That time of the year has arrived finally. It is time to take care of the lawn. But a word of caution: chemicals, sprays and powders used on lawns and other foliage help keep the yard green and insect free; but many pose a health threat to pets.

Powerful insect pesticides can be dangerous to pets (unlike most herbicides which are fairly harmless). These chemicals are known as organophosphates and include common pesticides such as diazinon and malathion. They are most potent when first applied and lose toxicity as they dry. Pet owners should read the product's label or ask the pesticide applicators when it is safe to return animals to the areas that have been sprayed. It should be noted, however, that pets are most often poisoned by chemicals in containers that are left within their reach. Chemical storage and proper disposal is critical.

If a pet becomes exposed to or ingests a pesticide, poisoning symptoms can include difficulty breathing, excessive salivation, drooling, vomiting, diarrhea, seizures, and even coma. Owners need to be aware of any strange behavior in their pets after the yard has been sprayed and consult a veterinarian if one or more of the above symptoms surface. Then the appropriate diagnosis and treatment can be given.

The best way to treat a poisoning, however, is to prevent it from occurring. Pets are as curious as children at times and need proper supervision around chemicals.

(The writers are Dr. Steven B. Holzman, Dr. William R. Haagenson and Dr. Kathleen Tapley. They are associated with the Nassau-Suffolk Veterinary Hospital of Farmingdale.)