1. Please state project objectives and what work was done this quarter to address them: This project aims to test SAMP efficacy in the field and greenhouse on important citrus varieties in Florida and California. A. Foliar spray of SAMP before exposure to non choice feeding of ACP reduced the infection rate on sweet orange and Lisbon lemon trees in the greenhouse trials. After 10 months of infection, the SAMP-treated trees have a significantly lower infection rate (23%) compared to the mock treated plants (100%). Much less ACP eggs were hatched to nymphs after the SAMP treatment. Similar results were observed on Tango mandarin on Carrizo rootstock. We are at the end of this experiment, and are getting the last measurement for publication. This study suggests that SAMP also has negative impact on ACP transmission and development. B. We have established collaboration with Dr. Megan Dewdney in UF for all the field trials in FL. A large scale field test on 240 young Hamlin trees with 4 different treatments, 60 trees per treatment, was laid out in a completely randomized design. The treatments are 1. Untreated control, 2. Treatment in the nursery 1 week prior to planting and field applications (10 µM in 158 ml/tree) every 2 months, 3. No nursery treatment with field applications every 2 months starting 10 days post-planting, 4. The injection treatment with Invaio simple injection device every 6 months. 23 months after tree planting in the field, the trees are showing declining symptoms caused by HLB. In four treatments, the treatment 2 which is with nursery spray followed by foliar spray every two months has the lowest declining rate of trees. The pandemic also caused a few treatment delays which may reduce the significant of SAMP treatment. Overall, we observed that the treatment can reduce the declining rate. However, we also found that injection on young trees can cause damage sometimes which could also impact on growth of the trees. Recent Hurricane hit in Florida has caused significant damage on many trees, we have to extend this experiment for at least 6-9 months to allow the trees to recover.We will continue to monitor the tree growth and to measure the CLas titer during the next 12-18 months. C. A second field test on infected 4-year old ‘Hamlin’ sweet orange bearing trees was also initiated. We have located grove in the Lake Wales region. The trial involves a total of 125 bearing trees and was laid out as a randomized complete block design with five blocks and five replicates per block. The treatments in this trial were an untreated control and bimonthly foliar application. The foliar spray treatment volume one treatment is 25 gal of 10 µM (60 mg/L) SAMP solution. Three additional treatments from an additional funding source are to look at the peptide as various injection treatments. Due to the pandemic, Dr. Megan’s group didn’t manage to collect the fruits and measure the fruit yield before the farmers collected everything, so we had to wait for the measurement for this year. All the treatment and measurement is still on going. THe Hurricane also caused significant damage on these bearing trees. More variable results will be expected.2. Please state what work is anticipated for next quarter: Test I: Field Test I- SAMP efficacy test on 240 newly planted ‘Hamlin’ sweet orange treesWe will continue to monitor the tree growth, to measure the size, disease levels and CLas titers in trees and ACP to evaluate the effectiveness of SAMP and better delivery methods. Test II: Field Test II- SAMP efficacy test on 125 infected 4-year old ‘Hamlin’ sweet orange trees.The second field trial was set up to test if SAMP can remediate an HLB-affected young citrus grove. This experiment is ongoing in the Ridge region of Florida on the deep sandy soils. The trial began in August 2021, and we are making bi-monthly foliar applications and continuing to monitor tree growth, disease severity, and CLas titers in trees and ACP. Considering the hurricane impact last year, we expect to monitor the trial until mid 2024 to get enough data.3. Please state budget status (underspend or overspend, and why):This project is in combination with the greenhouse and field trials supported by other funding source USDA NIFA. The CRDF buget was fully spent on purchasing large quantity of synthetic SAMP. All the other cost, such as the personnel and consumable cost, were supported by USDA NIFA (which is also at the end of the grant). We are in urgent need of new funding support to continue this SAMP project.