Persistence of deltamethrin and cypermethrin on wheat and sweetclover

Abstract

Residues of cypermethrin and deltamethrin in wheat herbage and grain and deltamethrin in sweetclover herbage were determined. Cypermethrin was applied at 28 g/ha to wheat and the residues on the herbage declined exponentially from 3.74 ppm immediately after spraying to 0.20 ppm 27 days after spraying. No cypermethrin residues were detected in the grain. Deltamethrin was applied at 6 g/ha to wheat and the residues on the herbage declined exponentially from 0.70 ppm immediatly after spraying to 0.05 ppm 27 days after spraying. No deltamethrin residues were detected in the grain. Deltamethrin was applied to sweetclover at 3, 4, 5, 10, and 16 g/ha. Residues on the herbage declined exponentially from 0.10, 0.16, 0.22, 0.40 and 0.70 ppm immediatly after spraying to 0.02, 0.03, 0.04, 0.15 and 0.18 ppm 5 days after spraying, respectively.     

Deltamethrin residues in milk and tissues of lactating dairy cows.

Lactating dairy cows were fed deltamethrin (2 or 10 mg kg-1 feed) for 28 consecutive days and deltamethrin residues measured in milk and tissues. Deltamethrin residues were higher relative to dose administered. The order of relative concentrations of deltamethrin in tissues, measured 1, 4, and 9 days after the last dose was: renal fat greater than subcutaneous fat greater than forequarter muscle greater than hindquarter muscle greater than liver greater than kidney. Depletion of deltamethrin residues in milk was very rapid indicating the half-life of the insectide of about 1 day. Trace amounts of deltamethrin metabolites 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylic acid (less than 0.0235 ppm) and 3-phenoxybenzoic acid (less than 0.034 ppm) were also detected in milk and tissues of treated cows.     

Fenvalerate concentrations in a mineral and an organic soil receiving multiple applications during the growing season

Abstract

Fenvalerate EC at 140 g AI/ha was applied 7 times at 2 wk intervals to duplicate plots of Plainfield sand and an organic soil contained in 2.2 x 0.9 m field microplots with and without an onion crop present in 1980 and 1981 respectively. Soil samples were taken immediately before and after each application and at 2, 4, and 6 wk after the last application in 1980. Additional samples were taken at 22 and 34 wk for the 1981 treatment. Concentrations of fenvalerate were determined by glc. In the crop‐free mineral soil, fenvalerate levels declined from. 0.07–0.11 ppm immediately after spraying to 0.01–0.03 ppm after 2 wk; in the organic soil the rate of addition of fenvalerate exceeded the rate of disappearance and the concentration in the soil gradually increased over the 14 wk treatment period to the 0.9–1.0 ppm range. This concentration decreased slowly over the next 10 wk to 0.7–0.8 ppm and was still 0.5–0.7 ppm the following spring. Results were similar for cropped soils. Concentrations in the top third of the 15 cm cores were 6x and 15x those in the middle third for sand and organic soil, respectively. Concentrations, in the onions at harvest were <0.01 ppm.     

Residues of chlorpyrifos-methyl in balsam fir foliage, forest litter, soil, stream water, sediment and fish tissue after double aerial applications of Reldan

Chlorpyrifos-methyl was applied twice at 70 g A.I./ha by means of a fixed-wing aircraft to a mixed coniferous forest near Allardville, New Brunswick. Residue in balsam fir foliage was highest (1 ppm wet wt) 1 hr after spraying and rapidly declined to about 30% within 1 day, but persisted at a very low level (0.03 ppm wet wt) for 125 days. Current year's foliage contained a higher level of residue than old foliage. Chlorpyrifos-methyl persisted longer in forest litter than in soil. After 125 days, trace amounts (less than 6 ppb wet wt) were still found in litter but were not detected in soil. In stream water the residue dissipated very rapidly; more than 90% disappeared 3 hours after the second application and were not detected after 4 days. Low-level residue (less than 0.1 ppm wet wt) was present in the sediment and persisted for 10 days. Although brook trout and slimy sculpin captured in the stream within 3 days of the second application contained residues (less than 0.05 ppm fresh wt) none were detected in any fish captured, 9 and 47 days later.     

