Yakima, WA — The Washington State Department of Agriculture (WSDA) has confirmed the first-ever North American detection of Orobanche cumana, commonly known as sunflower broomrape, in Yakima, WA. This marks the first known occurrence of this destructive and highly invasive parasitic weed in North America.
The parasitic plant was discovered by a homeowner and later confirmed by the WSDA State Plant Pathology and Molecular Diagnostic Lab and USDA Animal and Plant Health Inspection Service (APHIS). Confirmation included both morphological and molecular analysis.
Sunflower broomrape is a devastating root parasite of sunflower (Helianthus annuus) and other members of Asteraceae (the sunflower family), leading to significant crop losses. The plant is incapable of photosynthesis and relies entirely on the host plant for water and nutrients.
This detection is especially concerning due to the aggressive nature of this parasitic weed and its potential to spread rapidly if left unmanaged. Sunflower broomrape poses a serious threat to commercial sunflower production and could cause significant impacts to growers, processors, exporters and the agricultural economy if not swiftly contained.
The WSDA Pest Program is working closely with USDA and local stakeholders to investigate the source, assess the extent of the infestation, and implement response measures to protect North American agriculture.
Reporting suspected sightings of sunflower broomrape
WSDA is seeking help from the public to identify the other possible introductions of this invasive pest. If you suspect you have seen sunflower broomrape, do not disturb it as doing so may cause the seed to spread. Instead, photograph the suspected sighting and report it to WSDA immediately.
Report suspected sightings to WSDA immediately by emailing pest@agr.wa.gov or calling 1-800-443-6684 (option 1). Reports should include the reporting party’s name, location of the suspected weed, date encountered, and photos.
About Orobanche cumana
Native to Eurasia, Orobanche cumana is a quarantine pest in many countries due to its devastating impact on sunflower production. Although O. cumana attaches to the host plants’ roots, it does produce distinctive above-ground, leafless flower stalks. A single plant can produce hundreds of thousands of microscopic seeds that remain viable in the soil for decades, making eradication difficult once established.
Next steps
WSDA will continue to coordinate with USDA APHIS and affected stakeholders to implement mitigation strategies and determine the potential regulatory implications. Public outreach and grower engagement will be part of the integrated response plan.
For updates and reporting guidance, visit the WSDA website, email pest@agr.wa.gov, or call (800) 443-6684 (option 1).
