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United States Department of Agriculture

Agricultural Research Service

Research Project: Mortality of Asian Citrus Psyllid, Diaphorina Citri, in California Citrus During Packing and Export to Australia
2014 Annual Report


1a.Objectives (from AD-416):
The goal of this research is to systematically demonstrate complete ACP mortality over the course of harvesting, packing, and shipping periods of fresh California citrus destined for Australia.


1b.Approach (from AD-416):
Phase 1 (year 1) Objective: Design, refine and execute experiments that allow ACP population densities to be traced through chemical and physical processes that are consistent with CA citrus production and distribution to Australian markets. Specifically, we will test the following hypotheses:

a) Commercial harvesting, cleaning, and packing practices effectively remove or kill all ACP life stages. b) ACP life stages cannot survive a simulated shipping scenario at 3 - 6 C for greater than 14d, even with potential food sources present.

c) ACP mortality outcomes in a) and b) above are not statistically affected by citrus fruit age, species, and variety.

Phase 2 (year 2) Objective: Quantitatively monitor ACP population density and mortality as infested citrus fruit is harvested, cleaned, packed, and shipped to Australian ports (simulation). Specifically, we will test the following hypotheses: d) ACP population densities in the field have no statistical effect on mortalities observed in a-c above).

e) ACP mortalities observed in a-d) above are consistent between packing houses and shipping companies involved in the export of CA citrus to Australia. Documents Trust with the Citrus Research Board. Log 42163.


3.Progress Report:

This Trust agreement was established to support Objective 1 of the in-house project and is related to finding methyl bromide alternatives for postharvest applications. Asian citrus psyllid (ACP) is a pest of concern to certain countries that import fresh citrus from California. Trading partners can demand efficacy data that demonstrates ACP is removed from marketing channels prior to shipment. Commercial protocols used in California for cleaning and packing fresh citrus were used to demonstrate that adult ACP are removed from fruit that is dunked, soaked, rolled, brushed, flooded and sprayed at high-pressures (~200 psi), or dried in a commercial wax dryer. This research provides qualitative and quantitative precedence for using systems-based approaches to address phytosanitary treatment requirements and served as the technical basis for USDA-APHIS domestic quarantine policy related to the movement of fruit from ACP infested production areas to packing facilities. An additional direct result of this research was market access of California fresh citrus to Australia and New Zealand valued respectively at 25 and 10 million annually.


Last Modified: 12/19/2014
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