Disappearance of bromopropylate residues in artichokes, strawberries and beans

Residues of Bromopropylate were determine in artichokes, strawberries and beans after foliar spray of acaricide at two rates. The rates used were 1 g/l formulated product (normal recommended) and 1.5 g/l. The residue levels of bromopropylate in the three crops after 14 days were lower than 0.7 ppm and did not exceed the Maximum Residual Level (MRL) recommended by FAO. In the artichokes and strawberries, the total concentration of residues decreased by 50% of the initial level after 2-3 days. Only trace levels of the bromopropylate residues (less than 0.01 ppm) were detected in the "hearts" of the artichokes. Bromopropylate residues in the green beans were also less than 0.8 ppm after the first day of foliar spraying. The kinetic of degradation occurred in two different steps. In the first step (4-6 days) the dissipation of bromopropylate was faster whereas in the second step (7-14 days) the loss of residues was much slower.     

Residues of chlorpyrifos‐methyl in balsam fir foliage,forest litter,soil, stream water,sediment and fish tissue after double aerial applications of Reldan®

Abstract

Chlorpyrifos‐methyl was applied twice at 70 g A.I./ha by means of a fixed‐wing aircraft to a mixed coniferous forest near Allardville, New Brunswick. Residue in balsam fir foliage was highest (1 ppm wet wt) 1 hr after spraying and rapidly declined to about 30% within 1 day, but persisted at a very low level (0.03 ppm wet wt) for 125 days. Current year's foliage contained a higher level of residue than old foliage. Chlorpyrifos‐methyl persisted longer in forest litter than in soil. After 125 days, trace amounts (< 6 ppb wet wt) were still found in litter but were not detected in soil. In stream water the residue dissipated very rapidly; more than 90% disappeared 3 hours after the second application and were not detected after 4 days. Low‐level residue (< 0.1 ppm wet wt) was present in the sediment and persisted for 10 days. Although brook trout and slimy sculpin captured in the stream within 3 days of the second application contained residues (< 0.05 ppm fresh wt) none were detected in any fish captured, 9 and 47 days later.     

An impingement plate method to detect deposits of pyrethroid insecticides

A silica gel impingement plate for monitoring pyrethroid deposits in environmentally sensitive areas is described. The plate is simple, commercially available, and inexpensive. A residue analysis method is given for deltamethrin deposits with 83.3% mean recovery and a minimum quantifiable limit of 0.005 microgram/plate. Pyrethroid deposits are strongly adsorbed to the silica gel, which prevents wash-off by rainfall and slows photodegradation. In two field experiments, deltamethrin was readily detected 3 weeks after direct spray applications at 6 and 10 g ai/ha. Deltamethrin dissipation on the plates was first-order with a half-life of 2.9-3.7 d. Photoisomers of deltamethrin were also detected on the plates and the ratio of photoisomers to deltamethrin increased over time. This ratio will indicate the age of deposits in monitoring situations.     

Residues of lindane and its metabolites in eggs, chicks, and body tissues of hen pheasants after ingestion of lindane-14C via treated wheat seed or gelatin capsules.

Studies were carried out to investigate possible contamination of pheasants with residues of lindane used as seed dressings for the control of wireworms in cereal crops. One group of laying hen pheasants was fed 20 mg of lindane-14C in gelatin capsules while another group was fed wheat seed treated with 100 ppm of lindane-14C for 15 days. Residues in eggs were monitored for about 70 days. Residues in chicks hatched from the eggs were also measured. Concentrations of residues in muscle, liver, brain, and fatty tissues were determined at various times. 14C-labeled residues in eggs increased sharply in the capsule treated group and reached an average maximum of about 19 ppm in 8 days. This level decreased to less than 0.5 ppm in about 50 days. Residues in eggs from the pheasants fed treated seed increased gradually to an average maximum of 17 ppm 22 days after commencement of the feeding program. This level decreased to less than 0.5 ppm 50 days later. Residues in hatched chicks were significantly lower than those in the eggs. Highest concentrations of residues were found in fatty tissues which decreased to non-detectable level in 6 months. Several chlorobenzene metabolites were identified in egg yolk and chick tissues. Chlorophenolic metabolites were indicated only in chicks.     

Environmental fate of synthetic pyrethroids during spray drift and field runoff treatments in aquatic microcosms.

