This article has been adapted from an article written by Dr. Christelle Guédot, University of Wisconsin-Madison, and published in the Cranberry Crop Management Journal – Volume 36 (August 02).

Every 15 years, the Environmental Protection Agency (EPA) performs registration reviews to reevaluate pesticides 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 the shortages observed this summer. For more information about this agreement between EPA and the registrants reached in April, please see https://www.epa.gov/pesticides/epa-reaches-agreement-early-mitigation-measures-initiative-organophosphate-pesticide.

While there was some uncertainty surrounding the supply and forecast of production of the different formulations of Diazinon from Adama and Loveland Products this summer, an official statement was received from Adama stating that 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. As for AG600, Loveland Products have informally indicated to the Cranberry Institute 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 use pattern of Diazinon AG500, a link to the label can be found at https://s3-us-west-1.amazonaws.com/agrian-cg-fs1-production/pdfs/Diazinon_AG5001t_Label.pdf. 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.

Based on our degree-day (DD) model for Sparganothis fruitworm, peak flight is expected at around 884 DD (see chart). As of June 22, Sparganothis fruitworm has accumulated 827 DD (using April 15 as biofix; a biofix more realistic to New Jersey practices). Based on the April 15 biofix, egg laying should have been initiated. However, I do not expect peak flight and those eggs to start hatching until mid-next week. Larval injury to fruit usually begins after the eggs hatch. If treatment is required (based on pheromone trap counts), sprays should be done 10-14 days after peak moth captures, ca. 7-11 July. If Sparganothis fruitworm pressure has been high, it may be advisable to treat 3 weeks after the moth flight began (i.e., around 1-4 July) and again 10 days later. When bees are present your option is to use an insect growth regulator such as Confirm or Intrepid. Our “standard” recommendation has been, however, to wait until bees are removed to apply an insecticide. Your post-bloom options include Altacor, Delegate, Exirel, or Intrepid. The timing of insecticide application is critical; so, if needed, do not wait too long to manage this pest.

Degree-day model for Sparganothis fruitworm