Recent development in suspoemulsions

Suspension emulsions or suspoemulsions result from the combination of an emulsion phase, containing one or more active ingredients, with a continuous phase also containing active ingredients but in the form of a solid dispersion. Advantages of such products, which can contain as many as four complementary biologically active ingredients, are elimination of tank mixing; a reduced inventory of products; reduction in the number of applications to a given crop; and savings in time and money. The development of suspoemulsions is discussed and a novel, easy method for their preparation, using latexes, is described. Such products are also useful as feedstock emulsions for other suspension emulsions as well as constituting a stable oil-in-water emulsion delivery system in their own right.     

国内外杀虫绿僵菌制剂的登记现状与剂型技术进展

生物农药在植物保护工作中日益受到重视。绿僵菌是重要的昆虫病原真菌,作为真菌杀虫剂已被成功应用于蝗虫、金龟子、象甲等多种害虫的田间防治。近40年来,已有83个绿僵菌产品在13个国家或地区获得注册,制剂研究与加工技术方面取得了新进展,可湿性粉剂、悬浮剂等传统剂型质量得到改善,超低容量剂、浸渍剂等新剂型可适应特殊应用环境,产品的防治对象涵盖范围更广。本文就国内外绿僵菌产品注册登记情况、制剂类型特性及制剂技术的载体、助剂和加工过程等主要因素进行综述,以期为我国真菌生物农药的科研、应用及产业发展提供基础依据。     

高效低风险是农药发展的必由之路

农药是与人类生存活动紧密相关的一类重要的农用化学品,随着人们对环境安全和自身健康日益关注,对农药认识和理解趋于全面和理性.笔者认为,目前对农药发展的要求已由“高效、低毒、低残留”发展和延伸到高效低风险的阶段.农药产业也应调整思路,积极更新产品.高效低风险农药已成为当前农药发展的必由之路.     

Colloidal aspects of pesticidal and pharmaceutical formulations—An overview

In this overview, the colloidal aspects of pesticidal and pharmaceutical formulations of the dispersion type are described. The nature and magnitude of the interaction forces between particles or droplets in a dispersion are briefly described. These include double-layer, steric and van der Waals' interactions. Combinations of these interaction energies govern the stability/instability of dispersions. The various states of suspensions and emulsions can be described in terms of energy-distance curves. Particular attention is given to the various break-down processes, such as flocculation, coalescence, Ostwald ripening and phase inversion. Some guidelines for the stabilisation of suspensions and emulsions are given. The following practical aspects of dispersion and emulsion formulation are discussed: (a) creaming, sedimentation and their prevention; (b) the assessment of the state and long term physical stability of suspensions, including particle and droplet size analysis and rheology. In the latter case, both steady-state shear stress–shear rate and low deformation (oscillatory, constant stress and shear wave propagation) are very useful in the control and assessment of the long term physical stability; (c) mixed suspensions and emulsions i.e. suspoemulsions. The possible interactions between suspension particles and emulsion droplets are briefly described; (d) multiple emulsions that can be applied for sustained release; (e) microemulsions, their formation and characterisation illustrating the potential application of these systems in formulations: (f) microencapsulation, describing the most common procedures for preparation of such systems. These include interfacial polymerisation and condensation and coacervation techniques.     

农药纳米混悬剂及其制备方法探析

纳米混悬剂是指药物有效成分以晶体或无定型状态,在表面活性剂的作用下,均匀分散至水中形成的稳定的纳米胶态分散体系。纳米混悬剂可增大难溶性药物的溶解度,提高药物的渗透性、生物活性及利用率。文章就纳米混悬剂的几种主要制备方法及其在医药和农药领域的研究应用进展进行了综述,初步分析了其贮存稳定性并就其未来发展进行了总结展望。农药纳米混悬剂制备方法主要有两种——自上而下法和自下而上法。其中自上而下法包括介质研磨法、活塞-裂缝均质化法和高压微射流法;自下而上法包括控制沉淀法和超临界流体法。自上而下法适用于疏水、疏油型农药原药的加工,其制备过程简单,易于扩大生产;缺点是其中的介质研磨法在研磨过程中也会出现介质腐蚀,易造成样品污染,活塞-裂缝均质化法则须预先将药物微粉化。自下而上法的优点是设备简单、耗能低,但要求农药原药需至少能溶解于1种溶剂中。介于各方法均有其优缺点,在实际应用中也会将几种方法结合使用。基于目前农药使用中存在的有效利用率低的问题,探析纳米混悬剂作为一种新型农药剂型的应用前景具有重要的现实意义。     

A simplified method for measuring dilute emulsion stability

A simple and rapid method for the assessment of the stability of diluted pesticide emulsifiable concentrates has been developed for use in China. It gives results comparable to those obtained with FAO and WHO methods. The importance of some other physical characteristics such as contact angle, surface tension and wetted area in pesticide application are also discussed.     

