Early embryogenesis study on a dimethoate containing formulation and Cd-sulphate in chicken embryos

The toxic effects of a widely used organophosphate insecticide (BI 58 EC containing 38% dimethoate as active ingredient) applied alone or in combination with cadmium sulphate modelling the heavy metal load of the environment were studied on chicken embryos in the early phase of development. Solutions and emulsions of different concentrations were made from the test materials and injected in 0.1 ml volume into the air space of eggs on the first day (day 0) of incubation. Subsequently, on days 2 and 3 of incubation permanent preparations were made from the embryos in order to study the early developmental stage. Embryos fixed on slides and stained with osmium tetroxide solution were studied under light microscope. Summarising the findings, it can be established that the embryotoxicity increased after the simultaneous administration of Cd-sulphate and 38% dimethoate containing insecticide formulation compared to the control or the individually treated groups.     

Teratogenicity study of some pesticides in chicken embryos

The use of pesticides involves the risk of poisoning on wild animals. Teratological tests carried out on avian embryos provide useful data for environmental protection and facilitate the development of environment-friendly chemical plant protection techniques. A 30% dimethoate containing insecticide formulation (BI 58 EC) and a 20% benfluralin containing herbicide formulation (Flubalex) and a 960 g/l S-metolachlor containing herbicide formulation (Dual Gold 960 EC) were studied in chicken embryos after single administration by immersion and injection technique. Treatment was done on day 0 of incubation. Applied concentration of pesticides were 0.1% (dimethoate) and 2.05% (S-metolachlor) and 0.375% (benfluralin) corresponding to that used in plant protection practice. Test materials were injected into the air chamber in a volume of 0.1 ml/egg, or eggs were treated by the immersion technique for 30 min. at 37 degrees C. Evaluation was done on day 19 of incubation. Injection treatment: the administration of S-metolachlor and benfluralin did not result a significant decrease in the average body weight of embryos. At the same time the body weight of embryos significantly decreased because of single administration of dimethoate. The embryomortality increased markedly after the administration of test materials (S-metolachlor, benfluralin, dimethoate). Immersion treatment: the administration of S-metolachlor and benfluralin and dimethoate did not result a significant decrease in the average body weight of embryos. The rate of embryomortality was low after the administration of S-metolachlor, benfluralin and dimethoate. After the immersion and the injection treatment the incidences of developmental anomalies were sporadic. In summary it can be established that the injection treatment was more toxic than immersion technique of the test materials in our study.     

Toxicity of S-metolachlor containing formulation and heavy metals to chicken embryos

Environmental pollution of metal modelled by copper sulphate, cadmium sulphate and a 960 g/l S-metolachlor containing herbicide formulation (Dual Gold 960 EC) were studied on chicken embryos after administration as a single compounds or in combination. The test materials were injected into the air-chamber in a volume of 0.1 ml/egg on day 0 of incubation. The concentration of copper, and cadmium sulphate was 0.01%. The applied concentration of Dual Gold 960 EC was 0.375%. Evaluation was done on day 19 of the hatching period. In comparison with the values of the control group, the rate of embryomortality also increased significantly in the groups which were treated by herbicide and heavy metals individually. When the herbicide (Dual Gold 960 EC) was used individually, one quarter of the treated animals died in comparison with the values measured in the control group. In the groups which were treated with cadmium sulphate and Dual Gold 960 EC embryomortality increased significantly in comparison with both the control and individually treated groups. In the groups, which were treated together, the occurrence of development disorders remained as low level as in the case individual treatments. Looking at the types of development disorders, the most frequent problems were the oedema, the shortening of the beak mandible, and the incorrect posture of the feet and the neck. As the collective result of the treatment with cadmium sulphate and Dual Gold 960 EC, the body mass of the treated embryos decreased significantly in comparison with the control and individually treated groups, therefore we can conclude that the combined treatment resulted in increased embryo toxic effect in comparison with the individual embryo damaging effect of the used components.     

