Field and laboratory studies were conducted from 1993 to 1997 to determine the feasibility of controlling nodding broomrape in sunflower by treating crop seeds with pronamide. Soaking sunflower seeds for 5 min in 50% pronamide solution or coating at the equivalent of 2 kg/ha with pronamide did not impair seed germination or seedling growth, and controlled nodding broomrape 49 to 68% and 51 to 77%, respectively, up to 105 d after planting. Studies of the effect of treated sunflower seeds on germination and seedling growth, at several time intervals after the herbicide application (0, 30, 60, and 90 d after treatment [DAT]), were conducted. Soaking with 50% solution or coating at 2 kg/ha reduced seedling growth by 20 and 24% 60 DAT, respectively, compared with the control.
Nomenclature: Pronamide; nodding broomrape, Orobanche cumana Wallr. #3 ORACU; sunflower, Helianthus annuus L.
Additional index words: Herbicide seed treatment, parasitic weed.
Abbreviations: DAP, days after planting; DAT, days after treatment; HST, herbicide seed treatment.
