Completed Projects

Proposed approach for assessing the value of CPDPD activities in Southern California

Since 2018, the Science Subcommittee has wrestled with how to determine whether Citrus Pest and Disease Prevention Division’s (CPDPD) regulatory activities are, or are not, supported by data, and how to judge if, when, or how activities should be restructured. We present here an process that could be utilized to move the discussion forward.

Origin:

Science & Technology SubCo

Completed:

Apr 7, 2021

Project Team

Dr. Jonathan Kaplan
Dr. Bruce Babcock
Holly Deniston-sheets
Dr. Neil McRoberts

Overview of ACP Trap Technology Research

DATOC was asked to review available methods of ACP trapping and recent research on the subject.
After discussions with the DATOC expert panel/review of the literature, we could not recommend any new technology for immediate utilization by the CPDPD, but there were a few options that could be tested experimentally.

Origin:

Operations SubCo

Completed:

Feb 25, 2021

Project Team

Holly Deniston-sheets
Rick Dunn
Dr. Neil McRoberts
Dr. Monique Rivera

Insecticide Treatments in Santa Clara

An informative briefing providing context for a 2020 decision to cease treatments in certain areas of Santa Clara.

Origin:

Operations SubCo

Completed:

Nov 19, 2020

Project Team

Environmental suitability of the San Joaquin Valley in relation to trap servicing interval

In the fall of 2020, the ACP-detection trapping program in the San Joaquin Valley was operated on a bi-weekly schedule, although the CDFA Action Plan dictates a monthly schedule. DATOC was requested to provide input on whether the program should shift to a monthly schedule or amend the Action Plan to indicate that bi-weekly trapping should be continued.

Origin:

Operations SubCo

Completed:

Nov 18, 2020

Project Team

Holly Deniston-sheets
Rick Dunn
Dr. Neil McRoberts
Dr. Greg Simmons

Optimizing residential insecticide applications for commercial grove protection

DATOC was asked to explore how the procedure for applying insecticides in residential areas (“buffer zones”) surrounding commercial groves under area-wide ACP control programs might be improved.

Origin:

Operations SubCo

Completed:

Nov 4, 2020

Project Team

Holly Deniston-sheets
Dr. Neil McRoberts
Dr. Monique Rivera

Evaluation of early detection technologies: concluding report

DATOC was requested to provide a report summarizing research done on Early Detection Technologies which was funded by the Citrus Research Board and HLB-MAC. The report is to include explanations of each technology, economic concerns, diagnostic accuracy, and more.

Origin:

CRB

Completed:

May 28, 2020

Project Team

Holly Deniston-sheets
Brianna McGuire
Dr. Neil McRoberts

Analysis of residential program

DATOC has been requested to analyze CDFA's program activities combating HLB in Southern California for efficiency and effectiveness.

Origin:

Science & Technology SubCo

Completed:

May 6, 2020

Project Team

Holly Deniston-sheets
Dr. Neil McRoberts
Dr. Monique Rivera
Dr. Mamoudou Setamou
Dr. Greg Simmons

Criteria for reducing the delimitation radius

This report proposes that the delimitation radius for tree surveys around an HLB+ tree be reduced from 400m to 300m. This change is suggested based on the geographic distribution of all trees confirmed to be positive for huanglongbing by March 2020, based on a methodology previously used by the CPDPC to make operational decisions.

Origin:

Operations SubCo

Completed:

Apr 8, 2020

Project Team

Holly Deniston-sheets
Brianna McGuire
Dr. Neil McRoberts

Early Detection Technology Guidelines

DATOC has produced guidelines for citrus growers who choose to use an EDT (for example, detector canines) to screen their groves.

Origin:

Internal Deliberations

Completed:

Jan 20, 2020

Project Team

Holly Deniston-sheets
Dr. Tim Gottwald
Dr. Beth Grafton-Carwell
Dr. Neil McRoberts

Areawide Management Strategy

Residential buffer zones around commercial citrus can be treated by CDFA with insecticides to suppress Asian citrus psyllid populations only if 90% of growers in that region apply insecticides within a designated 3-week window. While useful, this threshold created logistical difficulties and a new criterion for treatment was explored.

Origin:

Operations SubCo

Completed:

Jan 15, 2020

Project Team

Sara Garcia Figuera
Dr. Beth Grafton-Carwell
Dr. Neil McRoberts

Exposure on repeat properties

The goal of this analysis was to understand how likely it is for a site with 1 HLB-positive tree to develop another HLB-positive tree in the future.