硅藻土及其混配剂对书虱的防治效果

采用拌粮法 ,用硅藻土单剂、配方 1 (硅藻土 +95 %马拉硫磷EC)、配方 2 (硅藻土 +2 . 5 %溴氰菊酯EC)、配方 3 (硅藻土 +80 %敌敌畏EC)、配方 4(硅藻土 +0 . 4%天惠虫清EC)、配方 5 (硅藻土 +5 %双氧威WP)、配方 6(硅藻土 +5 %抑太保EC)对嗜卷书虱Liposcelisbostrychophila进行防治研究 ,结果表明 :配方 4为优选配方 ,处理 2 4h后 ,3种浓度的致死率均达到 1 0 0 % ;配方 1、配方 2、配方 3、配方 5、配方 6对嗜卷书虱的致死率处理 48h后达到 1 0 0 % ;单用硅藻土处理 96h后达到 1 0 0 % ,各配方处理间差异极显著。     

滁州市家蝇对6种杀虫剂的抗药性调查

采用微量滴定法测定了滁州市家蝇对6种常见杀虫剂的抗药性。结果表明,滁州市的家蝇对毒死蜱、敌敌畏、高效氯氰菊酯、敌百虫、辛硫磷、溴氰菊酯6种常用杀虫剂都产生了很高的抗性,其LD50分别为1.1858、1.9505、0.9530、47.1834、1.2120、1.0053μg/只,相对抗性系数分别为49.62、139.32、207.17、263.59、390.97、1675.50。滁州应停止使用这些杀虫剂,加强对家蝇抗性对策的研究,延缓家蝇抗性的发展。     

The susceptibility and resistance of fry and fingerlings of Oreochromis mossambicus Peters to some pesticides commonly used in Sri Lanka

The acute toxicity (48 hr LC₅₀) of seven herbicides, three acaricides and eight insecticides used in the Control of agricultural pests in Sri Lanka to the fry and fingerlings of Oreochromis mossambicus Peters were investigated in freshwater at 28–29°C under static laboratory conditions. The fry were more susceptible to the pesticides tested than were the fingerlings. Most of the pesticides tested induced severe behavioural changes in the exposed fish. Exposure to some herbicides and insecticides resulted in lateral and upward bending of the body, while higher concentrations of some pesticides caused excessive mucous secretions, rupturing of eyes and production of haemmorrhagic patches. Of the pesticides tested on fry and fingerlings, Ronstrar, Elsan and Endosulfan are the most toxic herbicide, acaricide and insecticide, respectively, while Basfapon, Rogor and Azodrin 60 are, respectively, the least toxic herbicide, acaricide and insecticide.     

Comparative evaluation of pyrethroid insecticide formulations against Triatoma infestans (Klug): residual efficacy on four substrates

We investigated the residual efficacy of four insecticide formulations used in Chagas disease vector control campaigns: cyfluthrin 12.5% suspension concentrace (SC), lambda-cyhalothrin 10% wettable powder (WP), deltamethrin 2.5% SC, and 2.5% WP on four types of circular blocks of wood, straw with mud, straw with mud painted with lime, and mud containing 5% of cement. Three concentrations of these insecticides were tested: the LC90 (previously determined on filter paper), the double of the LC90, and the recommended operational dose. For each bioassay test, 15 third-stage nymphs of Triatoma infestans (Klug) (Hemiptera: Reduviidae) were exposed for 120 h to each treatment at 24 h, 30, 60, 90, and 180 days post-spraying. Mortality rates, moulting history and behaviour were recorded at 24, 48, 72, and 120 h of exposure. Mortality rates were highest during the first 30 days post-spraying. Highest mortality rates (above 50%) were observed for deltamethrin 2.5% SC and lambda-cyhalothrin 10% WP on wood blocks up to three months post-spraying. Mud was the substrate on which treatments showed lowest persistence, with the other two substrates showing intermediate residual efficacy of all treatments. During the first 30 days WP formulations were not as effective as SC flowable formulations but, overall in the longer term, WP gave grater mortality rates of T. infestans nymphs exposed at up to six months post-spraying. Porous surfaces, especially mud, showed most variability presumably due to absorption of the insecticide. In contrast the less porous surfaces (i.e. wood and lime-coated mud) kept mortality rates high for longer post-treatment, irrespective of the insecticide concentration used.     

