Laboratory Assessment of Allelopathy in Recently-Developed Fine Fescue Cultivars.

Effective weed control without the use of herbicides is desirable in low-input turfgrass management. Previous research showed that a number of fine fescue (Festuca ssp.) cultivars exhibited allelopathic inhibition of weed species, specifically large crabgrass (Digitaria sanguinali) and curly cress (Lepidium sativum). Since that time, a number of improved fine fescue cultivars have been released but these newer cultivars have not been assessed for allelopathy. The objective of this study was to assess newer fine fescue varieties for allelopathic ability. Two cultivars from each of five fine fescue species (F. rubra. ssp. rubra, F. rubra. ssp. litoralis, F. rubra. ssp. commutata, F. trachyphylla, F. ovina) were tested for allelopathy against curly cress, a species which is commonly used for this type of screening. Older fine fescue cultivars that had been previously tested were also included.  The assay was repeated four times per cultivar and the experiment was repeated once. A weed-only control was also included. Allelopathy was assessed by planting curly cress seeds into 0.8 % water agar in Magenta tissue culture boxes 7 d after initial seeding of fine fescue cultivars. Fourteen days after initial seeding, the level of inhibition was evaluated by measuring the shoot and root lengths of curly cress. All ten fine fescue cultivars caused a significant inhibition of curly cress root growth ranging from 20% to 56%; however, there was no significant inhibition of shoot growth detected for any cultivar. These results suggest that further screening should be done using other important turfgrass weeds so that information about allelopathy can be utilized when selecting cultivars for low-input landscapes.