Farmers’ Knowledge and Awareness towards the Use of Agrochemicals in Vegetable Cultivation, Fako Cameroon

Agrochemicals are contemporary, omnipresent tool used in vegetable cultivation. Farmers’ knowledge and awareness of the proper usage of agrochemicals are critical for mitigating the negative effects on human health. This cross-sectional study was aimed at assessing the usage knowledge, risk awareness of toxicological and chemical classes, proper handling and use practices for agrochemicals homologated for use in vegetable farming, and the occurrence of health-related symptoms as a result of exposure among these farmers. The study included 93 vegetable growers from agricultural hotspot towns in Fako, southwest Cameroon. The field study, ran from November 2021 to December 2023, using a questionnaire to collect information on farmers demographic, and their knowledge of pesticide classes, and the related risk of associated with the handling of agrochemicals. Results show that all vegetable farmers, particularly those engaged in agribusiness, employ pesticide inputs to maximize production. Six pesticides, two fertilizer types, and one unknown substance were identified. While 23 active compounds were found, the most utilized were abamectin, emamectin (10.46%), dimethoate (9.30%,) and ethoprophos (8.13%). Two active chemicals, dimethoate and methalaxyl, are illegal yet remain in circulation. Toxicological classes I and II, with the greatest harmful effect on human health, were the most commonly utilized (64.27%). Thirty-nine percent of farmers never use personal protection equipment when working with agrochemicals, demonstrating a significant gap in knowledge and awareness of agrochemicals and their various applications and handling procedures in the field. The government should implement an intensive specialized educational program for on-field farmers with incentives in order to promote sustainable agriculture methods that ensure environmental and human safety.

Effects of Different Combinations of Fertilization and Agrochemical Application on Yield and Cost-effectiveness of Cucumber

This study was conducted to provide reference for rational fertilization and agrochemical application in cucumber plantation,and relieve the problem of environmental pollution and vegetable agrochemical residues. The effects of different combinations of fertilization and agrochemical application on cucumber yield and cost input were investigated. Four treatments were conducted,including T1（ conventional fertilization ＋ conventional agrochemical application,CK）,T2（ conventional fertilization ＋ recommended agrochemical application）,T3（ recommended fertilization ＋ conventional agrochemical application） and T4（ recommended fertilization ＋ recommended agrochemical application）. The results showed that T4 had fewer kinds of fertilizers and agrochemicals than that of T1,and had a yield increasing effect on cucumber,and the yield increase was 7 003. 5 kg/hm^2,with an increasing rate of 19. 25%; and it also had obvious cost-saving and benefit-increasing effects,specifically,the cost was saved by 10 941 yuan/hm^2 and the benefit was increased by 31 951. 5 yuan/hm^2. The results of this experiment were satisfactory,and higher benefit was obtained with lower input. This study will provide reference for cucumber planter to choose fertilizers and agrochemicals,and lays a foundation for alleviating the ecological soil problems.

英文版中国农药工业会刊--《China Agrochemicals》

《China Agrochemicals》—中国农药工业的第一份纯英文版刊物,于2006年10月创刊。本刊定位于国外的、关注于中国农药工业生产和发展的农药从业人员。通过对中国农药工业发展概况的描述与展望。

Arbuscular Mycorrhizal Fungi Colonization in Upland Rice as Influenced by Agrochemical Application

Mycorrhizal status of rice under upland conditions was studied using potted seedlings, Percentage of arbuscular mycorrhizal fungi （AMF） root colonization varied between 17.35% and 37.18% over an age series of 7 to 70 days old rice plants, AMF root colonization was increased up to 35-42 days, beyond which the root colonization steadily declined, The vesicles appeared after two weeks and reached their maximum intensity on the 35th day. The arbuscules were formed late on the 42^rd day （2.93%） and slightly varied up to the 70^th day （3.03%）. Higher dosage of urea application suppressed plant growth whereas the superphosphate treatment had no marked impact on plant growth. Generally, application of these agrochemicals registered less influence on the hyphal colonization of AMF in rice plants, whereas arbuscular colonization was adversely affected by higher dosages of fertilizers. There were pronounced decreases in both the plant growth and their AMF colonization due to the application of systemic fungicides, carbendazim and thiophanate methyl. The application of single sprays of fungicides was less deleterious over multiple sprays.

