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Distribution of Imidacloprid in Soil Following Subsurface Drip Chemigation
... Neonicotinoids are a class of pesticides which function as nicotinic acetylcholine receptor agonists, causing neuronal hyperexcitation and death in insects (Matsuda et al., 2001). Imidacloprid, one of the most commonly used neonicotinoid insecticides worldwide (Bass et al., 2015), is often applied as a soil drench in forest, nursery, and orchard systems to control bark and woodboring beetles, as well as other pest insects (Felsot et al., 1998;Cowles et al., 2006;Francis et al., 2009). Mason bees in the genus Osmia are an economically important group of solitary bees that are often managed for tree pollination in various orchard systems e.g., almond, apple, blueberry, cherry, and pear Kemp 2000, 2002;Monz on et al., 2004;Sampson et al., 2004). ...
... Imidacloprid residues in soil vary widely based on soil conditions, as clay content and organic material can affect the movement and concentration of the chemical within the soil matrix (Cox et al., 1998;Felsot et al., 1998;Liu et al., 2006aLiu et al., , 2006b, which creates a high variability in concentrations even within an immediate treatment area. Average concentrations have been found as high as 1200 ppb six months after soil injection treatment, with concentrations as high as 4000 ppb in the immediate treatment area within 1 m of the tree (Knoepp et al., 2012). ...
... The end concentrations of imidacloprid expected from these mixtures was 0, 35, 350 and 700 ppb in slurry. These concentrations were selected to reflect concentrations which have been detected in soil at or near the application site in the first six months after a soil drench or chemigation application (Felsot et al., 1998(Felsot et al., , 2002Knoepp et al., 2012). ...
We assessed impacts of direct acute contact with imidacloprid-treated soil on nesting behavior and mortality of the blue orchard mason bee (Osmia lignaria Say), which is a native solitary cavity-nesting species that collects mud for nest partitions. Laboratory-reared O. lignaria females were exposed to three concentrations of imidacloprid (0, 50, 390 and 780 ppb), in wet (30% moisture) soil for 20 min and released in large flight cages, where impacts on nesting activity and nest cell production were evaluated. Mortality was tested in another experiment using exposure at the same concentrations with two differing soil moisture levels (20% and 40%). Nesting activity was reduced by 42% for females exposed at 390 ppb and by 66% for females exposed at 780 ppb. Females treated at 780 ppb produced 40% fewer nest cells per day. Sex ratios of F1 generation were skewed toward male in the 50 ppb treatment group with 50% fewer females. The number of cells and pre-pupae per nest, as well as the weight of pre-pupal cocoons did not vary among exposure levels. There were no mortality effects at 20% soil moisture for any level of imidacloprid, but at 40%, mortality of females was >50% at all levels of imidacloprid. These results suggest that acute exposure to imidacloprid residue in soil can have negative impacts on soil-interacting bees, and the effects may be relative to the degree of soil moisture.
... bations and less than 90 h in light conditions. Imidacloprid movement and retention by soils is attributed to preferential fl ow path movement and adsorption to soil largely controlled by soil organic matter and clay content, followed by mass fl ow movement (Cox et al., 2004; Cox et al., 1998b; Fernandez-Perez et al., 1998; Papiernik et al., 2006). Felsot et al. (1998) studied the movement of imidacloprid through a very fi ne sandy loam soil using subsurface drip irrigation application and found that initial movement of imidacloprid was along preferential fl owpaths in the soil; imidacloprid was found throughout the 105-cm profi le within 7 d of application. At 60 d after application, imidacloprid con ...
... Felsot et al. (1998) studied the movement of imidacloprid through a very fi ne sandy loam soil using subsurface drip irrigation application and found that initial movement of imidacloprid was along preferential fl owpaths in the soil; imidacloprid was found throughout the 105-cm profi le within 7 d of application. At 60 d after application, imidacloprid concentrations were more homogeneous throughout the profi le (Felsot et al., 1998 ). examined imidacloprid movement after surface spray application to a greenhouse soil, made up of a 10-cm sand layer, above a clay layer on top of the native soil. ...
... type, on total organic carbon content. Th eir fi ndings, supported by the fi ndings of Papiernik et al. (2006), suggest that the nature of the organic matter may be more important in its adsorptive capacity than the total organic matter content. We found that imidacloprid moved over a greater distance than suggested by previous laboratory studies. Felsot et al. (1998) detected imidacloprid up to 105 cm depth in the soil profi le, with the greatest imidacloprid concentration at 45 cm depth, and concluded that initial movement of imidacloprid was along preferential fl ow paths. Examining imidacloprid movement in drained Dutch clay soils, Scorza Júnior et al. (2004) found the greatest concentrations in ...
Imidacloprid is a systemic insecticide effective in controlling the exotic pest (hemlock woolly adelgid) in eastern hemlock () trees. Concerns over imidacloprid impacts on nontarget species have limited its application in southern Appalachian ecosystems. We quantified the movement and adsorption of imidacloprid in forest soils after soil injection in two sites at Coweeta Hydrologic Laboratory in western North Carolina. Soils differed in profile depth, total carbon and nitrogen content, and effective cation exchange capacity. We injected imidacloprid 5 cm into mineral soil, 1.5 m from infested trees, using a Kioritz soil injector. We tracked the horizontal and vertical movement of imidacloprid by collecting soil solution and soil samples at 1 m, 2 m, and at the drip line from each tree periodically for 1 yr. Soil solution was collected 20 cm below the surface and just above the saprolite, and acetonitrile-extractable imidacloprid was determined through the profile. Soil solution and extractable imidacloprid concentrations were determined by high-performance liquid chromatography. Soil solution and extractable imidacloprid concentrations were greater in the site with greater soil organic matter. Imidacloprid moved vertically and horizontally in both sites; concentrations generally declined downward in the soil profile, but preferential flow paths allowed rapid vertical movement. Horizontal movement was limited, and imidacloprid did not move to the tree drip line. We found a negative relationship between adsorbed imidacloprid concentrations and soil microarthropod populations largely in the low-organic-matter site; however, population counts were similar to other studies at Coweeta.
... In the absence of light, neonicotinoids can persist in soil and be transported vertically into groundwater. Leachate concentrations may reach depths of 105 cm (Felsot et al., 1998) and concentrations of 0.005-1.32 μg/L (Gupta et al., 2008), 1-5 μg/L (Larsbo et al., 2013), and 100-400 μg/L (Felsot et al., 1998). ...
... Leachate concentrations may reach depths of 105 cm (Felsot et al., 1998) and concentrations of 0.005-1.32 μg/L (Gupta et al., 2008), 1-5 μg/L (Larsbo et al., 2013), and 100-400 μg/L (Felsot et al., 1998). Consequently, several studies have detected neonicotinoids in groundwater at maximum concentrations ranging from 1.93 μg/L (imidacloprid) to 8.93 μg/L (thiamethoxam) (Table A.1). Concentrations of thiamethoxam in irrigation water sourced from groundwater in a potato growing region of Wisconsin ranged from 0.31 to 0.58 μg/L, and state-wide sampling revealed noteworthy groundwater concentrations for clothianidin (0.21-3.43 μg/L), imidacloprid (0.26-3.34 μg/L), and thiamethoxam (0.20-3.34 μg/L) . ...
... Some of these concerns are: Imidacloprid has been shown to be persistent and its concentration did not decrease for a year following treatment. In addition, its ability to move in soil has been demonstrated by a variety of studies, so it is considered by the USEPA to be a potential water contaminant [4,5]. Imidacloprid is slightly toxic to fish, moderately toxic to aquatic invertebrates and is highly toxic to bees and house sparrow [6]. ...
... The pseudo second order equation can be expressed by the relation: (4) where K 2 (g mg -1 min -1 ) is the rate constant of adsorption, q (mg g -1 ) is the amount of imidacloprid adsorbed at equilibrium and qt at time t. ...
The adsorptive characteristics of imidacloprid on powdered activated carbon were described. The adsorption experiments were carried out as function of time, initial concentration and agitation speed. The equilibrium data fits well to Langmuir adsorption isotherm, while the kinetic data fits well to Pseudo second order kinetic model. The kinetic experiments were carried out at 200, 250, 300 and 350 rpm and it was found that the equilibrium time increases with increase in initial concentration and decreases with increase in agitation speed. This is due to the increased turbulence and as a consequence, the decrease boundary layer thickness around the adsorbent particles as a result of increasing the degree of mixing. At 300rpm the adsorption capacity was maximum and beyond this there was no significant increase in adsorption capacity. Weber intraparticle diffusion model was used to describe the adsorption mechanism. It was found that both the boundary layer and intraparticle diffusion for both adsorbents played important role in the adsorption mechanisms of the adsorbate. The effects of temperature and pH on adsorption were also studied. It was found that the adsorption capacity of the adsorbent decreases with increase intemperature. There was no significant change in adsorption from pH 2 to 8, however at high pH a decrease in adsorption of imidacloprid on activated carbon was observed.
... Also, applying pesticides uniformly and sufficiently to target pests under the soil or container substrates is a challenging constraint of current spray technologies. Drip irrigation, noted for its highly efficient water distribution capability to increase crop yields (Grabow et al., 2006;Plaut et al., 1996;Bryla et al., 2003;Lamm and Trooien, 2003;Zhu et al., 2004), offers an alternative strategy to carry the label-allowed pest control agents to the target areas in the soil for effective insect or disease control (Felsot et al., 1998). Uniform chemical distribution pattern in the soil plays an important role to achieve high pest control efficiency and a sustainable safe environment. ...
... Soil samples containing Imidacloprid were placed in glass jars, transported to the laboratory, and stored in a freezer at -40 °C until analysis. Methanol was used to extract Imidacloprid from the soil samples (Felsot et al., 1998) and ELISA kits (Envirologix, Inc., Portland, ME, USA) for Imidacloprid were used to determine the amount of Imidacloprid in the soil (Castle et al. 2005). Soil samples containing EPF were placed in glass jars, and sent overnight with an ice pack to a laboratory for analysis. ...
