Effect of thiamethoxam (organophosphate) on the flies and beetle visitation and cadaveric decomposition process

ABSTRACT Entomofauna associated with decaying cadavers may be useful in criminal investigation, either through the development of immature insects of interest or through entomological succession in corpses. These factors may vary if the insects are exposed to toxic substances that can modify the insect's developmental cycle, as well as its own occurrence, which would imply significant changes in the results of any investigation. However, there are few studies on how contamination by toxic compounds can affect the action of insects on carcasses and their consequence for forensic expertise. Therefore, this study aimed to test the hypothesis that the normal visitation of flies and beetles is altered in insecticide-contaminated carcasses. The experiment was carried out in a sugarcane plantation, using pig carcasses contaminated with insecticide and the same number of carcasses without any type of contamination as a control. In all experiments, the contaminated carcasses reached the final phase of decomposition in a longer time than the uncontaminated carcasses of the control group. A total of 2.767 specimens were collected and identified, 2.103 individuals from the order Diptera and 664 from the order Coleoptera. There was a significant geometric regression adjustment during the decomposition phases only for the control group, different from the contaminated carcasses in which this pattern did not occur. Results show that contamination by insecticide alters decomposition time and phase, altering the action of flies and beetles, affecting the abundance, composition of species as well as their activities, which can alter the data used by experts in criminal experts.

Dietary risk assessment of neonicotinoid pesticide in 21 kinds of market-sold vegetables in Guangzhou City / 预防医学

Objective@#To evaluate the dietary risk of neonicotinoid insecticides in market-sold vegetables in Guangzhou City, so as to provide insights into ensuring food safety for residents.@*Methods@#Forty-five samples of 21 kinds of vegetables were collected from supermarkets and farmer's markets in Guangzhou City from June to September in 2022, and 10 kinds of neonicotinoid insecticides were determined using liquid chromatography-mass spectrometry (LC-MS). The vegetable consumption was obtained through the survey of food consumption and nutrients intake of residents in Guangzhou City. The dietary risk was evaluated by calculating daily exposure and non-carcinogenic risk quotients of neonicotinoid insecticides. @*Results@#A total of 27 samples of vegetables were detected with neonicotinoid insecticides, and the detection rate was 60.00%. Among 10 kinds of neonicotinoid insecticides, 6 kinds were identified, including clothianidin, thiamethoxam, imidacloprid, acetamiprid, dinotefuranand and nitenpyram. The detection rates of clothianidin, thiamethoxam and imidacloprid were relatively high (26.67%, 11.11% and 6.67%), and some samples exceeded the standard, with the rate of 4.44%, 2.22% and 2.22%, respectively. The total exposure of neonicotinoid pesticides (IMIRPF) was 3 053.00 ng/g, and the contents and IMIRPF of imidacloprid were the highest in roots and tubers. The daily exposure of imidacloprid, acetamiprid, dinotefuran, clothianidin, thiamethoxam and nitenpyram was 34.58, 3.85, 1.20, 6.87, 7.19 and 0.86 ng/(kg·d). Non-carcinogenic risk quotients of imidacloprid, acetamiprid, dinotefuran, clothianidin, thiamethoxam and nitenpyram was 5.76×10-4, 0.55×10-4, 0.06×10-4, 0.69×10-4, 0.90×10-4 and 0.02×10-4, respectively, which was lower than 1; and the sum of non-carcinogenic risk quotients was 7.98×10-4, which was lower than 1. @*Conclusions@#The dietary risk of neonicotinoid pesticides is low in 21 kinds of market-sold vegetables in Guangzhou City; however, the contents of neonicotinoid insecticides in some vegetable samples exceed the standard. The supervision of vegetable markets should be strengthened.

