Question
I have a live oak in south florida that has a insect all over it. It has white on its backs and also what appears to be little spikes on its back as well. Thanks

Answer
Sounds like one of the tussock moth caterpillars. Tussock moth caterpillars are occasionally abundant and widespread in Florida. Besides the annoying presence of numerous hairy caterpillars, these insects may spin their difficult-to-remove cocoons on houses, boats, picnic tables and other outdoor articles. Feeding by the caterpillars usually has little impact on oak trees, their preferred hosts, but wind-blown caterpillars may land on and defoliate small trees and shrubs around the yard. Probably the WHITEMARKED TUSSOCK MOTH, Orgyia leucostigma

Severe defoliation for 2 or more consecutive years will stress trees. Death may result if other stress factors also weaken the trees. Its habit of falling or spinning out of trees is unnerving to most people.

Biology and Habits
Larvae emerge from eggs during leaf expansion in spring. They disperse readily on silk strands while still young. Older larvae are active crawlers. Pupation occurs in any shaded and protective site. Generally, the 2nd or 3rd generations are not as noticeable as the 1st or spring generation. Overwinter as eggs laid on the females' cocoons.  

Number of Generations 2 or 3 generations per year.
Signs of Infestation Loss of foliage. Falling frass (dark pellets of caterpillar excrement). Cocoons in bark crevices, under overhangs of buildings, and other shaded, protective sites. Crown thinning and/or branch dieback.  

Persons disturbed by tussock moth caterpillars may wish to do some of the following:

Apply an insecticide to the foliage of the host trees before the caterpillars mature and begin dispersing. Generally, however, only shrubbery threatened by the heavy feeding of immature wind-blown larvae would warrant a pesticide application. I would use Orthene insecticide. Check with your local nursery for this or other insecticide that will control caterpillar feeding on trees.
Walk around the house with a broom and sweep the climbing caterpillars into a pail of soapy water before they have a chance to spin their cocoons.
Remove cocoons by slipping tweezers or a similar instrument between the cocoon and the wall. Wear a long-sleeved shirt while doing this, as the caterpillar hairs in the cocoon may irritate the skin on the forearm.