... Insecticides of neonicotinoid group mainly imidacloprid, acetamiprid and thiamethoxam are best suitable through drip application as they are water soluble (potential to some amount of leaching), systemic in nature and highly effective at low application rates. The effect of imidacloprid will be rapid enough, when incorporated in Integrated Pest Management (IPM), to allow time for performing other methods of pest control (Felsot et al., 2000) but has the potential to leach to a depth of 150cm, if scheduling is not done properly (Felsot et al., 1998). The systemic insecticides with high solubility in water will easily get translocated, kills the pest more rapidly, but does not persist its action for long time and this problem can be overcome by using higher label rates. ...
The burgeoning human population requires raising food production and in order to meet the requirements, factors affecting yields viz. insects, pathogens, nematodes are necessary to be managed. Though the conventional methods of crop protection chemicals application is the major practice, the knowledge and awareness of novel methods play a major role in combating the target pest effectively and one such method is application of insecticides through drip irrigation system, termed as insectigation. This method predominantly used to control the sucking pests, soil residing insects and different stages of insects viz, egg, larvae, pupae and adult that requires soil for development. The approach seems to be more advantageous over traditional spraying enabling plants to absorb water and insecticide at same period of time along with drift reduction, decrease in residues and in curbing the human exposure to insecticides. The existing drip irrigation system needs certain extra paraphernalia viz. chemical mix tank, an injection system and most importantly, a back-flow prevention device to check the ground water pollution. In a nutshell, insectigation offers a wide range of benefits over other pesticide application methods to mitigate the insect pest population below threshold levels.
... As its application is relatively for a short period when compared to other insecticides, it is used in the largest volume world wide [14,15]. Due to its relatively high solubility (0.61 g/l) [16], imidacloprid moves easily from paddy fields to irrigation channels of the field [17] via input from spray drift, leaching, or runoff and eventually reaches the nearby aquatic ecosystem [18] inhabited by the postlarvae and juveniles of M. rosenbergii [4], where it is reported to be persistant [19]. The molecule exhibits a novel mode of action as it is an agonist of the nicotinic acetylcholine receptor (nAChR) interfering with neural control and coordination of various physiological activities [20]. ...
... This practice includes the injection of chlorine or other biocides, acids, or chelating agents to reduce emitter clogging due to calcium carbonate precipitation, prevent bacterial growth in emitters, laterals, filters, and pipe lines, as well as preventing root intrusion into emitters on subsurface drip irrigation (SDI) systems (FORD 1976aand 1976b, NAKAYAMA et al. 1977, ENGLISH 1985, FEIGIN et al. 1991, PITTS et al. 2003, DEHGHANISANIJ et al. 2005, CARARO et al. 2006. Other types of chemicals frequently and efficiently applied with irrigation water using microirrigation systems include, herbicides (LANGE et al. 1974, OGG 1986, FOURIE 1988, fungicides and insecticides usually systemic (ZENTMEYER et al. 1974, Young 1980, POTTER 1981, FELSOT et al. 1998, THREADGILL 1995, FELSOT et al. 2000, nematicides (OVERMAN 1975, JOHNSON 1978, SCHNEIDER et al.1995, THREADGILL 1995, growth regulators (EVANS and WALLER 2007) and microbial agents (BOARI et al. 2008). SDI systems are particularly amenable to the application of soil fumigants as well as other chemicals that tend to be fixed by the soil particles (GOLDBERG and UZRAD 1976, OVERMAN 1976, TROUT and AJWA 1999, AJWA and TROUT 2000, AJWA et al. 2002, THREADGILL 1995. ...
Microirrigation systems help to save considerable amount of water in various crops. They also were found to enhance crop yields, water productivity and fertilizer use efficiency, thus contributing to sustainable use of land and water resources. A holistic approach with a goal of increasing farmers income not just the “ concept of commissioning”, institutional support, standardization and quality control, human resource specialized in microirrigation technologies etc will be needed to remove the impediments and promote further the adoption of micro irrigation technology which at present accounts for only 3.5% of the total world irrigated area.
... The presence of hydrophilic bonding on functional groups of the insecticides which may bind to the phenolichydroxyl and carboxylic acidic groups of soil organic matter (J.M. . Neonicotinoids can remain in the soil for a long time and be transported vertically into groundwater in absence of light and concentrations may reach at soil depths of 105 cm (Felsot et al., 1998). Various studies has shown its detected concentrations in ground water ranging from 1.93 μg/L (imidacloprid) to 8.93 μg/L (thiamethoxam) (Christy et al., 2015). ...
Neonicotinoids, a systemic pesticide, have been detected at a considerable amount in various environmental compartments especially in soil and water. The compounds have adverse effects in many targeted or non-targeted species but few studies were performed about the human health effects of exposure. The objective of this systematic review is to summarize environmental fate of neonicotinoids related to soil and groundwater, identify their exposure pathway, risk and toxic behaviour related to human. The residues after the application in the field or from coated seeds can cause soil contamination. Factors particularly application rate, pH, temperature, plant cover, crop rotation control the further movement into the receiving body through soil and water. High water solubility and low adsorption capacity have verified their pollution in groundwater. Leaching has been proved to be the main mechanism responsible for the contamination of groundwater where dinotefuran and clothianidin pose high leaching potential. Lowest mobility has been observed in the soil with highest organic matter content. It has been found that most neonicotinoids pose low toxicity to human beings even in large ingestion although newborn, children and old people are more vulnerable. Dermal route has the greatest potential for exposure, with a minor contribution of the respiratory route (not that volatile) when aerosols or aerial spraying are used. Thiacloprid is found more likely carcinogenic to human than other compounds. Disorientation, sweating, vomiting, agitation, increased heart and respiratory rates are the few side-effects that are confirmed from the long-term exposure of neonicotinoids. Regular monitoring of its usage level in environmental compartments are required to control the concentration
... The presence of hydrophilic bonding on functional groups of the insecticides which may bind to the phenolichydroxyl and carboxylic acidic groups of soil organic matter (J.M. ). Neonicotinoids can remain in the soil for a long time and be transported vertically into groundwater in absence of light and concentrations may reach at soil depths of 105 cm (Felsot et al., 1998). Various studies has shown its detected concentrations in ground water ranging from 1.93 μg/L (imidacloprid) to 8.93 μg/L (thiamethoxam) ( Christy et al., 2015). ...
Neonicotinoids, a systemic pesticide, have been detected at a considerable amount in various environmental compartments especially in soil and water. The compounds have adverse effects in many targeted or non-targeted species but few studies were performed about the human health effects of exposure. The objective of this systematic review is to summarize environmental fate of neonicotinoids related to soil and groundwater, identify their exposure pathway, risk and toxic behaviour related to human. The residues after the application in the field or from coated seeds can cause soil contamination. Factors particularly application rate, pH, temperature, plant cover, crop rotation control the further movement into the receiving body through soil and water. High water solubility and low adsorption capacity have verified their pollution in groundwater. Leaching has been proved to be the main mechanism responsible for the contamination of groundwater where dinotefuran and clothianidin pose high leaching potential. Lowest mobility has been observed in the soil with highest organic matter content. It has been found that most neonicotinoids pose low toxicity to human beings even in large ingestion although newborn, children and old people are more vulnerable. Dermal route has the greatest potential for exposure, with a minor contribution of the respiratory route (not that volatile) when aerosols or aerial spraying are used. Thiacloprid is found more likely carcinogenic to human than other compounds. Disorientation, sweating, vomiting, agitation, increased heart and respiratory rates are the few side-effects that are confirmed from the long-term exposure of neonicotinoids. Regular monitoring of its usage level in environmental compartments are required to control the concentration
... IMI is considered as one of the most toxic insecticide which badly affects the bee population (Seifrtova et al., 2017). Residues of IMI may enter into the soil and water ecosystem indirectly through leaf fall or directly via off-site leaching, and their persistence is more in those soils which are deficit in organic matter or containing high percentage of clay (Felsot et al., 1998;Wilkins, 2000;Smelt et al., 2003). Persistence of IMI is so long that in some cases, even no IMI is used in a particular season (but applied in previous seasons), its residues still persist in soil and get translocated into plant parts (Benton et al., 2015). ...
The present study focused on assessing the effects of jasmonic acid (JA) seed treatment on the physiology of Brassica juncea seedlings grown under imidacloprid (IMI) toxicity. It has been observed that IMI application declined the chlorophyll content and growth of seedlings. However, JA seed treatment resulted in the significant recovery of chlorophyll content and seedling growth. Contents of oxidative stress markers like superoxide anion, hydrogen peroxide, and malondialdehyde were enhanced with IMI application, but JA seed treatment significantly reduced their contents. Antioxidative defense system was activated with IMI application which was further triggered after JA seed treatment. Activities of antioxidative enzymes and contents of non-enzymatic antioxidants were enhanced with the application of IMI as well as JA seed treatment. JA seed treatment also regulated the gene expression of various enzymes under IMI stress. These enzymes included respiratory burst oxidase (RBO), Ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO), NADH-ubiquinone oxidoreductase (NADH), carboxylesterase (CXE), chlorophyllase (CHLASE), cytochrome P450 monooxygenase (P450). JA seed treatment up-regulated the expressions of RUBISCO, NADH, CXE, and P450 under IMI toxicity. However, expressions of RBO and CHLASE were down-regulated in seedlings germinated from JA seed treatment and grown in presence of IMI. Seed soaking with JA also resulted in a significant reduction of IMI residues in B. juncea seedlings. The present study concluded that seed soaking with JA could efficiently reduce the IMI toxicity by triggering the IMI detoxification system in intact plants.
... Data on adsorption-desorption, degradation, and transport of the neonicotinoids in soils are critical for evaluating the fate and transport of these insecticides in soils and groundwater. Previous studies to obtain these data have been primarily focused on imidacloprid (Wu et al., 2012, Brozni c and Milin, 2012, Jeong and Selim, 2010Anhalt et al., 2008;El-Hamady et al., 2008;Papiernik et al., 2006;Flores-C espedes et al., 2002;Gonz alez-Pradas et al., 2002;Gupta et al., 2002;Sarkar et al., 2001;Oliveira et al., 2000;Baskaran et al., 1999;Celis and Koskinen, 1999;Cox et al., 1998;Felsot et al., 1998;Cox, 1997;Rouchaud et al., 1996). The data for clothianidin and thiamethoxam are still lacking. ...