Levels and health risks of exposure to neonicotinoid insecticides among 5-year-old children: Based on Laizhou Wan Birth Cohort in Shandong Province / 环境与职业医学

Background Neonicotinoid insecticides (NEOs) are emerging synthetic insecticides that have been used in various pest management regimens worldwide as alternatives to conventional insecticides. Recently, several studies have indicated that humans are widely exposed to NEOs, but limited is known about the levels and associated health risks of NEOs exposure among children. Objective To estimate exposure levels of four kinds of NEOs in urine samples among 5-year-old children from Laizhou Wan, Shandong Province, and to evaluate health risks of single and cumulative exposure to NEOs among children in this area. Methods A total of 205 children who participated in the 5-year-old follow-up in Laizhou Wan Birth Cohort (LWBC) were included. Urinary concentrations of four NEOs [imidacloprid (IMI), acetamiprid (ACE), clothianidin (CLO), and thiamethoxam (THM)] were measured by high-performance liquid chromatography coupled with triple quadrupole mass spectrometry. Based on the detected NEOs concentrations, estimated daily intake (EDI) was calculated, and the health risk of exposure to single NEO was assessed using hazard quotient (HQ, risk threshold=1). A relative potency factor (RPF) approach was used to standardize the concentrations of the four NEOs by IMI to calculate their cumulative concentrations. Then, the health risk of cumulative exposure to the four NEOs was further evaluated based on the HQ method. Results The detection rates of the four NEOs in the 5-year-old children were all above 90%, and their median creatinine-adjusted urinary concentrations were in the order from high to low as follows: CLO (1.373 μg·g−1) > THM (0.628 μg·g−1) > IMI (0.310 μg·g−1) > ACE (0.073 μg·g−1). Of the four NEOs, the median EDI of IMI was 0.035 µg·kg−1·d−1, higher than those of CLO (0.032 µg·kg−1·d−1), THM (0.012 µg·kg−1·d−1), and ACE (0.002 µg·kg−1·d−1). The maximum HQ values of IMI, CLO, THM, and ACE were 0.168, 0.152, 0.055, and 0.022, respectively, which were all far lower than the risk threshold of 1. The median concentration of cumulative exposure to the four NEOs standardized by IMI was 21.241 μg·g−1, and its median EDI was 2.370 µg·kg−1·d−1. The maximum HQ of cumulative exposure to the four NEOs was only 0.694, which also did not exceed the risk threshold of 1. Conclusion NEOs exposure is common among the 5-year-old children in Laizhou Wan, Shandong. Although there is no obvious health risk associated with single and cumulative exposure to NEOs in the children in this area, their exposure levels of NEOs are higher than those in some foreign areas. The adverse health effects of long-term exposure to low dose of NEOs deserve our extensive attention.

Pollution， human exposure and harmful effects of neonicotinoid pesticides / 上海预防医学

Neonicotinoid is a kind of neuroactive pesticide， and it has become the most widely used pesticide in the world. In recent years， neonicotinoid has been detected in the environment and food， suggesting that human can be exposed to this kind of pesticide through drinking water， ingestion and respiration， which poses potential health hazards to human. However， there is no comprehensive report on the pollution level of neonicotinoid pesticides in the environment and food and the impact on human health. In this paper， the pollution status， population exposure level and potential health risks of neonicotinoid pesticides in water， air and food were reviewed. We found that neonicotinoid residues are widespread in fruits and vegetables， of which imidacloprid has the highest detection rate. Except for a few samples with excessive neonicotinoid detection， the detection level in most samples did not exceed national food safety standards. A variety of neonicotinoid pesticides have been detected in the air， surface water， tap water and drinking water. External exposure studies in the population have shown that ingestion is the main route of exposure to neonicotinoid， and the external exposure level is much lower than its chronic reference dose. The internal exposure study mainly detected the concentration of neonicotinoid pesticides and their metabolites in urine. A variety of neonicotinoid pesticides and their metabolites are detected in urine， and the concentration range is ng/ml level. Internal exposure studies found that the detection rate of thiamethoxam and dinotefuran in urine is higher， and the detection rate of neonicotinoid in Asian countries is higher than that in European and American countries. Occupational exposure studies found that neonicotinoid exposure levels increased after pesticide spraying， and the exposure levels in rural areas where pesticides were commonly used were higher than those in neighboring urban areas. Animal experiments have found that neonicotinoid pesticides have reproductive toxicity， genetic toxicity， neurotoxicity， immunotoxicity， liver toxicity and nephrotoxicity to non-target organisms. Cell experiments suggest that neonicotinoid is an endocrine disruptor. The symptoms of acute exposure in humans are related to the exposure dose， route and physical condition of the exposed person， which ranges from mild symptoms （nausea， vomiting， headache and diarrhea） to death. Population epidemiological studies have shown that chronic exposure to neonicotinoid pesticides is associated with adverse health effects in humans such as neonatal tetralogy of Fallot， anencephaly， and adverse mental symptoms.

