{"id":297,"date":"2026-05-05T09:47:13","date_gmt":"2026-05-05T16:47:13","guid":{"rendered":"https:\/\/blogs.cdfa.ca.gov\/oars-blog\/?p=297"},"modified":"2026-05-05T09:47:13","modified_gmt":"2026-05-05T16:47:13","slug":"an-alternative-to-dacthal","status":"publish","type":"post","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2026\/05\/05\/an-alternative-to-dacthal\/","title":{"rendered":"An Alternative to\u00a0Dacthal\u00a0"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Author: Kari Arnold, PhD, Western Region IR-4 Associate Director, Environmental Toxicology Dept., UC Davis\u00a0<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">On\u00a0October 22, 2024,\u00a0EPA\u00a0prohibited the use of\u00a0all products\u00a0containing\u00a0the herbicide\u00a0dimethyl\u00a0tetrachloroterephthalate\u00a0(Dacthal\u00a0or DCPA) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). Although the reason for the cancellation was based in\u00a0science, the decision left many vegetable growers in California\u00a0at a loss for how to manage weeds at planting.\u00a0CDFA\u2019s\u00a0<a href=\"https:\/\/www.cdfa.ca.gov\/oars\/opca\/\">Office of Pesticide Consultation and Analysis<\/a>\u00a0(OPCA)\u00a0has been supporting\u00a0research into herbicide alternatives through the\u00a0<a href=\"https:\/\/www.ir4project.org\/\" target=\"_blank\" rel=\"noreferrer noopener\">IR-4 Project<\/a>, a\u00a0federal research program ensuring that specialty crop farmers have legal access to safe and effective crop protection products as regulations evolve. Through IR-4, OPCA has funded researchers spearheading the effort to register\u00a0pyraflufen-ethyl, an alternative to\u00a0Dacthal.\u00a0<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">EPA\u2019s cancellation came in response to robust studies\u00a0demonstrating\u00a0thyroid toxicity related to unborn babies of mothers exposed to\u00a0Dacthal\u00a0via handling or working in areas\u00a0where\u00a0it\u00a0was recently applied.\u00a0Prior to cancellation,\u00a0Dacthal\u00a0filled a niche\u00a0use pattern most herbicides\u00a0couldn\u2019t.\u00a0As a \u201cpre-emergent\u201d\u00a0herbicide, it could\u00a0limit\u00a0the\u00a0emergence of existing weed seed populations in the soil.\u00a0Dacthal\u00a0provided this type of protection long enough for a vegetable crop canopy to grow in, but with little\u00a0to no\u00a0injury to the various crops listed\u00a0allowed to use it.\u00a0This\u00a0unique\u00a0capability made many vegetable crops\u00a0reliant\u00a0on\u00a0Dacthal\u00a0as an integral step in their\u00a0Integrated Pest\/Weed\u00a0Management\u00a0(often referred to as\u00a0IPM)\u00a0Program.\u00a0<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Steven&nbsp;Fennimore, a retired UC Davis Professor of Cooperative Extension,&nbsp;invited me down&nbsp;in early 2023&nbsp;to visit&nbsp;his USDA Salinas station weed management studies. While&nbsp;walking to the trials, he&nbsp;remarked that&nbsp;many specialty crops&nbsp;have been&nbsp;reliant upon the same herbicide chemistries&nbsp;for 60 years,&nbsp;and that we need to see if there are applicable alternatives.&nbsp;Part of Steven\u2019s career consisted of collaborations with registrants and IR-4 to broaden the range of options for vegetable growers to&nbsp;accomplish&nbsp;that goal. In terms of&nbsp;Dacthal&nbsp;alternatives,&nbsp;pyraflufen-ethyl was one material of interest. Although this is a contact herbicide, meaning it must contact the weeds to work and cannot be used before weeds&nbsp;emergeSteven&nbsp;and the registrant,&nbsp;Nichino&nbsp;America Inc., had&nbsp;been testing varying rates and application times to determine an acceptable crop injury&nbsp;use pattern for an over-the-top application to onions and garlic. If successful, this material could control&nbsp;early emerging&nbsp;weed&nbsp;populations during the&nbsp;initial&nbsp;stages of crop development.&nbsp;&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Although&nbsp;there was&nbsp;till&nbsp;on-going research&nbsp;at that time,&nbsp;I encouraged&nbsp;Steven to&nbsp;submit&nbsp;the request in 2023.&nbsp;With&nbsp;support from CDFA-OPCA, the registrant,&nbsp;and&nbsp;Western Growers,&nbsp;submission was prioritized&nbsp;at the IR-4 Food Use Workshop&nbsp;and moved forward for the 2024 field research season.&nbsp;Given our current timeline, the product should be available to growers by 2030.