Studied were the adsorption-desorption and degradation of two widely used neonicotinoid insecticides clothianidin and thiamethoxam in three different agricultural soils in the state of Mississippi. The adsorptions of both the neonicotinoids fit a linear isotherm model. In different soils at different depths with different moisture contents, the adsorption distribution coefficients of clothianidin and thiamethoxam were found to be 0.62 to 1.94 and 0.59-2.03 L kg-1, respectively. These distribution coefficients showed strong positive correlations with organic carbon content and pH of the soils. The desorptions of clothianidin and thiamethoxam also followed a linear isotherm, but were irreversible in respect to their adsorption isotherms. The desorption distribution coefficients ranged from 0.14 to 0.62 L kg-1, increased with the decrease of organic carbon content. The degradations of clothianidin and thiamethoxam in the soils were found to be slow with half-lives ranged from 90 to 280 and 65 to 170 d for clothianidin and thiamethoxam respectively. The degradation rates increased with the increase of the organic carbon content in the soils. The moisture content in the soils had a positive effect on the degradation rates. The Groundwater Ubiquity Scores calculated from the adsorption distribution coefficient, organic content, and half-life suggest that clothianidin and thiamethoxam have moderate to high potential to leach to groundwater.
... Hence protect the plant from early pests infection. Because of its systemic nature, imidacloprid moves easily between plant tissues, and also from the roots to the soil and water in the field [8] . In this way, imidacloprid is gradually released into the aquatic ecosystem [9] , where it is stable to hydrolysis [10] . ...
... concentrations in the leachates were below Germany's regulation limit (<0.1 µg L -1 ). Felsot et al. (1998; evaluated IMD leaching after applications with subsurface drip chemigation in Aridisols from Washington State for hop production. The authors determined lateral and vertical movement of IMD from drip emitters, and found evidence of leaching beyond the hop root zone, mainly due to the high frequency of irrigation applied during the study (4 hr daily for the entire growing season). ...
Imidacloprid (IMD) is a pesticide soil-drenched to control Diaphorina citri Kuwayama or the Asian Citrus Psyllid (ACP). Fate and transport studies were conducted in laboratory and field conditions with soil samples from Immokalee fine sand. The goals were to estimate IMD leaching potential, to correlate IMD leaf concentrations versus psyllid populations control in young citrus trees, and to make recommendations to reduce leaching and increase control efficacy. IMD sorption kinetics were fitted by the one-site mass transfer model, reaching equilibrium between 6 and 12 hr. Batch equilibrium and degradation studies showed a weakly-sorbed (KOC 163-230) and persistent pesticide (t1/2 1.02-2.75 y) with a moderate to high leaching potential. Miscible displacement breakthrough curves showed evidence of nonequilibrium transport on A and Bh samples, and convective-dispersive transport in the E horizon samples. Field leaching experiments on young citrus were conducted during two summers and two springs between 2011 and 2013. IMD and Br- were soil-drenched around the trunk, and to a similar non-planted area. Br- tracer completely leached out about 1 week after, whereas IMD leached out about 4 to 6 weeks after application in summer, and from 6 to 8 weeks in spring. IMD showed retardation in the conditions studied (sandy soils, low in organic matter). There was evidence of a small fraction of IMD leaching beyond the root zone (45 cm deep) of less than 4% of the original mass applied. This study developed an extraction procedure for citrus leaves using HPLC-MS/MS detection. IMD in tissue data were in agreement with the findings in soils and ACP control. There was an effective ACP control especially two to four weeks after the soil-drench application. The control continued for about eight weeks after application with treated trees showing lower ACP counts and infestation rates. The recommendations to reduce leaching involve monitoring rainfall and irrigation closely, keeping soil moisture contents below field capacity to reduce hydraulic conductivity and to increase solute retardation. The study recommends more research on amendments to IFS with recalcitrant organic matter (biochar) or other organic materials, to further retard IMD movement in the citrus root zone.
... Thiamethoxam and imidacloprid are neonicotinoid insecticides, and are effective on sucking pests. Due to their polar chemical structure and high solubility in water, they are good candidates for drenching method (Felsot et al., 1998.) The objectives of this study were (1) to compare foliage spraying with drenching method against Dubas bug, (2) to determine insecticides efficacy, (3) to determine the optimal concentration for drenching method, and (4) to determine residue of insecticides in date fruits at harvesting time in drenching method. ...
Dubas bug, Ommatissus lybicus, is one of the key pests of date palms
in Iran. Chemical control is the most conventional control method of this
dangerous pest. The aim of this investigation was to compare efficacy,
advantages and disadvantages of drenching, and foliage spraying of
chemical control. The study was conducted in a Randomized Complete
Block Design with 10 treatments and 3 replications (trees) in a
completely infested date palm grove. Treatments included imidacloprid
SC350 (Confidor®) and thiamethoxam WG250 (Actara®) by foliar
spraying (4 g/tree) and by drenching method (10, 20, 80, and 100 g/tree),
diazinon EC600 (40 ml/tree) as recommended insecticide by foliar
spraying and then the check (without treatment). The nymph population
and number of honeydew drops were recorded one day before and 7, 14,
and 120 days after treatment. Insecticide residue of date palm and costbenefit ratio were calculated. The results showed that all foliage
application treatments had more efficacy compared to drenching
treatments at 1 and 2 weeks after spraying but at 120 days after
drenching, thiamethoxam (80 g/L) and imidacloprid (100 g/L) had 100%
efficacy, while the efficacies of thiamethoxam, imidacloprid, and
diazinon foliar spraying was zero. The residue of date fruit treated by
high doses of drenching was not detectable. The highest cost-benefit ratio
belongs to imidacloprid foliage spraying (24.86) followed by
imidacloprid drenching (15.67). The lowest ratio belongs to
thiamethoxam drenching (3.12). Comparison of different concentrations
of neonicotinoid drenching revealed that high concentration of
thiamethoxam and imidacloprid was more than two times effective.
... The trees within the 3-year study group are arranged in a windbreak with 2-3 m separating each tree, a spacing which results in trees with interdigitated canopies, and a high potential for root grafting in this shallow-rooted species (Eckenwalder 2009, Fowells 1965, Frothingham 1915. The short distances also create a high potential for lateral movement of imidacloprid through the soil (Felsot et al. 1998, Gupta et al. 2002. Both of these conditions could result in the presence of imidacloprid in varying concentrations within the control trees. ...
The systemic insecticide imidacloprid is commonly used to protect trees against attack by the Adelges tsugae (Hemlock Woolly Adelgid [HWA]), an invasive pest that threatens Tsuga canadensis (Eastern Hemlock) and T. caroliniana (Carolina Hemlock) in eastern North America. Although there have been some studies documenting the short-term (1-3 years) impact of imidacloprid on non-target arthropods in hemlock systems, almost nothing is known about the impact over longer time scales. Here, using a set of trees which were experimentally treated 3 and 9 years prior to this study, we found that while the impact of imidacloprid on HWA may be approaching the limits of detection and efficacy on trees treated 9 years ago, there is still an intermittently detectable impact on HWA density. Similarly, 9 years after application there is a subtle but detectable increase in arthropod richness and a shift in canopy-arthropod community composition. Results from the 3-year treated trees were, however, ambiguous, but may be the result of detectable cross-contamination of insecticide among trees.
... [15,16] Some studies concluded that IMDA was leached into groundwater through sandy loam soil, posing a high potential risk. [17] On the other hand, a contrasting outcome was reported in silty loam soils with high organic matter content (2.0-4.0%) into which no IMDA was leached. ...
Sorption-desorption of the insecticide imidacloprid 1-[(6-chloro-3-pyridinyl)-methyl]-N-nitro-2-imidazolidinimine onto a lacustrine sandy clay loam Egyptian soil and its clay and humic acid (HA) fractions was investigated in 24-h batch equilibrium experiments. Imidacloprid (IMDA) sorption-desorption isotherms onto the three sorbents were found to belong to a non-linear L-type and were best described by the Freundlich model. The value of the IMDA adsorption distribution coefficient, Kdads, varied according to its initial concentration and was ranged 40-84 for HA, 14-58 for clay and 1.85-4.15 for bulk soil. Freundlich sorption coefficient, Kfads, values were 63.0, 39.7 and 4.0 for HA, clay and bulk soil, respectively. The normalized soil Koc value for imidacloprid sorption was ∼800 indicating its slight mobility in soils. Nonlinear sorption isotherms were indicated by 1/nads values <1 for all sorbents. Values of the hysteresis index (H) were <1, indicating the irreversibility of imidacloprid sorption process with all tested sorbents. Gibbs free energy (ΔG) values indicated a spontaneous and physicosorption process for IMDA and a more favorable sorption to HA than clay and soil. In conclusion, although the humic acid fraction showed the highest capacity and affinity for imidacloprid sorption, the clay fraction contributed to approximately 95% of soil-sorbed insecticide. Clay and humic acid fractions were found to be the major two factors controlling IMDA sorption in soils. The slight mobility of IMDA in soils and the hysteresis phenomenon associated with the irreversibility of its sorption onto, mainly, clay and organic matter of soils make its leachability unlikely to occur.
... Environmental studies have indicated that imidacloprid can be detected in the soil 6,7 and can be carried by storm and rain runoff. Thus, imidacloprid can move into irrigation ditches, streams, and rivers and can leach into the water table. ...
Imidacloprid is a neonicotinoid insecticide that can have negative effects on non-target animals. The present study was conducted to assess the toxicity of various Imidacloprid doses (0.3, 1.25 and 5 mg/ml) on zebrafish sampled after 7, 14, 21 and 28 d of exposure. The levels of catalase (CAT), superoxide dismutase (SOD), reactive oxygen species (ROS), glutathione-S-transferase (GST), and malondialdehyde (MDA) and the extent of DNA damage were measured to evaluate the toxicity of imidacloprid on zebrafish. SOD and GST activities were noticeably increased during early exposure but were inhibited towards the end of the exposure period. In addition, the CAT levels decreased to the control level following their elevation during early exposure. High concentrations of Imidacloprid (1.25 and 5 mg/L) induced excessive ROS production and markedly increased MDA content on the 21st day of exposure. DNA damage was dose- and time-dependent. In conclusion, the present study showed that Imidacloprid can induce oxidative stress and DNA damage in zebrafish.
