Pesticide ecotoxicology Research Papers - Academia.edu (original) (raw)

Changes in the expression of isoenzymes, peptides and nerve cells of T. angustula and T. fiebrigi stingless bees were evaluated after in vitro contamination with Sanson® 40SC (nicosulfuron) and 200 Gramoxone® (paraquat) herbicides, and... more

Changes in the expression of isoenzymes, peptides and nerve cells of T. angustula and T. fiebrigi stingless bees were evaluated after in vitro contamination with Sanson® 40SC (nicosulfuron) and 200 Gramoxone® (paraquat) herbicides, and also the use of such bees as bioindicators of the presence of pesticides. After contamination, analyses of changes in expression of isoenzymes esterases (EST), malate dehydrogenase (MDH), superoxide dismutase (SOD) and nerve cells employing CEC (critical electrolyte concentration) were conducted. The herbicide nicosulfuron causes partial inhibition of esterases from T. angustula and T. fiebrigi. The herbicide paraquat promotes total inhibition of esterase activity in T. fiebrigi from the concentration of 1%, and in concentrations of 10% and 100% in T. angustula. The superoxide dismutase isoenzymes showed an increase in their relative activity after contamination with paraquat at 10% and 100% in both species. No changes were observed for MDH and peptid...

The DDT Malaria Debate: Discover Magazine, 2007

A variety of chemicals including foaming agents are used to aid in the protection of forest resources from the wild land fires. The fire-fighting foams (FFFs) are formulations composed principally of surfactants. As a part of Japanese... more

A variety of chemicals including foaming agents are used to aid in the protection of forest resources from the wild land fires. The fire-fighting foams (FFFs) are formulations composed principally of surfactants. As a part of Japanese national project, environmentally inert FFFs have been developed. There is an emerging need for testing the impacts of these FFFs on the living organisms composing the typical landscapes or ecosystems in Japan. In the present report, we aimed to describe our latest attempt for assessing both the short-tem and long-term impacts of FFFs in aquatic (fresh water) and semi-aquatic (wetland) ecosystems , by employing the laboratory-sized model assays (preliminary studies) and the biotope-based observation, respectively. In the biotope assays which was based on the observation in compact biotopes mimicking the fresh water environments and wetland, both the acute and long-term eco-toxic impacts of two FFFs (soap-based and synthetic detergent-based) were assessed. Spraying of synthetic detergent-based foam formula was shown to be more toxic compared to soap-based formula and mock water treatment.

The effects of acute toxicity of pesticide on oxygen consumption of Three species of fish were used: Gambusia affinis, Cyprinus carpio L and Ctenopharyngodon idella were determined using Chlorofete pesticide an organophosphate pesticide... more

The effects of acute toxicity of pesticide on oxygen consumption of Three species of fish were used: Gambusia affinis, Cyprinus carpio L and Ctenopharyngodon idella were determined using Chlorofete pesticide an organophosphate pesticide (active ingredient is Tc 48% Chloropyrfos). Four concentration 0.1, 0.5, 1 and 5 ppm were used with the control sample in experiment oxygen consumption measured after 24 hours , the results of the oxygen consumption showed increase in the rate of oxygen consumption with increased the concentration in all fish and the Common carp was more resistant to oxygen deficiency , compared to grass carp which is the least tolerant and died after 24 hours .

The effects of 55 pesticides (27 fungicides, 26 herbicides and 2 insecticides) on 25 Rhizobium strains were studied in laboratory tests. Fungicides, especially captan, fuberidazole, HPMTS and tilt were the most toxic preparations. Eleven... more

The effects of 55 pesticides (27 fungicides, 26 herbicides and 2 insecticides) on 25 Rhizobium strains were studied in laboratory tests. Fungicides, especially captan, fuberidazole, HPMTS and tilt were the most toxic preparations. Eleven preparations were not toxic, among them were benomyl, quintozene and thiophanate-methyl. The herbicides and insecti-cides tested were found to inhibit the growth of rhizobia to a lesser extent than the fungicides.

