Preventing young trees from psyllids and infection with CLas through use of protective netting

Preventing young trees from psyllids and infection with CLas through use of protective netting

Report Date: 09/11/2020
Project: 18-032C   Year: 2020
Category: ACP Vector
Author: FERNANDO ALFEREZ
Sponsor: Citrus Research and Development Foundation

1. Please state project objectives and what work was done this quarter to address them: As in the last quarter, work in this quarter has been affected by the UF work restrictions due to the COVID-19. However, as activities have been gradually resumed, we have been able to accomplish most of the work that was scheduled. These are: Objective 1. Assessing tree growth and absence of psyllids and HLB disease symptoms (including CLas bacteria titer) under protective covering (i.e., IPC). We have continued monitoring trunk diameter and canopy area. Trunk diameters in IPC covered trees continue to show bigger diameters with statistical significance. All IPC trees are still HLB-negative and show less incidence in canker. We have continued monitoring the incidence of pests and psyllids. In August 2020, we removed the IPC from the first experiment and we are now monitoring for potential HLB infection of the uncovered trees in real time (i.e., monthly). Objective 2. Assessment of alternative netting approaches involved in ‘targeted’, ‘alternated’ or ‘patterned’ setup of IPC in groves for more cost-effective protection. After planting the new 700 trees last quarter in an alternated pattern we are monitoring for CLas in trees adjacent to the IPC-covered trees. In addition we started collaborating with some commercial growers who are also evaluating different netting layouts. We plan to collect data on psyllid populations and HLB incidence. Objective 3. Monitoring the transition from vegetative to reproductive stage in the covered trees as compared to the uncovered. We are starting to collect data on parallel experiments at SWFREC, Hendry Co, and Central Florida using Bingo, Early Pride, and Tango trees. These experiments will allow us to determine the ability of these varieties to set fruit in the absence of pollinators. Objective 4. Comparing IPC with CUPS-like systems. We performed last season an experiment on the effect of deficit irrigation in all the varieties and we already saw that we can control blooming: we saw more bloom inside CUPS and IPCs after applying deficit irrigation. After June drop, we can now say that the same is true for fruit set. Outreach activities performed in this quarter:-Alferez, F. Online Presentation at Citrus Expo: “IPCs. New data on tree performance and lessons learned”. Fort Myers, August 2020. Impact: 146 views so far. -Gaire, S, Alferez, F and Albrecht, U. Use of protective covering and its effect on citrus tree physiology and HLB develpoment. Oral presentation at ASHS annual meeting. August 2020. Publications:-Individual Protective Covers for Psyllid Exclusion and HLB Disease Prevention in Young Trees. Fernando Alferez, Susmita Gaire, Ute Albrecht, Ozgur Batuman, Jawwad Qureshi and Mongi Zekri. Submitted to Citrus Industry Magazine. -Individual Protective Covers’ by Alferez, F, Gaire, S., Albrecht, U., Batuman, O., Qureshi, J., Zekri, M., IN PREPARATION,to be submitted to EDIS. -Gaire, S., Albrecht, U., Batuman, O., Qureshi, J., Zekri, M., Alferez, F. 2020. Horticultural performance of citrus trees grown under Individual Protective Covers (IPCs). IN PREPARATION, too be submitted to Plants, MDPI  2. Please state what work is anticipated for next quarter: Objective 1.We will continue monitoring parameters described in the first section. Also we will monitor HLB progression after IPC removal in the first experiment.Objective 2. We will start collecting data on psyllid populations and HLB incidence in the different netting layoutsObjectives 3 and 4.We will start to collect data on fruit quality and yield. Outreach: -F.Alferez, Citrus greening. Where are we now? Invited talk at the Southeast Regional Master Gardener Volunteer Virtual  Conference 2020. September 2020. -Protected citrus growing systems: from healthy trees to high quality fruit. F. Alferez, SWFREC Zoom seminar series.  -Canopy growth and physiological assesment of Valencia orange trees with and without protective covers. Gaire,S, Alferez, F and Albrecht, U. To be presented at FSHS annual meeting, October 2020.   3. Please state budget status (underspend or overspend, and why): We have spent about 40% of the budget. As in the last quarter, this means some underspending. The reasons are the same as in the last quarter:1) Budgeted meetings (national and international) and publications have not occurred yet, and 2) some expensive reactives for analysis have not been purchased as sampling has not been completed yet. Some delays in spending due to COVID ocurred, but as we have been resuming activities we are increasing our expenditure to normal levels.Budgeted amounts for salaries and student stipend and tuition are being spent as predicted. 


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