... It acts as an agonist of the postsynaptic nicotinic acetylcholine receptors (Matsuda et al., 2001), disrupting the normal neural processes, and is used mainly to control sucking insects on crops (Tomlin, 1997;Tomizawa and Casida, 2005). IMI is a potential groundwater and surface water contaminant (PAN Pesticides database, 2006), because it can leach and runoff from soil and crops (Felsot et al., 1998;Gonzalez-Pradas et al., 1999;Armbrust and Peeler, 2002;Gupta et al., 2002;Fossen, 2006). Additionally, it may enter water bodies from spray drift or accidental spills, leading to local point-source contaminations. ...
Imidacloprid (IMI) is at the moment the insecticide with the world's fastest growing sales and is considered possible replacement for the widely used organophosphorus pesticide, diazinon, which is subject to phased revocation in many countries. In this study, biochemical, reproductive and survival parameters of the water flea (Daphnia magna) after chronic exposure to IMI, its commercial liquid formulation Confidor SL 200 and diazinon are presented and compared. According to the lowest observed effect concentrations, diazinon is more toxic to the reproduction of D. magna than IMI and Confidor SL 200, which exert similar toxicity. The same was observed for the survival, except that Confidor SL 200 is more toxic than IMI. In polluted aquatic environments, the actual levels of diazinon are potentially chronically hazardous to the reproduction of D. magna (risk quotient >1). According to very few measured environmental levels of IMI, the latter is not expected to be chronically hazardous, unless it is accidentally spilled in a small pond. In such case, the predicted concentrations of IMI would present a potential chronic risk to D. magna, and a potential acute risk to other aquatic invertebrates. In the future, higher environmental levels of IMI are expected due to its increasing use and physico-chemical properties. The literature survey summarized in this work suggests that further ecotoxicological studies with a broader spectrum of aquatic organisms are needed before IMI is classified as safer than currently applied pesticides.
... Thus, these K OC values, together with reported K OW values (3.7) (Krohn, 2002) and a great water solubility (0.51gL1 ) (Krohn, 2002) suggest a potential of IMI to leach to groundwater. Field studies on the leaching potential of IMI provide variable results, with some studies reporting little or no movement below 30 cm depth (Rouchaud, Gustin and Wauters, 1996;Kalpana, Gajbhiye and Agnihotri, 2002), while others indicate signifi cant mobility in soil columns ( Gupta et al., 2002;Vollner and Klotz, 1997) and fi eld studies (Felsot et al., 1998). In addition, Schmidt (2010), Pradas et al. (2002) and Carbo et al. (2008) found IMI's residue in the groundwater in their fi eld studies about the mobility of IMI. ...
In Croatia, imidacloprid is increasingly used in olive growing areas against the olive fruit fly. Experiments were conducted to examine the relationship between soil properties, imidacloprid concentration and soil sorption capacity. The linear and the Freundlich model adequately described the imidacloprid sorption. Better sorption was observed at lower imidacloprid concentrations and in soils with higher organic carbon and clay content, but organic carbon content was predominant factor influencing sorption. Thus, for soils with lower sorption capacity a greater potential mobility of imidacloprid in the soil profile is expected, indicating a need for regular monitoring and strategy development against groundwater pollution.
... Comparative modeling conducted by the US EPA have shown that imidacloprid had the highest leaching potential among 14 turf insecticides (US EPA 1993b). This high mobility was also confirmed in a field experiment in which imidacloprid was shown to be very mobile in irrigated soil (Felsot et al. 1998). This is also the case for greenhouse soil; Gonzalez-Pradas et al. (2002) report that imidacloprid penetrates the first 40 cm of soil within 2 years of the first application in greenhouses. ...
Systemic insecticides are applied to plants using a wide variety of methods, ranging from foliar sprays to seed treatments and soil drenches. Neonicotinoids and fipronil are among the most widely used pesticides in the world. Their popularity is largely due to their high toxicity to invertebrates, the ease and flexibility with which they can be applied, their long persistence, and their systemic nature, which ensures that they spread to all parts of the target crop. However, these properties also increase the probability of environmental contamination and exposure of nontarget organisms. Environmental contamination occurs via a number of routes including dust generated during drilling of dressed seeds, contamination and accumulation in arable soils and soil water, runoff into waterways, and uptake of pesticides by nontarget plants via their roots or dust deposition on leaves. Persistence in soils, waterways, and nontarget plants is variable but can be prolonged; for example, the half-lives of neonicotinoids in soils can exceed 1,000 days, so they can accumulate when used repeatedly. Similarly, they can persist in woody plants for periods exceeding 1 year. Breakdown results in toxic metabolites, though concentrations of these in the environment are rarely measured. Overall, there is strong evidence that soils, waterways, and plants in agricultural environments and neighboring areas are contaminated with variable levels of neonicotinoids or fipronil mixtures and their metabolites (soil, parts per billion (ppb)-parts per million (ppm) range; water, parts per trillion (ppt)-ppb range; and plants, ppb-ppm range). This provides multiple routes for chronic (and acute in some cases) exposure of nontarget animals. For example, pollinators are exposed through direct contact with dust during drilling; consumption of pollen, nectar, or guttation drops from seed-treated crops, water, and consumption of contaminated pollen and nectar from wild flowers and trees growing near-treated crops. Studies of food stores in honeybee colonies from across the globe demonstrate that colonies are routinely and chronically exposed to neonicotinoids, fipronil, and their metabolites (generally in the 1-100 ppb range), mixed with other pesticides some of which are known to act synergistically with neonicotinoids. Other nontarget organisms, particularly those inhabiting soils, aquatic habitats, or herbivorous insects feeding on noncrop plants in farmland, will also inevitably receive exposure, although data are generally lacking for these groups. We summarize the current state of knowledge regarding the environmental fate of these compounds by outlining what is known about the chemical properties of these compounds, and placing these properties in the context of modern agricultural practices.
... Imidacloprid works by disrupting the insect nervous system, causing irreversible blockage of nicotinic acetylcholine receptors and thus producing lethal effects (Matsuda et al. 2001). In addition to locating in target organisms, imidacloprid may disperse in surface water, ground water, soil, plants, and other nontarget organisms after different types of application (Felsot et al. 1998;Phillips and Bode 2002;Laurent and Rathahao 2003;Juraske et al. 2009). Due to the concern over the widespread use of this insecticide, the effects of imidacloprid on nontarget species and the environment has been extensively investigated in previous studies. ...
Imidacloprid, a neonicotinoid insecticide, has been used widely in agriculture worldwide. The adverse effects of imidacloprid on exposed biota have brought it increasing attention. However, knowledge about the effects of imidacloprid on antioxidant defense systems and digestive systems in the earthworm is vague and not comprehensive. In the present study, the changes in the activity of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), cellulase, reactive oxygen species (ROS), and malondialdehyde (MDA) in the earthworm Eisenia fetida exposed to artificial soil treated with imidacloprid were examined systematically. The results showed that the activity of these biomarkers was closely related to the dose and duration of the exposure to imidacloprid. The activity of SOD was stimulated significantly at doses of 0.66 and 2 mg kg(-1) imidacloprid but markedly inhibited at a dose of 4 mg kg(-1) imidacloprid with prolonged exposure. The activities of CAT and POD increased irregularly at 0.2-4 mg kg(-1) imidacloprid over different exposure times. The level of ROS at a dose of 2 or 4 mg kg(-1) imidacloprid was significantly increased over the entire exposure period. When the concentration of imidacloprid was above 0.66 mg kg(-1), the balance of the activity of the antioxidant enzymes and ROS level was interrupted. The activity of cellulase decreased significantly with prolonged exposure. At the stress of 4 mg kg(-1) imidacloprid, the content of MDA was significantly increased with increasing exposure time. The results of the present study suggest that imidacloprid has a potentially harmful effect on E. fetida and may be helpful for assessment of the risk of imidacloprid to the soil ecosystem environment. However, to obtain more comprehensive toxicity data, it is necessary to investigate the effects of imidacloprid on earthworm using native soils in the future work.
... Thus, intensive use of IMI, in addition to its high water solubility (510 mg/L, 20 • C) (Tomlin, 1999), might impose a great risk of water resources' contamination, which is consistent with the USEPA statement regarding IMI's potential to leach to groundwater (USEPA, 1993). The review of literature revealed that few reports are available on leaching of IMI in soil (Carbo et al., 2008;Felsot et al., 1998;Gonzalez-Pradas et al., 2002;Gupta et al., 2002;Schmidt, 2010). For these reasons, there is a need for a more complete insight into IMI's fate in the soil (USEPA, 1993). ...
Sorption and desorption are important processes that influence the transport, transformation, and bioavailability of imidacloprid in the soils. Equilibrium batch experiments were carried out using six coastal Croatian soils. The equilibrium sorption and desorption experimental data showed the best fit to the Freundlich equation. Sorption parameters predicted with Freundlich model, KF and 1/n ranged from 2.92 to 5.74 (mg/kg)/(mg/L), and 0.888 to 0.919, recpectively. The sorption of imidacloprid was found to be sensitive to organic carbon (OC) content. The highest sorption was observed in Krk soil (OC 4.74%) and the lowest in Zadar soil (OC 1.06%). Fitted desorption parameter values, KF were consistently higher than those associated with sorption. The opposite trend was observed for the exponential parameter 1/n. Results also suggested that imidacloprid sorption-desorption by soil is concentration dependent, i.e. at lower imidacloprid concentrations a greater sorption percentage and lower desorption percentage occurred. Desorption studies revealed that there was a hysteresis effect in all the tested soils. Hysteresis coefficient values (H) varied from 0.656 to 0.859. The study results emphasize that the controled application of imidacloprid is obligatory, especially in the soils with a low organic carbon content in order to minimize a risk of environmental and groundwater pollution.
... Leaching of pesticides is one of the main mechanisms responsible for the contamination of groundwater and surface water. Felsot found that imidacloprid applied via drip chemigation leached significantly below the emitter depth [34]. The Groundwater Ubiquity Score (GUS) [35] of imidacloprid as calculated from the sorption coefficient (K oc ) and the soil halftime (DT 50 ) amounts to 3.76, indicating a high leaching potential [36]. ...
