Objective 1: Investigate the efficacy of bactericides treatments for preventing new infections for young citrus trees protection.Bactericidal treatments were applied from May 2019 through March 2020. CLas titer was monitored in leaf tissue in response to antibiotic treatments using quantitative real-time PCR analysis. In this report, the results of the CLas-infection rate in citrus leaves from May to September are described. Currently, citrus leaves tissue samples from October through March are being processed to analyze the CLas-infection rate. Trees and ACP were considered CLas-infected (positives) when CT values were below 35. 1. Bactericides (monthly rotation): Before the bactericide application, the overall CT mean of the treatment was 34.5. After bactericide applications from May to September, the CLas bacterial titers have fluctuated without showing constant patterns. In June, the overall CT mean of the treatment increased to 35.1. In July, the overall CT mean of the treatment decreased to 33.6. In August, the CT mean increased to 36.38. In September, the CT mean of the treatment decreased to 33.14 representing a higher rate of CLas infection on the trees sampled. 2. Bactericides (quarterly rotation): Before the bactericide application, the overall CT mean of the treatment was 39.18. After bactericide applications from May to September, the CLas bacterial titers have also fluctuated without showing constant patterns. In June, the overall CT mean of the treatment decreased to 33.99. In July, the overall CT mean of the treatment increased to 34.07. Similarly, in August, the CT mean increased to 36.38. However, In September, the CT mean of the treatment decreased to 34.28 representing a low rate of CLas Infection on the trees sampled. 3. Negative Control (insecticide + Tree defender exclusion netting): Before bactericide application, the overall CT means of the treatment was 38.61. After bactericide applications from May to September, the CLas bacterial titers showed similar patterns from August to September In June, the overall CT mean of the treatment decreased to 34.65. In July, the overall CT mean of the treatment decreased to 33.69. In August and September, the CT mean were 37.69 and 37.45, respectively, meaning low rates of CLas infection on this treatment. 4. Positive Control (insecticide only): Before the bactericide application, the overall CT mean of the treatment was 39.08. After bactericide applications from May to September, the CLas bacterial titers showed similar patters from August to September. In June, the overall CT mean of the treatment decreased to 36.11. In July, the overall CT mean of the treatment decreased to 34.48. In August and September, the CT mean were 37.69 and 37.45, respectively, meaning low rates of CLas infection on this treatment. ACP adults were counted bi-weekly from May 2019 through March 2020. Preliminary results showed a low ACP population in citrus locations due to the active vector management performed by the farm manager. Therefore, no ACP adults were collected to analyze the CLas-infection rate. Objective 2. Determine the effect of bactericides application frequency on Las infection of citrus.We applied bactericide treatments from May 2019 through March 2020. CLas titer was monitored in leaf tissue and the Asian Citrus Psyllid (ACP) in response to antibiotic treatments using quantitative real-time PCR analysis. In each treatment, the CLas infection rate was analyzed on five females and five males. In this report, the results of the CLas-infection rate in citrus leaves and ACP from May through September 2019 are described. Currently, citrus leaves tissue and psyllid samples from October through March are being processed to analyze the CLas-infection rate. 1. Bactericides (monthly rotation): Before bactericide application, the overall CT mean of the treatment was 28.09. After bactericide applications from May to September, the CLas bacterial titers fluctuated from May to June. However, the CT mean showed similar infection rates from July to September. In June, the overall CT mean of the treatment increased to 29.24. In July, the overall CT mean of the treatment increased to 31.12. In August and September, the CT mean decreased to 29.47 and 29.76. Bi-weekly collected ACP from the treatment from May and July showed CT means of 34.5 and 37, respectively. 2. Bactericides (quarterly rotation): Before bactericide application, the overall CT mean of the treatment was 27.89. After bactericide applications from May to September, the CLas bacterial titers fluctuated from May to June. However, the CT mean showed similar infection rates from July to September. In June, the overall CT mean of the treatment increased to 29.90. In July, the overall CT mean of the treatment increased to 30.73. In August and September, the CT mean decreased to 29.49 and 29.15. Bi-weekly collected ACP from the treatment from May and July showed CT means of 35 and 38, respectively. 3. Positive Control (insecticide only): Before the bactericide application, the overall CT mean of the treatment was 28.09. After bactericide applications from May to September, the CLas bacterial titers shown a constant pattern in the CT means from June to September ranging from 29.5-30 approximately. Bi-weekly collected ACP from the treatment from May and July showed CT means of 36 and 37, respectively.