Origin:

CPDPC

Completed:

Oct 1, 2019

Project Team

Holly Deniston-sheets
Brianna McGuire
Dr. Neil McRoberts

Density of new infections

As a part of DATOC's report on exposure to CLas in Southern California residential areas, DATOC was asked to evaluate exposure over smaller geographic scales. We also evaluated the changes in infection density in the most recent detections.

Origin:

Operations SubCo

Completed:

Oct 1, 2019

Project Team

Dr. Tania Brenes-Arguedas
Holly Deniston-sheets
Brianna McGuire

Seasonality of Ct Values in CA plant samples

There is no evidence thus far for seasonal patterns of Ct value variability from CA CLas+ plant samples.

Origin:

Internal Deliberations

Completed:

Jun 3, 2019

Project Team

Holly Deniston-sheets
Dr. Neil McRoberts

Recommended grower responses to HLB

DATOC compiled available research to help the CPDPC advise growers on how they should respond to an HLB find in or near their commercial grove. This was the basis of the "Best Management Practices in Response to Huanglongbing in California Citrus", approved by the CPDPC and published on CitrusInsider.org.

Origin:

Outreach Subco

Completed:

Jun 1, 2019

Project Team

Holly Deniston-sheets
Dr. Beth Grafton-Carwell

Growth of disease incidence in Southern California

An analysis of the growth rate in new detections of HLB in Southern California, to help determine if a threshold has been reached beyond which current management practices are unfeasible.

Origin:

Operations SubCo

Completed:

Mar 1, 2019

Project Team

Holly Deniston-sheets
Dr. Neil McRoberts

Recommended sampling plan

The CDFA action plan previously called for sampling 25% of an orchard should HLB be found within 400m. Best available evidence indicated that would be inefficient. DATOC suggested an evidence-based replacement plan, which was approved in March 2019.

Origin:

Internal Deliberations

Completed:

Feb 28, 2019

Project Team

Dr. Matt Daugherty
Holly Deniston-sheets
Dr. Beth Grafton-Carwell
Dr. Neil McRoberts

Equitable and effective transport quarantines

The industry should utilize geographically regulated areas to restrict ACP dispersal.

Origin:

CPDPC

Completed:

Jan 1, 2019

Project Team

Dr. Beth Grafton-Carwell
Dr. Neil McRoberts

Managing transportation risk

Analysis of transportation risk of CLas+ ACP between bulk citrus quarantine zones in California

Origin:

CPDPC

Completed:

Dec 6, 2018

Project Team

Sara Garcia Figuera
Holly Deniston-sheets
Dr. Neil McRoberts

Transovarial transmission of CLas

A report released in December 2018 on vertical transmission of CLas from ACP parent to progeny.

Origin:

CPDPC

Completed:

Dec 1, 2018

Project Team

Dr. Matt Daugherty
Holly Deniston-sheets
Dr. Greg McCollum
Dr. Neil McRoberts

Hand cleaning bulk citrus

Field cleaning by hand has not been shown to reduce the number of psyllids in bulk citrus bins or the potential risk of moving psyllids when the fruit is moved.

Origin:

Internal Deliberations

Completed:

Oct 9, 2018

Project Team

Dr. Matt Daugherty
Holly Deniston-sheets
Rick Dunn
Dr. Beth Grafton-Carwell
Dr. Neil McRoberts
Dr. Greg Simmons

Treatment area recommendation

The DATOC expert panel feels strongly that the find of a single Asian citrus psyllid (ACP) in an area which is not generally infested and eradication is still being attempted should trigger a treatment area around the detection that is never less than a 400 m radius.

Origin:

Internal Deliberations

Completed:

Oct 1, 2018

Project Team

Holly Deniston-sheets
Dr. Beth Grafton-Carwell
Dr. Neil McRoberts

Buffer treatments efficacy

An analysis of critical factors which determine the efficacy of areawide buffer treatments mitigation of ACP/HLB risk for commercial groves.

Origin:

Internal Deliberations

Completed:

Oct 1, 2017

Project Team

Dr. Matt Daugherty
Dr. Beth Grafton-Carwell
Dr. Greg Simmons

Evaluating exposure to HLB

Examination of the possibility to define a rigorous meaning for the word "exposed", as used in the California agriculture code, in relation to HLB

Origin:

CPDPC

Completed:

Project Team

Dr. Tania Brenes-Arguedas
Holly Deniston-sheets
Brianna McGuire
Dr. Neil McRoberts