Imidacloprid is one of the most widely used insecticides in the world. Its concentration in surface water exceeds the water quality norms in many parts of the Netherlands. Several studies have demonstrated harmful effects of this neonicotinoid to a wide range of non-target species. Therefore we expected that surface water pollution with imidacloprid would negatively impact aquatic ecosystems. Availability of extensive monitoring data on the abundance of aquatic macro-invertebrate species, and on imidacloprid concentrations in surface water in the Netherlands enabled us to test this hypothesis. Our regression analysis showed a significant negative relationship (P<0.001) between macro-invertebrate abundance and imidacloprid concentration for all species pooled. A significant negative relationship was also found for the orders Amphipoda, Basommatophora, Diptera, Ephemeroptera and Isopoda, and for several species separately. The order Odonata had a negative relationship very close to the significance threshold of 0.05 (P = 0.051). However, in accordance with previous research, a positive relationship was found for the order Actinedida. We used the monitoring field data to test whether the existing three water quality norms for imidacloprid in the Netherlands are protective in real conditions. Our data show that macrofauna abundance drops sharply between 13 and 67 ng l(-1). For aquatic ecosystem protection, two of the norms are not protective at all while the strictest norm of 13 ng l(-1) (MTR) seems somewhat protective. In addition to the existing experimental evidence on the negative effects of imidacloprid on invertebrate life, our study, based on data from large-scale field monitoring during multiple years, shows that serious concern about the far-reaching consequences of the abundant use of imidacloprid for aquatic ecosystems is justified.
... This is because it is less likely to come into direct contact with non-target insects such as pollinators (honey bee,…) which can often occur on the crops in the vicinity of vineyards. Felsot et al. (1998) suggested that chemigation via subsurface drip irrigation has advantages compatible with environmental stewardship. These advantages include: no worker exposed to foliar pesticide residues, reduction of waste from cleaning out spray tanks, elimination of drift, and less exposure of biological control species to pesticides. ...
Imidacloprid Applied Through Drip Irrigation as a New Promising Alternative to Control Mealybugs in Tunisian Vineyards
Mealybugs are serious insect pests in Tunisian vineyards where they can cause major production losses. Thus, a management program of these insects is a priority for grape growers. A summer pesticide trial was conducted in a vineyard, located in the Cap-Bon Region of Tunisia. The trial was carried out to assess the use of imidacloprid, a systemic insecticide, against mealybugs on vine. Imidacloprid was applied through the drip irrigation system for each vine and was then compared to methidathion, a contact insecticide. Imidacloprid was found to be more effective than methidathion on all mealybug developmental stages. In addition to its outstanding, up to 100% efficiency, imidacloprid provided an interesting long-term control of mealybugs. No significant difference was found between the two imidacloprid rates (1 and 2 ml/vine). Methidathion generated an overall low to intermediate efficacy on mealybugs and was more effective on both first instar nymphs and adult females than on the other mealybug developmental stages. Thus, imidacloprid applied through a drip irrigation system is a new promising option to control mealybugs in vineyards. For this reason it can be employed in an integrated management program against these pests in the Tunisian grape-growing area.
... gation system because they are effective against specific insect groups, they are soluble and have systemic properties, they are relatively nonphytotoxic, and they are considered reduced risk pesticides under the U.S. Environmental Protection Agency (USEPA) Federal Reduced Risk Pesticide Program (http//:epa.gov/opprd001/workplan/ reducedrisk.html). Felsot et al. (1998) examined the distribution of imidacloprid in soil when applied through a drip irrigation system, and concluded that imidacloprid was a good candidate for drip chemigation . Imidacloprid and other neonicotinoids applied through a drip system have been shown to provide effective control of whiteflies and aphids in desert vegetable crops ( ...
Drip, or trickle, irrigation was used as early as the late 1800s, although it was not until the development of modern plastics during World War II that drip irrigation became economically possible. Developed initially to reduce or prevent moisture stress in the plant, drip irrigation systems also offer an excellent method to apply agrichemicals to the root zone of plants. The application of insecticides through a drip irrigation system was first attempted in the 1980s by using various carbamates and organophosphates, although success was limited. Currently, several newly-developed insecticides such as the neonicotinoids and anthranilic diamides are drip-injected for the control of many vegetable insect pests. The advantages of drip-injection of insecticides over ground application methods include a uniform distribution of insecticide throughout the plant; a reduction in pesticide application inputs, including man-power and vehicle or tractor fuel; and a reduction in soil compaction, plant disturbance, and applicator exposure to pesticides. Insecti-cides applied through a drip irrigation system can replace or reduce the number of foliar insecticide sprays, reducing the risks to nontarget species.
... Such a deployment could saturate local binding capacity and permit mobilization through the organic layer, possibly through macropores and into lower soil strata where decomposition occurs slowly (Jú nior et al., 2004;Anhalt et al., 2008). This would be of special concern if considerable precipitation immediately followed soil application (Felsot et al., 1998). ...
Hemlock woolly adelgid (Adelges tsugae Annand) threatens native hemlock (Tsuga canadensis and T. caroliniana) in the eastern United States. Imidacloprid used as a soil-applied systemic insecticide is effective against A. tsugae in natural forests and in landscapes. Non-target impacts are a special concern because hemlock is ecologically important; often growing next to streams which contain aquatic species that are sensitive to imidacloprid, some of which are protected or endangered fauna. Environmental risk can be mitigated by determining the minimum effective dosage in forests. Adelgid populations responded to imidacloprid dosage with approximately a linear relationship between the percent population reduction (probability scale) vs. log of dosage; 50% reduction in populations could be achieved with 0.15 g per 2.5 cm of trunk diameter at breast height (dbh), or 10% of the maximum labeled dosage. However, effectiveness was found to vary based on dbh; the dosage predicted to give ∼90% reductions in adelgid populations is given by the equation log(dosage) = 0.0153 × dbh − 1.074, where the dosage is g imidacloprid per 2.5 cm of trunk dbh, and dbh is measured as cm. For trees less than 82 cm dbh, these dosages are less than the typical 1.5 g imidacloprid per 2.5 cm dbh currently used. Formulation into tablets rather than as a wettable powder reduced the maximum imidacloprid concentration in soil solution at 5 cm depth from 80 to 1.6 ppm in columns constructed with the organic soil found beneath forest hemlocks. A combination of optimum dosing of trees and adoption of the tablet formulation when treating trees in sensitive habitats should minimize the risk of contaminating aquatic resources with imidacloprid.
... It is possible that the increased need for drip irrigation, which was soil-applied beneath the plastic mulch, may have resulted in enhanced leaching (dissipation) of the transplant and chemigation treatments, given that the neonicotinoid insecticides are comparatively water-soluble. 17,18 Plant stress also is known to reduce leaf absorption of foliar-applied systemic insecticides due to induced epicuticular wax accumulation and rapid desiccation of insecticide spray droplets, 19 and to increase the dissipation rate due to higher photodegradation and evaporation. 20,21 Results showed that pollen and nectar residues were significantly different among imidacloprid treatment regimens within each year for the parent compound and combined metabolites. ...
Neonicotinoids are systemic insecticides widely used on many pollinated agricultural crops, and increasing evidence indicates that they move to some extent into pollen and nectar. This study measured levels of neonicotinoid residues in pollen and nectar from a pumpkin crop treated with formulated products containing imidacloprid, dinotefuran, and thiamethoxam using different timings and application methods. Environmental conditions have a significant effect on overall residue levels; nectar residues were 73.5-88.8% less than pollen residues, and metabolites accounted for 15.5-27.2% of the total residue amounts. Foliar-applied treatments and chemigated insecticides applied through drip irrigation during flowering resulted in the highest residues of parent insecticide and metabolites, which may reach average levels up to 122 ng/g in pollen and 17.6 ng/g in nectar. The lowest levels of residues were detected in treatment regimens involving applications of insecticides at planting, as either seed dressing, bedding tray drench, or transplant water treatment.
... Thus, intensive use of IMI, in addition to its high water solubility (510 mg/L, 20 °C) (Tomlin, 2001) might impose a great risk of water resources contamination which is consistent with USEPA statement regarding IMI's potential to leach to groundwater (USEPA, 1993). The review of literature revealed that few reports are available on leaching of IMI in soil ( Carbo et al., 2008;Felsot et al., 1998;Gupta et al., 2002;Schmidt, 2010). For these reasons, there is a need for a more complete insight into IMI's fate in the soil (USEPA, 1993). ...
... Physicochemical properties and acute toxicity of target insecticides Physicochemical data of imidacloprid and fipronil are given in Table 1. Imidacloprid has high water solubility, and though the active ingredient disappears quickly from surface waters (Kollman and Segawa 1995), it is more persistent in underground water environments (Felsot et al. 1998;Nemeth-Konda et al. 2002). By contrast, fipronil has low water solubility, is more stable and it is adsorbed more strongly onto soil (USEPA 1996;Ying and Kookana 2001;US Geological Survey 2006;Gunasekara et al. 2007) than imidacloprid. ...
Differences in susceptibility of five cladocerans to the neonicotinoid imidacloprid and the phenyl-pyrazole fipronil, which have been dominantly used in rice fields of Japan in recent years, were examined based on short-term (48-h), semi-static acute immobilization exposure tests. Additionally, we compared the species sensitivity distribution (SSD) patterns of both insecticides between two sets of species: the five tested cladocerans and all other aquatic organisms tested so far, using data from the ECOTOX database of U.S. Environmental Protection Agency (USEPA). The sensitivity of the test species to either imidacloprid or fipronil was consistent, spanning similar orders of magnitude (100 times). At the genus level, sensitivities to both insecticides were in the following descending order: Ceriodaphnia > Moina > Daphnia. A positive relationship was found between body lengths of each species and the acute toxicity (EC(50)) of the insecticides, in particular fipronil. Differences in SSD patterns of imidacloprid were found between the species groups compared, indicating that test cladocerans are much less susceptible than other aquatic species including amphibians, crustaceans, fish, insects, mollusks and worms. However, the SSD patterns for fipronil indicate no difference in sensitivity between cladocerans tested and other aquatic organisms despite the greater exposure, which overestimates the results, of our semi-static tests. From these results, Ceriodaphnia sp. should be considered as more sensitive bioindicators (instead of the standard Daphnia magna) for ecotoxicological assessments of aquatic ecosystems. In addition, we propose that ecotoxicity data associated with differences in susceptibility among species should be investigated whenever pesticides have different physicochemical properties and mode of action.
