Dodder (Cuscutaspp.) Control in Newly Seeded Alfalfa (Medicago sativa) with Glyphosate

A heavy, uncontrolled infestation of field dodder and largeseed dodder suppressed newly seeded alfalfa severely and killed many of the plants. Glyphosate at 75 or 150 g ae ha-1, sprayed over the top of the dodder-infested alfalfa, stopped the growth of dodder and did not injure alfalfa significantly. Treated dodder began to grow normally again 2 to 3 wk after treatment. This regrowth injured the alfalfa severely in spite of earlier control. Glyphosate at 75 or 150 g ha-1applied two or three times controlled dodder effectively and protected the alfalfa. A rate of 40 g ha-1was not effective.