Pest control through integrated pest management systems stands as a very convenient sustainable hazard-free alternative to pesticides, which are a growing global concern if overused. The ability of the soprano pipistrelle bat... more

Pest control through integrated pest management systems stands as a very convenient sustainable hazard-free alternative to pesticides, which are a growing global concern if overused. The ability of the soprano pipistrelle bat (Pipistrellus pygmaeus) to control the rice borer moth (Chilo supressalis), which constitutes a major pest of rice around the world, was studied in the Ebre Delta, Northeastern Iberia. Evidence was found on the ability of this particular bat species to control borer infestations: a) the moth was consumed during at least the last two peaks of the moth activity, when most crop damage is done; b) the activity of bats significantly increased with moth abundance in the rice paddies; c) the pest levels have declined in the study area (Buda Island, Eastern Ebre Delta) after the deployment of bat boxes and their subsequent occupation by soprano pipistrelles. The value of the ecosystem service provided by bats was estimated at a minimum of 21€ per hectare, equivalent to the avoided pesticide expenditure alone. We suggest that this natural service can be enhanced by providing bat populations with artificial roosts in rice paddies were some key ecosystem features are present.

This investigative article for Science Digest (March, 1983) revealed the high global death toll from accidental and occupational exposure (and suicides) involving Paraquat (Gramoxone), a revolutionary herbicide with the unfortunate... more

This investigative article for Science Digest (March, 1983) revealed the high global death toll from accidental and occupational exposure (and suicides) involving Paraquat (Gramoxone), a revolutionary herbicide with the unfortunate quality of being an extraordinarily awful poison. The piece won a 1983 Investigative Reporters & Editors Award (magazines).

Material Safety Data Sheet

Probably the most important threat currently affecting vultures worldwide is exposure to pesticides, both accidentally and through deliberate abuse. This is of special concern since around 70% of vulture species are threatened by human... more

Probably the most important threat currently affecting vultures worldwide is exposure to pesticides, both accidentally and through deliberate abuse. This is of special concern since around 70% of vulture species are threatened by human activities. However, information about this threat is sparse and geographically biased. We compiled existing knowledge about pesticide exposure in vulture species globally, providing unifying criteria to mitigate this problem with a joint global effort. Most information available about accidental exposure to pesticides in vultures is related to organochlorine pesticides. Non-lethal exposure to these compounds occurs on every continent that vultures inhabit. While concentrations of organochlorine pesticides reported in different samples appear to be too low to produce health impacts, some studies show vultures with levels compatible with health impacts. In addition, there are some reports of vultures contaminated accidentally by anticoagulant rodenticides and external antiparasitic drugs used in veterinary practices. Deliberate abuse of pesticides to poison wildlife also occurs on every continent where vultures live, affecting most (78%) vulture species. However, little information is available for some regions of America, Asia and Europe. The exact number of vultures killed due to deliberate poisoning with pesticides is not well known, but the available figures are alarming (e.g. up to 500 individuals in a single event). The most widely used pesticides affecting vulture populations, and associated with deliberate poisoning, are carbamates and organophosphorus compounds. Of particular concern is the fact that massive poisoning events with these compounds occur, in some cases, within protected areas. This suggests that if this situation is not reversed, some vulture populations could disappear. A combination of measures such as banning pesticides, controlling their distribution-acquisition and environmental education could produce better results that banning pesticides alone. If poisoning with pesticides is not stopped, this threatened avian group could inadvertently go extinct very soon.

Honey bee (Apis mellifera L.) health is compromised by complex interactions between multiple stressors, among which pesticides play a major role. To better understand the extent of honey bee colonies' exposure to pesticides in time and... more

Honey bee (Apis mellifera L.) health is compromised by complex interactions between multiple stressors, among which pesticides play a major role. To better understand the extent of honey bee colonies' exposure to pesticides in time and space, we conducted a survey by collecting corbicular pollen from returning honey bee foragers in 53 Italian apiaries during the active beekeeping season of 3 subsequent years (2012–2014). Of 554 pollen samples analysed for pesticide residues, 62% contained at least one pesticide. The overall rate of multiresidual samples (38%) was higher than the rate of single pesticide samples (24%), reaching a maximum of 7 pesticides per sample (1%). Over 3years, 18 different pesticides were detected (10 fungicides and 8 insecticides) out of 66 analysed. Pesticide concentrations reached the level of concern for bee health (Hazard Quotient (HQ) higher than 1000) at least once in 13% of the apiaries and exceeded the thresholds of safety for human dietary intake (Acute Reference Dose (ARfD), the Acceptable Daily Intake (ADI), and the Maximum Residue Limit (MRL)) in 39% of the analysis. The pesticide which was most frequently detected was the insecticide chlorpyrifos (30% of the samples overall, exceeding ARfD, ADI, or MRL in 99% of the positive ones), followed by the fungicides mandipropamid (19%), metalaxyl (16%), spiroxamine (15%), and the neonicotinoid insecticide imidacloprid (12%). Imidacloprid had also the highest HQ level (5054, with 12% of its positive samples with HQ higher than 1000). This 3year survey provides further insights on the contamination caused by agricultural pesticide use on honey bee colonies. Bee-collected pollen is shown to be a valuable tool for environmental monitoring, and for the detection of illegal uses of pesticides.

