Application Of Endosulfan Research Articles

Endosulfan has no adverse effect on soil respiration

Endosulfan (6,7,8,9,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide) is a chlorinated hydrocarbon used as a broad spectrum contact insect/acaricide. The continuous agricultural production of tomatoes, green beans, and squash make Miami-Dade County, Florida one of the heaviest users of this pesticide in the country. A field study was initiated at the USDA, Subtropical Horticulture Research Station in Miami, FL to examine the effects of endosulfan on soil respiration. Snap bean ( Phaseolus vulgaris) and adjacent bare soil plots were treated either with or without endosulfan. Soil respiration was measured weekly as the difference between CO 2 in the ambient air and that generated within a 10-cm diameter, 1178-cm 3 chamber secured at the soil surface. Treatments were replicated four times and the study continued over three growing seasons. Respiration from bare soil was similar to that from plots planted with snap bean implying soil microbes were the dominant source of CO 2 compared to root respiration. Endosulfan applications resulted in inconsistent increases in soil respiration. Increases were short-lived. By the end of the study more CO 2 evolved from endosulfan treated than untreated plots. Soil was kept well irrigated and the percent moisture remained near maximum and varied little, soil moisture was not a controlling factor for soil respiration. Endosulfan had a short-lived inhibitory effect on soil fungi but bacteria increased in number in response to endosulfan application. Individual microbial colonies were not identified and it is possible that one or two bacterial species decomposed the endosulfan and rapidly multiplied causing the increased bacterial colony count. There were no adverse effects of endosulfan found on soil respiration.

English

  In a trial to evaluate the impact of one of the commonly used insecticides in Egypt, a plot area cultivated with soybean was sprayed with endosulfan. Some of the biochemical criteria of the treated soybean and the biodiversity and biochemical activity of its companion cyanobacteria were compared with those of the untreated ones. The results revealed that endosulfan application caused inhibition in the attendance and biodiversity of the soil cyanobacteria found in the rhizosphere of the treated soybean, specially the filamentous species. The treated soil showed a highly significant inhibition in their ARA (acetylene-reducing activity) and exopolysaccharides. The biochemical analysis showed a high significant decrease in all the carbohydrate fractions as well as DNA and RNA contents of the treated soybean plants compared with the untreated ones. However, the total soluble proteins significantly Increased, indicating some defense pattern against the lethal effects of endosulfan. From the results, it could be concluded that application of endosulfan has a significant potential to change ecosystems and soil biological processes and could potentially reduce future farm productivity and cause harmful impact to agriculture.   Key words: Cyanobacteria, endosulfan, insecticide, soybean.

Human health risk assessment of endosulfan. Part III: Occupational handler exposure and risk

The United States Environmental Protection Agency (USEPA) and the California Department of Pesticide Regulation (CDPR) have authority to regulate pesticides, respectively, within the United States and within the state of California. Both agencies are obligated to protect human and environmental health within the geographical boundaries where they have authority. Risk assessment of pesticidal active ingredients is conducted by both USEPA and CDPR, yet the agencies have different legal mandates that influence how they conduct assessments. Exposure estimates are key inputs into the risk assessment. Both agencies released draft risk assessments for endosulfan in the same time frame, and while some exposure estimates were similar, many differed considerably. This paper focuses on the differences in exposure estimates for individuals involved in endosulfan applications (handler exposures). Although CDPR and USEPA relied on the same data sets for their exposure estimates for most handler scenarios, CDPR estimates were in some cases more than an order of magnitude higher than estimates from USEPA. Reasons underlying these disparities, and their effects on risk estimates and resulting regulatory decisions, are discussed in this paper. Additionally, because of differences in legal mandates, CDPR estimated exposures for scenarios lacking data, whereas USEPA did not.

