Measure the circumference of each orange tree.
Obtain 2-foot-wide pieces of sheet metal with the lengths equivalent to the circumference of each tree, plus a couple of inches.
Punch several 1/4-inch holes evenly spaced in either end of the sheet metal with an awl.
Secure the pieces of sheet metal about 6 feet up each tree with wire and springs. These are rodent guards to prevent critters from climbing the trees. The springs allow the trunk to expand as the tree grows.
Trim back orange tree branches that touch anything which rodents could use to gain access to the fruit, such as walls, buildings or unprotected trees. If squirrels are a problem, ensure there is a gap of at least 8 feet between the tree and the access point. Alternatively, fit a rodent guard or baffle on the access point as well. Squirrels are excellent jumpers.
Slit pieces of PVC pipe lengthwise, pull them apart slightly and clip them over any standing wires or lines, except power lines, near the orange trees. These spin when a rodent tries to climb over them, knocking it off.
Clear away all fallen fruit immediately to discourage rodents from feeding in the area.
Replace the guards or loosen the wire once the springs have reached their full extent.