&middotDrought damage - needles gradually turn yellowish-green and then light brown. This starts at the top of the tree and progresses downward and from the outside in. &middotAnimal injury - dog urine can cause some browning and dropping of lower branches on arborvitae and junipers.
There are many different brands of cat flea collars. Generally, flea collars work by either emitting a toxic gas to the local area (head/neck of the pet) or by exuding chemicals that are absorbed into the animal's skin. Some flea collars have an Insect Growth Regulator (IGR), to prevent development of cat fleas, eggs and larvae.
Frontline Tritak is a flea and tick preventative that is applied topically between the shoulders of dogs. Revolution, a topical that consists of a few drops on the skin at the base of the neck, prevents heartworms, hookworms and roundworms in cats, ear mites, and also does an excellent job of preventing fleas.