Toxicological implications of a commercial formulation of deltamethrin (Decis®) in developing chick embryo

A deltamethrin containing insecticide formulation (Decis®) was evaluated for its toxic potential in developing chick embryos. For the present study, three water emulsified concentrations of Decis® (12.5 mg L^?1, 25 mg L^?1, and 50 mg L^?1) were used. Fertilized eggs of Gallus domesticus were immersed in these three concentrations of the insecticide for 60 min at 37°C on day 0 of incubation and kept for incubation till embryonic day 7. Recovered embryos were evaluated for teratogenic and biochemical changes. The results revealed that administration of Decis® at its lower concentrations (12.5 mg L^?1 and 25 mg L^?1) did not show any significant teratological changes but the significant number of abnormal survivors was observed at 50 mg L^?1 of dose concentration when compared with vehicle-treated control. Among biochemical changes, total glycogen and RNA contents of embryos was significantly decreased at 25 mg L^?1 and 50 mg L^?1 of Decis® concentrations. Similarly, significant alteration (p ≤ .05) was observed in alanine transaminase activity at 50 mg L^?1 concentration of Decis®. Thus, the present study concluded that the no-effect-level for developmental toxicity for Decis® is below the concentration of 25 mg L^?1 under standard laboratory conditions.     

Combined Effects of Atrazine and Chlorpyrifos on Susceptibility of the Tiger Salamander to Ambystoma tigrinum Virus

Several hypotheses have been examined as potential causes of global amphibian declines, including emerging infectious diseases and environmental contaminants. Although these factors are typically studied separately, animals are generally exposed to both stressors simultaneously. We examined the effects of the herbicide atrazine and the insecticide chlorpyrifos on the susceptibility of tiger salamander larvae, Ambystoma tigrinum, to a viral pathogen, Ambystoma tigrinum virus (ATV). Environmentally relevant concentrations of atrazine (0, 20, 200 μg/L) and chlorpyrifos (0, 2, 20, 200 μg/L) were used along with ATV in a fully factorial experimental design whereby individually housed, 4-week-old larvae were exposed for 2 weeks. Atrazine alone was not lethal to larvae, and chlorpyrifos alone was lethal only at the highest concentration. When combined with ATV, chlorpyrifos increased susceptibility to viral infection and resulted in increased larval mortality. A significant interactive effect between atrazine and ATV was detected. Atrazine treatments slightly decreased survival in virus-exposed treatments, yet slightly increased survival in the virus-free treatments. These findings corroborate earlier research on the impacts of atrazine, in particular, on disease susceptibility, but exhibit greater effects (i.e., reduced survival) when younger larvae were examined. This study is the first of its kind to demonstrate decreases in amphibian survival with the combination of pesticide and a viral disease. Further examination of these multiple stressors can provide key insights into potential significance of environmental cofactors, such as pesticides, in disease dynamics.     

Risk and Prognostic Factors of Inpatient Mortality Associated with Unintentional Insecticide and Herbicide Poisonings: A Retrospective Cohort Study

Introduction

Pesticide poisoning is an important public health problem worldwide. The study aimed to determine the risk of all-cause and cause-specific inpatient mortality and to identify prognostic factors for inpatient mortality associated with unintentional insecticide and herbicide pesticide poisonings.

Methods

We performed a retrospective cohort study of 3,986 inpatients recruited at hospitalization between 1999 and 2008 in Taiwan. We used the International Classification of Disease, 9th ed., Clinical Modification external causes of injury codes to classify poisoning agents into accidental poisoning by insecticides and herbicides. Comparisons in mortality rates were made between insecticide poisoning patients and herbicide poisoning patients by using the Cox proportional hazards models to estimate multivariable-adjusted hazard ratios (HRs) and their 95% confidence intervals (CIs).