Sachet water in Nigeria, popularly called pure water is the most ubiquitous commercially packaged water in the country. As a result, they are cheaper and vended in several locations such as motor parks, markets, hospitals road sides,... more

Sachet water in Nigeria, popularly called pure water is the most ubiquitous commercially
packaged water in the country. As a result, they are cheaper and vended in several locations such as motor parks, markets, hospitals road sides, outskirt of schools and streets. Given the threat of potential health risk, there is therefore need to periodically ascertain its water safety qualities (physical, chemical and microbial) to protect public health. This study focuses on ascertaining the quality of selected Sachet water brands in 3 major areas of Ondo State namely Akure, Owo and Ondo metropolis. Sampling 100 retail outlets to inquire about the top 5 most consumed sachet water brands from each area which were subjected to analysis. The results showed that the sachet water samples had good aesthetic value as all the brands of sachet water evaluated met the recommended WHO standard for appearance, colour, odour and turbidity. Thirteen of the sachet water samples had pH values between 6.5 - 7.6 which met the limit described by WHO while the other three samples had pH value below 6.5 and did not fall within WHO drinking water standard. Other physico-chemical characteristics of all the brands of water evaluated such as electrical conductivity, total dissolved solid, chloride, magnesium, calcium and Nitrate were within the acceptable limits recommended by WHO for quality drinking water except for their chemical oxygen demand properties which was >10mg/L described by WHO. Two samples had values higher than the recommended 100mg/L for total alkalinity. The concentration of metals; Pb, As, Cr and Mn was not detected in all the water samples, however, Zn, Fe, Cd and Cu were found in some samples in values slightly higher than the value described by WHO for quality water in all the 3 locations. Results of the microbiological analyses further shows that all the brands of water had zero MPN/100mL count for coliforms except for only three brands with values higher than the 0 MPN/100 mL maximum limits recommended by WHO. Only two brands of the sachet water samples had value (113CFU/mL) above the 102 CFU/mL described by WHO for aerobic mesophilic count. This study suggests that maximum and effective treatment technique/method should be adopted by the water manufacturing industries to reduce or totally eradicate water-borne diseases.

In the last decade, the use of neonicotinoid insecticides increased significantly in the agricultural landscape and they are meanwhile considered a risk to honey bees. Besides the exposure to pesticides, colonies are treated frequently... more

In the last decade, the use of neonicotinoid insecticides increased significantly in the agricultural landscape and they are meanwhile considered a risk to honey bees. Besides the exposure to pesticides, colonies are treated frequently with various acaricides that beekeepers are forced to use against the parasitic mite Varroa destructor. Here we have analyzed the impact of a chronic exposure to sublethal concentrations of the common neonicotinoid thiacloprid (T) and the widely used acaricide τ-fluvalinate (synthetic pyrethroid, F) - applied alone or in combination - to honey bee colonies under field conditions. The population dynamics of bees and brood were assessed in all colonies according to the Liebefeld method. Four groups (T, F, F+T, control) with 8-9 colonies each were analyzed in two independent replications, each lasting from spring/summer until spring of the consecutive year. In late autumn, all colonies were treated with oxalic acid against Varroosis. We could not find a negative impact of the chronic neonicotinoid exposure on the population dynamics or overwintering success of the colonies, irrespective of whether applied alone or in combination with τ-fluvalinate. This is in contrast to some results obtained from individually treated bees under laboratory conditions and confirms again an effective buffering capacity of the honey bee colony as a superorganism. Yet, the underlying mechanisms for this social resilience remain to be fully understood.

