Development of methods for the analysis of crops and soils for residues of benzoylprop-ethyl and its breakdown products

Methods are described for the analysis of residues of the herbicide benzoylpropethyl, ethyl (±)-2-[ N-(3,4-dichlorophenyl)benzamido]propionate, and its breakdown product, (±)-2-[ N-(3,4-dichlorophenyl)benzamido]propionic acid, in wheat and soil. In wheat the acid degradation product conjugates with plant sugars and the present paper includes methods for determination of these residues either separately or as a combined residue with unconjugated acid. Efficient extraction procedures have been developed together with partition and column chromatographic techniques for purification of extracts. The full analytical procedures are described and the final determinations are by g.1.c. with electron capture detection with blank values for field samples in the range 0.01–0.05 mg/kg. Good recoveries were obtained. Radiochemical techniques have been used to verify the extraction and subsequent procedures in the methods.     

Efficacy and rates of diquat for reducing invasive knotweeds and potential for sequential use with imazapyr

Invasive knotweeds (Reynoutria spp.) pose an ongoing challenge for weed management programs worldwide, requiring years of persistent treatment. In this study, we tested efficacy of diquat applied as foliar spray early in the growing season for short-term suppression, and for potential to boost long-term control when applied sequentially with a mid-season treatment of imazapyr. We evaluated responses of knotweeds (R. japonica, R. × bohemica, and R. sachelinensis) treated with one of three diquat concentrations (0.25%, 0.50%, or 1.0%, v/v), using multiple metrics to capture changes in aboveground plant density and abundance. Canopy cover and biomass were significantly reduced by all diquat concentrations and resembled pre-treatment conditions at 8WAT, reflecting the shift toward reduced stem heights in treated compared with untreated plots. Stem counts at 8WAT, however, did not differ in response to diquat treatments. Sequentially applied early-season diquat and mid-season imazapyr treatments reduced canopy cover (66%–82%), biomass (65%–91%), and stem density (57%–79%) when evaluated 1 year after treatment; reductions were greatest in plots treated with medium and high diquat concentrations, suggesting that diquat treatments may have an additive effect. Overall, our study establishes rates of diquat to reduce biomass of invasive knotweed, and supports additional testing to assess improvement in long-term control when used sequentially with a systemic herbicide.     

新版欧盟原药和植物保护产品分析方法建立和报告指南文件概述

本文概述了欧盟最新发布的原药和植物保护产品分析方法建立和报告指南文件SANC0/3030/99第五版的基本内容.包括历史版本介绍、分析方法描述和报告的要求、用于产品登记的分析方法范围和适用性、分析方法确认过程中对各参数的要求、分析物定性确证要求以及跟我国相关文件的比较.作者认为本文的内容有助于国内相关从业人员更好地阅读和理解该指南文件,为他们在实验工作中提供更好的理论指导,也为我国今后更新《农药产品质量分析方法确认指南》提供重要参考.     

Analysis of soils for diclofop-methyl and diclofop

A method is described for the analysis of soils for residues of the herbicide diclofop-methyl, methyl (RS)-2-[4-(2,4-dichlorophenoxy)phenoxy]propionate, and its breakdown product diclofop, (RS)-2-[4-(2,4-dichlorophenoxy)phenoxy]propionic acid. Diclofop-methyl undergoes hydrolysis in the soil to diclofop, which also has herbicidal activity. A procedure, using a 1% phosphoric acid solution for extraction purposes, has been developed and gives good recoveries of both diclofop-methyl and diclofop at the 0.5 and 0.05 mg kg^?1 levels. After methylation, gas-liquid chromatography with electron-capture detection is used to determine total residue concentrations.     

The need for effective marking and tracking techniques for monitoring the movements of insect predators and parasitoids

Predators and parasitoids move through the landscape at a wide range of rates and over a broad range of spatial scales. Understanding the dispersal characteristics of such 'beneficials' is of crucial importance for classical, augmentative, inundative and conservation biological control. It is a key practice, following the release of 'classical' (exotic) and augmentative (indigenous) biological control agents, to assess whether they have become successfully established, and also to what extent the agent has spread from the release points. It is important in conservation biological control to understand the role that natural enemy movements play in the improvement of pest control achieved through the provision of pollen, nectar, shelter and/or alternative prey/hosts. Other aspects of predator and parasitoid movement pertinent to biological control are the role refugia play in influencing, via natural enemy movements, control of pest population numbers. In these areas and others, some form of marking and/or tracking of insect predators and parasitoids is usually required so that movements can be studied. This special issue considers the usefulness and limitations of marking and tracking techniques, through up-to-date reviews written by an international team of researchers who are actively involved in the study of predator and parasitoid ecology.     