Acute and joint toxicity of three agrochemicals to Chinese tiger frog （Hoplobatrachus chinensis） tadpoles

We studied acute and joint toxicity of three different agrochemicals （chlorantraniliprole, flubendiamide-abamectin and penoxsulam） to Chinese tiger frog （Hoplobatrachus chinensis） tadpoles with the method of stability water tests. Results showed that the three agrochemicals increased tadpole mortality. For acute toxicity, the LC50 values after 24, 48 and 72 h of chlorantraniliprole, flubendiamide-abamectin and penoxsulam exposure were 5.37, 4.90 and 4.68 mg/L; 0.035, 0.025 and 0.021 rag/L; 1.74, 1.45 and 1.29 mg/L, respectively. The safety concentrations （SC） of chlorantraniliprole, fiubendiamide-abamectin and penoxsulam to the tadpoles were 1.23, 0.30 and 0.003 mg/L, respectively. Based on these findings, chlorantraniliprole and penoxsulam were moderately toxic, while flubendiamide-abamectin was highly toxic. All pairwise joint toxicity tests showed moderate toxicity. The LCs0 values after 24, 48 and 72 h of exposure were 7.08, 6.61 and 6.03 mg/L for chlorantra- niliprole＋penoxsulam, with corresponding values of 2.455, 2.328 and 2.183 mg/L for chlorantraniliprole＋flubendiamide-abamectin, and 1.132, 1.084 and 1.050 mg/L for penoxsulam＋flubendiamide-abamectin, with safe concentrations of 1.73, 0.63 and 0.30 mg/L, respectively. For toxic evaluations of pairwise combinations of the three agrochemicals, only the joint toxicity of chlorantraniliprole and flubendiamide-abamectin after 24 h was found to be synergistic, whereas all other tests were antagonistic. Our findings provide valuable information on the toxic effects of agrochemicals on amphibians and how various types of agrochemicals can be reasonably used in agricultural areas.

Toxic Effects of Four Commonly-used Agrochemicals on Arma chinensis and Picromerus lewisi

This study was conducted to investigate the toxic effects of four different agrochemicals on Arma chinensis and Picromerus lewisi . Cypermethrin·phoxim, imidacloprid and fenvalerate had higher toxic effects on A. chinensis and P. lewisi . After the application of the agrochemicals, the released stink bugs could not well survive and propagate. Though the herbicide （glyphosate ammonium） had no direct toxic effects on A. chinensis and P. lewisi , their survival and propagation were affected after the application of the herbicide into natural environment. Therefore, to ensure better survival and propagation of the two kinds of stink bugs in natural environment, local agrochemical management should be strengthened, and the concept of green environmental protection should be constructed and popularized.

Herbicidal Activity of Chlorimuron-ethyl （107 g/kg） Associated with Metribuzin （643 g/kg） on Sugar Cane Weeds and Its Effects on Soil Agrochemical Properties, in Burkina Faso

The efficiency and selectivity of chlorimuron-ethyl （107 g/kg） associated with metribuzin （643 g/kg）, against weeds which causes big damages to sugar cane, have been studied on the sugar cane field of Beregadougou. The experimental design was a Latin rectangle with eight treatments in four replications including an untreated control, manual weeding, a control product （Trifloxysulfuron-sdium 1.85% ＋ Ametryn 73.15%） and five rates of chlorimuron-ethyl associated with metribuzin. Weeds counting and weighing their dry biomass have been done using 0.25 m2 quadrants to determine their biological efficiencies. The soil nitrogen nitrate and assimilable phosphorus contents were evaluated on a spectrophotometer, those of available potassium on a flame photometer. The biological efficiency coefficients of this herbicide, varied from 12.41% to 100%, according to their dry biomass. High rates, phytotoxics, showed the best coefficients. At the sugar cane complete maturation, the higher rates of imposter led to an accumulation of nitrogen nitrate content and lower available phosphorus and potassium contents, compared to the untreated control. The rate of 1.20 kg/ha became the dose to apply against weeds and less toxic to the soil.

