低、无毒农药防治花灌木主要刺吸式口器害虫

在查清天津市园林主要花灌木刺吸口器害虫桃粉蚜、绣线菊蚜、棉蚜和山楂红蜘蛛发生消长规律的基础上 ,确定了防治适期和结合点 ,筛选出 10 %吡虫啉、绿灵、蚧螨灵、 1. 8%齐螨素和花保5种低、无毒药剂 ,防效均达到 90 %以上。查出天敌 13种 ,并对优势种作了取食量调查     

Integrated Pest Management in Cocoa Agroforests in Southern Cameroon: Constraints and Overview

Imports of pesticides have long been subsidised for use in the cocoa agroforests of the humid forest zone of southern Cameroon. With the liberalisation of the cocoa and pesticides sectors and the devaluation of the local currency (CFA franc), farmers are facing fluctuations in the price paid for cocoa and the high cost of farm inputs. Without the support of the extension services, they themselves have developed traditional integrated control methods based on the use of plant extracts mixed with conventional pesticides. From a survey of 300 cocoa farmers, the study assesses the farmers' command of these methods, the pests controlled, the problems encountered and the institutional constraints in the definition and dissemination of integrated control methods. The study concludes with recommendations for research and development towards the better definition and dissemination of integrated control methods. This revised version was published online in July 2006 with corrections to the Cover Date.     

有效碳数法研究及其在农药气相色谱分析中的应用

有机化合物结构与其所含有的有效碳数有一定的关系，本文给出了２０类结构化合物及其所含有有效碳数的关系，并对理论计算值和实测值进行了比较，结果十分接近，利用有效碳数法可以设计农药分析实验方案和无标样的情况下测定农药杂质含量。     

大蒜素对番茄叶霉菌不同生理小种的抑制作用

研究大蒜素对番茄生产上叶霉菌主流生理小种1.2.3.4以及2014年新发现生理小种2.5、2.4.5和1.2.3.4.9的抑制作用,为开发安全、高效的植物源农药奠定基础。首先制备大蒜素抽提母液,采用定硫法对其中的大蒜素进行定量测定,发现当溶液中滴加4 m L浓硝酸、溶液p H值为2.0时能够更为准确地测得大蒜素的含量,试验测得大蒜素含量为0.52%。在此基础上,进行了大蒜素对4个叶霉菌生理小种菌丝生长、孢子萌发的抑制试验,离体叶片上的病害预防试验以及苗期药效试验。结果表明,当大蒜素剂量25μL/m L时,其对叶霉菌生理小种菌丝生长的抑制活性较高,其中对1.2.3.4的抑制率最高,对1.2.3.4.9的抑制率最低,对其他2个生理小种的抑制率差异不显著。当大蒜素剂量7.5μL/m L时,其对4个生理小种孢子萌发的抑制效应存在差异,其中对1.2.3.4.9的孢子萌发抑制率最低,对1.2.3.4的孢子萌发抑制率最高。当大蒜素剂量为125μL/m L时,其对叶霉菌4个生理小种在离体叶片上的预防效果均超过95%。苗期药效试验表明,在相等剂量下,大蒜素对叶霉菌的防治效果高于多菌灵和甲基托布津,说明大蒜素是一种可以替代化学药剂防治叶霉病的有效抑菌物质。     

基于模糊控制的水肥药一体化系统研究

为了提高目前水肥药一体化系统的自动化程度,设计了一种智能水肥药一体化系统;针对系统混肥精度不高的问题,设计了适用于营养液混合的模糊控制器,并利用Lab VIEW完成整个系统应用软件的开发。该系统不但能够实现独立灌溉、灌溉施肥一体化、灌溉施药一体化及水肥药一体化,而且还具备控制指令输入、系统工作监控和系统信息查询的功能。     

Proportionality principle revisited – relationship between application rates and pesticide residue concentrations in food commodities

BACKGROUND

The proportionality principle has been broadly used for over 10 years in regulatory assessments of pesticide residues. It allows extrapolation of supervised field trial data conducted at lower or higher application rates compared to the use pattern under evaluation by adjustment of measured concentrations, assuming direct proportionality between the rates applied and the resulting residues. This work revisits the principle idea by using supervised residue trials sets conducted under identical conditions but with deviating application rates. Four different statistical methods were used to investigate the relationship between application rates and residue concentrations and to draw conclusions on the statistical significance of the direct proportionality assumed.

RESULTS

Based on over 5000 individual trial results, the assumption of direct proportionality was not confirmed to be statistically significant (P > 0.05) using three models: direct comparison of application rates and residue concentrations ratios and two linear log-log regression models correlating application rate and residue concentration or only residue concentrations per se. In addition, a fourth model analysed deviations between expected concentrations following direct proportional adjustment and measured residue values from corresponding field trials. In 56% of all cases, the deviation was larger than ±25%, which represents the tolerance usually accepted for the selection of supervised field trials in regulatory assessments.