A new tool for entry and analysis of virulence data for plant pathogens

The methods of Habgood (1970) and Gilmour (1973) for the assignment of pathogen race names are discussed and the advantages of a reversed octal system, based on Gilmour's octal code, are emphasized. A new spreadsheet, 'HaGiS', exploits these two designation systems to provide user-friendly and fast access to some routine steps in the analysis of virulence data for plant pathogen populations. It produces graphs and tables for frequency distributions (of pathotypes, isolate complexities and cultivar susceptibilities); sorted lists (e.g. of the races ranked by predominance); indices (of sample diversity and of pathogenicity for each differential cultivar); and coloured proximity matrices. Use of HaGiS requires knowledge of only a few basic functions of MS Excel 97^®. All graphs, tables, indices and matrices are generated automatically and displayed by switching to the corresponding worksheet. In addition to data analysis, the spreadsheet is convenient for the entry of experimental data, allowing for all commonly used assessment scales.     

天敌动物对害虫控制作用的评估方法及其应用策略

客观评估天敌动物的控害作用是害虫生物防治研究和实践的重要一环。评估方法可概括为田间系统调查及相关分析、直接观察法、食痕法及标记法、天敌排除或添加法、实验种群观察法、生命表分析法。文中对这些方法及其最新进展做一简介 ,提出选用方法的基本策略。     

Evaluation of a predictive model for Mycosphaerella graminicola for economic and environmental benefits

A method was developed to evaluate crop disease predictive models for their economic and environmental benefits. Benefits were quantified as the value of a prediction measured by costs saved and fungicide dose saved. The value of prediction was defined as the net gain made by using predictions, measured as the difference between a scenario where predictions are available and used and a scenario without prediction. Comparable 'with' and 'without' scenarios were created with the use of risk levels. These risk levels were derived from a probability distribution fitted to observed disease severities. These distributions were used to calculate the probability that a certain disease induced economic loss was incurred. The method was exemplified by using it to evaluate a model developed for Mycosphaerella graminicola risk prediction. Based on the value of prediction, the tested model may have economic and environmental benefits to growers if used to guide treatment decisions on resistant cultivars. It is shown that the value of prediction measured by fungicide dose saved and costs saved is constant with the risk level. The model could also be used to evaluate similar crop disease predictive models.     

辽河流域跨省界断面生态补偿共建共享帕累托改进研究

辽河流域生态补偿研究对防治辽河流域环境破坏具有重要意义。文中通过消除福利经济学帕累托相关的外部性来实现流域生态补偿帕累托改进,进而建立了辽河流域跨省界断面的生态补偿共建共享帕累托改进模型,选择2003-2010年辽河流域生态服务功能系统上游地区环境保护投入及上、下游地区的GDP数据,测算得到辽河流域可以通过对下游征税并对上游补偿或者谈判方法实现帕累托改进整体最优的补偿量范围可在32.63亿元和86.11亿元之间选择,明确了补偿前后辽河上、下游地区的福利变化,为辽河流域生态补偿提供了一种新的思路。     

Development of a species-specific and sensitive detection assay for Phytophthora infestans and its application for monitoring of inoculum in tubers and soil

A specific and sensitive PCR assay for the detection of Phytophthora infestans , the cause of late blight of potato, in soil and plant tissues was developed. A P. infestans -specific primer pair (INF FW2 and INF REV) was designed by comparing the aligned sequences of rDNA internal transcribed spacer regions of most of the known Phytophthora species. PCR amplification of P. infestans DNA with primers INF FW2 and INF REV generated a 613 bp product, and species specificity was demonstrated against DNA from nine other Phytophthora species and seven potato-blemish pathogens. In a single-round PCR assay, 0·5 pg pure P. infestans DNA was detectable. Sensitivity was increased to 5 fg DNA in a nested PCR assay using Peronsporales-specific-primers in the first round. As few as two sporangia or four zoospores of P. infestans could be detected using the nested assay. Procedures are described for detection of P. infestans in leaves, stem and seed potato tubers before expression of symptoms. A soil assay in which 10 oospores per 0·5 g soil were detectable was developed and validated using samples of field soil. The PCR assay was used to examine the long-term survival of sexual (oospores) and asexual (sporangia and mycelium) inoculum of P. infestans in leaf material buried in a replicated experiment under natural field conditions. Oospores were consistently detected using the PCR assay up to 24 months (total length of the study) after burial in soil, whereas the sporangial inoculum was detected for only 12 months after burial. Sporangial inoculum was shown to be nonviable using a baiting assay, whereas leaf material containing oospores remained viable up to 24 months after burial.     

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。     

西瓜栽培专家系统中病虫害诊断知识组织与知识库构建策略

基于知识工程方法,阐述了西瓜栽培专家系统中病虫害诊断与防治知识组织与知识库构建策略。知识获取立足本地化、特色化,知识描述引入对象的概念对西瓜病虫害进行描述,知识库框架设计中建立分为侵染性病害、非侵染性病害、营养失调症、虫害诊断与防治决策的病虫害分辨决策模型。