&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.
Pest collars can be more effective at combating ticks than fleas, because the collars rest around the dogâs neck. This means the insecticide is most effective in the neck and face area, which also happens to be where ticks gravitate. If ticks are more of a concern for you than fleas, collars might be a great option.