Herbicides used on lawns are formulated to kill weeds, but many herbicides are toxic to dogs. Some pesticides used to kill white grubs and other insects that can damage lawns are also toxic to dogs. Humans can read labels on warnings and take measures to protect themselves from the effects of toxic chemicals, but dogs are at special risk. Studies show that herbicides and pesticides inhaled or eaten by dogs may damage their liver or kidney plus cause cancer and birth defects.
Studies Involving Dogs
Although the warnings on herbicides and pesticides are directed at people, more data are actually known about their effect on dogs because dogs are sometimes used as laboratory research subjects. Humans, not dogs, are a priority of companies marketing herbicides and pesticides, so the published data document possible harmful effects on humans, not dogs.
Special Risk for Dogs
Dogs sniffing grass treated with herbicides and pesticides can inhale toxins. It is common for dogs to walk and roll around on lawns treated with herbicides and pesticides. Dogs also absorb pesticide residues from chewing on plants that have been treated with insect killers.
A 1991 study published by The Journal of the National Cancer Institute reports that dogs are more likely to develop cancers if their owners sprinkled the herbicide 2,4-D on their lawns four or more times a year.
A 2004 study reported in the Journal of the American Veterinary Medicine Association reported that Scottish terriers had an increased risk of developing canine bladder cancers when exposed to lawns treated with herbicides containing the active ingredient phenoxy. Lawns sprayed with herbicides containing the active ingredient glysophate to kill broadleaf weeds can also cause dogs to vomit if the sprays drift onto their food bowls or chew toys.
Commercial insecticides containing organophosphates or carbamates as active ingredients are often applied to lawns to kill white grubs, the larvae of Japanese beetles that eat the roots of grass. Dogs rolling around on the grass can pick up both of these toxic insecticides. Animal scientist Julio E. Correa of the University of Alabama says that while dogs excrete both organophosphates and carbamates quickly, both varieties of insecticides can cause them to drool and have muscle tremors. According to Tina Wismer of the Animal Poison Control Center of the American Society for the Prevention of Cruelty Animals, dogs like to eat slug and snail bait that contains metaldehyde; she says eating metaldehyde can cause dogs to have seizures and die.
Herbicides and pesticides should be stored in the original containers in a place where dogs cannot get to them, and dogs should be kept away when pesticides are being applied. Dog dishes, balls and chew toys should be removed from lawns when the grass is being treated. Empty herbicide and pesticide containers should be rinsed, wrapped in newspapers and put in a trash can. Dogs should be kept away from a lawn treated with herbicides or pesticides until it is completely dry.