In cotton production, there are many factors that can reduce crop yield. One important cause is arthropod insects. Insects that cause loss to the fruit are frequently more destructive than those that damage leaves, stems, and roots.... more

In cotton production, there are many factors that can reduce crop yield. One important cause is arthropod insects. Insects that cause loss to the fruit are frequently more destructive than those that damage leaves, stems, and roots. Cotton in Zimbabwe is subjected to yield and quality loss due to various lepidopterous pests. The African bollworm (Helicoverpa armigera), red bollworm (Diparopsis castanea), spiny bollworms (Erias insulana and E. biplaga) and pink bollworm (Pectinophora gossypiella) causes the greatest yield loss annually. This review describes integration of pest control tactics directed against the bollworm pest complex which put
together the most effective mixture of tactics, allowing control of pests while keeping in mind the productivity of the fields, the role of beneficial organisms and safety considerations. Get more articles at: http://www.innspub.net/volume-7-number-1-july-2015-ijaar/

Mealy bugs infests anumber of crop plants and results a serious economic loss. Although, there are a number of insecticides to overcome the yeild losses in crop plants. But, the presence of waxy layer around its body that make them so... more

Mealy bugs infests anumber of crop plants and results a serious economic loss. Although, there are a
number of insecticides to overcome the yeild losses in crop plants. But, the presence of waxy layer around
its body that make them so difficult to control by means of insecticides. The waxy coating, high
reproduction rate, protection by ants and variety of hosts are some of the factors which contribute to the
pest status of this pest insect. Most of farmers mainly rely on synthetic chemicals for the management of
cotton mealy bug but due to rising environmental and economic concerns there is a dire need to develop
eco and environmental friendly measures to combat this menace. The use of synthetic insecticides is
extremely toxic to natural enemies of mealy bugs. Plant derivatives can be used as an alternative approach
to synthetic chemicals which are cost effective, easily available and safe to environment and biocontrol
agents. Similarly, olfactory studies show that odors emitted from plant and mealy bug itself can also be
used in pest management strategies.

Se describe la noción de la resistencia y se mencionan diferentes clases de este fenómeno, es decir, los tipos de morfológico, comportamental, y fisiológico o metabólico. Se destaca la historia y evolución de la resistencia en los... more

Se describe la noción de la resistencia y se mencionan diferentes clases de este fenómeno, es decir, los tipos de morfológico, comportamental, y fisiológico o metabólico. Se destaca la historia y evolución de la resistencia en los artrópodos. Se marcan los casos de resistencia en artrópodos y también la resistencia de éstos organismos a diferentes clases de plaguicidas. Se explica el proceso del metabolismo de los pesticidas en las plantas y los microorganismos y finalmente, los mecanismos de resistencia de las plantas hacia los estímulos.

En la República Argentina, existe una controversia creciente respecto de los efectos tóxicos a largo plazo de la exposición humana a agroquímicos de aplicación periurbana aérea o terrestre. El extensivo problema de la dispersión de los... more

En la República Argentina, existe una controversia creciente respecto de los efectos tóxicos a largo plazo de la exposición humana a agroquímicos de aplicación periurbana aérea o terrestre. El extensivo problema de la dispersión de los pesticidas en el aire afecta a una diversidad de comunidades a través de todo el país. En respuesta a la solicitud de asesoramiento de integrantes de los Consejos Deliberantes y de ONG’s de diversas localidades del interior de Argentina, el presente trabajo explora recientes evidencias científicas y adelantos técnicos que revelan subestimaciones de impactos sanitarios negativos potenciales e insuficiencias del valor protectivo de estrategias y políticas locales de evaluación de toxicidad crónica de pesticidas autorizados y de uso ilegal.
iNVESTIGACIÓN REALIZADA EN 2009

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee... more

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees’ susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers’ roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.

Trabajo incluido como introducción al capítulo de Informes Médicos del libro “Pueblos Fumigados”, investigación publicada en 2007 sobre la problemática del uso de plaguicidas en las principales provincias sojeras de la Argentina, fruto de... more

Trabajo incluido como introducción al capítulo de Informes Médicos del libro “Pueblos Fumigados”, investigación publicada en 2007 sobre la problemática del uso de plaguicidas en las principales provincias sojeras de la Argentina, fruto de la campaña Paren de Fumigar del GRR.

The honeybee (Apis mellifera L.) is an important pollinator and a model for pesticide effects on insect pollinators. The effects of agricultural pesticides on honeybee health have therefore raised concern. Bees can be exposed to multiple... more

The honeybee (Apis mellifera L.) is an important pollinator and a model for pesticide effects on insect pollinators. The effects of agricultural pesticides on honeybee health have therefore raised concern. Bees can be exposed to multiple pesticides that may interact synergistically, amplifying their side effects. Attention has focused on neonicotinoid pesticides, but flupyradifur-one (FPF) is a novel butenolide insecticide that is also systemic and a nicotinic acetylcholine receptor (nAChR) agonist. We therefore tested the lethal and sublethal toxic effects of FPF over different seasons and worker types, and the interaction of FPF with a common SBI fungicide, propicona-zole. We provide the first demonstration of adverse synergistic effects on bee survival and behaviour (poor coordination, hyperactivity, apathy) even at FPF field-realistic doses (worst-case scenarios). Pesticide effects were significantly influenced by worker type and season. Foragers were consistently more susceptible to the pesticides (4-fold greater effect) than in-hive bees, and both worker types were more strongly affected by FPF in summer as compared with spring. Because risk assessment (RA) requires relatively limited tests that only marginally address bee behaviour and do not consider the influence of bee age and season, our results raise concerns about the safety of approved pesticides, including FPF. We suggest that pesticide RA also test for common chemical mixture synergies on behaviour and survival.