Neonicotinoid insecticides: an emerging cause of acute pesticide poisoning

Neonicotinoids are a new class of insecticides widely applied for crop protection. Information on human exposures to neonicotinoids is limited. The most common routes of exposure were ingestion (51%), dermal (44%), and ocular (11%). These insecticides act as agonists at nicotinic acetylcholine receptors, which cause insect paralysis and death the high specificity for receptors in insects was considered to possess highly selective toxicity to insects and relative sparing of mammals. However, an increasing number of cases of acute neonicotinoid poisoning have been reported in recent years. Present study report three cases presented to us with acute neonicotinoid poisoning with different manifestations including acute myocardial infarction, central nervous system (CNS) depression, and acute kidney injury, who recovered subsequently with supportive care. A detailed literature review found that respiratory, cardiovascular and certain neurological presentations are warning signs of severe neonicotinoid intoxication. Supportive treatment and decontamination are the practical methods for the management of all neonicotinoid-poisoned patients.

Aptitud biológica de poblaciones de Bemisia tabaci (Gennadius) Biotipo B (Hemiptera: Aleyrodidae) con diferente susceptibilidad al insecticida thiametoxam / Fitness of Bemisia tabaci (Gennadius) B Biotype (Hemiptera: Aleyrodidae) populations with different levels of susceptibility to the thiametoxam insecticide

In two field-collected populations of de Bemisia tabaci (Gennadius) B biotype previously selected with the neonicotinoid insecticide thiamethoxam (NEO-R, NEO-N), and a population susceptible to insecticides (SUSC), the level of response to the insecticide thiametoxam, as well as the life and fertility tables were determined. At LC95, the NEO-R population showed a resistance ratio (RR95) value of 8.8-fold, an intrinsic rate of increase (r m) of 0.72. The fitness of the NEO-R and NEO-N populations in relation to the SUSC was 1.5 and 2.0, respectively. The RR95 value for NEO-N was 1.9-fold; it's r m value was 0.082, while in the SUSC population was 0.041. The developmental time of egg and adult were longer in NEO-R population, while the nymph and pupa lasted longer in the NEO-N and SUSC populations. The developmental time was different in the three NEO-R, NEO-N, and SUSC populations with 19.7 d (315.84 degree days or dd), 15.7 d (250.4 dd) and 18.5 d (296.6 d), respectively. The populations previously selected with thiamethoxam did not reproduce faster than their susceptible counterpart.