Lethal and Sublethal Effects of Endosulfan on <I>Apolygus lucorum</I> (Hemiptera: Miridae)

Various pesticides directly impact insect pest populations through acute toxicity (lethal) effects, but they also cause a range of indirect (sublethal) effects on pest physiology or behavior. In this study, we describe both lethal and sublethal effects of endosulfan on the survival, development, and fecundity of Apolygus lucorum Meyer-Dür (Hemiptera: Miridae), an important pest of Bacillus thuringiensis (Bt) cotton, Gossypium hirsutum L., in China. We quantify pesticide effects on adult mirids as well as on subsequent (F1, F2) generations. Toxicity bioassays determined the median lethal concentration (LC50) for adult A. lucorum as 0.58 ppm. To evaluate the sublethal effect of endosulfan, we used LC20 and LC40 concentrations at 0.30 ppm and 0.48 ppm, respectively. Sublethal concentrations of endosulfan significantly reduced longevity and fecundity of female adults, but slightly affected male longevity. We also found sublethal effects on the F1 generation, through a reduction of egg hatching rate, nymphal mortality, adult molting rate, and adult fecundity, and on the F2 generation, through a decrease of egg hatching rate. These results show that endosulfan has far greater effects on A. lucorum than estimated by acute toxicity tests, and the effects of this pesticide on surviving mirids can be comparatively long-lived. This pesticide likely causes severe disruptions of A. lucorum population dynamics, with single endosulfan application, invoking a great reduction of population growth of resident mirid populations. We discuss implications of this work for control programs for A. lucorum on Bt cotton.

Endosulfan Application to a Stream Mesocosm: Studies on Fate, Uptake into Passive Samplers and Caged Toxicity Test with the Fish M. ambigua

A model mesocosm system was used to simulate the effect of endosulfan entering a waterway from episodic events such as accidental overspray or in runoff water containing contaminated sediment following storm events. The fate of technical endosulfan applied to a 24-stream mesocosm was compared in experiments where the pesticide was applied either directly as water contamination or after being pre-bound to sediment. The flow of water through the streams was discontinued for a 10-12 h period following the pesticide application. Following the water application, only approximately 3% of endosulfan remained in the streams after 4 days and then was not detectable after 7 days. In contrast, after application pre-bound to sediment, approximately 33% of the endosulfan remained in the streams after 4 days and 14% after 7 days. Additionally, with the sediment-bound application, the proportion of endosulfan was higher in the substrate (11%) after 7 days than in the overlying water (3%), and approximately 1% was oxidised to the sulphate form. The dissipation of endosulfan in the water column of both experiments followed a two-parameter exponential decay model characterised by a relatively fast first-order single-phase process. In sediment of both experiments and the gravel of the sediment-dosing experiment, the dissipation of endosulfan followed more closely a four-parameter bi-exponential decay model characterised by first-order kinetics of two fractions: the first fraction dissipates quickly, and in the longer term the second fraction dominates the overall dissipation with a slower rate. In the gravel section of the water-dosing experiment, endosulfan dissipation was characterised by relatively very slow two-parameter exponential decay. The overall dissipation rates of the alpha- and beta-endosulfan isomers were significantly higher in the water-dosing than in the sediment-dosing experiment, except in the gravel section of the mesocosm. The uptake of the endosulfan into passive samplers constructed from polyethylene membrane bags containing trimethylpentane solvent (TRIMPS) placed in the overlying water was linear. In contrast, TRIMPS buried in sediment failed to uptake endosulfan from the sediment substrate, indicating that short-term deployment of passive samplers can only be used to determine time-weighted average concentrations of bioavailable chemicals in the water column. A 34-h LC50 of 2.8 microg/l [95% confidence interval (CI) 1.5-4.2 microg/l] for juveniles of the native fish Macquaria ambigua was obtained when exposed during the water-dosing experiment. This study demonstrated that the pulse entry of sediment contaminated with endosulfan into a receiving waterway was more persistent compared with direct aqueous contamination and the endosulfan would be bioavailable to pelagic organisms following a gradual partitioning to the water column.