The present study was aimed to evaluate the effects of acute dose of Cypermethrin (CYP), an extensively use synthetic pyrethroid, on hematology and morphology of the liver, gills and brain of Mahseer (Tor putitora). The effects were... more

The present study was aimed to evaluate the effects of acute dose of Cypermethrin (CYP), an extensively use synthetic pyrethroid, on hematology and morphology of the liver, gills and brain of Mahseer (Tor putitora). The effects were assessed on the basis of the previous results of acute toxicity test after exposing fish to acute concentration, 63 μg L-1 (LC50 of 96 h) of CYP. Light microscopic studies revealed severe histopathological changes in liver, gills and brain tissues. The morphological alterations in liver involved glycogen vacuolation, hemorrhage vacuolation, congestion, fatty infiltration and hepatic necrosis. In gills, it resulted in cellular infiltration, congestion, swollen tip of the gill filament, hetrophilic infiltration and damaged gill while in the brain it caused discoloration, neuronal degeneration, infiltration and severe spongiosis. Blood cell count also showed the toxic effect of CYP, as RBCs count decreased while WBCs count increased with time in the treated...

Traditionally grown "Alphonso" (Mangifera indica) belonging to the family Anacardiaceae is known as the king of fruits and it is famous for its specific taste and aroma. Pest control is the big challenge in front of mango farmers. The... more

Traditionally grown "Alphonso" (Mangifera indica) belonging to the family Anacardiaceae is known as the king of fruits and it is famous for its specific taste and aroma. Pest control is the big challenge in front of mango farmers. The correlation between expenditure on pesticide and production of mango which showed significant positive relationship which itself explains extent of pest infestation at the study area. However, farmers are using chemical pesticides indiscriminately. This activity of farmers ultimately introduced more heavy metals in the environment which are very harmful. Present work also tried to develop relationship between heavy metal concentration and expenditure on pesticide. Here it shows slightly positive but not significant relationship which may change into significant relation if rate of intrusion of heavy metals through chemical pesticides remains the same. The present study attempted to suggest strategic plan to minimise heavy metals pollution and cost management to increase net profitability.

This is a response to the European Food Safety Authority EFSA recommending the renewal of glyphosate. There is an introduction; a history of farming with chemicals in the UK; History of chemical regulation in Europe - in the hands of the... more

This is a response to the European Food Safety Authority EFSA recommending the renewal of glyphosate. There is an introduction; a history of farming with chemicals in the UK; History of chemical regulation in Europe - in the hands of the pesticides industry; Deterioration of health in the UK, the US and Latin America; Loss of biodiversity which correlates with the measurement of chemicals in the environment.

The study was designed to investigate the potency of O. majorana essential oil as a biocontrol agent against C. cephalonica and selected fungal pathogens. The essential oil proved to possess effective fumigant, insect repellent and... more

The study was designed to investigate the potency of O. majorana essential oil as a biocontrol agent against C. cephalonica and selected fungal pathogens. The essential oil proved to possess effective fumigant, insect repellent and contact toxicant activity against all the stages of C. cephalonica. On assessing the toxicity of the essential oil on human RBC, partial hemolysis was observed, which suggests relatively less toxic nature of the oil towards non targeted organisms. The work also emphasizes the minimal phytotoxic effect f the oil, hence less harmful to the environment. Inhibition of growth of selected food borne fungal pathogens exhibited the potent antifungal property of the oil. TLC was performed to separate the phytoconstituents of the oil using Hexane: Ethyl Acetate solvent system, which revealed 4 separate bands of Rf value in the range of 0.7-0.7 , suggesting the presence of monoterpenes in the oil. Further isolation of individual constituents and assessment of the bioactivity of the isolated components alone and synergistically, could pave way to the development of an effective biocontrol agent against C.cephalonica.

