Establishing Alfalfa on Dodder-Infested Soil

Abstract

Alfalfa ( Medicago sativa L.) was killed or severely injured by parasitism from dodder ( Cuscuta campestris Yunck. and C. indecora Choisy) when seeded August 1 or earlier in soil containing dodder seed. Alfalfa seeded August 15 or September 2 escaped injury from dodder, and became well-established before winter. Isopropyl m -chlorocarbanilate (chlorpropham) applied at 6 lb/A the following April controlled dodder effectively and did not injure alfalfa. A preemergence application of dimethyl tetrachloroterephthalate (DCPA) at 10 lb/A, followed by sprinkler irrigation, controlled 98 to 100% of the dodder at each of six dates of seeding in each of 2 years. DCPA often injured alfalfa seedlings severely, but most of them recovered and grew satisfactorily.