Hydrazone derivatives in agrochemical discovery and development

As a common active substructure,hydrazone has attracted increasing attention and is considered essential for pesticide discovery.It has been widely regarded as a potential insecticidal,antibacterial,antifungal,antiviral,and herbicidal agent.In this review,we highlight the pesticide versatility of hydrazone fragments and provide a comprehensive summary of the biological activity,structure-activity relationship analysis(SARs),and primary mechanism of their analogs.This profile is expected to give valuable information for discovering new pesticides.

Indole derivatives as agrochemicals:An overview

Indole is a biologically active compound formed by the fusion of benzene and pyrrole,and it is widely found in natural products and drugs.Due to the unique structure and properties of indole,its derivatives often exhibit distinctive physiological activities,which has led to widespread attention in the field of pesticide development.Analyzing the design strategies and structure-activity relationships(SARs)of compounds is a crucial step in developing novel pesticides.This review mainly summarizes indole compounds with plant growth regulating,antiviral,fungicidal,herbicidal,and insecticidal activities,with the aim of providing new insights into the discovery and mechanism of action of novel indole-based pesticides.

Engineering microbes to overproduce natural products as agrochemicals

Current agricultural practices heavily rely on the excessive application of synthetic pesticides and fertilizers to meet the food demands of the increasing global population.This practice has several drawbacks including its negative impact on the environment and human health.Recently,the use of natural products has gained interest as alternatives to these synthetic agrochemicals due to their selective working mechanisms and biodegradability.In order to efficiently produce these natural agrochemicals,engineering microorganisms is emerging as an increasingly viable approach,and it is anticipated that it will have a significant market share in the near future.This approach manipulates the metabolism of microbes to manufacture the desired natural compounds from low-cost starting materials.This review discusses recent examples of this approach.The produced natural products can serve as biopesticides or plant growth regulators for the sustainable improvement of plant growth and disease control.The challenges in further developing these strategies are also discussed.

Fluorine-containing agrochemicals in the last decade and approaches for fluorine incorporation

In this review, the methodologies for fluorine incorporation of 40 fluorine-containing agrochemicals that received an international standardization organization(ISO) name during the last decade are described.The predominant approach for fluorine introduction of these agrochemicals is to use a fluorine-containing building block. Here we present how the fluorine-containing building blocks are introduced into these agrochemicals. The synthetic methods of fluorine-containing building blocks that are not easily available are also specifically discussed. Fluoroarenes, difluomethylarenes and trifluomethylarenes are the main building blocks that have been used in this review. Fluorine-containing small molecules, such as alcohol,amine, ketoester, olefin are also widely used. The only example of late-stage fluorination is the synthesis of fungicide quinofumelin. We believe the fluorine introduction methods described here can provide ideas for the development of new and economical pesticide synthetic routes, and stimulate researchers to develop new fluorine incorporation methods and create new pesticides.

