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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised June 1996

Dienochlor

Tradenames: Trade names for products containing dienochlor include Pentac WP and Pentac Aquaflow. The compound may be found in formulations with a wide variety of other common pesticides.

Regulatory Status: Dienochlor is a General Use Pesticide (GUP). The U.S. EPA has classified it as toxicity class III- slightly toxic. Products containing dienochlor bear the Signal Word WARNING because they are moderately toxic when inhaled.

Chemical Class: organochlorine

Introduction: Dienochlor is an organochlorine insecticide with contact action. It is used for the control of plant-damaging mites on a variety of ornamental shrubs and trees outdoors and in greenhouses. The compound may also be used on non-food ornamental crops. Dienochlor disrupts the egg-laying ability (oviposition) of female mites.

Formulation: Not Available

Toxicological Effects:

• Acute toxicity: Symptoms of acute dienochlor exposure are similar to those of other organochlorine compounds and may include stimulation of the central nervous system (tremors, convulsions, agitation, and nervousness), slowing of breathing, nausea, vomiting, and diarrhea [47]. The oral LD50 for technical dienochlor is 3160 mg/kg in male rats, indicating that the compound is only slightly toxic by this route of exposure [47]. Dienochlor is only slightly toxic by exposure through the skin. The dermal LC50 for the compound is greater than 3160 mg/kg in rabbits [47]. Acute inhalation studies with the product Pentac 50 WP indicate that dienochlor is moderately toxic by this route of exposure. The LC50 value ranged between 1.4 mg/L and 2.4 mg/L in rats [47]. Dienochlor is not a primary skin irritant or a skin sensitizer, and is only a mild eye irritant. Rabbits exposed to a single dose of the technical product (dose undisclosed) experienced corneal opacity and irritation. The condition abated completely within 7 days [47].
• Chronic toxicity: Two subchronic feeding studies were conducted over 3-month periods. Above 6.3 mg/kg/day, rats experienced a reduction in body weight gain. At 64 mg/kg/day, mice experienced increased mortality, inactivity, hunchbacked-walk, decreased body weight gain, changes in blood and urine chemistry, and altered organ weights. The spleen and thymus also showed atrophy [17,47]. Rats fed dienochlor in their diets over 2 weeks had no effects at or below 5 mg/kg/day [17,47].
• Reproductive effects: No data are currently available.
• Teratogenic effects: No birth defects appeared in the offspring of pregnant rats fed up to 50 mg/kg/day dienochlor in their food [17].
• Mutagenic effects: Tests evaluating the mutagenicity of dienochlor have produced mixed results, but suggest that the compound is nonmutagenic or weakly mutagenic [47]. This indicates that the mutagenic risk to humans is unlikely.
• Carcinogenic effects: No data are currently available.
• Organ toxicity: Animal tests have shown the liver, kidneys, spleen, and thymus to be affected by dienochlor exposure.

• Fate in humans and animals: Female rats fed a single, low dose (1 mg/kg) of dienochlor excreted nearly 90% of the breakdown products of the compound in the feces and only 2% in the urine [48]. Nearly all of the dienochlor was broken down in the rats within 1 day. At this dose after 4 days, only 2% of the initial dose remained in the rat in the liver, kidneys, stomach, and intestines. Dienochlor is poorly absorbed through the stomach and intestines. This may account for its low oral toxicity (high oral LD50) [48]. When the compound was administered on the skin of the rats, only a very small amount passed through the skin to the blood stream (2%) [48]. It is expected that even less would penetrate the skin of humans. Only 1% of the applied dose was detected in the urine, and less than 0.2 % in the tissues.

Ecological Effects:

• Effects on birds: Dienochlor is practically nontoxic to bobwhite quail and to mallard ducks. The oral LD50 for the compound in the quail is 705 mg/kg and the 8-day dietary LC50 for dienochlor in mallards is nearly 4000 ppm [9,17].
• Effects on aquatic organisms: Tests with several species of fish indicate that the compound is highly to very highly toxic to this group of organisms. The LC50 for dienochlor is 0.6 mg/L in bluegill sunfish and 0.05 mg/L in rainbow trout [9,49]. Dienochlor is only moderately toxic to the freshwater invertebrate Daphnia magna. There are no data available on the potential of the compound to accumulate in aquatic organisms.
• Effects on other organisms: Dienochlor is practically nontoxic to bees [9].

Environmental Fate:

• Breakdown in soil and groundwater: There is very little information about the fate of the compound in the environment. Few studies have been conducted in this area. One study indicated that the compound is nonpersistent [50]. A nonpersistent compound only lasts in the environment from a few hours to up to 12 weeks [14]. Dienochlor is readily broken down by the action of sunlight [50].
• Breakdown in water: There is very little information about the fate of the compound in the environment. Few studies have been conducted in this area. One study indicated that the compound is nonpersistent [50]. A nonpersistent compound only lasts in the environment from a few hours to up to 12 weeks [14]. Dienochlor is readily broken down by the action of sunlight [50].
• Breakdown in vegetation: Not Available

Physical Properties:

• Appearance: Pure dienochlor is a colorless crystalline solid. The technical product is a light yellow powder [9].
• Chemical Name: perchloro-1,1'-bicyclopenta-2,4-dienyl [9]
• CAS Number: 2227-17-0
• Molecular Weight: 474.64
• Water Solubility: 25 mg/L @ 20-25 C [9]
• Solubility in Other Solvents: s.s. in hot ethanol, acetone, and cyclohexane; m.s. in benzene, xylene, and other aromatic hydrocarbons [9]
• Melting Point: 122-123 C [9]
• Vapor Pressure: 1.3 mPa @ 25 C [9]
• Partition Coefficient: 3.1495-3.3034 [9]
• Adsorption Coefficient: 1000 (estimated) [14]

Exposure Guidelines:

• ADI: Not Available
• MCL: Not Available
• RfD: Not Available
• PEL: Not Available
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

Sandoz Agro, Inc.
1300 E. Touhy Ave.
Des Plaines, IL 60018

• Phone: 708-699-1616
• Emergency: 708-699-1616
  

References:

References for the information in this PIP can be found in Reference List Number 6

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.