Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Report Date: 10/15/2020
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. Treatments of insecticides in soil and sprays were conducted to control ACP in trees planted on mulch and bare ground in all three experiments at the SWFREC, CREC, and Vero Beach locations. However, the irrigation deficit treatments to synchronize flush were not implemented due to avoid confounding effects of rains. At SWFREC, ACP adults were significantly less in the plants planted on the mulch than those on the bare ground determined using the tap sampling method. For treatments 2 and 4, we made spray applications when most flush was observed. ACP suppression was more in the treatments timed to target flush than the treatment using soil applications of neonicotinoids intercepted with foliar sprays. Another set of leaf samples was collected and submitted for HLB analysis. At CREC, the sampling date influenced the presence of all life stages of ACP, which is logical, given the biology of the pest. Only the ground cover influenced the number of ACP eggs and nymphs on the plants. Between the two locations, the influence of ground cover and spray timing on the psyllid populations adults or progeny suggests that mulch and timing spray applications to key flush periods provide good psyllid control, and the latter will save growers money in terms of insecticide applications and psyllid suppression. We were able to continue data monitoring for soil moisture, tree size and leaf nutrient status in the experimental blocks. Virtual results show vigorous tree growth in the reflective mulch treatments over bare ground. We will follow up with quantitative statistics in the near future to show the benefits of reflective mulch. In the next quarter, we will collect leaf and soil samples to document soil and tissue nutrient status and changes according to treatments. The trial at Vero Beach suffered significant damage from rains resulting in 36% dead plants on the mulch and 12% on bare ground.       


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