The aquatic fate and persistence of synthetic pyrethroids under spray drift and field runoff treatment regimens were determined in outdoor pond microcosms. In this paper, the experimental design and construction of outdoor microcosms is presented, as well as the aquatic fate of tralomethrin and deltamethrin. Tralomethrin is rapidly degraded to deltamethrin, with a half-life of 12.7 hours under spray drift conditions. Degradation profiles of tralomethrin in water indicated rapid conversion of deltamethrin and to less active isomers and then to decamethrinic acid (BR2CA). After 24 hours, the percent radioactivity of tralomethrin was 25% of the test material in the water column. In sediment, tralomethrin was immediately converted to deltamethrin. Deltamethrin is rapidly degraded with a half-life of 8 to 48 hours, depending on mechanisms of introduction into water. Degradation profiles of deltamethrin in water indicated rapid conversion of deltamethrin to decamethrinic acid (BR2CA), comprising approximately 90% of the radioactivity in the aqueous phase at 168 hours. Extraction and analysis of fathead minnows (Pimephales promelas) after 96 hours revealed that tissue residues contained parent compounds and metabolites alpha-R-deltamethrin, trans-deltamethrin and Br2CA. Fish residues are directly related to aqueous concentrations, thus bioavailability under field runoff regimes were an order of magnitude lower than tissue residues under spray drift conditions. Plant tissue was found to significantly accumulate pyrethroids.     

Terbufos residues in wheat and barley

A granular formulation of terbufos (Counter 15G) was added in-furrow at time of planting of wheat and barley. Foliage collected at several times was analyzed for total terbufos residues as terbufoxon sulfone. Maximum residues from application of 1.5 and 3.0 kg/ha were 7.4 and 10.6 ppm, respectively, in wheat foliage samples collected 10 days postseeding. Wheat foliage collected at 53 days postseeding had residues averaging 0.32 and 0.58 ppm from the 1.5 and 3.0 kg/ha applications, respectively. In 1985 residues in barley were consistently less than in wheat in 1985 with 4.4 and 7.0 ppm detected in foliage collected 10 days post application from the 1.5 and 3.0 kg/ha applications, respectively and 0.21 and 0.34 ppm detected at 53 days. Grain samples had 0.01 ppm or less residue at harvest. Straw samples had up to 0.75 ppm total terbufos residues at harvest.     

Simultaneous determination of fenitrothion and aminocarb in blueberry foliage and fruits: Application to the analysis of residues in field samples

Abstract

Samples of blueberry foliage and fruits were collected from spray blocks in Ontario after aerial application of fenitrothion and aminocarb at dosage rates of 210 g active ingredient (AI)/ha and 70 g AI/ha respectively. Residues were extracted from the samples by homogenizing with ethyl acetate, cleaned up by microcolumn chromatography using alumina as adsorbent, and analyzed by GLC‐AFID with a glass column packed with 1.5% OV‐17 and 1.95% OV‐210 on 80–100 mesh Chromosorb W‐HP. Average recoveries for fenitrothion and aminocarb from foliage at three fortification levels (1.0, 0.10 and 0.01 ppm) were respectively 99 and 96%. The corresponding values for the fruits were 99 and 95%. Foliage samples collected 1 h post‐spray contained on average 1.13 ppm of fe‐nitrothion and 1.14 ppm of aminocarb. However, residue levels reached below the detection limit (<0.01 ppm) in foliage collected 15 d after treatment. In addition, the fruit samples collected after 15 d post‐spray contained extremely low levels (0.03 ppm for fenitrothion and 0.02 ppm for aminocarb) of residues, and were barely above the detection limit.     

Bioefficacy of iprodione against two desapers, its compatibility with T. harzianum and residues on cabbage crop

Iprodione (3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxoimidazolidine-1-carboxamide) bio-assayed against fungi Alternaria brassicicola and Sclerotinia sclerotiorum was found to be highly effective for inhibiting these desapers. Inhibition of A. brassicicola was 100% up to the dose of 75 ppm and for S. sclerotiorum there was 50% inhibition for the same concentration. Formulation of the pesticide was applied @ 500 and 1000 g. a.i./ha on the cabbage crop grown in the fields. Residues in the edible sample of cabbage were analyzed by gas choromatography for the fungicide and its metabolites. The dissipation of residues of the fungicide and its bio-efficacy against two fungi are presented. It dissipated from 3.72 to 0.072 microg/g on cabbage head by 15 days after treatment. The EC50 values of iprodione were found to be 11.5 ppm and 79.4 ppm for A. brassicicola and S. sclerotiorum, respectively. Half-life of iprodione was found to be 3 days for both cabbage head and leaves. The compatibility of the fungicide with a bio agent, T. harzianum was also studied and these two were not found to be compatible.     

