EPA Decision: Insecticide Active Ingredient “Sulfoxaflor”

By Adam J. Varenhorst

The insecticide active ingredient sulfoxaflor is effective for managing insect pests with piercing sucking mouthparts including several species of aphids. In addition to being effective against major insect pests such as the soybean aphid, sulfoxaflor’s impact on natural enemies (e.g., damsel bugs, green lacewings, lady beetles, and minute pirate bugs) is reduced (Dow AgroSciences). This indicates that sulfoxaflor applications should not result in pest resurgences or replacements. That is, once an application is made the remaining natural enemy populations will provide effective management of any surviving insect pests, and secondary insect pest populations will not increase due to the absence of natural enemies.

Additional benefits associated with this active ingredient are that sulfoxaflor represents the new class of sulfoximine insecticides, which are distinct from neonicotinoids (e.g., clothianidin, imidacloprid, and thiamethoxam). Although sulfoximines and neonicotinoids are both active against insect nicotinic acetylcholine receptors, research has demonstrated that there is no cross resistance between these two classes of insecticides (Sparks et al. 2013). That is, insects that are resistant to neonicotinoid class insecticides are not resistant to sulfoximine class insecticides. Products containing sulfoxaflor as the active ingredient include Seeker and Transform, which are labeled for use in canola, soybean, and wheat for the management of aphid pests.

EPA Cancellation Order

On November 12, 2015, the United States Environmental Protection Agency (EPA) issued a cancellation of the active ingredient following a ruling “vacating” sulfoxaflor-containing product registrations by the Ninth Circuit Couth of Appeals. This ruling was in response to concerns regarding the safety of pollinators in areas where sulfoxaflor could be applied. Sulfoxaflor is known to be toxic to bees from the time of application and until the product dries. Labels for the sulfoxaflor-containing products included environmental hazard statements containing additional restrictions to mitigate this exposure.

In response to the ruling, the issue of pollinator safety will be addressed in further EPA reviews of the data available regarding sulfoxaflor. In a press release, Dow AgroSciences stated that “Dow AgroSciences continues to work diligently with EPA and states to achieve new registrations as quickly as possible to allow for your inventories to be sold to growers. To that end, Dow AgroSciences submitted new labels for consideration to EPA on November 16, 2015. In addition, it is our understanding that several states are now in the process of submitting or developing Section 18 applications for the 2016 season which can increase the potential to use your existing inventory.”