspp.)、丝核菌(Rhizoctoniaspp.)、链格孢(Alternariaspp.)和木霉(Trichoderma spp.)。青稞不同品种的种子表面及内部携带的真菌种类差异较大。致病性测定表明,镰刀菌对种子萌发和幼苗生长影响最大,后期出现幼苗坏死现象。45%咪鲜胺EW、75%百菌清WP、50%福美双WP对青稞种子携带真菌均有显著抑制作用和消毒效果,50%福美双WP消毒效果最优,达100%;45%咪鲜胺EW、75%百菌清WP、50%福美双WP处理对青稞种子发芽和幼苗生长均无显著影响。     

厚朴病虫害种类的初步调查

采用标准地法和线路调查法,对湖北恩施市新塘乡双河厚朴基地的厚朴病虫害进行了系统调查,记录主要虫害13种,其中叶部害虫9种,枝干害虫2种,根部害虫2种。厚朴主要病害5种。藤壶蚧、厚朴枝角叶蜂和厚朴新丽斑蚜为湖北省首次报道,小绿叶蝉为厚朴新寄主记录种。同时记录了藤壶蚧的天敌6种,其中寄生小蜂2种,瓢虫4种;厚朴新丽斑蚜的天敌昆虫8种。对藤壶蚧、厚朴枝角叶蜂和厚朴苗木根腐病等重要病虫害的发生规律进行了初步调查,同时提出了防治建议。     

Effects of timing and method of application of Penicillium oxalicum on efficacy and duration of control of Fusarium wilt of tomato

The effects of timing and method of application of Penicillium oxalicum on the control of fusarium wilt of tomato were investigated. Application of P. oxalicum to tomato seedlings in seedbeds reduced disease caused by Fusarium oxysporum f.sp. lycopersici in a growth chamber by 45–49% and in glasshouse experiments by 22–69%. Disease suppression was maintained for 60–100 days after inoculation with the pathogen in the glasshouse. No disease reduction was observed in tomato plants where P. oxalicum was applied to seeds. Treatment with P. oxalicum did not affect the population of F. oxysporum f.sp. lycopersici in the rhizosphere.     

Systems of designation of pathotypes of plant pathogens12

A variety of systems of designation has evolved to name pathotypes of plant pathogens. The systems were evaluated to determine those best suited for particular purposes. Virulence and avirulence/virulence formulae of pathotypes have advantage over the use of consecutive numbers or letters given in chronological order of pathotype discovery. As soon as pathotype information exceeds a certain level of complexity, mathematical codes are most advantageous, in particular two codes, octal notation and coded triplets. A more universal adoption of the most appropriate codes is recommended to ease communication and comparisons of results.     

Mode of action of etoxazole

The mode of action of the 2,4-diphenyl-1,3-oxazoline acaricide/insecticide etoxazole has been argued to be moulting inhibition, but experimental results supporting this hypothesis are lacking. This study investigated the effect of etoxazole on chitin biosynthesis in the fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae). Etoxazole induced moulting defects in fall armyworm larvae similar, if not identical, to those caused by benzoylphenylureas, a well-known class of insecticidal chitin biosynthesis inhibitors. Furthermore, in contrast to untreated larvae, the chitin content in the integuments of larvae several days after treatment did not differ from that in freshly ecdysed individuals, thus suggesting strong chitin biosynthesis inhibition in vivo. A more detailed investigation of the inhibitory potential by incubating cultured integument pieces from larvae of S. frugiperda with [14C]N-acetyl-D-glucosamine, a radiolabelled chitin precursor, revealed I50 values of 2.95 and 0.071 microM for etoxazole and triflumuron respectively. The incorporation of radiolabel into potassium hydroxide-resistant material was inhibited by etoxazole in a dose-dependent manner. Based on these results, it is concluded that the acaricidal and insecticidal mode of action of etoxazole is chitin biosynthesis inhibition.     

Mode of action of meturine

The effect of meturine on the light processes of photosynthesis was studied.Meturine is a herbicide for weed control in potato and cotton crops. It is a N-phenyl—N-hydroxy—N′-methylurea.The experiments were carried out on isolated pea and spinach chloroplasts.When examining photosystem I, reduced DPIP was used as an electron donor, whereas methyl-viologen served as an electron acceptor. When examining photosystem II, DPIP represented the electron acceptor.The obtained experimental results have pointed to the absence of the effect of meturine upon the photoreaction I.Unlike N-phenyl—N′, N′-dimethylureas (CMU, DCMU) meturine has been a very weak inhibitor of photoreaction II.The authors explain the photoreaction II inhibition of chloroplasts from plants treated with herbicidal doses of meturine by conversion of N-phenyl—N-hydroxy—N′-methylurea into Hill reaction inhibitor(s). N-Phenyl—N′-methylurea can be one of such meturine metabolites.Meturine herbicidal action is accounted for by meturine transformation into Hill reaction inhibitor(s) in the plant tissues.     

甲基硫菌灵标样的制备

本文介绍了用进口甲基硫菌灵样品，采用溶剂萃取，高速离心，重结晶，高效液相色谱，红外光谱等分析方法进行系统分离与鉴定，得到其标样的方法。