We talk about herbicide resistance all of the time in California rice, but how does it evolve in a field? Understanding how herbicide management selects for resistant populations is an important part of preventing the problem from occurring in your fields.
We have many weed species in CA rice that are confirmed to be herbicide resistant. The major herbicide-resistant species are late watergrass, early watergrass, barnyardgrass, smallflower umbrella sedge, ricefield bulrush (roughseed), sprangletop, and redstem. For this illustration of how herbicide resistance evolves in a field, we use redstem as our example.
Year 1, Beginning of season: A population of redstem is found in a...
- Author: Sarah Morran
- Posted by: Gale Perez
Annual bluegrass is a common winter growing grass in agricultural and urban environments. It is a well-known weed of turfgrass systems but its ability to grow in a range of environments makes it an increasing problem for other agricultural systems. Annual bluegrass has a short life cycle which may range from annual to perennial, seeds can germinate rapidly and multiple times in a growing season and has a high degree of survival when defoliated or trampled (Galera, Chwedorzewska et al., 2015).
All of these traits make chemical control an attractive and primary mode of management for annual bluegrass. This is true for turfgrass systems where managers use regular applications of PRE and POST herbicides and orchard systems where...
- Author: Steven Fennimore
Dear Weed Managers
Wednesday Feb. 15 of this week the Weed Science Society of America (WSSA) hosted a 4 hour listening session at the Tulare UCCE office conference room. In attendance were growers, consultants, ag industry personnel and university extension personnel. The WSSA is hosting 7 of these sessions around the US, the Tulare session was for the Southwestern US. The consensus was that people were aware of the difficulties that growers in the southeastern US were having with herbicide resistant weeds, but that outside of rice, herbicide resistant weeds in California are of concern but not a major problem. Worries about labor shortages, costs and regulations were of greater concern for California weed...
- Author: Brad Hanson
A few weeks ago, we announced the California leg of a series of six national workshops to discuss herbicide resistant weeds.
We're finalizing the list of invitees for the meeting in Tulare on February 15th. This is during the World Ag Expo, and right across the street from the Expo grounds so it's a convenient two-fer for anyone interested in both events. There are still a few participant slots left - here are three links if you're interested:
1. Original post about the series of workshops sponsored by the Weed Science Society of America:
- Author: Brad Hanson
Requesting growers and ag industry members to contribute to the national conversation on herbicide-resistant weeds
As part of a national effort on developing research and regulatory priorities related to the challenging problems of herbicide-resistant weeds, the Weed Science Society of America is sponsoring a series of half-day regional workshops to discuss the issues, potential solutions, and technical and economic barriers related to resistant weeds.
To date, much of the conversation about herbicide resistance at the national level has been dominated by the large acreage row crops of the Midwest, East, and South. These cropping systems, particularly the glyphosate-based...