Is there an inverted U-shaped curve？ Empirical analysis of the Environmental Kuznets Curve in agrochemicals

As the largest contributor to water impairment, agriculture-related pollution has attracted the attention of scientists as well as policy makers, and quantitative information is being sought to focus and advance the policy debate. This study applies the panel unit root, heterogeneous panel cointegration, and panel-based dynamic ordinary least squares to investigate the Environ- mental Kuznets Curve on environmental issues resulting from use of agricultural synthetic fertilizer, pesticide, and film for 31 provincial economies in China's Mainland from 1989 to 2009. The empirical results indicate a positive long-ran co-integrated relationship between the environ- mental index and real GDP per capita. This relationship takes on the inverted U-shaped Environmental Kuznets Curve, and the value of the turning point is approximately 10,000-13,000, 85,000-89,000 and over 160,000 CNY, for synthetic fertilizer nitrogen indicator, fertilizer phos- phorus indicator and pesticide indicator, respectively. At present, China is subject to tremendous environmental pressure and should assign more importance to special agriculture-related environmental issues.

Overhauling the assessment of agrochemical-driven interferences with microbial communities for improved global ecosystem integrity

Recent studies have shown that various agrochemicals can substantially affect microbial communities;especially those that are associated with cultivated plants.Under certain circumstances,up to 50% of the naturally occurring microorganisms can be negatively affected by common agricultural practices such as seed coating with fungicide-based matrices.Nevertheless,the off-target effects of commonly applied agrochemicals are still understudied in terms of their interferences with microbial communities.At the same time,agrochemical inputs are steadily increasing due to the intensification of agriculture and the increasing pathogen pressure that is currently observed worldwide.In this article,we briefly reflect on the current knowledge related to pesticide interference with microbial communities and discuss negative implications for the plant holobiont as well as such that are spanning beyond local system borders.Cumulative effects of pesticide inputs that cause alterations in microbial functioning likely have unforeseen implications on geochemical cycles that should be addressed with a high priority in ongoing research.A holistic assessment of such implications will allow us to objectively select the most suitable means for food production under the scenario of a growing global population and aggravating climatic conditions.We present three hypothetical solutions that might facilitate a more sustainable and less damaging application of pesticides in the future.

Facile pathway to generate agrochemical nanosuspensions integrating super-high load, eco-friendly excipients, intensified preparation process, and enhanced potency

An aqueous nanosuspension of agrochemicals unlike pharmaceutics has to achieve massive production in an effective way,capable to ensure sufficient profits in commercialization.This work implements the flash nanoprecipitation(FNP)technique to effectively generate agrochemical nanosuspension,anticipatedly overcoming such an obstacle.Azoxystrobin,a broad spectrum fungicide,in either acetone or ethanol is used herein as a mode agrochemical.To ensure a green and practical utilization,three kinds of commercially available and eco-friendly surfactants,i.e.,poly(ethylene glycol)-block-poly(lactic-co-glycolic acid)(PEG-b-PLGA),Tween 80 and alkyl polyglucosides(APGs),are employed for stabilizing the nanoparticles.The results show that the polymeric stabilizer,PEG-b-PLGA,has the best stabilization efficiency,and can maintain the particles below 100 nm for at least three weeks.The azoxystrobin load of the nanoparticles reaches as high as 77 wt.%,beneficial to enhancing the biological potency.Moreover,the FNP brings the particles a much smaller size,narrower size distribution,better size stability,and higher biological efficacy than the ones made via a traditional method of the drop and stir(DS).The nanosuspensions present superior fungicidal performances over a prevailing counterpart from Syngenta.This study proves an enhanced biological potency and reduced dosage of agrochemical nanosuspension made via the FNP,indicating a remarkable advantage of the FNP over the conventional preparation.The integration of a super-high load,eco-friendly excipients,intensified preparation process,enhanced potency,and reduced dosage creates a promising pathway to generate a green aqueous nanosuspension of agrochemicals.

