Developing a pesticide risk assessment tool to monitor progress in reducing reliance on high-risk pesticides

A methodology is presented for the development of a pesticide risk assessment tool that was used to monitor progress in reducing use of high-risk pesticides in Wisconsin potato production. Multi-attribute toxicity factors are calculated that reflect each pesticide’s acute and chronic toxicity to mammals, birds, fish and small aquatic organisms, and compatibility with biointensive Integrated Pest Management. These factors are then multiplied by the pounds of active ingredient of a given pesticide applied to estimate pesticide-specific toxicity units. Wisconsin potato industry baseline toxicity units by type of pesticide and for 11 targeted higher-risk pesticides are presented for 1995. Reductions in toxicity units from this baseline are reported for 1997 and 1999, as are reductions achieved in a commercial-scale field experiment in 2000.     

Risk analysis of pesticides applied to rice paddies using RICEWQ 1.6.2v and RIVWQ 2.02

Rice is commonly cultivated in Southern Europe in large river basins where the extensive use of herbicides may impact water quality at basin scale level. Consequently, pesticide risk assessment would be more relevant when considering a rice cultivation area as a whole. Accordingly, two watershed-scale scenarios were developed to represent the specific agronomic, water and pesticide management practices of rice cultivation in Greece. These scenarios were utilized for the parameterization of the rice water quality model (RICEWQ) 1.6.2v and the surface water model river water quality (RIVWQ) 2.02. in order to predict the environmental concentrations of pesticides in groundwater (GW) and surface water (SW) systems within a rice area. The annual average pesticide concentrations at 1 m depth, predicted by RICEWQ were used to assess the risk for GW contamination. The predicted exposure concentrations derived through modelling and eco-toxicological endpoints obtained from the literature, were used to calculate acute and long-term toxicity exposure ratios (TERs) for aquatic organisms. Application of these scenarios with RICEWQ and RIVWQ models enabled us to perform a risk assessment exercise for several herbicides registered in Greece for use in rice. Such a risk assessment approach could be further scaled up to represent a whole rice cultivated basin in order to be used for regulatory purposes.     

不同栽培方式下豇豆中4种农药的残留消解

为了研究保护地和露地2种栽培模式下高效氯氰菊酯、苯醚甲环唑、乐果和乙酰甲胺磷4种农药在豇豆中降解残留规律,分别采用气相色谱法电子捕获检测器和火焰光度检测器测定豇豆中高效氯氰菊酯、苯醚甲环唑和乐果、乙酰甲胺磷的残留量。结果表明：4种农药在豇豆中的消解都遵循指数型降解规律。保护地栽培下农药的降解速率总体上比露地的慢,一方面可更长时间的对害虫产生防治作用,但另一方面可能更易引起农药残留的安全隐患。因此,在豇豆的种植中,应当规范农药的使用,选用半衰期较短、降解较快的农药。     

The environmental yardstick for pesticides: a practical indicator used in the Netherlands

The environmental yardstick for pesticides has been developed as a tool for farmers to select pesticides with the least environmental impact and to quantify the impact of their use at the crop/farm level, regional level and national level. For each pesticide the yardstick assigns environmental impact points for the risk to water organisms, the risk of groundwater contamination and the risk to soil organisms. It is presently used in the Netherlands as a management tool for farmers and technical consultants, as a tool for monitoring the environmental performance of farmers, as a tool for setting standards for ecolabels and as a policy evaluation tool.     

Non-target effects of dimethoate and acephate against Eusieus tularensis Congdon and Aphytis melinus DeBach on lemons in California

Understanding the non-target effects on pesticides used in crop production systems is essential for the development of IPM programmes in those systems. Two organophosphates for control of citrus thrips in citrus were compared at commercial field rates in a lemon orchard for their effect against a predacious mite and a parasitic wasp, both of which have a significant role in coastal lemon IPM. Dimethoate and acephate greatly reduced populations of both beneficial insects, holding them to below detectable levels for 8 weeks post-treatment. Moreover, citrus red mite, a secondary pest, developed beyond the economic treatment threshold in both the dimethoate and acephate plots 10 weeks and 4 weeks post-treatment, respectively. In addition to predatory mite mortality, hormoligosis is suspected in both instances, and especially with acephate, of causing this secondary pest problem.     

