Objective 1: Investigate efficacy of bactericide treatments for preventing new infections. This objective is necessary to determine the potential role of bactericides in an integrated pest management program for young tree protection. Experiment were initiated in new tree plantings in a Wauchula grove.Initial leaf samples were collected prior to treatments to evaluate CLas titers in the uninfected trees. The following treatments were applied this second quarter of 2019: Treatments were applied to trees as follows:1. Antibiotics (monthly rotation) 2. Antibiotics (quarterly rotation)3. Negative Control (insecticide + Tree defender exclusion netting)4. Positive Control (insecticide only)Tree height and circumference were quantified. ACP populations were monitored biweekly (eggs, nymphs, adults). No flush, eggs, or nymphs were detected after treatment applications. Tap sampling of adults was conducted, and insects are currently being processed to determine the infection rate. Objective 2. Determine the effect of bactericide application frequency on Las infection of citrus.This experiment will determine the most effective application frequency for bactericides to maximize tree health. This will inform revised recommendations for the use of antimicrobials in commercial citrus groves. Experiment were initiated in new tree plantings in a Lake Alfred grove. Initial leaf samples were collected prior to treatments to evaluate CLas titers in the uninfected trees, then one week after treatment applications. The following treatments were applied this second quarter of 2019: 1. Antibiotics (monthly rotation) 2. Antibiotics (quarterly rotation)3. Positive Control (insecticide only) Tree height and circumference were quantified. ACP populations were monitored biweekly (eggs, nymphs, adults). No flush, eggs, or nymphs were detected after treatment applications. Tap sampling of adults was conducted, and insects are currently being processed to determine the infection rate. Objective 3: Quantify the effect of repeated inoculation of the efficacy of bactericides. This experiment will determine whether bactericides are sufficient to overcome the pressure of repeated Las inoculation by ACP. This will inform revised recommendations for integrated pest management programs to improve use of insecticides in conjunction with bactericides in commercial citrus groves. We have procured trees and will initiate experiments next quarter.