&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.
Flea powders and sprays are relatively inexpensive methods of repelling fleas for cats. Be cautious when applying these products, however, as the spray or fine powder can be irritating to the mouth and lungs if breathed in (for both animals and humans). Also be sure to use caution around the eyes, nose, and mouth.