Incidents of poisoning of honeybees (Apis mellifera) by agricultural pesticides in Great Britain 1981–1991

Suspected cases of poisoning of honeybees by agricultural pesticides are investigated by the Ministry of Agriculture, Fisheries and Food (in England and Wales) and the Scottish Office Agriculture and Fisheries Department (in Scotland). Studies include field visits to sites where bee mortality is recorded, examination of dead bees for disease, and analysis for the presence of pesticide residues. This paper reviews the results of these investigations for the period 1981–1991. Pesticide poisoning is diagnosed from the detection of residues in dead bees, through interpretation in relation to the median lethal dose (LD₅₀), and ‘subsequent residue level’ (SRL) determined from laboratory studies in which bees were exposed to one LD₅₀ dose. Overall, an annual average of 50 incidents were confirmed as due to pesticide poisoning, involving 30 pesticide active ingredients during the 1981–1991 period. In England and Wales, the principal hazards were caused by misuse of the insecticide triazophos on oilseed rape, a problem that has been reduced to low levels during the 1980s, and by dimethoate use on a variety of arable crops. In Scotland there were fewer incidents, most of which were associated with use of fenitrothion on raspberries, and gamma-HCH on oilseed rape. Opportunities for reducing the risks of poisoning, and for refining the investigation of suspected incidents, are discussed.     

Spray mass balance in pesticide application: A review

When pesticides are applied to arable and orchard crops, the pesticide will be deposited in the field on either the crop or the ground, or the pesticide can be transported outside the treated area as spray drift. Spray drift is divided into two fractions, sedimenting spray drift and airborne spray drift. Deposits on the crop and the ground as well as sedimenting spray drift are measured using documented and validated methods. Airborne drift is more difficult to quantify, and the methods need to be improved. A review of studies reporting crop and soil deposits in the treated area was used to calculate spray mass balances. Taking into account standard values of sedimenting spray drift for the application method applied, the airborne spray drift fraction was calculated as the difference between the applied dose and the sum of the recovered doses on crop and soil and sedimenting spray drift. This resulted in high values for airborne spray drift with the lowest values recorded in studies on application in field crops using boom sprayers and in vineyards using tunnel sprayers. In studies using traditional orchard sprayers in vineyards and tree fruit, large fractions of the spray were not found in the recovery analysis.     

Evaluation of neonicotinoids as pyrethroid alternatives for rice water weevil management in water-seeded rice

The rice water weevil (RWW), Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is the most destructive insect pest of rice in the United States. Water-seeded rice, which is flooded at an earlier stage of crop development than drill-seeded rice, is at heightened risk of loss from root-feeding RWW larvae. Pyrethroids, the most widely used group of foliar insecticides for RWW control, have inherent limitations such as limited residual activity, narrow window of activity and extreme toxicity to non-target aquatic organisms. An array of field, lab and greenhouse experiments was conducted to compare the activity of two neonicotinoids with that of λ-cyhalothrin, a widely used pyrethroid, against the RWW. Small-plot efficacy trials were conducted during 2009, 2010 and 2011. Foliar clothianidin (Belay 2.13 SC) and a granular formulation (3%) of dinotefuran applied to plots were as effective as, and showed greater residual activity than, foliar applications of λ-cyhalothrin. Topical bioassays on adult weevils revealed that clothianidin possessed lower contact toxicity than λ-cyhalothrin. Residual assays using weevils placed on foliage of sprayed plots revealed that the toxic and sublethal behavioral effects of clothianidian on adult weevils were more persistent for clothianidin than for λ-cyhalothrin. Granular dinotefuran applied to greenhouse-grown plants previously infested with weevil larvae showed excellent larvicidal activity. Overall, these studies showed that neonicotinoids have potential as pyrethroid replacements against the RWW in water-seeded rice culture.     

