Flurprimidol preplant corm soaks or drenches affect potted gladiolus production

Efficacy of flurprimidol was studied for growth control of potted gladiolus (Gladiolus L. hybrids) using a 10 min preplant corm soak at 0, 5, 10, 20, or 40 mg L-1 for 'White Prosperity' and 0, 5, 10, 20, or 30 mg L-1 for 'Priscilla'. In a second study, flurprimidol drenches at 0, 0.5, 1.0, 2.0, or 4.0 mg of active ingredient per pot were used for both cultivars. With increasing flurprimidol dose, plant growth (plant height, leaf length, and fresh and dry weight of a stem) decreased for both cultivars. When used as a preplant corm treatment for 10 min, 20 mg L-1 flurprimidol resulted in 41 and 30% shorter plant height, 48 and 25% smaller leaves, 14 and 20% less fresh weight, and 20 and 24% less dry weight of 'White Prosperity' and 'Priscilla' gladiolus, respectively, compared to untreated plants. Drenches of 2.0 or 1.0 mg of flurprimidol for 'White Prosperity' and 'Priscilla, respectively, resulted in ample growth control with 40 and 40% shorter plant height and 12 and 24% less dry weight for 'White Prosperity' and 'Priscilla, respectively. With increasing flurprimidol dose, the number of stems that flowered decreased in all experiments. In summary, preplant corm soaks at 20 mg L-1 or 1.0-2.0 mg drenches per pot of flurprimidol effectively controlled excessive plant growth and may be used by the growers for potted gladiolus production, but may reduce plant quality.