&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Author: Kari Arnold, PhD, Western Region IR-4 Associate Director, Environmental Toxicology Dept., UC Davis\u00a0 On\u00a0October 22, 2024,\u00a0EPA\u00a0prohibited the use of\u00a0all products\u00a0containing\u00a0the herbicide\u00a0dimethyl\u00a0tetrachloroterephthalate\u00a0(Dacthal\u00a0or DCPA) under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). Although the reason for the cancellation was based in\u00a0science, the decision left many vegetable growers in California\u00a0at a loss for how to manage &hellip; <a href=\"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2026\/05\/05\/an-alternative-to-dacthal\/\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">An Alternative to\u00a0Dacthal\u00a0<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":6,"featured_media":298,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[4],"tags":[9],"class_list":["post-297","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-informational","tag-opca","fallback-thumbnail"],"jetpack_featured_media_url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/Dactal.png","jetpack_sharing_enabled":true,"jetpack-related-posts":[{"id":313,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2026\/05\/05\/how-opca-is-making-sense-of-californias-pesticide-use-trends\/","url_meta":{"origin":297,"position":0},"title":"How OPCA Is Making Sense of California\u2019s Pesticide Use Trends","author":"Sureena Johl","date":"May 5, 2026","format":false,"excerpt":"California leads the nation in\u00a0data transparency through\u00a0the\u00a0collection\u00a0and sharing\u00a0of pesticide use data,\u00a0providing\u00a0stakeholders, state agencies, and the public with valuable insights into\u00a0pest management throughout the state.\u00a0The Pesticide Use Reporting (PUR) Database\u00a0maintained\u00a0by the California Department of Pesticide Regulation (DPR)\u00a0serves as a resource for\u00a0the public to\u00a0track and understand how pesticide use has changed in\u2026","rel":"","context":"In &quot;Informational&quot;","block_context":{"text":"Informational","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/informational\/"},"img":{"alt_text":"A rice field with groundwater irrigation in the agriculture region of Yuba County east of Marysville, California. Photo taken May 27, 2009. Dale Kolke \/ California Department of Water Resources","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/DBK_Yuba_River-2695.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":70,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2025\/03\/28\/what-is-the-office-of-pesticide-consultation-and-analysis\/","url_meta":{"origin":297,"position":1},"title":"What is the Office of Pesticide Consultation and Analysis?","author":"Sureena Johl","date":"March 28, 2025","format":false,"excerpt":"The California Department of Food and Agriculture\u2019s (CDFA\u2019s) Office of Pesticide Consultation and Analysis (OPCA) was formed in 1992 following the formation of CalEPA\u2019s Department of Pesticide Regulation (DPR). Prior to this time CDFA was responsible for pesticide regulation in the state. OPCA's primary role is to provide DPR with\u2026","rel":"","context":"In &quot;Informational&quot;","block_context":{"text":"Informational","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/informational\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/03\/Meet-Our-Team-OPCA.png?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":193,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2025\/08\/05\/a-note-from-our-director-august-2025\/","url_meta":{"origin":297,"position":2},"title":"A Note from Our Director | August 2025","author":"Sureena Johl","date":"August 5, 2025","format":false,"excerpt":"Dear Stakeholders,\u00a0 I hope you enjoy this newsletter showcasing the accomplishments of our grantees and partners and giving you a peek at how we lead our programs to serve producers while contributing to the state\u2019s sustainability goals. Additionally, I want to take this opportunity to summarize the funding status of\u2026","rel":"","context":"In &quot;Informational&quot;","block_context":{"text":"Informational","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/informational\/"},"img":{"alt_text":"August 2025 OARS Director Report","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/08\/Blog-image-3-2.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/08\/Blog-image-3-2.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/08\/Blog-image-3-2.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/08\/Blog-image-3-2.png?