CONCLUSION

Overall, the assumption of direct proportionality between application rates and resulting residue concentrations of pesticides was not statistically significant. Although the proportionality approach is highly pragmatic in regulatory practice, its use should be considered carefully on a case-by-case basis. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

污灌区有机氯农药的土—气交换行为与影响因素分析

以我国东北典型污灌区为研究区域,获取相关数据及模型参数,并应用逸度方法探讨了有机氯农药的土-气交换行为及其分馏效应。研究结果表明,在土壤有机质含量一定的情况下,日均温度最大时有机氯农药六六六(HCHs)和滴滴涕(DDTs)之间土-气分配系数(KSA)的差异比日均温度最小时高出一个数量级,HCHs比DDTs更容易挥发重新释放进入环境中而进行二次分配,土壤有机质质量分数每提高1%而引起的KSA值的变化率不同,且这种变化会随着有机质质量分数的提高而趋于平稳;辛醇-气分配系数(KOA)与土-气交换逸度分数ff呈负相关关系,当土壤有机质质量分数为1%、2%和3%时,其相关系数分别为-0.743(P0.05)、-0.763(P0.05)、-0.776(P0.05);应用土-气浓度比(Cs/a),进一步判定土壤浓度和大气浓度在其他参数不变的情况下,将会对HCHs及DDTs的土-气交换行为产生影响;HCHs与DDTs的初次分馏及二次分馏效应进一步说明土壤性质及其自身的理化性质均会对分馏效应产生影响。     

基于生态管理的山东苹果无袋栽培“依历按需用药”病虫害综合防控方案

山东产区苹果实施无袋栽培首先要选择苹果轮纹病、苹果炭疽病、桃小食心虫、梨小食心虫等果实病虫发生基数较低的果园。实施无袋栽培前,治理果园内外环境,压低病虫基数,防止果园病虫大量繁殖蔓延。在此基础上,依据本地主要病虫害种类及其防治关键时期,设计周年监测与防治预案,即防治历:以10 d为1个周期,监测和预测病虫害的发生动态;当病虫需要用药防治时,选择相应药剂及时防治。苹果无袋栽培的病虫害防控可划分为休眠期、幼果期、雨季和果实采收前4个时期,各个时期的重点防控对象和目标各不相同。休眠期主要铲除在树体和周边环境中越冬的各种病虫,减轻生长期的防治压力;幼果期以防治苹果霉心病、苹果锈病、红蜘蛛、蚜虫、绿盲蝽等为主,兼治其他病虫;雨季以防治苹果轮纹病、苹果炭疽病、桃小食心虫、梨小食心虫为主,兼治其他病虫;采收前,病害以防止弱寄生菌在果面定殖为主,虫害主要防治各种危害果实的害虫。3年来在多个园片试验示范,绝大部分果园病虫果率控制在10%以下。     

Experiences derived from the Carabid Beetle Laboratory Test

The Carabid Beetle Laboratory Test using Poecilus cupreus (L.) was developed for the assessment of effects of pesticides on beneficial arthropods and is now available as an official guideline published by the BBA and the IOBC for the registration of pesticides. In this contribution some of the experiences in performing the test are summarized. In total, 126 compounds (mainly herbicides) were tested in 190 test runs (including water controls). In this acute laboratory test, the three parameters mortality, behaviour and feeding rate are investigated. Due to experiences with other ecotoxicological tests a one-way Analysis of Variance or ANOVA, followed by a Bonferroni Test, was used for the statistical evaluation of the feeding rates. The results presented here show that a statistical evaluation of the feeding data is possible and that this parameter is useful for the assessment of side-effects of chemicals for these predatory arthropods. In testing the reference substance pyrazophos (formulation: ‘Afugan’ 294 g litre⁻¹ EC) the mortality varied considerably. It is proposed that at a given value (30%) for effects on the mortality and the feeding rate, a test substance should be tested in a semi-field or field situation.     

1-Octanol/Water Partition Coefficient (Kow) and pKa for Ionisable Pesticides Measured by apH-Metric Method

pK_a values for a wide range of commonly used ionisable pesticides, together with the log K_ow values of the most lipophilic form of each, have been measured using pH-metric techniques. Examples of acids, bases and multiprotic compounds from the major classes of herbicides, and a number of insecticides and fungicides that contain ionisable groups, are included. The pK_a and log K_ow values so obtained were generally in good agreement with values taken from the literature that were measured by other methods. The lower limit of log K_ow that could be measured by the pH-metric method lay below the -0·97 obtained for amitrole, but the method could not be applied to glyphosate for which shake-flask measurements indicated log K_ow below -3. The highest log K_ow obtained in this study was 5·12 for pentachlorophenol. The pH-metric technique offers a rapid and convenient method to determine pK_a and log K_ow for ionisable compounds, especially when utilising an automatic titration system linked to a dedicated computer.