Endosulfan in China 1—gridded usage inventories

Endosulfan, an organochlorine pesticide (OCP), is genotoxic in mammalian cells and generally considered to be toxic and classified by the World Health Organization and the US Environmental Protection Agency as priority pollutants and a nominator for inclusion in a future iteration of the persistent organic pollutants treaty. Endosulfan is a currently used pesticide and still being used worldwide. The general trend of total global endosulfan use has increased continuously since the first year when this pesticide was applied. It is critical to create national endosulfan usage/emission inventories for China to carry out source-receptor relation analysis, risk assessment, and other research related to endosulfan in this country. Chinese inventories have been published for some OCPs, such as technical HCH and lindane, DDT, and chlordane; for endosulfan, however, there has not been any usage inventory available on any scales (national or provincial), although endosulfan has been widely used since 1994 in this country. This is the first part of the work. The goal of this paper is to quantify the historical production and usage of endosulfan in China and to compile gridded historical usage inventories of endosulfan for this country. Based on these usage inventories, emission and residue inventories will be created, which is the goal of the second part of the work. Due to the lack of national production and usage information of endosulfan in China, a method to estimate the use of endosulfan was developed. First, information of crops on which endosulfan is applied and average endosulfan use and annual application frequencies of endosulfan on these crops were collected. Secondly, usage of endosulfan on each crop was estimated using the national cropland area for each province from Chinese government reports. Finally, with the help of GIS (geographic information system), the usage data of this insecticide was allocated to a grid system, with a 1/4 degrees longitude by 1/6 degrees latitude resolution, with a size for each grid cell of approximately 25 km by 25 km. The use of endosulfan in agriculture in China started on cotton in 1994, and on wheat, tea, tobacco, apples, and other fruits in 1998. Endosulfan usage on cotton, wheat, tea, tobacco, and apples in China has been estimated to be approximately 25,700 t between 1994 and 2004. The province with the highest usage of endosulfan is Henan Province, with a total usage reaching 4,000 t, followed by the uses in Xinjiang Autonomous Region (3,200 t), Shandong Province (3,000 t), Hebei Province (2,100 t), and Anhui Province (1,900 t). Gridded usage inventories of endosulfan at a 1/4 degrees longitude by 1/6 degrees latitude resolution have been created, which indicate that the intensive endosulfan use was in the south of Hebei Province, west of Shandong Province, east of Henan Province, north of Anhui Province, east of Jiangsu Province, and some areas in Yunnan Province and Xinjiang Autonomous Region. General agreement has been found between the usage data from our estimation and the small amount of usage data published in China. This is the first national gridded endosulfan usage inventory produced for China. The annual applications of endosulfan from 1994 to 2004 in China were estimated based on the total areas of major crops, on which endosulfan was applied, and spatial distribution of the application was generated at provincial and prefecture levels. With the help of GIS, endosulfan usage based on prefecture was transferred to a 1/4 degrees longitude by 1/6 degrees latitude gridding system. The satisfaction of the inventories was supported by the consistence between the estimation of the annual usage and the reported annual production of endosulfan. This gridded endosulfan usage inventory created in this study will be improved upon availability of new information of endosulfan. The usage inventories can be used to create gridded emission and residue inventories for this insecticide. It is believed that this work will pave the way for further endosulfan studies in China and beyond.

Insecticide resistance inFrankliniella occidentalis: Corroboration of laboratory assays with field data and cross-resistance in a cypermethrin-resistant strain

Field efficacy of five insecticides to a greenhouse strain ofFrankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) of known resistance status was studied. In a greenhouse trial, the mortality of aF. occidentalis strain (Uncali) which exhibited resistance only against cypermethrin in laboratory assays, reached 56%, 68%, 82%, 94% and 99%, 24 h after application of abamectin, cypermethrin, endosulfan, malathion and methomyl, respectively. In the laboratory, for larval mortality equal to that achieved in the field, much lower doses — half of the field dose of cypermethrin and endosulfan, and one-third and one-sixth of malathion and methomyl, respectively, were required in topical application. Because of differences between laboratory and field responses ofF. occidentalis to insecticides, a sound resistance evaluation program to determine field efficacy of insecticides is needed. Resistance increased 28.0- and 139.3-fold at LC50 in theF. occidentalis strain subjected to 27 and 44 cycles of cypermethrin selection, respectively. A slight cross-resistance of two- to threefold was found with endosulfan, malathion and methomyl and no cross-resistance was observed with abamectin.