Agrochemical Concentration Level in Zaria Dam Reservoir and Ground Waters in the Environs

This study examines the effect of agrochemical used for faming in the Galma Dam area on the quality of water in the reservoir and well water around the reservoir. Nine sampling points upstream of the Galma Dam were randomly se- lected for the study. Also, six hand dug wells in use by adjacent communities were identified for ground water samples. The study covered the period July to September 2011. All measurements were in accordance with the Standard Methods for the Examination of Water and Wastewater. The parameters measured and their mean concentrations from the reser- voir are in the order of: Chlorides (0.600 - 0.900 mg/l);Nitrates (0.009 - 0.019 mg/l);Bicarbonates;0.444 - 1.900 mg/l);Total Phosphates (0.173 - 3.077 mg/l);Sulphates (0.617 - 3.587 mg/l);and pH (6.4 - 7.5). For the well water samples, the results ranged from 1.58 - 3.10 mg/l;0.14 - 0.03 mg/l;0.60 - 2.73 mg/l;0.08 - 1.89 mg/l;0.33 - 2.66 mg/l and 6.05 - 7.0 respectively in the order previously listed. The results were statistically analyzed using ANOVA at 95% confidence level. Chlorides showed no significant variation between sampling points but significant variation with dates of sam- pling for surface and well waters. Nitrates variations with both sampling points and dates of sampling were insignificant. Bicarbonates variations with sampling points and dates of sampling were highly significant. Total Phosphates and Sul- phates variations with sampling points and dates of sampling were insignificant and significant respectively. pH values variations with sampling points and dates of sampling were insignificant and highly significant respectively. Generally, the mean concentrations are within the WHO maximum limits of the parameters in drinking water and recommenda- tions were made regarding the use of agrochemicals for farming in the area.

Agrochemicals and the Ghanaian Environment, a Review

Agrochemicals are generally recognized as a significant factor in enhancing the ability to meet Ghana’s need for sufficient, safe and affordable food and fiber, however, increased usage have led to environmental deterioration. In Ghana agriculture and public health sectors remain the major contributors of pollutants into the environment. This is a systematic review of studies done in Ghana to give an integrated picture of agrochemicals especially pesticides exposure to humans, animals, plants, water, soil/sediment and atmosphere in Ghana. Although the widespread usage of agrochemicals in Ghana has contributed immensely to increased food supply and improvement in public health, it has caused tremendous harm to the environment. Water bodies, fish, vegetables, food, soil and sediment have been found to be pesticide contaminated. There is considerable evidence that farmers have overused agrochemicals especially pesticides. It is evident from biological monitoring studies that farmers are at higher risk for acute and chronic health effects associated with pesticides due to occupational exposure. Furthermore the intensive use of pesticides involves a special risk of for field workers, consumers and unacceptable residue levels in exportable products may serve as barrier to international trade. This review will set the future course of action of different studies on agrochemical usage and pesticide exposure in Ghana.

Assessing the impact of agrochemicals on schistosomiasis transmission: A mathematical study

Schistosomiasis is a snail-borne parasitic disease,which is affecting almost 240 million people worldwide.The number of humans affected by schistosomiasis is continuously increasing with the rise in the use of agrochemicals.In this paper,a mathematical model is formulated and analyzed to assess the effect of agrochemicals on the transmission of schistosomiasis.The proposed model incorporates the effects of fertilizers,herbicides and insecticides on susceptible snails and snail predators along with schistosomiasis disease transmission.The existence and stability of the equilibria in the model are discussed.Sensitivity analysis is performed to identify the key parameters of the proposed model,which contributes most in the transmission of this disease.Numerical simulations are also performed to assess the impact of fertilizers,herbicides and insecticides on schistosomiasis outbreaks.Our study reveals that the agricultural pollution can enhance the transmission intensity of schistosomiasis,and in order to prevent the outbreak of schistosomiasis,the use of pesticides should be controlled.

