Pyridaben

SRP: At the time of review, criteria for land treatment or burial (sanitary landfill) disposal practices are subject to significant revision. Prior to implementing land disposal of waste residue (including waste sludge), consult with environmental regulatory agencies for guidance on acceptable disposal practices.

Wash hands before eating, drinking, chewing gum, using tobacco, or using the toilet. Remove clothing immediately if pesticide gets inside. Remove PPE immediately after handling this product. Wash the outside of gloves before removing. As soon as possible, wash thoroughly and change into clean clothing. /Pyramite/

Tolerances are established for residues of the insecticide pyridaben (2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one) on the following plants, and of the insecticide pyridaben and its metabolites (2-tert-butyl-5-(4-(1-carboxy-1-methylethyl)benzylthio)-4-chloropyridazin-3(2H)- one) and (2-tert-butyl-5-(4-(1,1-dimethyl-2-hydroxyethyl)benzylthio-4-chloropyridazin-3(2 H)-one) on animals, as follows: almond, hulls: 4.0 ppm; apple: 0.5 ppm; apple, wet pomace: 0.75 ppm; apricot: 0.05 ppm (revocation/expiration date 6/30/04); cattle, fat: 0.05 ppm; cattle, meat: 0.05 ppm; cattle, meat byproducts: 0.05 ppm; cherry, sweet: 0.05 ppm (revocation/expiration date 6/30/04); cherry, tart: 0.05 ppm (revocation/expiration date 6/30/04); citrus: 0.5 ppm; citrus, dried pulp: 1.5 ppm; citrus, oil: 10.0 ppm; goat, fat: 0.05 ppm; goat, meat: 0.05 ppm; goat, meat byproducts: 0.05 ppm; grape: 1.5 ppm; hog, fat: 0.05 ppm; hog, meat: 0.05 ppm; hog, meat byproducts: 0.05 ppm; horse, fat: 0.05 ppm; horse, meat: 0.05 ppm; horse, meat byproducts: 0.05 ppm; milk: 0.01 ppm; nectarine: 2.5 ppm; nut, tree crop group: 0.05 ppm; peach: 2.5 ppm; pear: 0.75 ppm; pistachio: 0.05 ppm; plum: 2.5 ppm; prune: 2.5 ppm; sheep, fat: 0.05 ppm; sheep, meat: 0.05 ppm; and sheep, meat byproducts: 0.05 ppm.

Tolerances with regional registration, as defined in section 180.1(n) are established for residues of the insecticide pyridaben (2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one) in or on the following raw agricultural commodity: cranberry, 0.5 ppm.

For handling activities, use a dust/mist filtering respirator... or a NIOSH approved respirator with a N, P, R, or HE prefilter. Wear long-sleeved shirt and long pants, socks and shoes and waterproof gloves. ...Wear goggles, face shield, or safety glasses. /Pyramite/

LD50 Bobwhite quail oral >2250 mg/kg

LD50 Mallard ducks oral >2500 mg/kg

LC50 Rainbow trout 1.1-3.1 ug/l (96 hr) /Conditions of bioassay not specified/.

LC50 Bluegill sunfish 1.8-3.3 ug/l (96 hr) /Conditions of bioassay not specified/.

For more Ecotoxicity Values (Complete) data for PYRIDABEN (6 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), a Koc value >5000(5) indicates that pyridaben is expected to be immobile in soil(SRC). Volatilization of pyridaben from moist soil surfaces may occur(SRC) given an estimated Henry's Law constant of 4.7X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 1.18X10-6 mm Hg(4), and water solubility 0.012 mg/l(4). Pyridaben is not expected to volatilize from dry soil surfaces(SRC) based upon an experimental vapor pressure of 1.18X10-6 mm Hg(4). Pyridaben may undergo photolysis in surface soils and it has been reported that the photolytic half-life for the reaction is 12 days(5). Studies have shown that hydrolysis and biodegradation are not important environmental fate processes(5).

