Orthene is a product name for a general-use insecticide for both commercial farmers as well as homeowners to kill any number of biting or sucking insects on crop or ornamental plants. It is purchased in liquid-concentrate, soluble-grain or wettable powder forms and then appropriately mixed into water for application on plant leaves, stems and buds. In the United States, this colorless to white insecticide is manufactured by Valent USA of Walnut Creek, California.
The active chemical ingredient in Orthene insect spray is acephate. Once applied, acephate is quickly absorbed into the tissues and transported throughout all parts of the treated plant. According to the Extension Toxicology Network, 24 hours after application, only 25 percent of the chemical remains on the plant leaf or stem surface.
Acephate is an organophosphate class chemical that inhibits cholinesterase, an enzyme in animal (and human) tissues that facilitates transmission of nerve impulses. Exposure to cholinesterase-inhibiting products, in high or prolonged doses, impairs neurological development in fetuses, leads to chronic fatigue syndome in infants and can lead to Parkinson's disease, according to the Alaska Community Action on Toxins.
Acephate is deadly to many insects, including beneficial ones like honeybees. It is only moderately toxic to birds and minimally toxic to freshwater fish. It is only a suspected carcinogen, but no substantial research measuring the dangers to human subjects has taken place. Human exposure to forms of acephate can cause eye watering and irritation, damage to the structure or functioning of the gastrointestinal tract, gall bladder or liver, according to the Alaska Community Action on Toxins. Moreover, acute exposure can cause cardiac responses, dark or blurred vision, cataracts, abdominal cramps, heartburn, hyperperistalsis, chest tightness, productive cough, wheezing, pulmonary edema, and death due to respiratory failure. All products labeled Orthene that contain acephate display the signal word "caution" on the label.
Proper safety precautions are warranted when using Orthene. Product labels guidelines, instructions and dosages must be followed, according to U.S. Federal Law, including the use of personal safety equipment such as clothing, gloves and eye wear. Pets and children must not come in contact with treated garden areas until the spray has fully dried.
Acephate dissipates rapidly when in contact with soil, in less than three days (or six days in soggy, oxygen-depleted ground). On plants, residues of the chemical persist from one to 14 days, according to the Extension Toxicology Network. Factors that affect the half-life or natural breakdown of acephate include the particular plant species (and its metabolism or leaf/stem characteristics) or timing and amount of rainfall that occurs after application.