Abstract
1) Many wild bee species interact with soil either as a nesting substrate or material. These soil interactions create a risk of exposure to agrochemicals such as imidacloprid or other neonicotinoid pesticides that can persist in soil for months after application. At the landscape level, concentrations of imidacloprid residue in soil are limited to the immediate treatment area, and thus risks to soil-interacting bees could be low if they avoid contaminated soils. 2) We utilized Osmia lignaria (Say), a solitary cavity nesting bee which collects mud to partition and seal nests, and conducted two laboratory experiments to test whether nesting females select or avoid soils containing various levels of imidacloprid residue. For the first experiment, we assessed behavioral responses of females to treated soil utilizing a choice arena and pairing various choices of soil with imidacloprid residues ranging between 0 and 780 ppb. For the second experiment, we developed a laboratory assay to assess soil selection of actively nesting O. lignaria, by providing choices of contaminated soil between 0 and 100 ppb and 0 and 1,000 ppb to nesting females. 3) We found no evidence that O. lignaria females avoided any level of imidacloprid contamination, even at the highest residue level (1,000 ppb) in both the experiments, which may have implications for risk. The in situ nesting methodology developed in this study has future applications for research on soil or pollen preferences of cavity nesting Osmia species, and potential for breeding of O. lignaria in laboratory.
The main purpose of this review is to find the diversity in research studies of subsurface irrigation systems in the past two decades. Two periods of five years were selected to reflect the research studies at the beginning and the end of the comparing periods range. A statistical sorting was used to investigate the distribution of papers according to objectives, types of irrigation systems, research methods, and limitations of the studies. Results showed that the measurements and evaluations were the most presented objectives of the selected papers for both periods. Furthermore, almost 90 percent of the recent papers used multiple research methods, unlike the papers published in the former period which only 56 percent of them used multiple methods. Also, more than 90 percent of the recent papers used a single irrigation system. In conclusion, knowledge of subsurface irrigation systems had been advanced in the former studies mostly by analyzing the measurements and evaluations of the traditional irrigation systems. Unlike the former period, the advancement in knowledge has been produced in the current period by introducing new subsurface irrigation systems and more concentration by the order of measurements, evaluation, and designing, respectively.
In Ukraine, the application of pesticides along with irrigation water (pestigation) is becoming more widespread and popular. The use of insecticides when applying them along with irrigation water on reclamation systems (insecticide method) is a reliable way to reduce the number of dangerous pests. The advantage of this method is the possibility of timely delivery of plant protection products to crops during their critical periods, and rapid application of pesticides regardless of weather conditions.
The use of insecticides along with drip irrigation to control owlet moth caterpillars was carried out in the II-III decades of June. The most effective products were: Woliam Flexi 300 SC, Ampligo 150 ZC FC and Enzhio, 247, SC. Among the one-component products reliable protection of crop plants was provided by Actara, 240 SC. Under drip irrigation, owlet moth larvae control proved was rather effective, reaching 85,7-100%. On the variant with the maximum rate of insecticides, the highest efficiency was provided by the preps of Woliam Flexi 300 SC, Ampligo 150 ZC and Enzhio, 247 SC (97,1-100%).
Against the larvae of Agriotes the reliable protection of corn when applying insecticides along with drip irrigation, was obtained on the variant with Voliam Flexi 300 SC, KS, where having an application rate of 0,3 l/ha, the protection level was 97,1%.
Reduction in the number of owlet moth caterpillars and Agriotes arvae on the variants of the experiment provided crop density and enabled to obtain a higher yield of corn grain. When applying Woliam Flexi 300 SC, Ampligo 150 ZC and Enzhio, 247 SC, at the maximum application rates, the crop density averaged 84-88 thou /ha. In general, on the variants of the experiment when the maximum rates of multi-agent preps were applied, the maize productivity was 2,0-2,4 t/ha. higher than the figures on the reference variants.
Currently, imidacloprid (IMI) is the first insecticide and the second agrochemical highly applied all over the world. Here we report on the impacts of IMI on neurobehavioral performance, oxidative stress, and apoptotic changes in the brain in either adult or adolescent rats. Forty male rats (adult and adolescent) were allocated to four groups. IMI groups were orally given 1 mg IMI/kg b.wt. dissolved in corn oil, whereas the controls were orally administered corn oil daily for 60 days. The obtained results demonstrated that IMI exposure resulted in less exploratory activity, deficit sensorimotor functions, and high depression. Levels of neurotransmitter including serotonin, gamma-aminobutyric acid, and dopamine were significantly reduced. Oxidative damage of brain tissues was evident following IMI exposure represented by the high levels of protein carbonyl, 8 hydroxyguanosine, and malondialdehyde, but total antioxidant capacity was reduced. Histopathological investigations of the brain tissues of IMI treated group revealed varying degrees of degeneration of the neuron. The immunohistochemical evaluation revealed a strong presence of glial fibrillary acidic protein (GFAP) and Bax positive cells, but a low expression of Bcl-2. These injurious impacts of IMI were very prominent in the adult rats than in the adolescent rats. Conclusively, exposure to IMI even at very low concentration could induce multiple neurobehavioral aberrations and neurotoxic impacts, especially in adults.
The application of pesticides through a drip irrigation system has been used successfully for the control of a variety of vegetable pests. Because many vegetable growers already use a drip irrigation system for water management, the injection of a pesticide can easily and inexpensively be achieved with the addition of an injection pump and the required safety equipment for the injection of soluble pesticides. The current availability of novel, systemic insecticides such as neonicotinoids or anthranilic diamides, as well as additional future pesticides under development, has advanced the opportunities for drip chemigation as an effective and environmentally sound pest management tactic. History, need for drip chemigation, selection of chemicals, chemigation system, and considerations for drip chemigation with insecticides in vegetable crops are discussed.
Introduction: Pesticides are considered as the most important pollutants in surface water and groundwater.
Neonicotinoids are new group of insecticides, derived from nicotine. Their physicochemical properties render
them useful for a wide range of application techniques, including foliar, seed treatment, soil drench and stem
applications. Confidor, the representative of the first generation of neonicotinoid insecticides, was patented in
1985 by Bayer and was placed on the market in 1991. The Canadian Pest Management Regulatory Agency
considers confidor to have high potential for surface water contamination, leaching to groundwater and
persistence in soils. Biodegradation is one of the most effective ways to destroy pesticides in the environment.
The application of Bioremediation techniques is taken into consideration as an option to reduce or remove
pollutants from the environment due to their low cost, high efficiency and environmentally friendly features.
Bioremediation by using microorganisms has not any adverse effect after cleanup. The accumulator
microorganism species, haven’t pathogenic properties and aren’t the cause of disease on the other organisms.
The selection of a biomass for using in bioremediation is very important, it should be abundant in environment
and adapted to environmental conditions. The aim of this study was to investigate the ability of various species
of Trichoderma fungi to remove Confidor from contaminated water influenced by variables like pH,
concentration of the confidor and time.
Materials and Methods: In order to conduct this study three different fungal species belonging to the genus
Trichoderma were used. The samples were transferred to PDA (Potato Dextrose Agar) sterile solid media for in
vitro testing usage. The samples were kept in refrigerator at 4◦C temperature, after the fungal biomass reached to
maximal growth; the colonies were transferred to new media and used in our experiments as resources. After
complete fungal growth on the solid media, liquid media were prepared with the formula containing 250 g/l
potato extract, 20 g/l dextrose and 0.25 g/l Tetracycline antibiotic (to prevent bacteria growth) in three pH (5,7,9)
and three toxicant concentrations (1, 3 and 5 mg/l). Lactic acid and KOH (3%) were used to adjust pH in the
prepared media. The degradation experiments were performed in a 50 ml falcon for 1 month. All experiments
were maintained under similar conditions. The samples were shacken daily. After 1 month of incubation,
aliquots (2 ml) were removed; centrifuged and the supernatants were used for the estimation of concentration of
residual confidor by spectrophotometer. The results were analyzed by SPSS software.
Results and Discussion: According to the results T.harzianum with 60.34% confidor removal had the
highest ability and T.tomentosum with 44.60% had the lowest ability to biological degradation of confidor from
the polluted waters. The maximum confidor removal (75.89%) using T.harzianum was accrued to acidic media
with 5 mg/l of confidor. The minimum confidor removal (53.09%) using T.asperellum was accrued to alkaline
media with 1 mg/l of confidor. Using T.tomentosum the efficiency of confidor removal in media with pH=5 and
concentration of 5 mg/l was increased by 10.95% and 15.63% compared to the environments with the
concentrations of 3 and 1 mg/l, respectively. In the media containing T.harzianum, the percentage of confidor
removal after 4 weeks was increased by 46.21% Compared to the first week. In the media containing
T.harzianum, T.asperellum and T.tomentosum, the percentage of confidor removal after 4 weeks was increased
by 46.21%, 37.06% and 32.84% respectively, Compared to the first week. Totally, the results showed that all the
fungi species are capable to remove confodor. Toxicant concentration increasing from 1 mg/l to 5 mg/l, results in
increasing the percentage of toxicant removal. The results of confidor removal from mediums with different pH
demonstrated that in all studied fungi, toxicant removal at pH=5 is higher than other pH. The results obtained
from this study confirm the hypothesis of positive effect of passing the time on confidor removal efficiency by
different Trichoderma species.
Conclusions: In general, we can conclude that three species of studied Trichoderma in this research can be
applied for bioremediation of agricultural waters which are contaminated by confidor. As a result, by collecting
the agricultural water that are contaminated with confider and application of these fungi as biological purifiers,
we will access to a considerable amount of non-conventional water resources to irrigate of downstream. It is
noteworthy that Trichoderma species in addition to the biorefinery potential of pollutants , are able to improve
soil structure and increase plant resistance.
Quimigação é a distribuição de produtos químicos e biológicos pela água de
irrigação. Os principais produtos aplicáveis são fertilizantes (fertigação ou
fertirrigação), herbicidas (herbigação), inseticidas (insetigação), fungicidas
(fungigação), nematicidas (nematigação) e produtos biológicos (bioinsetigação).
The farm-level economic implications of microirrigation will vary among farms and regions, and among crops and resource endowments. Farmers producing high-valued crops in arid and semi-arid regions have a greater likelihood of gaining financially by adopting microirrigation than farmers producing low-valued crops in humid and sub-humid climates. The farm-level value of water saved by reducing irrigation requirements will vary with the cost and availability of irrigation water, and with the cost of energy and the labor required to obtain and deliver the water. Farm-level gains due to increased yields will vary with the crops produced and prices received.