Such a large number of chemical pesticides that are meant to perform different functions, fall into different classes, depending on their chemical nature, toxicity, their targets etc. They have accordingly been classified by their... more

Such a large number of chemical pesticides that are meant to perform different functions, fall into different classes, depending on their chemical nature, toxicity, their targets etc. They have accordingly been classified by their chemical structure, specificity to target pests, name and action. They have been named by their chemical properties, chemical structure, composition, formulation, mode of action and by their target pests i.e. insects, fungi, weeds, nematodes etc.

This study was conducted to establish the potential of lettuce (Lactuca sativa L. var. buttercrunch) seeds as a bioindicator (BI), or a biological tool for detecting the presence of some toxic materials used in tanning industry and... more

This study was conducted to establish the potential of lettuce (Lactuca sativa L. var. buttercrunch) seeds as a bioindicator (BI), or a biological tool for detecting the presence of some toxic materials used in tanning industry and determining their concentrations using the germination percentage as a parameter (indicator). Samples of Gezira Tannery Corporation (GTC) wastewater (WW) were collected from both the mouth and the tail of the drainage stream. Lettuce seeds (10/Petri dish, replicated 3x and each experiment was repeated 3x) were treated by GTC WW and other important tanning agents (chromium oxide , sodium sulfide, Preventol® WB) in solution using different concentrations of each and their mixture. The bioassay experiment revealed that the seeds were intoxicated (i.e. reduced the germination percentage), when exposed to the WW. On exposure to several concentrations from each input, the concentrations that can be measured by this BI (i.e. sensitivity and reliability) are: chromium oxide from 0.1 to 3.25%, sodium sulfide from 0.19 to 1.5% and Preventol® WB from 18.75 to 150 ppm. Lower concentrations cannot be measured, and higher concentrations resulted in 100% inhibition. The IC50 was determined by probit analysis for the WW, mixture of the three inputs, chromium oxide alone, sodium sulfide alone and Preventol® WB alone were: 35.5, 14.5, 0.44, 0.45 and 0.005%, respectively. The slopes of the log-dose probability lines (Ld-P) showed that this BI response to all treatments was homogeneous (＞2) (tabulated X2 (df=n－2) at 5%=0.172, 0.11, 0.064, 0.05 and 0.05). It is concluded that lettuce seeds satisfy almost all the required properties of the ideal BI.

Neonicotinoids alone or in combination with pathogens are considered to be involved in the worldwide weakening of honey bees. We here present a new approach for testing sublethal and/or synergistic effects in free flying colonies. In our... more

Neonicotinoids alone or in combination with pathogens are considered to be involved in the worldwide weakening of honey bees. We here present a new approach for testing sublethal and/or synergistic effects in free flying colonies. In our experiment individually marked honey bees were kept in free flying mini-hives and chronically exposed to sublethal doses of the neonicotinoid clothianidin. Additional groups of bees were challenged with Nosema infections or with combinations of the pesticide and pathogens. Longevity and flight activity of the differentially treated bees were monitored for a period of 18 days. In contrast to previous laboratory studies, no effect of the neonicotinoid treatment on mortality or flight activity could be observed. Although the lifespan of Nosema infected bees were significantly reduced compared to non-infected bees a combination of pesticide and pathogen did not reveal any synergistic effect. Our results indicate that individual bees are less impaired by neonicotinoids if kept within the social environment of the colony. The effect of such a " social buffering " should be considered in future risk assessments.

The mealybug Phenacoccus solenopsis is a destructive pest of cotton with the potential to develop resistance to most chemical classes of insecticides. Six populations of P. solenopsis from cotton crops at six different locations in... more

The mealybug Phenacoccus solenopsis is a destructive pest of cotton with the potential to develop resistance to most chemical classes of insecticides. Six populations of P. solenopsis from cotton crops at six different locations in Pakistan were evaluated for resistance to selected organophosphate and pyrethroid insecticides. Resistance ratios (RRs) at LC50 were in the range of 2.7–13.3 fold for chlorpyrifos, 11.6–30.2 fold for profenofos and for the three pyrethroids tested were 10.6–46.4 for bifenthrin, 5.8–25.2 for deltamethrin and 4.1–25.0 for lambda-cyhalothrin. This is the first report of resistance to organophosphate and pyrethroid insecticides in Pakistani populations of P. solenopsis. Regular insecticide resistance monitoring programs are needed to prevent field control failures. Moreover, integrated approaches including the judicious use of insecticides and rotation of insecticides with different modes of action are needed to delay the development of insecticide resistance in P. solenopsis.

