The Almond Board of California (ABC) is advising California almond handlers to maintain careful stewardship of pest management products in processing and storage facilities to support strong insect control programs while meeting residue expectations in key export markets.
Dichlorvos and piperonyl butoxide (PBO) as a synergist to pyrethrins or pyrethroid remain useful tools in stored product insect management, but the way these materials are used, timing, preparation, and precision play a significant role in whether shipments meet the strictest international Maximum Residue Limits (MRLs).
Over the last years a few almond shipments have been rejected due to levels of dichlorvos or PBO that exceeded the importing country’s tolerance. While the number is small, these incidents highlight the importance of careful stewardship to ensure continued market access for the broader industry.
MRL Realities in Key Markets
International tolerance levels vary significantly, and several major destinations maintain extremely low limits for both dichlorvos and PBO.
In the European Union, dichlorvos defaults to 0.01 ppm. PBO tolerances differ by member state, with some as low as 0.01 ppm and others allowing 3 or 8 ppm (the current US tolerance is 8 ppm) for tree nuts. Because synergists maximum residue limits are not harmonized across the EU, a shipment may meet the requirements in one country but not another.
South Korea currently applies a default limit of 0.01 ppm for both compounds for tree nuts. Their ability to review import tolerance submissions remains delayed until U.S. EPA completes its ongoing registration review of PBO and dichlorvos. EPA still needs to review newly submitted data and complete the Endangered Species Act compliance consideration for PBO, which EPA is reviewing together with pyrethrins, and the synergist MGK-264. Dichlorvos is in a similar stage of regulatory uncertainty, as EPA considers the next steps for the remaining organophosphate insecticides.
Until EPA’s reviews are completed, South Korea is unable to review import tolerance packages for tree nuts. Therefore, almond shipments must adhere to the strictest market limits, regardless of U.S. tolerances.
Emphasizing Thoughtful Use
To help in this area, dichlorvos or PBO should be used deliberately and in coordination with a well-managed facility program. Many residue issues can be prevented through careful monitoring, preparation and follow up. These products are typically used to treat spaces, not the nuts directly, but nuts that are in the space or come in contact with surfaces that were treated can pick up residues.
Monitoring First
Accurate monitoring, using traps, pheromone lures and routine inspections, helps determine when treatment is warranted. Treating only when pest pressure justifies it reduces overall application frequency and limits residue opportunities.
