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Residential Activities Analysis: Part 1

  At the CPDPC Operations meeting September 5th, 2018, it was requested that DATOC provide an analysis of CDFA's residential activities. Some items brought up were: does the science support the current activities, when should they be stopped, and what would the consequences be of ceasing those activities. At the CPDPC full committee meeting September 12th, the committee agreed that DATOC should go forward with this analysis. 

Spring 2019

DATOC framed some possible approaches to this work in early March, 2019. At that time, we assembled a smaller break-out team to work on it in more detail. The break-out team met in late March and hashed out some next steps.

In early May, the team met again to discuss progress to-date, and we decided to pursue moving forward using 2 modeling interfaces to address the questions posed: the Cambridge Modeling Interface (CMI) and the Agent-Based Model (ABM) from a USDA team in Ft. Pierce, FL. 

Summer 2019


In July, discussions began with the CMI team regarding funding to run the model in CA. At the end of May we met for a walk-through of the CMI, and a walk-through of the ABM followed in June.

Fall 2019


In September 2019, we decided on a plan to move forward using the ABM: we decided to create a potential counter-factual in San Gabriel, comparing model output of a few management scenarios with what was known about disease prevalence in the city. Specifically, we decided to use the model to simulate tree removal and insecticide applications.

By November, preliminary runs under this framework were complete.

Winter 2019/2020





Work using the ABM continued in close collaboration with the model development team.

Spring 2020

Replicated simulations with the ABM were finalized and presented to the CPDPP Joint Science & Operations subcommittee meeting on May 6, 2020. Results indicated that tree removal alone is unlikely to significantly limit disease spread compared to implementing no control, but that vector suppression was a vital aspect of disease control, and may interact synergistically with tree removal over time.

A proposal to fund work with the CMI is submitted and approved under the Plant Protection Act.

Winter 2020/2021


After feedback from the Citrus Research Board, it was decided to expand the project to include an evaluation of the hypothetical spread of HLB from residential areas under management into commercial areas. This was completed and presented to the Science Subcommittee in February, 2021, with an associated briefing paper including an update on completed work using the CMI.

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