Results

There were 168 deaths during 21,583 person-days of follow-up evaluation (7.8 per 1,000 person-days). The major causes of mortality for insecticide poisonings were the toxic effect of organophosphate and coma, and the major causes of mortality for herbicide poisonings were the toxic effect of other pesticides and the toxic effect of organophosphate. The mortality for herbicide exposure was fourfold higher than that for insecticide exposure. The factors associated with inpatient mortality were herbicide poisonings (HR = 4.58, 95% CI 3.29 to 6.37) and receiving mechanical ventilation treatment (HR = 3.85, 95% CI 2.73 to 5.42).

Conclusions

We demonstrated that herbicides stand out as the dominant agent for poisoning-related fatalities. The control of and limiting access to herbicide agents and developing appropriate therapeutic regimens, including emergency care, should be priorities.     

不同除草剂的田间杂草防效及对糜子生长发育的影响

筛选糜子适宜除草剂来防范农田药害,是糜子高效安全生产和改善生态环境亟待解决的关键问题。本研究以粳性糜子品种‘榆糜2号'为材料,探究22种除草剂对糜子田间杂草的防除效果及对糜子生长发育的影响。结果表明: 1)喷施土壤封闭型除草剂谷友、丁草胺、莠去津、苄嘧·丙草胺和茎叶型除草剂苯唑·二甲钠、阔世玛、藤净、陶氏·优先、阔菲后,基本无药害作用,糜子幼苗生长正常,其余除草剂均对糜子有不同程度的药害影响;2)参试的22种除草剂在糜子田中对杂草均表现出一定的防除效果,总体而言,土壤封闭型除草剂的杂草防效相对优于茎叶型除草剂,但所有参试除草剂对糜子株高、功能叶片叶绿素含量、单株穗重均造成不同程度的影响;3)与人工除草相比,参试除草剂均导致糜子产量有不同程度的下降;但与不除草对照相比,部分除草剂有明显的增产增效作用。土壤封闭型除草剂中,谷友、丁草胺、莠去津、苄嘧·丙草胺的杂草防效较好,较不除草对照增产60%以上;茎叶型除草剂中,阔世玛、苯唑·二甲钠的杂草防效较好,较不除草对照增产50%以上。因此,在糜子出苗前可用38%莠去津或44%单嘧磺隆进行土壤封闭处理,或在出苗后喷施茎叶型除草剂3.6%二磺·甲碘隆或55%苯唑·二甲钠,农田杂草防效较好,且对糜子生长发育的负面影响较小。     

氯氟氰菊酯与阿维菌素增效混配制剂对美洲斑潜蝇的防治效果

低毒化学杀虫剂氯氟氰菊酯与生物源农药阿维菌素混配,通过其对美洲斑潜蝇室内毒力实验,测定共毒系数CTC为161～232,处于明显增效范围内。据此确定最佳配比,配制此增效混剂2%渗透型可湿性粉剂。在北京、山东两地防治美洲斑潜蝇幼虫的田间试验表明药效优良,制剂用量50 g/667m²药后3、7、11天两地区校正防效分别为85.26%～90.76%和86.74%～94.02%,制剂用量25g/667m2两地区相应防效分别为75.28%～85.17%、79.96%～88.68%。该增效混剂防治斑潜蝇速效性和持效性皆佳,成本有所下降,使用可湿粉与乳油相比较,可减少投放入环境的化学品数量,以减少环境污染。     

Insecticidal effect on a population of Spilarctia obliqua (Lepidoptera: Arctiidae)

