Here is a brief explanation of why there is an ISD tag on your citrus tree:
Propagating citrus nursery are required by the State of Florida's Ag Department to treat every tree that leaves their screen-house facility with the systemic insecticide, at that time an ISD tag is placed on the plant with the date of application, as well an expiration date, which is 6 months later than the date of application. The primary reason for the use is to prevent Psyllids from spreading HLB (citrus Greening), not every Pysllid is a carrier of HLB, but the effort is to protect the plant from HLB.
The treatment also prevents other insects that might feed on the tree from doing so as well, like Aphids, white flies, citrus leaf minors and any other piercing or sucking insects. What this means to a homeowner is that it gives added protection against pests. Another way of looking at it is that it helps reduce the amount of open wounds on a leaf's surface, which reduces the point of entry for citrus canker. Learn more about citrus canker by visiting our citrus canker page.