Modern toxicology is seeking new testing methods to better understand toxicological effects. One of the most concerning chemicals is the neonicotinoid pesticide imidacloprid. Although imidacloprid is designed to target insects, recent studies have shown adverse effects on non-target species. Metabolomics was applied to investigate imidacloprid-induced sublethal toxicity in the CNS of the freshwater snail Lymnaea stagnalis. The snails (n=10 snails) were exposed for 10 days to increasing imidacloprid concentrations (0.1, 1, 10 and 100 µg/L). The comparison between control and exposure groups highlighted the involvement and perturbation of many biological pathways. The levels of several metabolites belonging to different metabolite classes were significantly changed by imidacloprid exposure. A change in the amino acids and nucleotide metabolites like tryptophan, proline, phenylalanine, uridine and guanosine was found. Many fatty acids were down-regulated and the levels of the polyamines, spermidine and putrescine, were found to be increased which is an indication of neuron cell injury. A turnover increase between choline and acetylcholine led us to hypothesize an increase in cholinergic gene expression to overcome imidacloprid binding to the nicotinic acetylcholine receptors. Metabolomics revealed imidacloprid induced metabolic changes at low and environmentally relevant concentration in a non-target species and generated a novel mechanistic hypothesis.
This study examines the response of three aquatic species to the common
agricultural insecticide imidacloprid. Imidacloprid is a species-specific soluble insecticide applied for the protection of potato crops. Due to imidacloprid’s solubility, it is likely that agricultural watersheds become contaminated by run-off, putting aquatic biota at risk. Therefore, monitoring the effects of novel unlegislated insecticides, such as imidacloprid, is warranted. Two common mayfly species Epeorus spp. and Baetis spp., as well as an aquatic oligochaete Lumbriculus spp., were examined. Response variables included feeding rate and egestion; larval development and adult body size. At low concentrations, imidacloprid caused mayflies to have reduced feeding, hampered development and growth, as well as caused mortality. Similarly, oligochaetes were rendered immobile at low concentrations of imidacloprid and likewise exhibited reduced egestion (feces deposition). Modern insecticides, like imidacloprid, have been designed to target specific terrestrial pests. However, I have observed that imidacloprid also causes effects to ‘non-target’ aquatic species. Reduced feeding, egestion, larval development and adult body-size all indicate a reduction in the fitness and fecundity of mayfly and oligochaete populations. Because fecundity is positively related to invertebrate development and body size, sublethal doses of this widely applied agricultural insecticide have the potential to reduce reproductive success of mayfly populations.
In order to elucidate the adsorption and leaching characteristics of the insecticide imidacloprid in two types of paddy soils near Suwon, this experiment was carried out with imidacloprid as a radiotracer. In an adsorption study conducted using imidacloprid in 2 test soils, the adsorption coefficient was higher in soil A than that in soil B . As calculated from Freundlich constant, distribution coefficients and half lives in soils, GUS indices showed low leachabilities of imidacloprid treated on the paddy soils into the groundwater. The amount of imidacloprid leached from the soil columns during the 4 weeks of leaching was less than 2% of the originally treated . In the leaching test the amounts of activities distributed in the soil layer of 0-10 cm were more than 80% of the originally tented and those in rice plants were less than 3% of the originally treated , suggesting that imidacloprid has very low teachability and bioavailability.
When compared with other irrigation systems, subsurface drip irrigation (SDI) has advantages and disadvantages that should be carefully considered. There are many design and management similarities to surface drip irrigation (DI), but there are also some unique differences that affect uniformity, operation, and system longevity. Factors that affect SDI uniformity are emitter clogging, root intrusion, root pinching, mechanical and pest damage, soil overburden and compaction, soil hydraulic parameters, and, possibly, system age. A typical SDI system often requires additional components, compared to DI, such as flushlines, additional air/vacuum relief valves, and pressure gauges and a flowmeter for system monitoring. Emitter flowrate and spacing, and dripline diameter, wall thickness, spacing, and depth are all important design criteria for SDI systems. Flushing of SDI driplines is also a key design criterion, and some designers prefer to begin their design with the flushing system. SDI can potentially provide a more consistent soil water and nutrient environment for optimum crop growth, but there can also be challenges in some regions, such as crop establishment, salinity management, soil water redistribution, and application of some agrochemicals. The application of SDI for some of the lower-value grain and fiber crops has been increasing, and this trend is likely to continue.
A micro paddy lysimeter (MPL) was employed to monitor the behavior of nursery-box-applied imidacloprid granules in the rice paddy environment using two treatment methods, i.e. before transplanting (BT) and at sowing (AS). Tested application rates were three-fold the recommended rate. Under a water management scenario in an actual field, the behavior of nursery-box-applied imidacloprid granules in paddy water and paddy soil in MPL was comparable with field monitoring data in the literature. Imidacloprid concentration in water peaked at 189 +/- 36 mu g/L and 13.1 +/- 1.4 mu g/L at 1 day after transplanting (DAT), and the half-lives (DT50) were 2.5 days, and 4.7 days for BT and AS treatments, respectively. In the soil profile, the maximum concentration of imidacloprid at 21 DAT was 65.6 +/- 0.4 mu g/kg and 39.7 +/- 4.9 mu g/kg in the 0-2.5 cm layer in the inter-row zone for BT and AS treatments, respectively. Imidacloprid was found in the 12.5-15.0 cm layer at 3.2 +/- 0.7 mu g/kg for BT treatment and 13.7 +/- 3.8 mu g/kg for AS treatment, in the inter-row zone. In AS treatment, imidacloprid mainly stayed in the root zone (0-5 cm surface soil layer), and its concentration was 895 +/- 4 mu g/kg at 21 DAT. MPL presented as a convenient and alternative tool to monitor the behavior of nursery-box-applied pesticide in the rice paddy environment. (C) Pesticide Science Society of Japan
Sorption-desorption behavior of imidacloprid in six soils collected from five coastal regions in Croatia at 20, 30 and 40°C was investigated using batch equilibrium technique. Isothermal data were applied to Freundlich, Langmuir and Temkin equations, and the thermodynamic parameters ΔH°, ΔG°, ΔS° were calculated. The sorption isotherm curves were non-linear and may be classified as L-type, suggesting a relatively high sorption capacity for imidacloprid. Our results showed that the K( sor ) ( F ) values decreased for all the tested soils as the temperature increased, indicating that the temperature strongly influences the sorption. Values of ΔG° were negative (-4.65 to -2.00 kJ/mol) indicating that at all experimental temperatures the interactions of imidacloprid with soils were spontaneous processes. The negative and small ΔH° values (-19.79 to -8.89 kJ/mol) were in the range of weak forces, such as H-bonds, consistent with interactions and partitioning of the imidacloprid molecules into soil organic matter. The ΔS° values followed the range of -57.12 to -14.51 J/molK, suggesting that imidacloprid molecules lose entropy during transition from the solution phase to soil surface. It was found that imidacloprid desorption from soil was concentration and temperature-dependent, i.e. at lower imidacloprid concentrations and temperature, lower desorption percentage occurred. Desorption studies revealed that hysteretic behavior under different temperature treatments existed, and it was more pronounced at 20°C in the soils with higher OC content. The study results emphasize the importance of thermodynamic parameters in controlling soil pesticide mobility in different geographical locations, seasons and greenhouse conditions.
The adsorptive characteristics of imidacloprid on magnetic activated carbon (MAC12) in comparison to powdered activated carbon (PAC) were investigated. Adsorption of imidacloprid onto powdered activated carbon and magnetic activated carbon was studied as a function of time, initial imidacloprid concentration, temperature and pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models for both carbons were used to describe the kinetic data. The adsorption equilibrium data were analyzed using the Langmuir and Freundlich models. For powdered activated carbon the isotherm was ‘H’ type, and ‘L’ type for magnetic activated carbon. Equilibrium data fits well to the Langmuir model in the studied concentration range of imidacloprid. It was found that both the boundary layer and intraparticle diffusion for both adsorbents play an important role in the adsorption mechanisms of imidacloprid. The adsorption of imidacloprid on PAC and MAC12 followed a pseudo-second-order kinetic model rather than pseudo-first-order model. A decrease in the adsorption of imidacloprid on powdered activated carbon and magnetic activated carbon was observed with the increase in temperature. The pH of the solutions had no effect on the adsorption capacity of the adsorbents.
Larvae of scarabs, also known as white grubs, are subterranean insects that damage ornamental nursery crops when they feed on roots. Management is generally based on application of chemical insecticides to the soil surface, followed by supplemental water to leach the toxicants into the soil. Drip irrigation systems have the potential to deliver insecticides and insect pathogens to the root zones of crops to control subterranean insects. From 2004 through 2006, we tested the effi cacy of imidacloprid (2004-2006), clothianidin (2006), or entomopathogenic nematodes (EPN) + imidacloprid (2005) applied through drip irrigation to control white grubs in an ornamental nursery. Insecticides (imidacloprid or clothianidin) or EPN + imidacloprid were injected into drip irrigation lines at the upstream end of rows in a commercial nursery. EPN + imidacloprid was also injected into the root zone of trees or applied as a surface drench. In 2004 and 2005, imidacloprid applied at a preventive timing through drip irrigation lines signifi cantly reduced the numbers of white grubs in the root zones of Kousa dogwood (Cornus kousa Hance) trees. In 2006, variation in the data resulted in no signifi cant differences at the P = 0.05 level, although, the percentage reductions of grubs by imidacloprid and clothianidin applied through drip irrigation were similar to trials in 2004 and 2005. EPN + imidacloprid applied through drip irrigation, injected into the soil, and surface drenched at a curative timing all signifi cantly reduced the numbers of grubs compared to untreated trees. These data indicate drip irrigation is a viable delivery system for controls of white grubs in nursery crops.