Clinical Characteristics of Patients with Neonicotinoid Insecticide Poisoning

PURPOSE: Neonicotinoid insecticides are widely used as they have been proven by experimental studies to have low toxicity to mammals, including humans. As the use of neonicotioids increases, the number of patients with neonicotinoid poisoning has also increased. We conducted a study to investigate the clinical manifestations of neonicotinid poisoning. METHODS: We retrospectively analyzed the patients who ingested neonicotinids and who visited the emergency department located in Korea from March 2002 to February 2010. We reviewed the patients' age, gender, the amount of exposure, the elapsed time to presentation, the treatment and the outcome. According to the poisoning severity score, we divided the patients with a Poisoning severity score (PSS) of 0 or 1 into the mild/moderate toxicity group and the patients with a PSS of 2 or 3 into the severe/fatal toxicity group. RESULTS: A total of 24 patients were analyzed. The most common clinical manifestations of neonicotinoid insecticide toxicity were gastrointestinal symptoms (66.7%) such as nausea, vomiting and abdominal pain and the others are respiratory symptoms (16.7%), cardiovascular symptoms (12.5%), metabolic imbalance (12.5%), renal dysfunction (8.3%), CNS symptoms (8.3%), and asymptomatic (29.2%). Twenty patients (83.3%) showed mild/moderate toxicity and 4 patients (16.7%) showed fatal conditions such as shock and mutiorgan failure. The mortality rate was 4.2%. In these fatal cases, the patients developed respiratory failure, hypotension, altered mentality and renal failure at the acute stage and they deteriorated to a more serious condition. This severe toxicity was caused by decreased renal excretion of neonicotinid metabolite, and this was improved after hemodialysis. CONCLUSION: Most patients with neonicotinoid poisoning and who showed mild toxicity usually improved after symptomatic treatment. However, some patients showed significant toxicity with respiratory failure and renal function deterioration, and intensive care needed, including mechanical ventilation and hemodialysis.

Atividade residual in vitro do pelo de cobertura de cães tratados com dinotefuran sobre larvas e adultos de Ctenocephalides felis felis (Bouché, 1835) (Siphonaptera: pulicidae) / Residual activity in vitro of treated dog's hair coat with dinotefuran on larvae and adults of Ctenocephalides felis felis (Bouché, 1835) (Siphonaptera: Pulicidae)

The aim of this study was to evaluate the residual activity of treated dog's hair coat with dinotefuran on larvae and adults of Ctenocephalides felis felis. Three female Beagle dogs were used. One female dog was treated with 0.834 percent dinotefuran spray, the second was treated with 30 percent dinotefuran strip-on and the third was not treated. Some areas of dog's hair were clipped on days 2, 9, 16, 23, 30, 37 and 44 after treatment. For the evaluation of adulticidal and larvicidal activities, flea adults and larvae from the laboratory colony were used. Six repetitions were used with 10 samples of each flea stage per day, placed in assay tubes. In each repetition we added 0.02 g of treated or untreated dog's hair and larval diet for the immature stage. Flea adult assay was evaluated with 24 hours and the flea larvae 20 days after treatment. The residue on hair coat of both treated dogs showed efficacy on the flea larvae control for 44 days. Regarding the flea adults control the spray and strip-on formulations showed efficacy until days 16 and 23, respectively.

O objetivo deste trabalho foi avaliar a atividade in vitro do resíduo em pelo de cobertura de cães tratados com dinotefuran sobre larvas e adultos de Ctenocephalides felis felis. Foram utilizadas três cadelas da Raça Beagle: a nº 1 foi tratada com uma formulação spray de dinotefuran a 0,834 por cento, a nº 2 com uma formulação "strip-on" de dinotefuran a 30 por cento e a nº 3 foi mantida sem tratamento. Pequenas áreas foram tricotomizadas nos dias 2, 9, 16, 23, 30, 37 e 44 após o tratamento. Para avaliação adulticida e larvicida, foram utilizados pulgas de uma colônia mantida em laboratório. Seis repetições com cada uma contendo 10 exemplares de C. f. felis, acondicionados em tubos de ensaio, da etapa correspondente foram utilizados por dia de desafio. Em cada repetição foi adicionado 0,02 gramas de pelo de cada área tricotomizada e dieta na etapa de larvas. O material da etapa adulto foi avaliado num período de 24 horas, o da etapa larvas foi avaliado após 20 dias de cada desafio. O resíduo no pêlo de cães tratados com ambas as formulações de dinotefuran foi eficaz no controle de larvas por um período de 44 dias, e no controle de adultos as formulações spray e a "strip-on" foram eficazes por um período de 16 e 23 dias, respectivamente.

