Potential for Selective Activity of the ALS Inhibitors Penoxsulam, Bispyribac-sodium, and Imazamox on Algae Responsible for Harmful Blooms

摘要

In 2007, there were 45 acetolactate synthase (ALS) inhibiting herbicides registered for use by the U.S. Environmental Protection Agency (USEPA; WSSA 2007). The registration of such a large number of herbicides with the same mode of action is based largely on the differential selectivity exhibited by these products. Slight changes in the molecular structure of ALS-inhibiting herbicides can greatly affect their potency and weed control spectrum (Ren et al. 2000). The selectivity of the ALS herbicides is due to the ability of different plant species to metabolize the herbicide, or in some cases tolerant plants can have an altered target enzyme site. The ALS herbicides are widely used in cropping, forestry, right of way, and aquatic sites. From an aquatic registration perspective, ALS inhibitors exhibit a high margin of safety for fish and wildlife, and mesocosm screening suggests they can be selective against numerous aquatic macrophyte species (Nelson et al.