Roof rat and citrus rat are alternative names for the black rat. The black rat (Rattus rattus) used to be the most widespread species of rat, and is the one that carried the bubonic plague throughout Europe. Now the black rat has been superseded in European and North American homes by the Norwegian, or brown rat (Rattus norvegicus), but the black rat still flourishes outside in gardens and on farmland. It is also the most common rat in Florida. This rat likes fruit and is an excellent climber. If you own a citrus tree, you may be less than delighted to discover you are sharing your crop with local rodents. Fortunately, it is not particularly difficult to rat-proof a tree.
Prune all branches and twigs that touch fences, walls, the ground, or anything else. These form bridges, allowing rats easy access to your tree.
Measure the circumference of your tree near the bottom.
Purchase a piece of sheet metal about 20 inches wide. The length should be the circumference of the tree plus 2 inches. Ask the supplier to punch five or six holes in both ends.
Bend the sheet around the bottom of the tree, and use strong wire to secure the ends together. This forms a slippery guard that rats cannot climb.
Remove all fruit immediately after it falls to discourage rats from staying nearby.
Encourage natural predators such as snakes and small mammalian carnivores by piling up scrap wood and twigs in an undisturbed corner of your land. Minimizing the use of outdoor lights at night encourages owls. Natural predators keep rodent populations under control.