Scheduling ACP spring spray selection based on the Citrus Flowering Monitor System

Scheduling ACP spring spray selection based on the Citrus Flowering Monitor System

Report Date: 03/31/2017
Project: 850   Year: 2017
Category: ACP Vector
Author: Leo Gene Albrigo
Sponsor: Citrus Research and Development Foundation

This project has been reported under ‘Epidemiology and Cultural Control’, but it seems more appropriate to be under ‘Vector Management’, see the category above. Trees and branches to monitor for vegetative and reproductive bud development were selected in the test blocks and initial ratings were established. The Flowering Monitor System provided a first wave flowering full bloom date of February 11 to 20 depending on the location within the Florida citrus production regions, but actually occurred a day earlier. A second wave of flowering was projected to occur from March 8 to 11 depending on location, but this wave was a week early. Warmer than normal weather caused the advanced development and initiation of earlier full bloom. Data collection was started with bud break estimated to occur in early January. It appeared that bud break may be more reliably estimated from initiation of differentiation than from the estimation of full bloom date. Some preliminary plotting showed that in several years mean temperature the first 2 or 3 weeks after initiation of growth was important to determining how many weeks were required to reach full bloom. Dr. L. Stelinski agreed to cooperate in evaluating psyllid control when a block is sprayed at the beginning of spring budbreak rather than later after feather leaves are present. Two properties near Fort Meade were evaluated from early January until present. At one property, 2 blocks were sprayed January 3rd and at the other location two blocks were sprayed January 17th. No adult psyllids were detected by tap counts in 30 days where the spray was applied at budbreak in early January. However adults psyllids were detected at the location where the spray was applied later even though this was a shorter control time. The idea of spraying at budbreak but before feather flush appears to have some merit. We had information for growers on full bloom and 10 % open flowers but did not work out a way to make this information available to bee keepers. We need to develop an extension plan for bee keeper information. We had some success in an associated project in reducing off-season winter bloom by applying gibberellic acid monthly in the fall. We will monitor these trials to see if yields were improved. It did appear however that fewer flowers were present in the first flowering wave also. We will monitor the five locations that growers sprayed and one we sprayed to determine yield of the next crop.


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