Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Report Date: 07/15/2020
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 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. 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. At the SWFREC and CREC locations, trees planted on mulch and bare ground received deficit irrigation and full irrigation treatments during this quarter. However, due to the COVID-19 restrictions, we were not able to follow up with the treatments for ACP control using sprays on the plots treated with deficit irrigation intended to produce synchronize flush and soil-applied neonicotinoids interspersed with sprays of a different mode of action insecticide on the plots receiving full irrigation until the middle of the May. All data collection activities were also suspended during that time. Six weekly samplings were conducted during remainder of May and June at SWFREC. There was an average of 4.5 flushes per plant and not different between those on mulch and bare ground or between the deficit and full irrigation treatments. Trunk diameter measurements were taken in June. Trunk diameter of both the rootstock and scion of trees on mulch was significantly larger than those on the bare ground, and those receiving full irrigation had a larger diameter than the ones receiving deficit irrigation. We are also testing tree defenders on the plants in bare ground. Trunk diameter of both the rootstock and scion of trees covered with tree defenders was not different from those planted on mulch but was larger than those planted on the bare ground but not covered with tree defenders. Soil moisture monitoring continued in the past and this quarter at SWFREC and CREC sites. Soil moisture data are being recorded continuously every 30 minutes at 6 inch and 18-inch depth.  There was 5-10% relatively greater soil moisture under mulch than the bare ground at the CREC location. Plants at the Vero Beach location were planted in March and are currently maintained at full irrigation until they are well established and ready for deficit irrigation treatment.At SWFREC, ACP adults were significantly less in the plants planted on the mulch than those planted on the bare ground averaging 0.3 and 0.1 per tap sample, respectively, but did not differ between the treatments of foliar sprays and soil applications of neonicotinoids intercepted with foliar sprays. Significantly less flush was infested with eggs of ACP on mulch than bare ground, averaging 9% and 16%, respectively. A similar effect was observed for flush infestation with nymphs, averaging 13% and 17%, respectively. However, there was no difference in flush infestation with eggs and nymphs between plants receiving treatments of foliar sprays and soil applications of neonicotinoids intercepted with foliar sprays. Sampling on ACP infestation was also conducted at CREC.      


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