Silício e imidacloprid na colonização de plantas por Myzus persicae e no desenvolvimento vegetativo de batata inglesa / Silicon and imidacloprid on plants colonized by Myzus persicae and on vegetative development of potato

O pulgão Myzus persicae (Sulzer) é considerado praga-chave da cultura da batata inglesa, cuja produtividade depende do uso de inseticidas para o seu controle. Este trabalho foi conduzido para verificar o efeito do silício e do imidaclopride na colonização de plantas por M. persicae e seus possíveis reflexos positivos no desenvolvimento da batata inglesa. Foram testados cinco tratamentos, com sete repetições: 1- testemunha; 2- ácido silícico a 1 por cento; 3- imidacloprid na dosagem recomendada (252g ha-1); 4- ácido silícico a 1 por cento e imidacloprid na metade da dosagem recomendada (126g ha-1); e 5- imidaclopride na metade da dosagem recomendada (126g ha-1). Após 20 dias do plantio, as plantas (cv. Emeraude) foram infestadas com dez pulgões adultos. Avaliaram-se, após 20 dias da infestação, o número de ninfas e de adultos de pulgões, a altura, o diâmetro, o número de folhas e a fitomassa fresca e seca das plantas. As plantas tratadas com o inseticida foram pouco colonizadas pelos pulgões e aquelas tratadas com silício apresentaram menor infestação em relação à testemunha. Em relação à altura, ao diâmetro e à fitomassa, não houve diferença significativa entre os tratamentos, porém a testemunha apresentou menor número de folhas. Assim, o silício diminuiu a colonização da batata por M. persicae e o uso da metade da dosagem recomendada de imidacloprid (126g ha-1) foi igualmente eficiente para impedir a colonização, tornando a adubação silicatada mais uma tática a ser testada no manejo integrado de pragas da batateira.

The aphid Myzus persicae (Sulzer) is a key pest of potato crops, the yield of which depends on insecticides for its control. This research was carried out to verify the effect of silicon and imidacloprid on the colonization of potato plants by M. persicae and its possible positive consequences on development parameters. Five treatments with seven replications were tested: 1- control treatment; 2- 1 percent silicic acid; 3- imidacloprid at the recommended dosage (252g ha-1); 4- 1 percent silicic acid and imidacloprid at half recommended dosage (126g ha-1) and 5- imidacloprid at half the recommended dosage (126g ha-1). Twenty days after planting, the plants were infested with ten adult aphids. After 20 days of infestation, the number of nymphs and of adult aphids; the height, the diameter, the number of leaves and the fresh and dried weights of the plants were evaluated. The plants treated with insecticides were not so colonized by the aphids and those with silicon presented lower infestation in relation to the control. In relation to the height, diameter and weights, there was no significant difference among the treatments, however the control presented the lowest number of leaves. Therefore, silicon reduced the colonization of potato by M. persicae and the use of half dosage of imidacloprid (126g ha-1) was equally efficient to prevent the colonization, making silicated fertilization one more strategy to be tested in the integrated management of potato plant pests.

Imidacloprid impact on arthropods associated with canopy of common beans / Impacto do imidaclopride em artrópodes associados ao dossel do feijoeiro

The present work aimed at assessing the temporal and spatial effect of applying the insecticide imidacloprid on the arthropod community associated with the canopy of common beans (Phaseolus vulgaris). About 2 ha of bean field was divided into two adjacent fields subjected to the same crop management practices except for insecticide application. Imidacloprid 700 GrDA (147 g a.i./ha) was applied to 20-day old plants. Three transects were extended from the mid-part of the sprayed area to the mid-part of the non-sprayed area. Nine sampling points 10 m apart were established in each transect. Arthropods were sampled from the plant canopy before and 3, 8, 14, 22, 29 37 and 44 days after insecticide application. There was a strong temporal effect of the insecticide on some arthropod guilds, but the spatial effect of the insecticide application was only noticeable in Empoasca kraemeri Roos & Moore whose dispersion from the non-sprayed area masked the insecticide effect on the treated area. The insecticide decreased the Thrips tabaci (Lind.), Caliothrips brasiliensis (Morgan), and E. kraemeri populations until 22 days after its application. Imidacloprid also prevented population increase of springtails (Collembola), but it did not significantly affect plant-chewing insects nor Frankliniella sp., Liriomyza spp. and Bemisia (Genn.). Imidacloprid was selective in favor of the most common bean pest predators and parasitoids.