农药新剂型——微乳粒剂配制的可行性研究

以三唑磷为模式农药,研究了一种外观为颗粒状、用水稀释后成微乳液的农药新剂型——微乳粒剂配制的可行性。以乳状液的中位径(D50)为因变量,各表面活性剂用量为自变量,采用混料均匀试验设计并结合偏最小二乘回归法筛选表面活性剂品种;用比例法与对分法优化各表面活性剂用量;采用旋转挤压造粒法造粒。将筛选获得的农乳500与农乳602号用于配制15%三唑磷微乳粒剂,其乳状液外观为淡蓝色透明状,分散相颗粒迁移速度为0,且不同水质(水硬度:0~3 420 mg/L,水温:10~50 ℃)下乳液稳定性均合格;乳状液D50为54.2 nm,粒径分布范围为15.7~122 nm,粒径增大速率为0.01%/min;乳状液在相对离心力10 730×g下离心5 min未发生相分离。结果表明:该三唑磷微乳粒剂的乳状液为微乳液,微乳粒剂可以成功配制。     

Microbiome facilitated pest resistance: potential problems and uses

Microbiome organisms can degrade environmental xenobiotics including pesticides, conferring resistance to most types of pests. Some cases of pesticide resistance in insects, nematodes and weeds are now documented to be due to microbiome detoxification, and is a demonstrated possibility with rodents. Some cases of metabolic resistance may have been misattributed to pest metabolism, and not to organisms in the microbiome, because few researchers use axenic pests in studying pesticide metabolism. Instances of microbiomes evolving pesticide resistance contributing to resistance of their hosts may become more common due the erratic nature of climate change, as microbiome populations typically increase and evolve faster in stressful conditions. Conversely, microbiome organisms can be engineered to provide crops and beneficial insects with needed resistance to herbicides and insecticides, respectively, but there has not been sufficient efficacy to achieve commercial products useful at the field level, even with genetically engineered microbiome organisms. © 2017 Society of Chemical Industry     

A renaissance for botanical insecticides?

Botanical insecticides continue to be a subject of keen interest among the international research community, reflected in the steady growth in scientific publications devoted to the subject. Until very recently though, the translation of that theory to practice, i.e. the commercialisation and adoption of new botanical insecticides in the marketplace, has seriously lagged behind. Strict regulatory regimes, long the bane of small pesticide producers, are beginning to relax some of the data requirements for ‘low‐risk’ pesticide products, facilitating movement of more botanicals into the commercial arena. In this paper I discuss some of the jurisdictions where botanicals are increasingly finding favour, some of the newer botanical insecticides in the plant and animal health arsenal and some of the specific sectors where botanicals are most likely to compete effectively with other types of insecticidal product. © 2015 Society of Chemical Industry     

有机硅表面活性剂Tech-408和Fairland2408对农药雾滴在烟草叶片上覆盖面积的影响

[目的]研究有机硅表面活性剂Tech-408和Fairland2408对农药雾滴在烟草叶片上覆盖面积的影响,寻找提高农药使用效率的途径.[方法]将10％吡虫啉乳油稀释3 000倍,分别加入有机硅表面活性剂Fairland2408和Tech-408以及农乳500#后,采用连续拍摄的方法,测试直径范围为340～360 μm单个雾滴在‘NC471,、‘云110,和‘T66'3种烟叶片上的蒸发时间和覆盖面积,重点研究Fairland2408和Tech-408对药液雾滴在烟草叶片上覆盖面积的影响规律.[结果]表面活性剂不同,雾滴覆盖面积的扩展程度也不同.当Tech-408、Fairland2408和农乳500#的添加比例为0.03％时,雾滴覆盖面积在上述3种烟叶片上扩展的平均倍数分别为8.1、6.4倍和1.2倍.表面活性剂添加比例不同,其对农药雾滴覆盖面积的影响程度也明显不同.随着Tech-408、Fairland2408和农乳500#的添加比例从0.03％增加到0.1％,雾滴在‘T66’烟叶片上覆盖面积分别增大了39.8％、156.1％和53.3％.[结论]有机硅表面活性剂Tech-408和Fairland2408和其添加比例均对吡虫啉在烟叶上的雾滴覆盖程度有明显影响.     