Pollen Treated with a Combination of Agrochemicals Commonly Applied During Almond Bloom Reduces the Emergence Rate and Longevity of Honey Bee (Hymenoptera: Apidae) Queens

Honey bee (Apis mellifera L.) colonies that pollinate California’s almond orchards are often exposed to mixtures of agrochemicals. Although agrochemicals applied during almond bloom are typically considered bee-safe when applied alone, their combined effects to honey bees are largely untested. In recent years, beekeepers providing pollination services to California’s almond orchards have reported reductions in queen quality during and immediately after bloom, raising concerns that pesticide exposure may be involved. Previous research identified a synergistic effect between the insecticide active ingredient chlorantraniliprole and the fungicide active ingredient propiconazole to lab-reared worker brood, but their effects to developing queens are unknown. To test the individual and combined effects of these pesticides on the survival and emergence of developing queens, we fed worker honey bees in closed queen rearing boxes with pollen artificially contaminated with formulated pesticides containing these active ingredients as well as the spray adjuvant Dyne-Amic, which contains both organosilicone and alkyphenol ethoxylate. The translocation of pesticides from pesticide-treated pollen into the royal jelly secretions of nurse bees was also measured. Despite consistently low levels of all pesticide active ingredients in royal jelly, the survival of queens from pupation to 7 d post-emergence were reduced in queens reared by worker bees fed pollen containing a combination of formulated chlorantraniliprole (Altacor), propiconazole (Tilt), and Dyne-Amic, as well as the toxic standard, diflubenzuron (Dimilin 2L), applied in isolation. These results support recommendations to protect honey bee health by avoiding application of pesticide tank-mixes containing insecticides and adjuvants during almond bloom.     

A meta analysis of spray drift sampling

There are many methods available for sampling spray drift, and a great variety of estimates of spray drift have been published. Available data on spray drift were collected from different studies and the measurements of spray drift were analysed to determine similarities and differences between the individual studies. Each of the methods varied significantly in their estimates of spray drift. This variation was due to many factors that differed between the published sources, such as environmental conditions, cropping system, equipment used and the tracer used. It is suggested that in order to compare drift measurements between published studies, measurement techniques and sampling distances must be standardised, and environmental conditions (humidity and temperature) should be restricted to within certain boundaries in the field, and controlled within artificial tests, unless, of course, the effect of this variable on drift is being examined.     

基于点评估方法的两广地区番木瓜中农药残留膳食暴露风险研究

为评估两广地区番木瓜中主要农药的残留情况及其产生的风险,采集了广东、广西地区40个生产基地的番木瓜样品进行测试分析,研究其生产过程中使用的杀虫剂、杀菌剂、杀螨剂和植物生长调节剂等各种农药残留情况,并对我国不同人群的膳食暴露风险进行了评估。结果显示,40批次番木瓜中检出农药残留32批次;在检出的32份番木瓜样品中,检出率超过10%的有咪鲜胺、吡虫啉、多菌灵、啶虫脒和苯醚甲环唑5种农药,检出率分别为51.1%、21.5%、13.3%、11.1%、10.9%。采用点评估方法,选择检出率在10%以上的咪鲜胺、吡虫啉、多菌灵、啶虫脒和苯醚甲环唑,进行农药残留慢性膳食摄入风险（%ADI）评估、急性膳食摄入风险（%ARfD）评估,并进行不同消费人群暴露点评估。结果显示：检出的5种农药%ADI均低于100.00%,为0.00023%~0.0059%;%ARfD远低于100%,为0.50%~28.3%,5种农药的急性和慢性摄入风险均为儿童高于成年人,绝大多数女性的摄入风险高于男性;5种农药急性摄入风险均高于慢性摄入风险,风险水平由高到低为咪鲜胺>啶虫脒>苯醚甲环唑>多菌灵>吡虫啉,但点评估结果均远低于100%,说明通过食用番木瓜摄入的农药残留极其微量,不会对人体产生急性或慢性风险。     