Field efficacy of azadirachtin‐A, tetrahydroazadirachtin‐A, NeemAzal® and endosulfan against key pests of okra (Abelmoschus esculentus)

BACKGROUND Unlike synthetic pesticides, azadirachtin-based neem pesticides are environmentally friendly and are well known for their diverse pest control properties. Their use is, however, limited by the instability of azadirachtin, necessitating application at short intervals. The efficacy of relatively stable tetrahydroazadirachtin-A, therefore, needed to be established under field conditions. Azadirachtin-A (Aza-A), its stable derivative tetrahydroazadirachtin-A (THA) and other neem pesticides have been evaluated for their field efficacy against major insect pests of okra, Abelmoschus esculentus (L.) Moench., during summer (kharif) 2003 and 2004. The optimum doses of Aza-A and THA against the fruit borer, Earias vittella F., were also established. Reductions in population of whitefly, Bemisia tabaci (Genn.), and leafhopper (jassid), Amrasca biguttulla biguttulla Ishida, after application of THA or endosulfan was evident up to 10 days after treatment (DAT), whereas with Aza-A and NeemAzal (NZ) the effect was observed up to 7 DAT only. Endosulfan and THA also caused higher reduction in the larvae of shoot and fruit borer E. vittella and E. insulana Boisd., and recorded the highest yields of 4600 and 4180 kg ha(-1). The efficacy of THA (0.05 g L(-1) emulsion) was comparable with that of 0.5 g L(-1) endosulfan emulsion in reducing fruit borer infestation, the reduction over the control being 86.0 and 87.3%, 84.9 and 94.1% and 90.2 and 92.6% at first, second and third picking. THA 0.02 g L(-1) and Aza-A 0.05 g L(-1) were on a par. Laboratory-made neem oil emulsifiable concentrate was the least effective, but was superior to untreated check. Three consecutive sprays of THA, a neem-based biopesticide, and endosulfan have been found to be superior in controlling field pests of okra to Aza-A and NZ, which were on a par. THA thus holds potential as a component of pest management strategies against okra pests.

Effects of glyphosate and endosulfan on soil microorganisms in soybean crop

Transgenic soybean, resistant to glyphosate, is the most dominant transgenic crop grown commercially in the world. Research works on herbicide and insecticide mixtures and their effects on microorganisms are rarely reported. This work aimed to study the impact of glyphosate, endosulfan and their mixtures on the microbial soil activity in soybean crop. The experiment was carried out in a complete randomized block design with four treatments and five replications. The treatments were glyphosate 480 SL [540 g of active ingredient (a.i.) ha-1], endosulfan 350 EC (525 g a.i. ha-1), the glyphosate 480 SL [540 g of active ingredient (a.i.) ha-1] mixed with endosulfan 350 EC (525 g a.i. ha-1) and the control. Microbial activity was evaluated five days after treatment application. Glyphosate application was not an impacting factor for soil CO2 production. Endosulfan application (alone or mixed with glyphosate) suppressed CO2 production by microorganisms in the soil. Microbial biomass and microbial quotient were lower in the treatments using endosulfan alone and in those using endosulfan mixed with glyphosate than in the treatments using glyphosate alone and control.

