|Weed Control - 72
Project Leader and Principal UC Investigators
D.E. Bayer,Weed Control in Rice by Herbicides and Cultural Management
Rice growers have already benefited from research on better use of existing
herbicides. Certain combinations of herbicides hold promise of
broader-spectrum weed control, thereby eliminating separate applications. A
practice already yielding economies is combining cultural practices (for
example, applying fertilizer and herbicides together). Potential
combinations should be checked with Extension Service or your chemical
A main thrust of this research is potential herbicides, with 67 evaluated in the last 3 years. Several promising ones are under further study. Current tests are focusing on economy and safety to the environment. Examples of herbicides on the horizon are Hydrothol 191® and Bolero®. (Bolero is not registered for use on rice at this publication date.)
Hydrothol 191 has provided outstanding control of pondweed, promising significant and economic yield increases where infestations are heavy (Glenn and San Joaquin Counties). Hydrothol 191 can also be used to control submersed aquatic weeds in irrigation ditches serving rice fields.
Bolero is primarily a grass herbicide that, applied postflood, is showing promise for controlling sprangletop as well as watergrass. Sprangletop is becoming a problem to growers using shallow-water culture for high rice yields. Bolero is also effective against ducksalad, a new problem in the northern ricelands.
Coordinated research on propanil has helped retain its use south of Sacramento. (RP1)