An impingement plate method to detect deposits of pyrethroid insecticides

Abstract

A silica gel impingement plate for monitoring pyrethroid deposits in environmentally sensitive areas is described. The plate is simple, commercially available, and inexpensive. A residue analysis method is given for deltamethrin deposits with 83.3% mean recovery and a minimum quantifiable limit of 0.005 μg/plate. Pyrethroid deposits are strongly adsorbed to the silica gel, which prevents wash‐off by rainfall and slows photodegradation. In two field experiments, deltamethrin was readily detected 3 weeks after direct spray applications at 6 and 10 g ai/ha. Deltamethrin dissipation on the plates was first‐order with a half‐life of 2.9 ‐ 3.7 d. Photoisomers of deltamethrin were also detected on the plates and the ratio of photoisomers to deltamethrin increased over time. This ratio will indicate the age of deposits in monitoring situations.     

Residues of phosphamidon in rice fields

Thirty-day-old seedlings of rice plants (IR-20 variety) from the nursery were transplanted into experimental plots and after 52 days were sprayed with phosphamidon (Dimecron 85% EC) at two dose-rates (0.38 kg a.i. ha(-1) and 0.76 kg a.i. ha(-1)). Residues of phosphamidon in the plant, soil and water were analysed by GLC, at various time intervals, and were found to decrease steadily up to 15 days. A second application of the pesticide was made on day 113 and grains harvested on day 138. The residue level in the plants was 0.12 microg g(-1) and in the grains 0.04 microg g(-1) with the high dose. This is slightly below the EPA prescribed tolerance level of 0.05 microg g(-1). The residues in both soil and water were very low, 24 h after spraying.     

Degradation of disulfoton,oxydemeton‐methyl,methamidophos and demeton in asparagus plant

Abstract

Disulfoton and methamidophos (both at 1.12 kg a.i./ha), oxydemeton‐methyl and demeton, (both at 0.56 kg a.i./ha) were applied as post‐harvest foliar sprays to control the European asparagus aphid, Brachycolus asparagi. Oxidation of disulfoton, oxydemeton‐methyl and demeton to their corresponding sulfoxides and sulfones occurred in asparagus foliage 2 to 5 days after application. The total residues of these three compounds, including their toxic oxidative metabolites declined to less than 0.5 ppm about 47 days after the spray application whereas methamidophos persisted longer; 0.84 ppm of its residue was found even after 85 days. No residue was found above the limit of detection of 0.002 ppm in any asparagus spears which were produced in the following spring; the four compounds were sprayed on the asparagus plants during the previous season at realistic rates for aphid control.     

Determination of pesticide residues in IPM and non-IPM samples of mango (Mangifera indica)

Studies were conducted to analyze the residue of commonly used pesticides viz. methyl parathion, chloropyrifos, endosulfan, cypermethrin, fenvalerate, carbendazim, imidacloprid and carbaryl in mango, Dashehari variety, integrated pest management (IPM) and non-IPM samples were collected from the IPM and non-IPM orchards, Lucknow, India. We also present a method for the simultaneous determination of these pesticides in mango samples. Residues of methyl parathion, chloropyriphos, endosulfan, cypermethrin, fenvalerate were extracted from the samples with acetone: cyclohexane: ethyl acetate in the ratio 2:1:1 followed by cleanup using neutral alumina. Analysis was performed by gas chromatography-electron capture detector (GC-ECD) with a megabore column (OV-1). Residues of carbendazim, imidacloprid and carbaryl were extracted with acetone and after cleanup, analysis was performed by high performance liquid chromatography (HPLC) using photo diode array (PDA) detector. Recoveries of all the pesticides ranged between 72.7 – 110.6%, at 0.1 and 1.0 μg g^{? 1} level of fortification. The residues detected in non-IPM samples of mango were found to be below the prescribed limits of maximum residue limit (MRL) while IPM samples were free from pesticide residues.     

