Fluvellin, sharppoint (Kickxia elatine)

Seedlings of this soft, hairy annual are upright, but as plants mature they develop prostrate stems. Leaves on stems resemble those of bindweed, but fluvellin is in the snapdragon family. It has pale yellow flowers with a narrow spur and a purple upper lip. This weed is spreading into cropland throughout the Willamette Valley of Oregon and is of particular concern in spring-planted tall fescue grown for seed among other grass grown for seed species. Roundleaf fluvellin (Kickxia spuria) is present in southern Oregon and may be more invasive than sharppoint fluvellin. Both species probably react similarly to herbicides.

Remarks Control is difficult, although tribenuron methyl tank mixes with oxyfluorfen or 2,4-D plus dicamba appear promising in grass grown for seed efficacy trials. Use only the 0.008 lb ai/a rate on tall fescue and perennial ryegrass and low rates of oxyfluorfen ranging from 0.03 to 0.046 lb ai/a (2 to 3 oz/a Goal 2XL or Galigan 2E). Apply when the sharppoint fluvellin is no larger than a half-dollar in size and prior to stem elongation.

Site of action (tribenuron) Group 2: acetolactate synthase (ALS) inhibitor; (oxyfluorfen) Group 14: protoporphyrinogen oxidase inhibitor; (dicamba and 2,4-D) Group 4: synthetic auxin.

Chemical family (tribenuron methyl) sulfonylurea; (oxyfluorfen) diphenylether; (dicamba) benzoic acid; (2,4-D and MCPA) phenoxy acetic acid;