Vetiver oil and nootkatone effects on the growth of pea and citrus

Studies have indicated that vetiver oil and one of its components, nootkatone, possess insecticidal and herbicidal activities. The compounds appear to be good candidates as novel pesticides for substrate (soil, wood, and mulch) treatments. Phytotoxicity is a concern for substrate treatment agents against soil dwelling organisms. Using treated potting media the phytotoxic effect of vetiver oil and nootkatone was evaluated on the pea plants (Pisum sativum L.; cv, “Kelvedon Wonder”) in the laboratory and on citrus trees (Citrus unshiu Marcovitch) under field conditions. All the tested chemicals at various concentrations (20, 500, and 2000 μg/g soil) reduced the pea plant growth (plant height, root length, dry weight). Nootkatone treatments had the lowest inhibitory effect on growth, followed by vetiver oil and disodium octaborate tetrahydrate (Tim-bor^®), a registered pesticide with known phytotoxicity. The most inhibitive and injurious effects occurred with Tim-bor^® at concentrations of 500 and 2000 μg/g soil, causing plant mortality of up to 38.9%. No pea plant mortality was observed in nootkatone and vetiver oil treatments. Vetiver oil and nootkatone treatments at the rates of 30 and 100 μg/g potting media had no adverse effect on the citrus plant growth rates. These results support the possible usage of the two chemicals around buildings and in nurseries for the management of termites, ants, and weeds; or in the nursery industry where quarantines may be in place to prevent the movement of invasive pests.     

Spray drift review: The extent to which a formulation can contribute to spray drift reduction

Mitigation of risk arising from spray drift in Europe is achieved mostly by implementation of no-spray buffer zones and the use of approved drift-reducing techniques. Although physicochemical properties of spray solutions are known to influence spray drift, they are not yet incorporated into regulatory risk assessments at the European level. In this review we give a systematic report on the relevant physical properties of agricultural spray liquids and how these influence spray characteristics. According to the data reported in literature, it can be concluded that not only spray-mix additives but also certain formulation types can be used to reduce spray drift. To complete the picture, existing drift mitigation techniques and conditions have been reviewed along with measuring equipment which is commonly used to characterize agricultural sprays and the droplet size-related biological aspects of the application process. In a final step, we discuss the possibility of estimating drift risk based on the physicochemical properties of spray liquids induced by different formulation types.     

Screening of different citrus rootstocks and citrus-related species for resistance to Phyllocnistis citrella (Lepidoptera: Gracillariidae)

Nine citrus-related species and 349 citrus rootstocks were evaluated under either field or laboratory conditions for resistance to the citrus leafminer, Phyllocnistis citrella (Stainton). Field results confirmed the widespread susceptibility of citrus to the leafminer. Only 0.9% of the trees checked during one growing season escaped damage by flushing once early in the season. Laboratory assays showed that differences among citrus rootstocks existed, but levels of resistance detected were not high enough to establish a breeding program. Contrary to these results, two citroids, Murraya koenigii (L.) Sprengel and Glycosmis pentaphylla (Retzius) Corrêa, exhibited antibiotic effects against first instar larvae and may provide a source of pest-resistance genes for breeders.     

Spray drift: impact of requirements to protect the environment

Spray drift studies in the US have evaluated the effects of application, meteorological and tank mix variables on spray drift. The data have been incorporated into models to predict drift from aerial applications, and to evaluate worst-case drift from ground rig (boom) and orchard airblast applications. An atomisation model has also been developed to predict droplet size for applications of tank mixes with user-defined or reasonable worst-case physical properties through a wide range of hydraulic nozzles applicable to aerial applications. The database and models help provide the exposure risk input to risk assessments for developing appropriate labelling based on exposure and toxicity risk to non-target sensitive areas. This needs to be balanced with allowing crop protection using careful risk/benefit assessments. Buffers or no spray zones may be based on spray quality, release height and other variables such as wind speed where necessary for protecting specific sensitive areas. The impact of protection measures aimed at minimising the incidence and impact of spray drift is discussed in the present paper.     