硅氧烷类助剂的环境残留及其农用之环境安全风险

硅氧烷类助剂(或有机硅助剂)系硅油类有机硅产品,其结构是以硅氧键为骨架组成的聚硅氧烷,因其具有超强渗透和扩散性能而被广泛用于日化和工业产品等助剂,并作为农用助剂在农业上得到推广使用。当前,我国有机硅制品产销量约200万t,生产和消费量均占世界50%以上,已成为全球最大的有机硅生产、消费和原材料净出口国,聚硅氧烷产能占比已经达到全球60%以上。随着硅氧烷类助剂的广泛应用所导致的硅氧烷环境残留(尤其在水体、污泥/土壤等环境样本中、水生食物链以及人体组织中均被检出)及其对农业生态环境的影响日益暴露,硅氧烷类助剂农用的环境安全性(包括生态毒性及其环境安全风险)也引起诸多关注。近年来,挥发性环甲基环硅氧烷(如D4(八甲基环四硅氧烷)、D5(十甲基环五硅氧烷)和D6(十二甲基环六硅氧烷)等)因其具有环境持久性、生物积累性及潜在毒性等特性而被欧盟等国家认定为新兴有机污染物或被列入优先控制化学品。本文通过对1991年以来国内外公开发表的关于硅氧烷类助剂(包括农用助剂)应用的环境残留及其生态环境安全风险相关文献检索调研,从两个方面综述分析硅氧烷类助剂的环境残留去向及其农用对农业生态环境安全的直接或间接影响,主要包括:(1)硅氧烷的环境残留及其对农业生态环境安全的影响(包括污水处理过程中硅氧烷残留及去向,水体中硅氧烷残留及水生食物链污染风险,污泥中硅氧烷残留及土壤生态污染风险,以及食品中硅氧烷残留及人体健康风险等);(2)硅氧烷类助剂农用现状及环境安全风险(包括硅氧烷类助剂农用后残留及其毒性风险,以及硅氧烷类助剂农用的安全性管理问题)。本文并就国内外对环硅氧烷类产品管理现状及问题进行了探讨。对于硅氧烷类助剂农用,由于助剂成分多被视为“生物惰性”,通常硅氧烷类助剂农用无需毒理检测和环境监管等风险评估;此外,助剂成分往往被声称为“商业机密”而受到保护,其成分一般不会在产品标签上标明。目前,我国对硅氧烷类助剂作为农用助剂(如叶面肥添加剂等)添加使用尚无监管要求,农用助剂添加缺乏安全使用规范,存在环境安全风险。本文针对硅氧烷类农用助剂添加过量可能增加其在土壤-作物-水体中残留及其生态毒性风险,以及对食品安全和人类健康存在潜在威胁等问题,建议有关管理和研究单位进一步重视硅氧烷类助剂使用过程中的残留和去向的监测,尤其加强硅氧烷类农用助剂残留对水体、土壤、动植物生长发育和人体健康影响的研究工作。

Making the Complicated Simple:A Minimizing Carrier Strategy on Innovative Nanopesticides

The flourishing progress in nanotechnology offers boundless opportunities for agriculture,particularly in the realm of nanopesticides research and development.However,concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides.It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return,and if the complex material composition genuinely improves the efficiency,safety,and circularity of nanopesticides.Herein,we introduced the concept of nanopesticides with minimizing carriers(NMC)prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations,and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers(NNC).We further summarized the current development strategy of NMC and examined potential challenges in its preparation,performance,and production.Overall,we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides,offering a way out of the current predicament.

拟除虫菊酯类杀虫剂的研究与开发进展

综述了拟除虫菊酯类杀虫剂的发展历程、作用机理、结构分类和近些年的结构修饰研究。天然除虫菊素具有高效、低毒、低残留的优点,一直被认为是理想的杀虫剂。然而,由于其易被日光分解,一直无法大规模推广。多年来,为了克服天然除虫菊素光稳定性差、合成成本高等缺点,科研人员通过对天然除虫菊素进行立体构型分析以及结构修饰,开发了一大批广谱且高效的拟除虫菊酯。相比天然除虫菊素,人工合成的拟除虫菊酯的光稳定性有了很大的改善。但是,害虫却容易对其产生抗性,且对鱼类等水生动物有毒,因此,这对拟除虫菊酯类杀虫剂的开发又提出了新的要求。