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/08\/Blog-image-3-2.png?resize=1050%2C600&ssl=1 3x"},"classes":[]},{"id":150,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2025\/07\/28\/cdfa-looks-to-get-ahead-of-invasive-agricultural-pests\/","url_meta":{"origin":297,"position":3},"title":"CDFA Looks to Get Ahead of Invasive Agricultural Pests","author":"Sureena Johl","date":"July 28, 2025","format":false,"excerpt":"California leads the nation in specialty crop production, growing more than 400 different crops across its diverse agricultural landscape. With such variety comes a complex web of pest management challenges that demand innovative, research-driven solutions. The OARS Office of Pesticide Consultation and Analysis is continuously working to support pest management\u2026","rel":"","context":"In &quot;Informational&quot;","block_context":{"text":"Informational","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/informational\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Tuta-absoluta-herbivory-test-on-commercial-tomatoes-vs-wild-South-American-tomato-species.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Tuta-absoluta-herbivory-test-on-commercial-tomatoes-vs-wild-South-American-tomato-species.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Tuta-absoluta-herbivory-test-on-commercial-tomatoes-vs-wild-South-American-tomato-species.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Tuta-absoluta-herbivory-test-on-commercial-tomatoes-vs-wild-South-American-tomato-species.jpg?resize=700%2C400&ssl=1 2x"},"classes":[]},{"id":188,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2025\/07\/31\/collaborative-orchard-studies-improve-efficiency-and-sustainability\/","url_meta":{"origin":297,"position":4},"title":"Collaborative Orchard Studies Improve Efficiency and Sustainability\u202f","author":"Sureena Johl","date":"July 31, 2025","format":false,"excerpt":"State and industry representatives visit Bowman Orchards. Almonds are California\u2019s #1 export crop for good reason. No place in the world has a climate better suited to consistent, high-quality almond production. Furthermore, the constricting labor market in the state has encouraged farmers to move towards almonds, with their relatively lower\u2026","rel":"","context":"In &quot;Producer Success Story&quot;","block_context":{"text":"Producer Success Story","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/producer-success-story\/"},"img":{"alt_text":"State and industry representatives visit Bowman Orchards.","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=700%2C400&ssl=1 2x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=1050%2C600&ssl=1 3x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2025\/07\/Almond-Board-Staff-Explaining-Almond-Lifecycle-scaled.jpg?resize=1400%2C800&ssl=1 4x"},"classes":[]},{"id":300,"url":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/2026\/05\/05\/community-science-ground-nesting-bees-project\/","url_meta":{"origin":297,"position":5},"title":"Community Science Ground Nesting Bees Project","author":"Sureena Johl","date":"May 5, 2026","format":false,"excerpt":"Bee pollination contributes hundreds of billions of dollars annually to the global economy. Wild bees provide\u00a0free\u00a0pollination services to farmers, which\u00a0significantly\u00a0improve\u00a0both the quality and quantity of crop yields.\u00a0Seventy percent\u00a0of\u00a0wild\u00a0bees\u00a0nest in the ground and some species form large, long-standing nesting sites while others are more solitary.\u00a0Our knowledge\u00a0on the ~20,000\u00a0global bee species is\u2026","rel":"","context":"In &quot;Informational&quot;","block_context":{"text":"Informational","link":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/category\/informational\/"},"img":{"alt_text":"Community Science Ground Nesting Bees Project","src":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/2-aidan_orig.png?resize=350%2C200&ssl=1","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/2-aidan_orig.png?resize=350%2C200&ssl=1 1x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/2-aidan_orig.png?resize=525%2C300&ssl=1 1.5x, https:\/\/i0.wp.com\/blogs.cdfa.ca.gov\/Oars-blog\/wp-content\/uploads\/2026\/05\/2-aidan_orig.png?resize=700%2C400&ssl=1 2x"},"classes":[]}],"_links":{"self":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/posts\/297","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/comments?post=297"}],"version-history":[{"count":1,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/posts\/297\/revisions"}],"predecessor-version":[{"id":299,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/posts\/297\/revisions\/299"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/media\/298"}],"wp:attachment":[{"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/media?parent=297"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/categories?post=297"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.cdfa.ca.gov\/Oars-blog\/index.php\/wp-json\/wp\/v2\/tags?post=297"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}