Survivors of Spilarctia obliqua derived from 3^rd instars that had ingested LC₅₀ of imidacloprid (0.025%), dichlorvos (0.014%) and endosulfan (0.012%) were studied through the life table method. Survivorship was reduced in insecticide exposed populations as compared to 45‐day in the control groups. Egg hatching was significantly decreased for the insecticide treated populations. Total larval mortality was the highest for endosulfan (36.76%) as compared to the individuals that died among control groups (14.29%). Life expectancy (e_x) was decreased gradually over time and stage of development for insecticides tested and the control groups. Dichlorvos (0.014%) has caused a significant reduction in the potential fecundity i.e. 315 females/female/generation, while 415 in the unexposed cohorts. Net reproductive rate (R_o) was the lowest in endosulfan (118.47 females/female/generation) treatment followed by dichlorvos (141.97), imidacloprid (144.49) and the control groups (272.42). Similarly, the intrinsic rate of increase (r_m) was substantially decreased after exposure with endosulfan (0.124 females/female/day) as compared to 0.135 in the unexposed cohort. The finite rate of increase (λ) was not significantly different among the insecticide treatments and control groups. Mean generation time was significantly reduced after exposure to dichlorvos (37.19 days). However, 41.34 days were required to complete one generation by S. obliqua in the absence of insecticides. Based on these results, population of S. obliqua would double in 5.19 days under the influence of dichlorvos while requiring 5.13 days for unexposed cohorts.     

Growth and denitrifying activity of Xanthobacter autotrophicus CECT 7064 in the presence of selected pesticides

The effects of the application of nine pesticides used commonly in agriculture (aldrin, lindane, dimetoate, methylparathion, methidation, atrazine, simazine, captan and diflubenzuron) on growth, CO₂ production, denitrifying activity [as nitrous oxide (N₂O) released] and nitrite accumulation in the culture medium by Xanthobacter autotrophicus strain CECT 7064 (Spanish Type Culture Collection) (a micro-organism isolated from a submerged fixed-film) were studied. The herbicide atrazine and the insecticide dimetoate totally inhibited growth and biological activity of X. autotrophicus at 10 mg l⁻¹, while the rest of the tested pesticides delayed the growth of strain CECT 7064 but did not drastically affect the bacterial growth after 96 h of culture. The denitrifying activity of X. autotrophicus was negatively affected by the pesticides application with the exception of fungicide captan. The release of N₂O was strongly inhibited by several pesticides (aldrin, lindane, methylparathion, methidation and diflubenzuron), while dimetoate, atrazine and simazine inhibited totally the denitrifying activity of the strain. The effects of the pesticides on denitrifying submerged fixed-film reactor are discussed.     

Attractiveness and toxicity of an attracticide formulation on adult males of ash leaf cone roller, Caloptilia fraxinella

A biodegradable attracticide formulation containing the pyrethroid insecticide permethrin and the sex pheromone of the ash leaf cone roller, Caloptilia fraxinella (Ely) (Lepidoptera: Gracillariidae), was tested for attractiveness and toxicity to males of this invasive pest of horticultural ash, Fraxinus spp. Marsh. (Oleaceae). Trap capture in attracticide‐baited traps was equal to capture in traps baited with rubber septa lures releasing the known attractive pheromone. Pheromone response by male C. fraxinella was not affected by the presence of permethrin as equal numbers of males were captured in traps baited with the attracticide formulation with and without permethrin. Attraction to the attracticide containing both pheromone and insecticide active ingredients did not vary with dose as 10, 50, and 100 mg droplets of the formulation attracted similar numbers of male moths in a field experiment. Equal numbers of male moths were captured in traps baited with droplets that had aged for 0–5 weeks in a laboratory fume hood before deployment in the field. The permethrin constituent of the attracticide formulation was toxic to male moths treated through tarsal contact and resulted in 73 and 100% mortality at 24 and 72 h post‐treatment, respectively. Leg autotomy occurred in over 80% of males 24 h post‐treatment to formulations containing permethrin. Mortality of moths was greater 24 h after treatment with a fresh attracticide source as compared to a 5‐week‐old source. However, mortality as a result of treatment with fresh and aged attracticide droplets was equal at 48, 72, and 96 h post‐treatment. This formulation has the potential to become a useful tool in an integrated pest‐management system for C. fraxinella on horticultural ash.     