The most natural waterways in Thailand are utilized for conventional agricultures, e.g. irrigation and wastewater discharge. Concentrations of 20 organochlorine pesticides (OCPs) were measured in surface sediments collected from the... more

The most natural waterways in Thailand are utilized for conventional agricultures, e.g. irrigation and wastewater discharge. Concentrations of 20 organochlorine pesticides (OCPs) were measured in surface sediments collected from the tributaries of the Mae Klong river during 2003–2005. The sampling sites chosen were nearby the rice paddy which organochlorine pesticides were intensively used for crop cultivation. Solid–liquid extraction technique was used for sediment extraction, and gas chromatography with electron capture detector was applied for pesticides determination. Total concentrations of OCPs found were ranged from 4.12 to 214.91 g g −1 dw in the first year. In the second year, total residue concentrations in the surface sediments were in the range of 3.26–215.09 g g −1 dw. Concentrations of pesticides were greater in dry-season rice cultivation period in both sampling years, and heptachlor epoxide was the contaminant found at highest concentration in this study. In addition, the occurrence of some selected contaminants including DDT, DDD and DDE reflects the recent contamination in the study area. This demonstrates not only that the natural waterway was polluted and contained much pesticide residues, but it also illustrates the necessity of a continuous long-term monitoring of the affected environment.

Plant immune systems rely on their ability to recognize enemy molecules, carry out signal transduction, and respond defensively through pathways involving many genes and their products. This Perspective paper aims to explore current views... more

Plant immune systems rely on their ability to recognize enemy molecules, carry out signal transduction, and respond defensively through pathways involving many genes and their products. This Perspective paper aims to explore current views on the vaccination (immunization) of plants against diseases caused by microorganisms and their (macro)molecular components, paying special attention to practical applications. We conclude that the technique of vaccination to control plant disease needs to be further investigated, developed, and considered for wider implementation in plant protection practice.

Paramecium bursaria is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the cells of P. bursaria as micro-machines... more

Paramecium bursaria is an unicellular organism that lives widely in fresh water environments such as rivers and ponds. Recent studies have suggested that in vivo cellular robotics using the cells of P. bursaria as micro-machines controllable under electrical and optical stimuli, has a variety of engineering applications such as transport of micro-sized particles in the capillary systems. The present study aimed to test if the swimming cells of P. bursaria, implementable in capillaries or on chips, are applicable for detection of metal ions. For model assays, rare earth elements (REEs) were chosen as target chemicals. In P. bursaria, LC 50 values for REE ions ranged between 2.0 and 62.7 µM. Among them, Sc was shown to be most toxic. In addition to the lethal impacts of REE ions, most of REE ions at sub-lethal concentrations at around 10-30 µM, showed inhibitory action against the motility of the cells during the electrically forced motility known as galvanotaxisis. In conclusion, in the non-lethal ranges of REE concentration, swimming cells of P. bursaria report the presence of REE ions, by lowering the motility.

The purpose of this study was to determine if chronic exposure to the glyphosate-based herbicide VisionMax® affects the survival, development, growth, sex ratios and expression of specific genes involved in metamorphosis of wood frog... more

The purpose of this study was to determine if chronic exposure to the glyphosate-based herbicide VisionMax® affects the survival, development, growth, sex ratios and expression of specific genes involved in metamorphosis of wood frog tadpoles (Lithobates sylvaticus). We hypothesized that expo- sure to this herbicide will affect developmental rates by disrupting hormone pathways, sex ratios and/or gonadal morphology. Tadpoles were chronically exposed in the laboratory from Gosner developmen- tal stage 25 to 42 to four different concentrations of VisionMax® (ranging from 0.021 to 2.9 mg acid equivalents/L). Chronic exposures to VisionMax® had direct effects on the metamorphosis of L. sylvaticus tadpoles by decreasing development rates, however, there was a decrease in survival only in the group exposed to the highest dose of VisionMax® (2.9 mg a.e./L; from approximately 96% in the control group to 77% in the treatment group). There was a decrease in the number of tadpoles reaching metamor- phic climax, from 78% in the control group to 42% in the VisionMax® (2.9 mg a.e./L) group, and a 7-day delay to reach metamorphic climax in the same treatment group. No effects of exposure on sex ratios or gonadal morphology were detected in tadpoles exposed to any of the concentrations of VisionMax® tested. Gene expression analyses in brain and tail tissues demonstrated that exposure to VisionMax® alters the expression of key genes involved in development. Results showed significant interaction (two- way ANOVA, P < 0.05) between developmental Gosner stage and treatment in brain corticotropin-releasing factor, deiodinase type II (dio2) and glucocorticotiroid receptor (grII) and tail dio2 and grII. This demon- strates that mRNA levels may be differently affected by treatment depending on the developmental stage at which they are assessed. At the same time there was a clear dose–response effect for VisionMax® to increase thyroid hormone receptor ˇ in tadpole brain (F(2,69) = 3.475, P = 0.037) and tail (F(2,69) = 27.569, P < 0.001), regardless of developmental stage. Interestingly, delays in development (or survival) were only observed in the group exposed to 2.9 mg a.e./L of VisionMax® , suggesting that tadpoles need to be exposed to a “threshold” concentration of glyphosate-based herbicide to exhibit phenotypic observable effects. We suggest that the upregulation of genes that trigger metamorphosis following VisionMax® herbicide exposure might result from a compensatory response for the delays in development observed. Further studies are needed to determine if disruption of expression of these key genes leads to long-term effects when metamorphs reach adult stages.

