The use of antimicrobials is one of the few effective treatments against HLB in citrus trees. However, penetration of substances into trees is hindered by the presence of protective layers such as the thick cuticle on leaves, and cork on stems. To overcome the obstacles imposed by the cuticle to increase penetration of externally supplied substances, we have successfully tested laser light. Laser light technology involves the use of low level light energy to disperse the cuticle creating microscopic and superficial indentations of approximately 250 �m. In doing so, infiltration of substances into the leaf is greatly enhanced. Once inside the leaf tissue, substances can follow the natural transport pathway through the apoplast, absorbed by phloem cells, and transported throughout the tree. Specific goals are 1. To build and test a more flexible and elaborate laser machine that will allow for more decisive experiments in the greenhouse; 2. Test for the effectiveness of several antimicrobials; 3. Carry out initial field experiments with young trees. The laser machine was delivered and tested under laboratory conditions. A series of initial experiments were conducted in efforts to fine tune the machine in terms of energy, distance, speed of laser and striking angle. Additional experiments have been conducted comparing the effectiveness of laser in enhancing penetration of oxytetracycline compared to untreated leaves. We have also tested the effect of waxing the lasered area to prevent dessication. In some key experiments we have tested the changes in titer numbers of samples treated with antimicrobial in the presence and absence of laser. At the moment, the data collected indicate the superior penetration and effect of antimicrobials when leaves are subjected to a laser treatment. Additional experiments to quantify the penetration improvement and movement of oxytetracycline down the phloem are being conducted.