毒死蜱在表面活性剂混合体系中的增溶规律及其药效评价

为明确表面活性剂在农药制剂微乳化中的作用和评价农药制剂微乳化对药剂生物效果的影响,通过测定毒死蜱在有机溶剂-表面活性剂混合体系中的最大增溶浓度和在不同表面活性剂 /水微乳体系中的最高浓度,研究了毒死蜱在表面活性剂混合体系中的增溶规律,得到了毒死蜱微乳剂的优化配方,并对30%毒死蜱微乳剂对棉铃虫Helicoverpa armigera的生物活性进行了室内外药效试验。结果表明:毒死蜱在有机溶剂-表面活性剂混合体系中的最大增溶浓度和在有机溶剂-表面活性剂-水微乳体系中的最高浓度分别随体系中表面活性剂浓度和表面活性剂 /水(质量比)的增加而增大,但表现出不同的增溶规律;优化后的毒死蜱微乳体系分散液滴呈球形,流体力学半径约25.9 nm;30%毒死蜱微乳剂与40%毒死蜱乳油对棉铃虫的室内LC50值分别为500和561 mg/L,无显著差异;在相近有效使用剂量下,微乳剂的田间防效并未比乳油显著提高。研究表明,保证制剂中足够的表面活性剂质量分数是农药制剂微乳化形成与稳定的关键,农药制剂微乳化带来的农药有效成分分散度提高并不能显著提高药剂的生物活性。     

农药乳油中有害有机溶剂替代的研究进展

农药乳油中含有苯、甲苯、二甲苯等有害有机溶剂，这些溶剂闪点低、易挥发、毒性高，对生态环境和人类健康具有潜在风险。本文主要综述了农药乳油中有机溶剂的使用现状、危害及可能的解决措施，重点介绍了以生物源溶剂、矿物源溶剂、人工合成溶剂替代乳油中有害有机溶剂的研究进展。这些替代溶剂低毒、环保，在乳油中具有很好的应用前景，但通过实验筛选替代溶剂通常费时费力，而热力学模型COSMO-RS可以从理论上预测替代溶剂对农药的溶解性，再通过实验加以验证，省时省力，可加快乳油中替代溶剂的筛选，对开发环境友好型乳油具有指导意义。     

我国高风险农药管理进展与趋势

高风险农药是社会关注的热点,也是农药管理的重点。本文从技术和管理两个层面论述了我国农药管理的现状与趋势。从技术上看,把安全性作为农药登记技术评估的焦点,从源头提高登记门槛,建立农药风险评估机制,推进残留标准体系化建设,严控有害杂质和启动助剂管理,确保农药质量;从政策上看,对高风险农药源头管控力度日趋强化,扩大禁限用范围,加强潜在风险产品和剂型的管控,监管链条初具雏形。农药发展趋势是强化安全与环保要求,鼓励开发低风险产品,推进先进环保施药技术,促进社会诚信风尚。     

国际农药管理的现状及趋势(下)

在世界农药管理日趋严格,公众参与度日益增加,新产品和新技术不断涌现的大背景下,本文借笔者一年在联合国粮农组织作物生产和保护司病虫害和农药管理组做访问学者的经历,结合工作实际,从国际组织广泛参与、区域间加强协调、统一标准和准则等方面,对当今世界农药管理现状进行了总结分析。同时以《国际农药管理守则》倡导的对农药实行“全生命周期”管理方式为起点,对未来农药管理的趋势进行了分析。农药不尊重国界,未来世界农药管理势必越来越突破区域和国家的界限,以地球村为视角,实现全球可持续发展的目标。     

17O-核磁共振法研究农药微乳剂浊点与 其组份之间的相关性

农药微乳剂浊点是微乳剂的主要质量技术指标之一。研究了3种不同种类农药的微乳剂组份与浊点的关系,并利用17O-核磁共振(17O-NMR)方法对其机理进行了探究。研究表明:浊点与表面活性剂、助表面活性剂与水之间形成的氢键强度成正相关;随着水质硬度的上升,浊点下降。建议选用亲水性强的表面活性剂和极性较强的助表面活性剂来配制微乳剂,同时为了节约成本和便于工厂生产,可采用自来水来配制农药微乳剂,而采取其他措施来提高农药微乳剂的浊点。     