Factors driving growers’ selection and implementation of an apple crop protection strategy at the farm level

While protecting their crops, apple growers must also satisfy the requirements of their buyers regarding pesticide residues and fruit characteristics. Based on an analysis of farm pesticide application schedules and semi-structured interviews of 35 apple growers in two areas of France, this study described how growers designed and implemented their apple protection strategies, and identified the factors which helped and/or prevented them from using less pesticide. Different combinations of economic and environmental concerns led to three main protection strategies. Growers implementing the bio-ecological strategy (S1) had high environmental concerns, used no synthetic pesticides, and compensated their lower yields with high selling prices. Growers implementing the combined strategy (S2) had moderate environmental concerns. They planted scab-resistant varieties and sprayed natural products, while diversifying their outlets and cultivars to compensate for low selling prices. The low risk strategy (S3) was implemented by growers from cooperatives with low environmental concerns who aimed for high yields and visual quality by using mainly synthetic pesticides. S2 and S3 growers were constrained by low selling prices and by the increased workload and economic risks represented by alternative methods. Extending the range of alternatives to pesticides and implementing innovative advice methodologies could be levers to reduce pesticide use.     

Risk assessment of pesticides in paddy fields and the Safīdrūd River in Gīlān,Iran

Safīdrūd River is the longest river in northern Iran and serves 2.5 million people as a water resource for drinking, irrigation, pisciculture, and recreation. To evaluate the fate of pesticides in paddy fields on the Safīdrūd river bank and the Safīdrūd basin, a comprehensive model is developed in this paper to predict pesticide concentration. The model includes degradation and sorption to soil in paddy field and two-dimensional turbulent with degradation in river. To investigate the effects of pesticides on health, an inclusive risk assessment is defined by parameters such as the maximum annual prediction environmental concentration and mean prediction environmental concentration of pesticides in the intake zone of the Safīdrūd river for the Rasht water treatment plant. The risk quotient of all pesticides were higher than 1 (i.e., for Diazinon it was calculated to be 670) which indicate high risk in the Rasht potable water and can potentially cause various digestive cancers and other refractory and mutagenic diseases. As a result, it is necessary to codify the global planning of pesticide application in the paddy fields by the local government.     

辽宁省玉米田农药使用现状、存在问题与建议

针对辽宁省玉米田农药使用情况进行深入调查,结果表明,当前辽宁省玉米田病虫草害防治以化学农药为主,用量最大的除草剂为莠去津,用量最大的杀虫剂是二嗪磷,用量最大的杀菌剂为福美双。在农药的使用过程中,存在农民对农药科学使用技术认知不足、用药技术落后、抗药性发展等问题。建议采取普及农药科学使用方法和安全使用准则、推广高效高质量施药机械、制定并实施合理的抗性治理对策应对玉米生产中病虫草的抗药性威胁,解决目前春玉米生产中农药不合理使用问题。     

Development of an innovative conceptual model and a tiered testing strategy for the ecological risk assessment of rice pesticides

Rice paddies constitute a very special agrobiosystem, which for some circumstances, could be considered as a human driven wetland. The complexity of such dynamic systems is a key element for conducting ecological risk assessments, in addition, the proximity of rice paddies to areas of high ecological value must be considered. This paper presents a new conceptual model for conducting ecological risk assessments of pesticides and other agrochemicals in rice, based on a combination of three main elements, the source of the stressor, the exposed environmental compartments and the relevance of the ecological receptors. A tiered testing strategy, starting with the standard requirements for pesticides and moving to specific higher tier studies with three levels of risk refinement is also presented.     

6种农药对海南中蜂的急性毒性测定

利用摄入法和点滴法测定高效氯氟氰菊酯、溴氰菊酯、顺式氯氰菊酯、三唑磷、杀螟丹和杀虫双对海南中蜂工蜂的急性经口和接触毒性。结果表明,高效氯氟氰菊酯、溴氰菊酯、顺式氯氰菊酯、三唑磷、杀螟丹和杀虫双对海南中蜂经口毒性(48 h)的LC50分别为3.845、2.527、1.518、0.363、26.866和38.187 mg/L,6种农药对海南中蜂接触毒性(24 h)的LD50分别为42.485、41.292、7.793、18.467、1 027.577和4 049.884 ng/蜂;6种农药对海南中蜂的经口毒性分别为高毒、高毒、高毒、剧毒、中毒和中毒,接触毒性除杀虫双为中毒外,其余均为高毒。