AQUATIC FATE: Based on a classification scheme(1), a Koc value of >5000(6) indicates that it is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(SRC) based upon an estimated Henry's Law constant of 4.7X10-5 atm-cu m/mole(2), derived from its vapor pressure, 1.18X10-6 mm Hg(3), and water solubility 0.012 mg/l(3). Using this Henry's Law constant and an estimation method(2), volatilization half-lives for a model river and model lake are 28 hours and 14 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 60 years(SRC) if adsorption is considered(5). According to a classification scheme(4), an estimated BCF of 7500(SRC), from its water solubility of 0.012 mg/l(3), and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is very high(SRC). However, experimental data has shown that pyridaben has a low potential for bioconcentration in fish based on studies with rainbow trout and fathead minnow(6). It has been reported that photolysis is the main degradation route in water and that the photolytic half-life is 30 minutes(6). In an outdoor microcosm study, pyridaben was applied as an aqueous suspension at three concentrations (0.34, 3.4, 34.0 ug/l) to control tanks once in April and once in May. The dissipation half-life in microcosm water for the low, middle, and high treatment concentrations for both applications ranged from 11.8 to 28.5 hours(6). After both applications at 3.4 ug/l, pyridaben was not detected in sediment within 24 hours, whereas non-linear regression of residue data from the 34.0 ug/l tanks gave a dissipation half-life in sediment of approximately 9.8 days(6). Aerobic aquatic metabolism studies indicate that biodegradation and hydrolysis are not important routes for removal of pyridaben in aquatic systems(6).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), pyridaben, which has an experimental vapor pressure of 1.18X10-6 mm Hg at 20 °C(3) is expected to exist in both the vapor and particulate phases in the ambient atmosphere(1). Vapor-phase pyridaben will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(2); the half-life for this reaction in air is estimated to be 9.4 hours(SRC). The rate constant for the vapor-phase reaction of pyridaben with ozone has been estimated as 1.7X10-16 cu cm/molecule-sec at 25 °C(SRC) which was derived using a structure estimation method(2). This corresponds to an atmospheric half- life of about 7 days(SRC) at an atmospheric concentration of 7X10+11 ozone molecules per cu cm. Pyridaben may also be susceptible to photolysis in the atmosphere since it has been shown to undergo aqueous photolysis(SRC). Particulate-phase pyridaben will be removed from the atmosphere by wet and dry deposition(2).

/AQUATIC SPECIES/ Residual toxicities of avermectin b1 and pyridaben for 2- to 28-day exposure periods were assessed in laboratory and greenhouse trials for eight species of beneficial arthropods that are commercially produced for greenhouse pest management. In laboratory trials, Amblyseius degenerans (Berlese), Aphidius colemani (Viereck), Aphidoletes aphidimyza (Rondani), Dacnusa sibirica (Telenga), Encarsia formosa (Gahan), and Orius insidiosus (Say) showed high mortality (>85%) when exposed to 6-day residues of both acaricides. Lower toxicities were observed for pyridaben to the predatory mites Amblyseius cucumeris (Oudermans) and Phytoseiulus persimilis (Athias-Henroit), and for avermectin b1 to A. cucumeris after exposure to 6-day residues. In greenhouse trials, pyridaben showed significantly higher residual toxicity to all beneficial species than avermectin b1. Pyridaben had high residual toxicity (40-60% mortality) to E. formosa, A. colemani, A. aphidimyza, A. degenerans, and P. persimilis 6 days after treatment. Residual toxicity of pyridaben to D. sibirica, A. cucumeris, and O. insidiosus decreased to a low level (<15% mortality) after 6 days. Based on the results of the greenhouse trials, ...Pyridaben can ...be combined in Integrated Pest Management (IPM) programs with A. cucumeris, O. insidiosus, and D. sibirica after a 6-day residual period.

An estimated BCF of 7500(SRC) was calculated for pyridaben, using an experimental water solubility of 0.012 mg/l(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is very high(SRC). However, experimental data has shown that pyridaben has a low potential for biocentration in fish based on studies with rainbow trout and fathead minnow(4).

The Henry's Law constant for pyridaben is estimated as 4.7X10-5 atm-cu m/mole(SRC) derived from its vapor pressure, 1.18X10-6 mm Hg(1), and water solubility, 0.012 mg/l(1). This estimated Henry's Law constant indicates that pyridaben may volatilize from water surfaces(2). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 28 hours(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 14 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 60 years(SRC) if adsorption is considered(4). Pyridaben's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). Pyridaben is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure of 1.18X10-6 mm Hg(2).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 90-day rat study, plasma cholinesterase enzyme (ChE) was statistically-significantly inhibited in the females at the highest dose tested (HDT) of 350 ppm (25.71 mg/ kg/day for males or 27.68 mg/kg/day for females).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ In a 21-day dermal toxicity study, repeated doses of pyridaben were applied topically to approx 10% of the body surface area of rats at doses of 0, 30, 100, 300, or 1,000 mg/kg/day for 21 days. Increased squamous cell hyperplasia and/or surface accumulation of desquamated epithelial cells were noted sporadically in the 100, 300, and 1,000 mg/kg/day dose groups. These findings appear to be due to abrasions of the skin when the powdered substance was applied onto the skin, rather than a dose-related effect. No gross dermal irritation effects were noted. Based on the results of the study, the systemic dermal toxicity NOAEL is 100 mg/kg/day. The systemic dermal toxicity LOEL is determined to be 300 mg/kg/day based on decreased body weight in the females. The dermal irritation NOAEL is 100 mg/kg/day.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ There are developmental toxicity studies in rats and rabbits (by the oral or dermal routes), and a multi-generation reproduction study in rats. The developmental and reproduction toxicity studies showed no effect on reproduction and no increased susceptibility of rats or rabbits to in utero and/or postnatal exposure to pyridaben as demonstrated by a higher developmental lowest observed adverse effect level (LOAEL) than those observed to produce maternal toxicity.

