Festuca sp. interfere with germination and early growth of three weeds

Herbicide restrictions require alternative strategies for turfgrass weed control. This growth chamber study investigated the interference of 27 Festuca cultivars selected from five Festuca species using white clover (Trifolium repens L.), lawn daisy (Bellis perennis L.), and yarrow (Achillea millefolium L.) as indicator species. At 13 days after sowing (DAS), 20 weed seeds were placed in between 60 grass seeds. Lawn daisy was highly sensitive to the presence of all grasses, and results are not presented. Festuca species or individual cultivars did not affect the germination percentage and mean germination period of white clover and yarrow. The presence of tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.]) species reduced white clover root length by 71.6% and slender creeping red fescue [Festuca rubra L. ssp. littoralis (G.Mey.) Auquier] by 44.5% at 30 DAS. Within cultivars, reductions of white clover roots ranged from 81.7% (Regenerate) to 24.8% (Cathrine). Root length for yarrow was reduced by an average of 75% with no difference among Festuca species. Cultivar effects ranged from 91.8% for Barcesar to 62.9% for Samanta. For both white clover and yarrow, negative correlations were determined between Festuca biomass and the root length of both weeds: −0.241*** (white clover) and yarrow −0.168* (yarrow). Such a relationship suggests that part of the inhibiting effect can be directly attributed to Festuca biomass. We conclude that differences in interference potential between cultivars within species are as important as differences between species. White clover appeared to be the most discriminative species for growth interference studies with Festuca.