Determination of pesticide residues in IPM and non-IPM samples of mango (Mangifera indica)

Studies were conducted to analyze the residue of commonly used pesticides viz. methyl parathion, chloropyrifos, endosulfan, cypermethrin, fenvalerate, carbendazim, imidacloprid and carbaryl in mango, Dashehari variety, integrated pest management (IPM) and non-IPM samples were collected from the IPM and non-IPM orchards, Lucknow, India. We also present a method for the simultaneous determination of these pesticides in mango samples. Residues of methyl parathion, chloropyriphos, endosulfan, cypermethrin, fenvalerate were extracted from the samples with acetone: cyclohexane: ethyl acetate in the ratio 2:1:1 followed by cleanup using neutral alumina. Analysis was performed by gas chromatography-electron capture detector (GC-ECD) with a megabore column (OV-1). Residues of carbendazim, imidacloprid and carbaryl were extracted with acetone and after cleanup, analysis was performed by high performance liquid chromatography (HPLC) using photo diode array (PDA) detector. Recoveries of all the pesticides ranged between 72.7-110.6%, at 0.1 and 1.0 microg g(-1) level of fortification. The residues detected in non-IPM samples of mango were found to be below the prescribed limits of maximum residue limit (MRL) while IPM samples were free from pesticide residues.     

Bioefficacy of Iprodione Against Two Desapers,its Compatibility with T. harzianum and Residues on Cabbage Crop

Iprodione (3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxoimidazolidine-1-carboxamide) bio-assayed against fungi Alternaria brassicicola and Sclerotinia sclerotiorum was found to be highly effective for inhibiting these desapers. Inhibition of A. brassicicola was 100% up to the dose of 75 ppm and for S. sclerotiorum there was 50% inhibition for the same concentration. Formulation of the pesticide was applied @ 500 and 1000 g. a.i./ha on the cabbage crop grown in the fields. Residues in the edible sample of cabbage were analyzed by gas choromatography for the fungicide and its metabolites. The dissipation of residues of the fungicide and its bio-efficacy against two fungi are presented. It dissipated from 3.72 to 0.072 μg/g on cabbage head by 15 days after treatment. The EC₅₀ values of iprodione were found to be 11.5 ppm and 79.4 ppm for A. brassicicola and S. sclerotiorum, respectively. Half-life of iprodione was found to be 3 days for both cabbage head and leaves. The compatibility of the fungicide with a bio agent, T. harzianum was also studied and these two were not found to be compatible.     

Persistence of chlorpyrifos in a mineral and an organic soil

Chlorpyrifos (Lorsban emulsifiable concentrate) was applied at 3.4 kg AI/ha and incorporated into sand and muck soil contained in small field plots. Soil samples were taken at intervals over 2 yr. Radishes and carrots, seeded yearly, served as indicator crops for absorption of insecticide residues. Samples were extracted and analyzed, by gas-liquid chromatography, for chlorpyrifos, oxychlorpyrifos, and 3,5,6-trichloro-2-pyridinol. Chlorpyrifos residues declined rapidly, with 50% of the initial application remaining after 2 and 8 wk in sand and muck, respectively, and 4 and 9% after 1 yr. Pyridinol residues increased to 13 and 39% of the initial chlorpyrifos application in sand and muck after 1 and 8 wk, respectively, and declined thereafter. Oxychlorpyrifos was detected in the 2 soils at very low levels only in immediate posttreatment samples. In the first year of the study low levels (less than 0.1 ppm) of chlorpyrifos and the pyridinol were detected in radishes and carrots.     

Persistence of herbicide fenoxaprop ethyl and its acid metabolite in soil and wheat crop under Indian tropical conditions

The persistence of fenoxaprop ethyl {Ethyl (RS)-2-[4-(6-chloro-1,3-benzoxazol-2-yloxy) phenoxy] propionate} herbicide and its active metabolite fenoxaprop acid was investigated in soil and wheat crop. Fenoxaprop acid was prepared by alkaline hydrolysis of fenoxaprop ethyl. A HPLC method was developed in which fenoxaprop ethyl herbicide and its acid metabolite showed sharp single peak at 6.44 and 2.61 min respectively. The sensitivity of the method for ester and acid was 2 and 1 ng respectively with limit of detection of 0.1 and 0.05 μg mL^?1. The recovery of fenoxaprop ethyl and fenoxaprop acid from soil, wheat straw and grain ranged between 73.8–80.2%. In a field experiment fenoxaprop ethyl (Puma super® 10 EC) when applied to wheat crop at the rate of 120 g and 240 g a.i. ha^-1 as post emergence spray, fenoxaprop ethyl converted to fenoxaprop acid. Residues of fenoxaprop ethyl and acid dissipated in soil with a half-life of 0.5 and 7.3 days, respectively. At harvest no detectable residues of fenoxaprop ethyl or acid were observed in soil, wheat grain and straw samples.