/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ In a developmental toxicity study, Sprague-Dawley rats (22/group) from Charles River, U.K., received NC-129 (Pyridaben, 98.0% active ingredient (a.i.)) via gavage at dose levels of 0, 2.5, 5.7, 13.0, or 30.0 mg/kg/day from gestation day 6-15, inclusive. Natural mating was used. Maternal toxicity, observed at 13.0 and 30.0 mg/kg/day, consisted of decreased body weight/weight gain and food consumption during the dosing period. Based on these effects, the Maternal Toxicity LOEL is 13.0 mg/kg/day and the Maternal Toxicity NOAEL is 4.7 mg/kg/day (82% of 5.7 mg/kg/day based on concn analysis). Developmental toxicity NOAEL is 13.0 mg/kg/day based on observed decreased fetal body weight and increased incomplete ossification in selected bones at 30.0 mg/kg/day (LOEL).

For more Non-Human Toxicity Excerpts (Complete) data for PYRIDABEN (6 total), please visit the HSDB record page.

The rate constant for the vapor-phase reaction of pyridaben with photochemically-produced hydroxyl radicals has been estimated as 4.1X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 9.4 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of pyridaben with ozone has been estimated as 1.6X10-16 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(1). This corresponds to an atmospheric half-life of about 7 days at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(1). Hydrolysis is not expected to be an important route for removal of pyridaben in aquatic systems(2). It has been reported that photolysis is the main degradation route in water and that the photolytic half-life is 30 minutes(2). The photolytic half-life in soil has been reported as 12 days(2). In an outdoor microcosm study, pyridaben was applied as an aqueous suspension at three concentrations (0.34, 3.4, 34.0 ug/l) to control tanks once in April and once in May. The dissipation half-life in microcosm water for the low, middle, and high treatment concentrations for both applications ranged from 11.8 to 28.5 hours(2). After both applications at 3.4 ug/l, pyridaben was not detected in sediment within 24 hours, whereas non-linear regression of residue data from the 34.0 ug/l tanks gave a dissipation half-life of approximately 9.8 days(2). Studies indicate that hydrolysis of pyridaben is not an important environmental fate(2).

New Active Ingredients ... includes pesticide active ingredients initially registered after November 1, 1984, that currently have active product registrations. By law, these newer pesticides are not subject to the reregistration program. They must, however, meet the new safety standard of the FQPA, and will be reviewed on a 15-year cycle under the registration review program. ... Active Ingredient Number: 129105; Type of Pesticide: conventional-insecticide/miticide; Use Site: food use, greenhouse ornamentals; Year: 1995.

Tolerances are established for residues of the insecticide pyridaben (2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one) on the following plants, and of the insecticide pyridaben and its metabolites (2-tert-butyl-5-(4-(1-carboxy-1-methylethyl)benzylthio)-4-chloropyridazin-3(2H)- one) and (2-tert-butyl-5-(4-(1,1-dimethyl-2-hydroxyethyl)benzylthio-4-chloropyridazin-3(2 H)-one) on animals, as follows: almond, hulls; apple; apple, wet pomace; apricot (revocation/expiration date 6/30/04); cattle, fat; cattle, meat; cattle, meat byproducts; cherry, sweet (revocation/expiration date 6/30/04); cherry, tart (revocation/expiration date 6/30/04); citrus; citrus, dried pulp; citrus, oil; goat, fat; goat, meat; goat, meat byproducts; grape; hog, fat; hog, meat; hog, meat byproducts; horse, fat; horse, meat; horse, meat byproducts; milk; nectarine; nut, tree crop group; peach; pear; pistachio; plum; prune; sheep, fat; sheep, meat; and sheep, meat byproducts.

Tolerances with regional registration, as defined in section 180.1(n) are established for residues of the insecticide pyridaben (2-tert-butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one) in or on the following raw agricultural commodity: cranberry.