Comparison of the relative dissipation rates of endosulfan pesticide residues between oolong and green tea

The dissipation behaviour of endosulfan in dry made-tea leaves of oolong and green tea was compared to establish whether there was any difference in dissipation rates between the two teas. The dissipation of endosulfan in oolong and green tea corresponded with a first-order kinetics curve. The average half-life of endosulfan (n = 12) was 1.60 ± 0.44 days in green tea and 2.01 ± 0.55 days in oolong tea, showing a statistically significant difference, and indicating that the dissipation of the pesticide was significantly slower in oolong tea than that in green tea. Although the initial levels of residual endosulfan were lower in oolong tea, due to the slower dissipation rate, the residues 5–7 days after application were higher in oolong than in green tea. It is suggested that the minimum interval between endosulfan application and tea leaf harvesting is 7 days for green tea and 10 days for oolong tea in the case where the maximum residue limit of endosulfan in made-tea is fixed as 10 mg kg−1.

Dissipation of Endosulfan in Field-Grown Tomato (Lycopersicon esculentum) and Cropped Soil at Akumadan, Ghana

The dissipation and persistence of endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide) applied to field-grown tomato (Lycopersicon esculentum) were studied at a vegetable-growing location in Ghana. Plant tissue samples and cropped soil collected at 2 h-14 days and 8 h-112 days, respectively, after application, were analyzed by gas chromatography-electron capture detection (63Ni) to determine the content and dissipation rate of endosulfan isomers (alpha- and beta-endosulfan) and the major metabolite, endosulfan sulfate. After two foliar applications of commercial endosulfan at 500 g of active ingredient/hectare, the first-order reaction kinetic was confirmed to describe the dissipation of endosulfan residues in tomato foliage and cropped soil. However, functions that best fit the experimental data were the biphasic process for foliage and the monophasic process for cropped soil. Calculated DT 50 and DT 90 values for endosulfan residues in cropped soil were not significantly (p<0.05) different for each of the two isomers.

Endosulfan and Bifenthrin: Applied Alone, Alternatively or in Combination for Control of the Silverleaf Whitefly Bemisia argentifolii Bellows and Perring (Homoptera: Aleyrodidae) in Cotton

Insecticide treatments against the silverleaf whitefly, Bemisia argentifolii, has been the most important control method for this pest. In this study, the efficacy of bifenthrin and endosulfan applied alone, alternatively or as a tank mixture was evaluated against the silverleaf whitefly. Adult populations were reduced from 27 to 60% following 10 sprays of bifenthrin alone or the bifenthrin endosulfan tank mixture. All insecticidal treatments resulted in lower numbers of 2nd and 3rd larval stages and were significantly different from the untreated control. Yield was the lowest in the control where the populations of whitefly adults, eggs, larval stages and pupae were consistently greater than in each insecticidal treatment. Applications of both bifenthrin and endosulfan, alternatively or as a tank mixture, did not increase control of whitefly over each insecticide applied alone. Bifenthrin alone was more effective than endosulfan alone.

Effect of Insecticide Spray Applications, Sowing Dates and Cultivar Resistance on Insect Pests of Cowpea in the Delmarva Region of the United States

ABSTRACT Field studies were conducted to determine the effect of insecticide spray applications, sowing dates and cultivar resistance in diverse cowpea genotypes in the Delmarva (Delaware, Maryland and Virginia) peninsula region of the United States. A mixture of cypermethrin and dimethoate was applied in the first experiment and the number of spray applications ranged from two to six. The second experiment had two sowing date treatments and received four spray applications of endosulfan. Also, ten genotypes of cowpea were planted and observations were taken on the incidence of major insect pests and pod damage. There was a 30% increase in cowpea seed yield as a result of spraying the mixture of cypermethrin + dimethoate insecticides. The damage to cowpea pods was also significantly reduced in the sprayed treatments. The first and second sowing dates of cowpea sprayed treatments gave 30% and 45% increase in the seed yield over the first and second unsprayed dates of sowing cowpea treatments, respectively. The first sowing date treatment gave significantly higher seed yield than the second sowing date treatments. There were significant differences in the number of some major insect pests and also on pod damage among the ten diverse cowpea genotypes grown under the Delmarva field conditions. This study provides information on the incidence of insect pests of cowpea in the Delmarva region, the potential of insect pests to cause significant yield losses, and variation in insect pest resistance among ten diverse cowpea genotypes.