Botanical Pesticides and Their Mode of Action

Pest management is facing economic and ecological challenge worldwide due to human and environmental hazards caused by majority of the synthetic pesticide chemicals. Identification of novel effective insecticidal compounds is essential to combat increasing resistance rates. Botanical pesticides have long been touted as attractive alternatives to synthetic chemical pesticides for pest management because botanicals reputedly pose little threat to the environment or to human health. The body of scientific literature documenting bioactivity of plant derivatives to arthropod pests continues to expand, yet only a handful of botanicals are currently used in agriculture in the industrialized world, and there are few prospects for commercial development of new botanical products. Pyrethrum and neem are well established commercially, pesticides based on plant essential oils have entered the marketplace, and the use of rotenone appears to be waning. A number of plant substances have been considered for use as pest antifeedants, repellents and toxicants, but apart from some natural mosquito repellents, a little commercial success has ensued for plant substances that modify arthropod behavior. Several factors appear to limit the success of botanicals, most notably regulatory barriers and the availability of competing products (newer synthetics and fermentation products) that are cost-effective and relatively safe compared with their predecessors. In the context of agricultural pest management, botanical pesticides are best suited for use in organic food production in industrialized countries but can play a much greater role in the production and postharvest protection of food in developing countries. Botanicals have been in use for a long time for pest control. The compounds offer many environmental advantages. However, their uses during the 20th century have been rather marginal compared with other bio-control methods of pests and pathogens. Improvement in the understanding of plant allelochemical mechanisms of activity offer new prospects for using these substances in crop protection. I’m trying in this article to present different kinds of botanical pesticides came from different recourses and their mode of actions as well as I will try to examine the reasons behind their limited use (disadvantages) and the actual crop protection developments involving biopesticides of plant origin for organic or traditional agricultures to keep our environment clean and safer for humankind and animals.     

Determinants of farmers’ decisions on pesticide use in oriental tobacco: a survey of common practices

Information about pesticide use and perceptions of their risks among farmers is important for identifying problems associated with pest-control decisions and developing appropriate management practices in given crops. In tobacco, a plant sensitive to many pests and diseases, such information is lacking. The patterns of pesticide use in oriental tobacco, as well as the most important factors for farmers’ decisions relating to chemical pest control were studied among randomly selected farmers in northern Greece on the basis of self-reported information acquired through a pre-tested questionnaire. High reliance of farmers on pesticides and field use of all well-known classes of chemical pesticides were reported. While all the active ingredients reported were registered for pest control in tobacco, they differed considerably in terms of toxicity. A normal cropping season received at least 14–16 pesticide applications for soil disinfection, pest control, and weed control. Most farmers stated that they usually spray chemicals on a calendar basis or on the first appearance of a pest. Efficacy on target pests and market price of the pesticide products to be used were the most important criteria for selection of pesticides, i.e. products that are considered to be highly effective and/or that are cheap are more likely to be selected. Better-educated and more experienced farmers were found to pay more attention to environmental safety and pesticide toxicity. Most farmers felt that pesticide use can reduce crop damage by more than 75%, assuring high yields. Main determinants of pesticide use were primarily the fear of severe yield and economic losses and the doubts about the effectiveness and the correct implementation of alternative pest-control methods. Pesticide use could be reduced by exposing farmers to improved pest-control practices such as site-specific integrated pest management.     

农药助剂的应用与研究进展

农药助剂种类繁多,应用广泛,并且对农药剂型的发展与产品的质量和安全有着密切的关系。随着对农药安全性和环境影响的要求不断提高,农药助剂应用与管理问题显得日益重要。本文分析和讨论了我国农药助剂的应用发展以及国外对农药助剂的管理情况,对于农药剂型产品的开发和助剂的管理有一定借鉴作用。     

Strategies for the prevention of development of pesticide resistance in the UK—lessons for and from the use of herbicides,fungicides and insecticides

Since the 1950s, pesticide resistance has been identified in many species. This paper considers the role of resistance action groups and notes that they were all formed in response to resistance problems occurring. Data now exist on the strategies which are most effective and the paper aims to bring together information from the fields of weeds, pests and diseases. Pesticide mixtures, sequences or rotations have been demonstrated as having a clear role in resistance management strategies. Resistance management would be improved if there was agreement on uniform test methodology and interpretation of results. The industry must work together to agree what constitutes an anti-resistance strategy, whether this is for prevention or cure, and to ensure that this is then included within regulatory frameworks. Future developments such as patch treatment, biotechnology and biocontrol are discussed. It is concluded that, to date, there has been little discussion between specialists in the field of resistance to herbicides, fungicides or insecticides and it is clear there are significant advantages to be had from more interaction. ©1997 SCI