Larvae of scarabs, also known as white grubs, are subterranean insects that damage ornamental nursery crops when they feed on roots. Management is generally based on application of chemical insecticides to the soil surface, followed by supplemental water to leach the toxicants into the soil. Drip irrigation systems have the potential to deliver insecticides and insect pathogens to the root zones of crops to control subterranean insects. From 2004 through 2006, we tested the effi cacy of imidacloprid (2004–2006), clothianidin (2006), or entomopathogenic nematodes (EPN) + imidacloprid (2005) applied through drip irrigation to control white grubs in an ornamental nursery. Insecticides (imidacloprid or clothianidin) or EPN + imidacloprid were injected into drip irrigation lines at the upstream end of rows in a commercial nursery. EPN + imidacloprid was also injected into the root zone of trees or applied as a surface drench. In 2004 and 2005, imidacloprid applied at a preventive timing through drip irrigation lines signifi cantly reduced the numbers of white grubs in the root zones of Kousa dogwood (Cornus kousa Hance) trees. In 2006, variation in the data resulted in no signifi cant differences at the P = 0.05 level, although, the percentage reductions of grubs by imidacloprid and clothianidin applied through drip irrigation were similar to trials in 2004 and 2005. EPN + imidacloprid applied through drip irrigation, injected into the soil, and surface drenched at a curative timing all signifi cantly reduced the numbers of grubs compared to untreated trees. These data indicate drip irrigation is a viable delivery system for controls of white grubs in nursery crops.
Broadleaf plantain plant (Plantago major L.) was used in phytoremediation of imidacloprid insecticide in water and soils. For the Freundlich model the constant related to the biosorption capacity (Kf) of imidaclaprid were respectively, 7.94, 6.31, and 2.51 ug/g for dry roots, fruits (seeds with shells) and leaves of broadleaf plantain plant. Viable whole broadleaf plantain plant in water solution reduced imidacloprid residues by 55.81-95.17%, during 1-10 days of exposure periods compared with 13.71-61.95% in water solution without the plantain. In water solution, imidacloprid significantly accumulated in plantain roots, leaves and fruits to reach the maximum levels after 6, 1 and 3 days of treatment, respectively. The maximum levels were 15.74, 37.21, and 5.74 ug/gm, respectively. These values were decreased to 6.95, 1.46, and 0.12 ug/ gm after 10 days of treatment. The growing cells of short-rod gram-negative bacteria that isolated from the water solution containing broadleaf plantain plants was able to induce 93.34% loss of imidacloprid as a source of both carbon and nitrogen within a short period (48 hr) compared with 31.90% in un inoculated medium. Half-life (t 1/2) in soil planted with broadleaf plantain plants and in unplanted soil were found to be 4.8 and 8.4 days, respectively.
Sorption-desorption of imidacloprid [1-[(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine] and metabolites 1-[(6-chloro-3-pyridinyl)methyl]-2-imidazolidinone (imidacloprid-urea), 1-[(6-chloro-3-pyridinyl)methyl]-4,5-dihydro-1H-imidazol-2-amine (imidacloprid-guanidine), and 1-[(6-chloro-3-pyridinyl)methyl]-1H-imidazol-2-amine (imidacloprid-guanidine-olefin) in three soils was determined using the batch equilibration technique with initial concentrations for the four chemicals ranging from 0.05 to 1.5 mu g mL(-1), which corresponds to a field application rate of 0.2-1.0 kg ha(-1) Calculated slopes of the Freundlich sorption isotherms were significantly less than 1. The order of sorption (K-f) was imidacloprid-guanidine > imidacloprid-guanidine-olefin > imidacloprid > imidacloprid-urea in the three soils. Average Kf-oc values were 203, 412, 2740, and 3200 for imidacloprid-urea, imidacloprid, imidacloprid-guanidine-olefin, and imidacloprid-guanidine, respectively. Desorption was hysteretic for all chemicals in all soils. Greatest hysteresis was observed with imidacloprid-guanidine and imidacloprid-guanidine-olefin. Sorption-desorption of imidacloprid determined at half the solubility (250 mu g mL(-1)) (K-oc = 77) greatly overpredicts potential leaching compared to K-oc determined at field application rates (Kf-oc = 411).
The distribution of napropamide [2‐(α‐naphthoxy)‐ N,N ‐diethylpropionamide] and bromacil (5‐bromo‐3‐ sec ‐butyl‐6‐methyluracil) when applied from a point source was determined in several soils. The parameters studied were application rate (4 and 1.5 L/h) and the effect of wetting and drying cycles. In general, napropamide, which was moderately adsorbed by the soils, was concentrated around the emitter; at a high application rate the compound moved laterally more than vertically and at a lower application rate it penetrated to a greater depth. After several cycles of wetting and drying, napropamide was partially leached out of the emitter zone into the soil volume, the amount of leaching being related to the soil texture. Bromacil, which was weakly adsorbed by the soils, was more uniformly distributed in the soil but did exhibit slight retardation in the heavier soils. The effect of application rate was similar to that observed for napropamide; however, after several cycles of wetting and drying, bromacil was completely leached from around the emitter in all soils and was concentrated at the outer edges of the wetted zone.
Disulfoton 8 emulsifiable concentrate was applied through a biwall tubing drip irrigation system at the rate of 1.1 kg (AI)/ha for Brachycorynella asparagi (Mordvilko) control. Aphid numbers in treated asparagus were significantly lower than in untreated asparagus and protection lasted up to 54 days. In gas chromatographic residue analysis for disulfoton and its toxic metabolites, greater levels of residues were recovered from asparagus fern the 2nd year of the study, indicating increased asparagus root development in response to drip irrigation and subsequent greater efficiency in insecticide uptake. Disulfoton residues in spears exceeded federal tolerance limits.
Elution of atrazine and metolachlor residues from a long-contaminated soil under saturated flow was compared to elution of freshly-injected compounds from the same soil. The mobility of the injected herbicide was far greater than the native. A two-compartment diffusion sorption model-having a fast compartment S1 in rapid exchange with water and a slow compartment S2 with exchange by radial diffusion kinetics-gave good simultaneous fits to native and injected elution curves and predicted flow rate effects and postleaching soil herbicide profiles. An analogous model with first-order kinetics was less successful. The diffusion model parameters indicated that (i) at apparent equilibrium, the bulk (82-92%) of the sorbate was in S2; (ii) the short-term (24-h) batch partition coefficient greatly underestimates the apparent true value and instead reflects partitioning into S1; and (iii) the time scale for sorption is many months. The absence of particle-size size effects on desorption rates suggests that the diffusive medium of S2 is microparticles or microstructures (less-than-or-equal-to 1 mum) distributed among all particle-size fractions.
Aldicarb was applied to potato plants in two locations in Wisconsin to determine the effects of application procedures and irrigation on degradation and movement of aldicarb residues, plant uptake, insect control and crop yield. Two application procedures (3.36 kg. AI/ha applied in the furrows at planting and 2.24 kg AI/ha applied as a top-dress application consisting of a surface-applied band covered with soil at plant emergence) and two irrigation regimens (medium water use based on evapotranspiration and heavy water use based on evapotranspiration plus 60%) were tested. The emergence application was effective in reducing the downward movement of aldicarb residues without significantly affecting performance as measured by insecticidal efficacy, crop residues and yield. Excess irrigation increased downward movement of aldicarb residues in soil, diminished foliar residues and resulted in decreased insect control and crop yield. Differences in soil characteristics, primarily in water-holding capacity, were important in reducing downward movement of aldicarb in soil.
The persistence and mobility of fenamiphos and its toxic oxidation products in soil with pineapple cropping were studied in three field experiments on the islands of Oahu and Lanai, and by sampling three commercial fields on Oahu. Fenamiphos was applied by drip irrigation after planting, following pre-plant application of 1,3-dichloropropene (1,3-D) in most treatments. The Oahu experiments, conducted on highly weathered Oxisol and Ultisol soils, evaluated the impact of restricted irrigation to reduce leaching and also the effect of 1,3-D on fenamiphos behavior. Total toxic residue (TTR) concentrations of 1000 ug kg−1 or greater were maintained in the root-zone with fenamiphos applications of 3.4 kg ha−1 tri-monthly on the Oxisol (Kunia site) and bi-monthly on the Ultisol (Whitmore site). The relatively high applications, along with weekly irrigations and unseasonably high rainfall, resulted in leaching of fenamiphos TTR out of the root-zone with concentrations between 10 and 100 ug kg−1 at 3 m depth. Reduced leaching with restricted irrigation was evident in the early months of both Oahu experiments. The potential to minimize leaching of fenamiphos by reduced application rates and limited irrigation during rainy periods was evident from nematicide concentration profiles measured on three commercial pineapple fields on Oahu; little fenamiphos TTR was detectable below 1 m.
The behavior of two herbicides (bromacil and napropamide) applied to a Mediterranean red loam soil (hamra) from a point source is presented. Neither herbicide was degraded during the period of the study. Bromacil was only slightly adsorbed by the soil (K
d
– 0.1 ml/g; Fig. 1) and was evenly distributed in the soil volume when applied at a constant concentration (Fig. 3). The distribution of napropamide, which was adsorbed by the soil (K
d
– 1.2 ml/g; Fig. 1), was restricted to the zone immediately around the emitter (Fig. 3). Application of the herbicides to previously wetted soils increased the vertical and lateral movement of both herbicides (Fig. 4). Leaching of the chemicals was more pronounced for bromacil than for napropamide (Fig. 5). Cycles of irrigation and evaporation at two irrigation frequencies demonstrated that bromacil can be leached quickly from the emitter zone whereas naproparnide will move only slowly into the soil volume (Fig. 8).
Persistence of the DDT pesticide in the Yakima River Basin Washington. U. S. Geological Survey Circular 1090 Soil biodegradation and leaf transfer of insecticide imidacloprid applied in seed dressing in sugar beet crops
- Rinella Jf
- Hamilton Pa Mckenzie
- Sw
Rinella JF, Hamilton PA, McKenzie SW (1993) Persistence of the DDT pesticide in the Yakima River Basin Washington. U. S. Geological Survey Circular 1090, Denver, CO Rouchaud J, Gustin F, Wauters A (1994) Soil biodegradation and leaf transfer of insecticide imidacloprid applied in seed dressing in sugar beet crops. Bull Environ Contam Toxicol 53:344-350
Control of insects and mites on hops
- Cone
- Wright Lc Ww
- Perez Aj
- Conant
- Mm
Cone WW, Wright LC, Perez AJ, Conant MM (1996) Control of insects and mites on hops. 1996 Hop Research Council Annual Reports, Salem, OR, pp 63-90