Yield Reduction in &lt;I&gt;Brassica napus, B. rapa, B. juncea&lt;/I&gt;, and &lt;I&gt;Sinapis alba&lt;/I&gt; Caused by Flea Beetle (&lt;I&gt;Phyllotreta cruciferae&lt;/I&gt; (Goeze) (Coleoptera: Chrysomelidae)) Infestation in Northern Idaho

Phyllotreta cruciferae is an important insect pest of spring-planted Brassica crops, especially during the seedling stage. To determine the effect of early season P. cruciferae infestation on seed yield, 10 genotypes from each of two canola species (Brassica napus L. and Brassica rapa L.) and two mustard species (Brassica juncea L. and Sinapis alba L.) were grown in 2 yr under three different P. cruciferae treatments: (1) no insecticide control; (2) foliar applications of endosulfan; and (3) carbofuran with seed at planting plus foliar application of carbaryl. Averaged over 10 genotypes, B. rapa showed most visible P. cruciferae injury and showed greatest yield reduction without insecticide application. Mustard species (S. alba and B. juncea) showed least visible injury and higher yield without insecticide compared with canola species (B. napus and B. rapa). Indeed, average seed yield of S. alba without insecticide was higher than either B. napus or B. rapa with most effective P. cruciferae control. Significant variation occurred within each species. A number of lines from B. napus, B. juncea, anid S. alba showed less feeding injury and yield reduction as a result of P. cruciferae infestation compared with other lines from the same species examined, thus having potential genetic background for developing resistant cultivars.

Potential Acaricides for Management of Blueberry Bud Mite in Michigan Blueberries

The goal of this study was to evaluate potential alternatives to endosulfan for control of the blueberry bud mite (Acalitus vaccinii), because the availability of this acaricide may be restricted in the future. Laboratory evaluations of potential acaricides showed that endosulfan and a combination of abamectin plus oil provided 97% and 100% control, respectively. Pyridaben and fenpropathrin were less effective, reducing mite survival by 49% and 57%, respectively. Further laboratory evaluation of the abamectin plus oil treatment showed that each component applied alone provided a high level of control of blueberry bud mite. Field trials in Michigan on a mature highbush blueberry (Vaccinium corymbosum) planting were conducted to compare control of this pest by postharvest applications of endosulfan, delayed-dormant application of oil, or a combination of both treatments. The oil provided a 40% reduction in mite scores, while endosulfan was more effective (48%) and similar to the combination of endosulfan and oil (52%). A separate field trial using a multifan/nozzle sprayer that applied the pesticide in 233.8 L·ha-1 (25 gal/acre) of water suggested that the level of control from one application of endosulfan was not as effective as two applications. Results are discussed in relation to developing future bud mite control programs in blueberry and the need to address gaps in our understanding of the biology of blueberry bud mite. Endosulfan (Thiodan 50 WP), Endosulfan (Thiodan 3 EC), Abamectin (AgriMek 0.15 EC), Fenpropathrin (Danitol 2.4 EC), Pyridaben (Pyramite 60 WP).

Environmental exposure to residues after aerial spraying of endosulfan: residues in cow milk, fish, water, soil and cashew leaf in Kasargode, Kerala, India.

