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。     

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.     

百合地下害虫主要种类调查及生物（源）农药筛选

调查了甘肃省临洮县为害百合的地下害虫种类, 并以主要发生为害种类为供试对象, 采用拌土法测定了几种生物（源）农药对主要害虫的室内毒力和致死中时。调查发现小云斑鳃金龟Polyphylla gracilicornis、棕色鳃金龟Holotrichia titanis为主要发生及为害种类, 不同时间发生种类存在差异, 9月份以小云斑鳃金龟幼虫发生为害为主, 发生量占地下害虫总数的66.16%, 平均种群密度为10.48头/m2, 10月份, 则以棕色鳃金龟幼虫发生为主, 发生量占地下害虫总数的96.86%, 平均种群密度为7.79头/m2, 主要取食百合根系和鳞茎, 造成根系数量减少, 鳞茎出现不规则褐色缺口或凹陷斑。药剂筛选结果表明, 1.8%阿维菌素乳油、200亿孢子/g球孢白僵菌粉剂对两种蛴螬均具有较高的杀虫活性和速效性, 药后7 d时, 校正死亡率在82.22%以上, 对小云斑鳃金龟幼虫和棕色鳃金龟幼虫的LC50分别为0.161、0.060 mg/g和5.558×107、0.362×107孢子/g, LT50分别为2.237 d（2.2 mg/g）、1.393 d（2.2 mg/g）和6.645 d（40.0×107孢子/g）、4.940 d（2.0×107孢子/g）, 这两种生物（源）农药对两种蛴螬的LC50和LT50值均略大于两种化学农药25%二嗪磷乳油、40%辛硫磷乳油处理的, 且对小云斑鳃金龟幼虫的杀虫活性均低于对棕色鳃金龟幼虫的杀虫活性, 致死中时则长于对棕色鳃金龟幼虫的致死中时。     

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.     

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。     

莠去津的药害问题及药害防范技术研究概述

本文概述了使用莠去津以来，有关该药的药害情况及药害解除方法的研究状况。     

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.