Dechlorination of Atrazine by a Rhizobium sp. Isolate

A Rhizobium sp. strain, named PATR, was isolated from an agricultural soil and found to actively degrade the herbicide atrazine. Incubation of PATR in a basal liquid medium containing 30 mg of atrazine liter(sup-1) resulted in the rapid consumption of the herbicide and the accumulation of hydroxyatrazine as the only metabolite detected after 8 days of culture. Experiments performed with ring-labeled [(sup14)C]atrazine indicated no mineralization. The enzyme responsible for the hydroxylation of atrazine was partially purified and found to consist of four 50-kDa subunits. Its synthesis in PATR was constitutive. This new atrazine hydrolase demonstrated 92% sequence identity through a 24-amino-acid fragment with atrazine chlorohydrolase AtzA produced by Pseudomonas sp. strain ADP.     

Organic Amendments to Enhance Atrazine and Metamitron Degradation in Two Contaminated Soils with Contrasting Textures

Among all types of xenobiotics, pesticides such as herbicides play a significant role in soil and water pollution due to their wide usage all over the world. This study addresses the ability of organic amendments to enhance atrazine and metamitron degradation in two herbicide-contaminated soils with contrasting textures under laboratory conditions. Soil samples were collected from surface soils with textures of sandy loam and silty clay, from northeastern Iran. Initial concentration of herbicides was 50 mg · kg^{? 1} soil. Contaminated soil samples were treated with manure, compost and vermicompost at rates of 0, 0.5, and 2% (w/w). Residual concentrations of atrazine and metamitron were determined by HPLC at the end of incubation periods of 20, 40, and 60 days. Residual concentrations of atrazine were 46.5, 38.9, and 36.2 mg · kg^{? 1} after 20, 40, and 60 days incubation, respectively. Residual metamitron concentrations were clearly lower than atrazine. After 20, 40, and 60 days, concentrations of metamitron were 2.9, 1.0, and 0.6 mg · kg^{? 1}, respectively. Organic amendments at the rates of 0.5 and 2% showed similar effects on the enhancement of herbicide degradation in soils. However, no statistically significant effect was observed among types of organic amendments (α = 0.05). Degradation was affected by soil textures. Residual concentrations of herbicides were higher in sandy loam than in silty clay soil.     

Estimation of mutagenicity and metabolic activation after recurrent exposures ofnicotiana tabacum L. var.xanthi to 14 pesticides

Recurrent application (17 administrations in 38 days) of 14 pesticides (Karathane FN 57, Fundazol 50 WP, Dithane M 45, Topsin M 70 WP, Perozin 75 B, Fademorf EK 20, Novozir MN 80, Metation E 50, Pirimor DP, Decemtion EK 20, Zeazin 50 DP, Fatex EK 80, maleic hydrazide and Ethrel) did not increase (with the exception of maleic hydrazide) the frequency of somatic mutations in a heterozygous chlorophyll mutant ofNicotiana tabacumL. var.xanthi n. c. None of the four tested pesticides (Fademorf EK 20, Decemtion EK 20, maleic hydrazide and Ethrel) were transformed in tobacco plants to a stable mutagenic or promutagenic product active in theSalmonella (Ames) mutagenicity assay.     

Effects of the herbicide atrazine on adenine nucleotide levels in Zostera marina L. (eelgrass)

Response of adenine nucleotides (ATP, ADP, AMP) and adenylate energy charge (EC) to atrazine, a triazine herbicide, was evaluated as an indicator of metabolic state in Zostera marina L. (eelgrass), a submerged marine angiosperm. Short-term (6 h) atrazine stress reduced ATP and total adenylates (AT) at both 10 and 100 ppb, but EC remained constant. Net productivity decreased at 100, but not at 10 ppb atrazine over 6 h. Long-term (21 day) atrazine stress was evidenced by growth inhibition and 50% mortality near 100 ppb. EC was reduced at 0.1, 1.0 and 10 ppb atrazine, but ATP and EC increased with physiological response to severe stress (100 ppb) after 21 days. Apparently, ATP and AT decrease over the short-term but rebound over the long-term with severe atrazine stress, increasing beyond control levels before plant death results. Supplementing adenine nucleotide and EC results with more conventional quantitative analyses should afford greater knowledge of physiological response to environmental variation.