A detailed study has been conducted to evaluate the residues of endosulfan and its principal metabolite (alpha-endosulfan, beta-endosulfan and endosulfan sulfate) which may have accumulated in environmental samples due to regular aerial spray application of endosulfan on cashew leaf plantation for a period of 20 years. Three months after the last spray of endosulfan 350 g litre-1 EC at 300 ml acre-1 (equivalent to 105 g AI acre-1 = 42.5 g ha-1), a total of 93 samples of cow milk, fish, water, soil and dried cashew leaf were collected from a village in Kasargode District, Kerala, India, where endosulfan contamination was likely to have occurred. All the samples were analyzed for total residues of endosulfan (comprising alpha- and beta-endosulfan), endosulfan sulfate and also the potential hydrolysis product endosulfan diol, using gas chromatography with electron capture detection. The minimum detection limits of total endosulfan was 0.001 microgram g-1. Analysis of soil samples showed the deposition of total endosulfan residues in the range < 0.001-0.010 microgram g-1, and dried leaf samples showed residues of endosulfan in the range < 0.001-3.43 micrograms g-1 dry weight. In cow milk, fish and water, endosulfan residues could not be detected above the minimum detection limit. Endosulfan diol was not observed in any sample. The data obtained was confirmed by GC-MS-EI using selective ion monitoring (SIM) mode.

Management practices for control of runoff losses from cotton furrows under storm rainfall. II. Transport of pesticides in runoff

Pesticide transport in runoff was measured using a rainfall simulator on cotton hill–furrow systems with a range of on-ground cover (0–60&amp;percnt;), each with and without prior wheel traffic. The scenario was a 65-mm storm, 3 weeks after planting cotton with associated herbicide applications and 2 endosulfan applications after planting. Concentrations of &amp;alpha;, β, and total endosulfan in runoff decreased significantly with increasing cover, irrespective of cover type (wheat stubble or cotton trash) or placement (in furrow or overall). Concentrations of endosulfan sulfate, trifluralin, and DDE decreased with cover, but were affected by cover placement. With 45–60&amp;percnt; cover, concentrations were reduced 5-fold for &amp;alpha;, β, and total endosulfan; halved for endosulfan sulfate, trifluralin, and DDE; and unchanged for prometryn. Cover had more effect on endosulfan because cover intercepted and dissipated the sprayed endosulfan, reducing concentrations in surface soil and therefore in runoff. This is a mechanism for reducing pesticide runoff additional to effects of cover on runoff and sediment. Cover placement affected pesticide concentrations because cover in the furrows was more effective in trapping larger sediment than evenly spread cover. Pesticide concentrations (mg&amp;sol;kg) were apparently greater in larger, aggregated sediment than in fines, probably because of more organic matter in larger sediment. Cover had more effect on total pesticide losses (g&amp;sol;ha) than on concentrations, because cover reduced runoff and soil loss considerably. With 45–60&amp;percnt; cover, total losses of &amp;alpha;, β, and total endosulfan were 1.4&amp;percnt; of losses from bare plots, endosulfan sulfate and DDE 3&amp;percnt;, trifluralin 5&amp;percnt;, and prometryn 8&amp;percnt;. Avoiding wheel traffic gave 20–30&amp;percnt; lower concentrations and 40&amp;percnt; lower losses, due to lower transport in the water phase and enhanced the effect of cover, but did not prevent large pesticide losses from bare plots. Prometryn was transported mostly in the water phase while other pesticides were transported mostly with sediment. Cover provided more control of more soil-sorbed pesticides (endosulfan, trifluralin, and DDE) due to a large reduction in soil loss with cover. Control of the less sorbed prometryn was largely due to cover reducing runoff. agricultural chemicals, endosulfan, prometryn, trifluralin, DDE, cover, controlled traffic, water quality.

Evaluation of Application Methods for the Chemical Control of Striped Cucumber Beetle (Coleoptera: Chrysomelidae) Attacking Seedling Cucurbits

