The emergency crisis exemption for Malathion has been approved for red sunflower seed weevil control in sunflowers in South Dakota from August 16-31, 2023. After August 31, 2023, this product cannot be applied to sunflower for red sunflower seed weevil management.
This request was submitted due to the pyrethroid-resistance and large populations of red sunflower seed weevils present in South Dakota’s sunflower production areas. For the last few years, South Dakota sunflower farmers have been dealing with populations of red sunflower seed weevils that do not respond to pyrethroid insecticide applications (lambda-cyhalothrin, esfenvalerate, zeta-cypermethrin have been tested). The Environmental Protection Agency decision to revoke the food tolerances of chlorpyrifos caused increased use of pyrethroids for red sunflower seed weevil and, as a result, an increase in the observances of field failures.
Pyrethroid-resistance in red sunflower seed weevils has not been detected in North Dakota’s sunflower production areas to date based on insecticide bioassay research over the last several years. However, populations have been detected throughout the sunflower production areas in South Dakota.
Thanks to support from the National Sunflower Association for the red sunflower seed weevil research.
Source: sdstate.edu
Categories: South Dakota, Crops