Maize is consumed by over 95% of the Ghanaian populace and the practice of using Atrazine and Lindane (an Organochlorine) pesticides in its production has raised concerns about potential adverse effects on human health and the... more

Maize is consumed by over 95% of the Ghanaian populace and the practice of using Atrazine and Lindane (an Organochlorine) pesticides in its production has raised concerns about potential adverse effects on human health and the environment. A field survey was conducted in this study to assess farmers' knowledge of safe handling and use of these chemicals as well as toxicity awareness and symptoms among farmers and traders. Residues of these pesticides in maize samples as well as the potential health risk associated with exposure to them were also evaluated. Composite maize samples were collected for nine of ten regions in Ghana and analyzed. Data obtained from the field survey indicate that a large proportion of farmers are at risk of pesticide poisoning through occupational exposure. Over 80% of applicators do not apply safety precautions during pesticide mixing and application; resulting in considerable prevalence of pesticide related illnesses in the study area. Residues of Lindane and atrazine were below detection limits of 0.005 mg/kg and 0.010 mg/kg respectively; except in the Ashanti region where atrazine was 0.05 mg/kg which was within the EU-MRL of 0.1 mg/kg. However, minute concentrations of other Organochlo-rines (endrin—0.007 mg/kg; heptachlor—0.023 mg/kg; alpha-endosulfan—0.013 mg/kg) were found in maize samples from Brong Ahafo, eastern, central and upper west regions. Though endrin and alpha-endosulfan were below the EU-MRL of 0.01 mg/kg and 0.10 mg/kg respectively, hep-tachlor was slightly above the EU-MRL of 0.01 mg/kg. The estimated dose for all these pesticides E. D. Miensah et al. 1106 however does not pose direct hazard to human health although present in the maize samples since the values were lower than toxic thresholds and reference doses. However, due to the unsafe application practices by applicators, there exists a potential risk for systemic and carcinogenic health effects by these chemicals in the study area.

Over the past decades, both wild and domesticated insect pollinators are in dramatic decline, which puts at stake the existence of species, ecosystem resilience and global food security. Globally, 87 of major food crops depend on animal... more

Over the past decades, both wild and domesticated insect pollinators are in dramatic decline, which puts at stake the existence of species, ecosystem resilience and global food security. Globally, 87 of major food crops depend on animal pollination. Together these account for 35 % of the world food production volume. Pollinator mediated crops are indispensable for essential micronutrients in the human diet. Many ornamental plants as well as crops for fibre, fodder, biofuels, timber and phytopharmaceuticals also depend on insect pollinators. This article aims to map the current situation of pollinators worldwide, with a focus on the critical role of pollinators in the human food chain and ecosystem sustainability, their intrinsic and extrinsic value, as well as the causes of their declines and the interventions needed to conserve them, in order to develop an argument for the importance of conserving and restoring pollinator populations and diversity. The present pollinator crisis threatens global and local food security, can worsen the problems of hidden hunger, erodes ecosystem resilience, and can destabilise ecosystems that form our life support system. An integrated approach that simultaneously addresses the key drivers is needed. This includes creation and restoration of floral and nesting resources, a global phase out of prophylactic use of neonicotinoids and fipronil, improvement of test protocols in authorisation of agrochemicals, and restoration and maintenance of independence in regulatory science. The authors argue that an international treaty for global pollinator stewardship and pollinator ecosystem restoration should be initiated in order to systemically counteract the current crisis.