Herbicides Applied to Dodder (Cuscutaspp.) after Attachment to Alfalfa (Medicago sativa)

Abstract

When glyphosate [N-(phosphonomethyl)glycine] at 0.075 kg/ha, DCPA (dimethyl tetrachloroterephthalate) at 10 kg/ha, and H 26905 [O-ethyl-O-(3-methyl-6-nitrophenyl)-N-sec-butyl phosphorothioamidate] at 0.25 and 0.5 kg/ha were sprayed on foliage of alfalfa (Medicago sativaL. ‘Vernal’) on which field dodder (Cuscuta campestrisYunck.) and largeseed dodder (Cuscuta indecoraChoisy) were attached and growing vigorously, almost all visible dodder tissue was killed and alfalfa was not injured noticeably. Some dodder recovered from haustoria within the alfalfa stems and from remnants of twined tendrils, but devastation of the alfalfa by uncontrolled dodder was prevented. PP 009 (butyl 2-[4-(5-trifluoromethyl-2-pyridyloxy)phenoxy] propionate), BAS 9052 (2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one) and RO 13-8895 (acetone-O-[D-2-[p-[(α,α,α-trifluoro-p-tolyl)-oxy] phenoxy] propionyl] oxime) at 0.25, 0.50, or 1.0 kg/ha did not control dodder.