- Author: Mariano Galla
During this time of the year when your wheat is tillering, it is really important to monitor fields for weeds and Italian ryegrass infestations in particular.
Information about weed management can be found on the UC IPM guidelines for small grains: http://ipm.ucanr.edu/PMG/r730700211.html
Pre-emergent herbicides are not commonly used in small grains production in California, but there are several options for POST emergent herbicides. UC Cooperative Extension (UCCE) Farm Advisor Steve Wright and his group conducted some testing and found that Osprey, Simplicity CA and Axial were effective in controlling Italian ryegrass. Broadleaf herbicides, such as Express or MCPA, can also be mixed with Simplicity CA and Axial to broaden the spectrum of weeds controlled (Figure 2).
Unfortunately, cases of Italian Ryegrass populations resistant to one or more herbicide modes of action have been reported in California and in other states. Brunharo and Hanson (cit newsletter) reported a population of Italian Ryegrass from Hamilton City resistant to Gramoxone, Envoy and Osprey. In Oregon, Liu et al. (cit) found a ryegrass population resistant to pinoxaden, the active ingredient of Axial.
In the Sacramento Valley, the short rotation interval already limits the availability of effective herbicides because of safety concerns for the next crop. The spread of herbicide resistant ryegrass could further reduce our viable options.
If you are looking for more information or interested in cooperating in Italian ryegrass management trials, feel free to contact me at the UCCE office [(530) 865-1105] or via email (firstname.lastname@example.org).