ABSTRACT Bioassays of treated field-aged leaves were conducted in 1998 and 1999 to determine the efficacy of various chemicals for control of striped cucumber beetle (SCR), Acalymma vittatum. In 1998, imidacloprid (GAUCHO® 480F) as a seed treatment was evaluated on cucumber (Cucunus sativis), cv. Pioneer, and squash (Cucurbita maxima), cv. Mini Green Hubbard. Three rates, 1.0 mg, 5.0 mg and 10.0 mg a.i./seed were evaluated for squash and one rate, 1.0 mg a.i./seed, for cucumber. Cucumber seeds treated with GAUCHO at rates higher than 1.0 mg a.i./seed did not germinate in this trial. All treatments protected growing cucumber and squash seedlings from SCB feeding. In 1999, the study was expanded to include foliar, seed, and planting water treatments. A single foliar application of endosulfan (THIODAN® 4EC), azinphosmethyl (SNIPER® 50WP), cypermethrin (RIPCORD® 400 EC) or imidacloprid (ADMIRE® 240F) applied to both cucumber cv. Calypso and pumpkin (Cucurbita pepo), cv. Howden, did not adequately protect rapi...

Dust and Endosulfan Deposition in a Cotton‐Growing Area of Northern New South Wales, Australia

AbstractThe pesticide endosulfan (6,7,8,9,10,10‐hexachloro‐1,5,5a,6,9,9a‐hexahydro‐6,9‐methano‐2,4,3‐benzodioxathiepin‐3‐oxide) has been detected in rivers in the cotton (Gossypium hirsutum L.)‐growing area of northern New South Wales at a 5 yr mean (1991–1995) concentration of 0.06 µg L−1. One pathway by which endosulfan reaches the riverine environment is transport on contaminated dust. Our objectives were to examine: (i) dust deposition from vehicular traffic on an unsealed road on a cotton farm, and around a cotton field in the 11 to 65 h period after endosulfan application; (ii) endosulfan deposition in the 11 to 65 h period after endosulfan application, and over a 3‐mo period at on‐farm and off‐farm (nontarget) locations. Dust deposition rates from vehicular traffic varied from 0.013 g m−2 vehicle−1 at 1 m distance, to 0.002 g m−2 vehicle−1 at 100 m distance from an unsealed road (soil surface, no gravel added). The maximum endosulfan deposition in the 11 to 65 h post‐spraying period was 95 µg m−2 at 5 m from the field. Over a 3‐mo monitoring period (December 1996–March 1997), the average daily deposition rate of endosulfan was 0.16 µg m−2 d−1 for the off‐farm sites compared with 0.35 µg m−2 d−1 for the on‐farm site. As the measurement period was one of the wettest on record and the number of endosulfan applications was less‐than‐normal, the dust and endosulfan deposition results may be interpreted as minima.

Anthropogenic dust and endosulfan emissions on a cotton farm in northern New South Wales, Australia

Dust has been implicated as a pathway for endosulfan transport to the riverine environment in New South Wales. Anthropogenic dust, expressed as total suspended sediment (TSP), and particle associated endosulfan emissions were estimated on a cotton ( Gossypium hirsutum L.) farm in northern New South Wales, Australia, using a combination of direct measurements and modelling. A vehicle travelling at 80 km h −1 on an unsealed road was a greater source of TSP emission (3.7 g m −1) than an 8-m wide inter-row cultivator travelling at 8 km h −1 (1.7 g m −1). However, the particle size distribution of the TSP from inter-row cultivation was finer (mode of 19–22 μm) than that from vehicular traffic on unsealed roads (mode of 32 μm) and hence may be transported further. Endosulfan source strength from inter-row cultivation was 3.6 μg m −1 of travel (or 0.45 μg m −2) which was only 6.0E-4% of that applied, 4 days after endosulfan application. This was slightly higher than the endosulfan source strength from vehicular traffic on an unsealed road (3.1 μg m −1 of travel), only 2 days after spraying. On unsealed roads, particle-associated endosulfan mass fractions declined rapidly with time due to volatilisation and photodegradation and a decrease in endosulfan-enriched source sediment due to the removal by repeated vehicle passes. For unsealed roads, TSP at 0.63 m height showed endosulfan-enrichment ratios of approximately four, compared to the surface soil 0–1 cm depth, for inter-row cultivation and vehicular traffic.