Wild oat (Avena fatua) seed production in spring barley (Hordeum vulgare) is affected by the interaction of wild oat density and herbicide rate

Abstract

The efficacy of current wild oat herbicides and their high cost have resulted in use rates that are less than those recommended. While acceptable weed control may be attained at less cost, this practice does not consider the potential for increased wild oat seed production. The objective of this experiment was to determine the interaction of wild oat density and reduced imazamethabenz rates on wild oat seed production in spring barley. As wild oat densities increased from 8 to 1,100 plants m−2, wild oat seed production increased from 180 to 9,950 seed m−2without herbicide, and from 0 to 2,810 seed m−2using 0.53 kg ai ha−1imazamethabenz. This general pattern was modeled using a cumulative logistic function. Estimates from this model indicated that < 1 wild oat seed m−2was produced at population densities of ≤ 20 plants at any imazamethabenz rate. Imazamethabenz rates of 0.26 kg ha−1or greater at wild oat densities of less than approximately 190 plants m−2did not result in wild oat seed production above the initial population density. As wild oat density increased, however, imazamethabenz rates below 0.40 kg ha−1resulted in substantially greater wild oat seed production compared to the recommended rate.

Spatial stability of Avena sterilis ssp. ludoviciana populations under annual applications of low rates of imazamethabenz

“…Spandl et al (1997) working with four specific herbicides for the control of Avena fatua L. (diclofop, imazamethabenz, fenoxaprop and difenzoquat), found that reducing herbicide rates generally reduced weed density while grain yield and the net economic return was not different from full dose applications. Similar results were obtained by Wille et al (1998) working with imazamethabenz. They found that all of the herbicide dose rates tested (0.13, 0.26, 0.40 and 0.53 kg a.i.…”

The Biology of Canadian Weeds. 27.Avena fatuaL. (updated)

“…More recent studies found that A. fatua plants at varying densities in spring barley or wheat produced between 20 and 70 seeds per plant (Thill and Mallory-Smith 1997;Belles et al 2000;Van Wychen et al 2004). In spring barley in Idaho, A. fatua seed production was 180 to 9950 seeds m (2 as plant densities increased from 8 to 1100 plants m (2 , respectively (Wille et al 1998). In Washington state, A. fatua planted at 3-m spacing in bare ground produced an average of 19 tillers with 1070 seeds per plant (Morrow and Gealy 1983).…”

Controls over native perennial grass exclusion and persistence in California grasslands invaded by annuals

“…To do so, we reparameterized the models by setting a as ¼ /a aa and a ps ¼ /a pa , where / is uniformly distributed from zero to one. Data to parameterize the model came from many published studies (Dyer et al 1996, Dyer and Rice 1997, Wille et al 1998, Hamilton et al 1999, Brown and Rice 2000, Dyer 2003, Corbin and D'Antonio 2004, Malmstrom et al 2005, Buisson et al 2008, Seabloom 2011, Wainwright et al 2012, Stahlheber and D'Antonio 2014, and one unpublished study (N. A. Molinari and C. M. D'Antonio, unpublished data). These studies measure plant demographic rates such as seed production, germination, and survival in the field as part of broader ecological experiments.…”