Selectivity of florasulam in 4 grass species during the seed harvest year

Results from one year indicated that florasulam (Primus) and its combination with fluorxypyr applied in spring of the seed harvest year, were completely selective in seed crops of 4 grass species; namely Agrostis stolonifera, Festuca rubra rubra, Koeleria macrantha and Lolium multiflorum. Experimental treatments also included a reference product i.e. bentazone + dichlorprop-P and an untreated control; in total 7 treatments were involved. The prime objective of this study was to investigate not only the effect on vegetative crop growth, but also the impact on generative growth. The main topics were: visual phytotoxicity, lodging, seed yield, straw yield, thousand seed weight, germination capacity, cleaning efficiency, harvest index, seed number per unit area and ear density. The reference treatments (bentazone + dichlorprop-P) were insufficiently selective in Koeleria spp. for vegetative parameters and seed yield, and less selective in Festuca spp. during establishment year but without any effect on seed yield. The so-called "non-sitting" seed crops following above treatments in creeping fescue and Italian ryegrass could be attributed to an inhibition effect.