2019-12_18-055C – Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Optimizing Benefits of UV Reflective Mulch in Solid Block Citrus Plantings

Report Date: 02/03/2020
Project: 18-055C   Year: 2019
Category: ACP Vector
Author: Jawwad Qureshi
Sponsor: Citrus Research and Development Foundation, Inc.

This project evaluates young tree protection from ACP/HLB using approaches to integrate ground cover, insecticides, and irrigation management under four treatments at three locations. Treatments include 1) soil applied neonicotinoids interspersed with sprays of 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 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. Designated soil and spray applications of insecticide treatments were made to the trees planted on mulch and bare ground at the Gulf and Ridge locations in Immokalee (SWFREC) and Lake Alfred (CREC), respectively. In Immokalee, 1148 trees observations each on mulch and bare ground trees were made overtime during this quarter to look for the plant colonization with adult psyllids and plant infestation with eggs and nymphs. Only 2 trees on mulch were observed to contain adult psyllids compared to 7 on the bare ground, averaging 0.002 and 0.006 adults per plant, respectively. Only one plant on mulch was infested with 2 eggs but no nymphs (0.09% infestation rate) compared with 5 plants on bare ground infested with both eggs and nymphs (0.4% infestation rate). In Lake Alfred, 432 trees observations each on mulch and bare ground trees were made during this quarter to look for the plant colonization with adult psyllids and infestation with eggs and nymphs. Adult psyllids were observed on 3 trees on mulch, averaging 0.02 adults per plant, and on 23 trees on the bare ground, averaging 0.2 adults per plant. Thirteen plants on mulch were observed with eggs and nymphs, infestation rate of 3% compared with 93 plants on bare ground, infestation rate of 22%. Soil moisture sensors were installed in plots with and without the reflective mulch at CREC and SWFREC this quarter. Data will be collected continuously during the duration of the project to document water savings and applicability of the irrigation schedules and rates in a commercial setting. Irrigation installation is underway in Vero Beach, at a grower site and tree planting will be completed in the next quarter. Deficit irrigation treatments to regulate tree flushing will be imposed in Spring 2020, to compare flush sprays against rotation of soil and calendar spray applications. Trees were young and planted late, therefore, allowed to establish through spring 2020 before subjecting to reduced irrigation to synchronize flush and evaluate spray applications.


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