The Effect of Indaziflam on Seed Production in Perennial Cool-Season Grasses

Annual invasive grass weeds are a major problem in grass seed production as they contaminate seed lots and decrease the quality. Few effective herbicides are available to control invasive grass weeds in seed production systems. Indaziflam is a pre-emergence herbicide capable of providing annual weed control for 3-5 years after application. Indaziflam is not labeled for use in seed production as little is known of the effect it will have. The purpose of this study was to measure total seed yield, seed germination, seed mass, and seedling vigor when applying 0, 40, 77, and 93 g ai ha-1 of indaziflam to existing perennial cool-season seed fields in northern Utah, U.S.A. Two years of data was collected on 11 different species (12 cultivars). Control of annual weeds was excellent in treated plots. Year two of the study showed a decrease in total seed production and seedling vigor in all levels of indaziflam, including the control. Seed germination was not affected and seed mass increased slightly in year two in all levels of indaziflam. Year one was dry and hot while year two was wet and slightly cooler. Additional research is needed to test different environmental conditions that may cause indaziflam to have a negative effect on the above-mentioned traits.