Mike Basedow and Monique Rivera

This information was provided to us by Christelle Guédot, UW-Madison, Department of Entomology

The Environmental Protection Agency (EPA) performs registration reviews to reevaluate pesticides every 15 years to assess environmental and occupational risk. In March 2023, the EPA announced that it would accelerate the review process of Diazinon and other pesticides that were due to conclude in 2026. As part of the review process of Diazinon, EPA reached an agreement with the pesticide registrants to develop voluntary mitigation measures by the registrants several years ahead of the normal registration review process to reduce occupational risk. This has led registrants to start implementing these measures this summer and resulted in diazinon shortages. For more information about this agreement between EPA and the registrants reached in April, please see this article.

While there has been some uncertainty surrounding the supply and forecast of production of the different formulations of Diazinon from Adama and Loveland Products this summer, Adama has stated they will continue to produce AG500 into 2024, and that they will cease production of Diazinon 50W. For AG500, new labels that will contain occupational risk mitigation measures and endangered species language are expected to be approved by the end of 2023 and should be in place through 2026 when the EPA will complete the registration review process. The difference between Diazinon 50W and Adama’s AG500 is a difference in formulation and percent active ingredient. Adama’s Diazinon AG500 is an emulsifiable solution, while 50W is a wettable powder packaged in water soluble bags. AG500 is 47% active ingredient, while 50W is 50%.  Loveland Products AG600 is a water-based concentrate formulation, at 56% active ingredient.

As for AG600, Loveland Products have informally indicated that they do not intend to produce Diazinon AG600 any longer.

Once stocks of Diazinon 50W and AG600 run out, Diazinon will only be produced and available from Adama in the AG500 formulation.

For more information about the use pattern of Diazinon AG500, the label can be downloaded from the DEC NYSPAD Page.

It is expected that EPA will announce the notice of the agreed upon mitigation measures later this year and that an interim or final decision will be reached in 2026 under the regular review process timeline.