Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Report Date: 06/03/2020
Project: 18-055C   Year: 2020
Category: ACP Vector
Author: Jawwad Qureshi
Sponsor: Citrus Research and Development Foundation

This project evaluates young tree protection from ACP/HLB using approaches to integrate ground cover, insecticides, and irrigation management. Treatments include 1) soil-applied neonicotinoids interspersed with sprays of a different mode of action on a calendar basis to trees on UV reflective mulch, 2) rotation of insecticide modes of action sprayed twice on each major flush to trees on UV reflective mulch, 3) soil-applied neonicotinoids interspersed with sprays of a different mode of action on a calendar basis to trees on bare ground, 4) rotation of insecticide modes of action sprayed twice on each major flush to trees on bare ground. This experiment is planted at three locations 1) Southwest Florida Research and Education Center (SWFREC), Immokalee, FL, 2) Citrus Research and Education Center (CREC), Lake Alfred, Fl, and 3) Florida Research Center for Agricultural Sustainability, Vero Beach Florida. During this quarter, irrigation set up for the experiment was completed, metalized reflective mulch installed, and 600 Ruby Red grapefruit trees on US 897 rootstock planted at the location in Vero Beach. These trees will receive irrigation at the same rate for a couple of months so that they are well established before they are subjected to deficit irrigation treatment to synchronize flush and start comparing the treatment of soil-applied insecticides rotation with foliar sprays against sprays on synchronized flush. The locations at SWFREC and CREC were already planted and were subjected to treatments of soil and spray applications for ACP control. However, the treatments to control irrigation to synchronize flush were initiated in February this year. In Immokalee, observations were made overtime during this quarter to look for the plant colonization with adult psyllids and plant infestation with eggs and nymphs. For plants on mulch, there was an average of 0.02 adults per plant (n = 984) much less than those on the bare ground averaging 0.08 adults per plant (n = 864). On mulch and bare ground plantings, the percentage of plants observed with adults was 0.6% and 4.7%, respectively. The plants treated with soil-applied neonicotinoids rotation with spray applications averaged 0.04 adults per plant (n = 930) and those treated with spray applications only averaged 0.06 adults per plant (918). There was no difference in the flushes between the mulch and bare ground treatments. There was not much impact of the deficit irrigation treatment to regulate tree flushing probably because the time to measure the impact was not enough for the reported period, or the irrigation schedules need to be adjusted. The percentage of flush infested with psyllid immatures averaged 1% on the mulch, and 10% on the bare ground planted trees. Plant tissue samples (n = 80) were collected and processed from the SWFREC experiment for PCR analysis, and none were positive for HLB. Data on plant growth and incidence of ACP was also recorded at the CREC location. We have also been continuously collecting data on soil moisture, and soil temperature changes by treatments at both locations and soil moisture sensors were installed at the Vero Beach location this quarter.    


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