O presente trabalho objetivou verificar o efeito temporal e espacial da aplicação do inseticida imidaclopride na comunidade de artrópodos associados ao dossel do feijoeiro (Phaseolus vulgaris). Cerca de dois hectares de feijoeiro foram divididos em duas partes. Ambas receberam as mesmas práticas culturais, exceto pela aplicação do inseticida. Imidaclopride 700 GrDA (147 g i.a/ha) foi aplicado aos 20 dias de idade das plantas. Foram traçados três transectos abrangendo as áreas pulverizadas e não-pulverizadas. Cada transecto foi composto por nove pontos amostrais eqüidistantes 10 m. Amostrou-se a parte aérea das plantas antes da aplicação e aos 3, 8, 14, 22, 29 37 e 44 dias após a aplicação do imidaclopride. Verificou-se efeito temporal do inseticida em algumas guildas de artrópodos, mas o efeito espacial da aplicação do inseticida foi verificado apenas para Empoasca kraemeri Roos & Moore, onde a dispersão da área não-tratada mascarou o efeito do inseticida sobre a área tratada. O inseticida afetou as populações de Thrips tabaci (Lind.), Caliothrips brasiliensis (Morgan) e E. kraemeri, mantendo-as em baixos níveis até 22 dias após a aplicação. Imidaclopride também preveniu o incremento de Collembola, não apresentando, porém, efeito significativo sobre insetos mastigadores, Frankliniella sp., Liriomyza spp. e Bemisia tabaci (Genn.). Imidaclopride foi seletivo, não afetando predadores e parasitóides comumente associados às pragas do feijoeiro.

Avaliação de Inseticidas Visando ao Controle de Eurhizococcus brasiliensis (Hempel) (Hemiptera: Margarodidae) em Novos Plantios de Videira / Insecticide Evaluation for Eurhizococcus brasiliensis (Hemiptera: Margarodidae) Control on New Vineyards

The ground pearl, Eurhizococcus brasiliensis (Hempel), is a parthenogenetic univoltine soil scale, which attacks roots of grapes (Vitis sp.) causing plant death. Infested areas became restricted to cultivation of grapes and other temperate fruits. Neonicotinoid insecticides imidacloprid and thiamethoxan were evaluated for soil application seeking for new alternatives for pest control on young plants (one year old). Imidacloprid was drenched using one liter of water per plant while thiamethoxan was applied direct to the soil using granular formulation. A single application in November provided a control higher than 80%, similar to the standard compound vamidothion (90 ml/100 L, three times a year). The dose of 0.14 g/plant of imidacloprid and thiamethoxan was enough to protect young plants for one season. These results show the possibility of controlling E. brasiliensis with neonicotinoid insecticides and hence implant new vineyards in infested areas.

A pérola-da-terra Eurhizococcus brasiliensis (Hempel) é considerada a principal praga da videira (Vitis sp.), causando morte de plantas em várias regiões do Brasil. Até o momento, somente o vamidotiom apresentou resultados promissores de controle da praga na cultura. O objetivo deste trabalho foi avaliar a eficiência dos inseticidas neonicotinóides imidaclopride e tiametoxam comparando-os ao vamidotiom no controle da pérola-da-terra. Os experimentos foram realizados com plantas de um ano de idade em casa-de-vegetação e a campo. O controle exercido pelos inseticidas foi avaliado através da contagem do número de insetos presentes nas raízes das plantas. Os inseticidas imidaclopride e tiametoxam, na dose de 0,14 g/planta, aplicados via solo, no mês de novembro, reduziram a população da praga em níveis superiores a 80%, proporcionando resultados similares ao vamidotiom. Este somente foi eficiente no controle da praga quando aplicado via foliar, na dose de 90 ml/100 litros de água, nos meses de novembro, janeiro e março. Com base nos resultados, verifica-se que é possível controlar a pérola-da-terra em plantas novas de videira e conseqüentemente implantar parreirais em áreas infestadas pela praga.