- Author: Ben Faber
- Re-posted by: Gale Perez
From the Topics in Subtropics blog ∴ June 15, 2016
Researchers have now confirmed that six glyphosate-resistant weed species have been identified in California. Four have been known to exist for some time; they are horseweed (marestail, Conyza spp.), hairy fleabane, rigid ryegrass and annual ryegrass. To that list, junglerice and Palmer amaranth in the Central Valley have been recently added to the list. Additional weeds that have become more of a challenge to control and are on the suspect list are goosegrass and, in the central San Joaquin Valley, the summer grasses sprangletop and witchgrass.
There have never been a lot of...
- Author: Richard Smith
- Posted by: Gale Perez
On January 12, 2016 the Federal EPA label for Kerb SC was reinstated for leaf lettuce. The registration on leaf lettuce was pulled in 2009 and Dow AgroSciences worked in the intervening years reregister Kerb. The new label allows for the use of Kerb from 25 to 55 day prior to harvest (Table 1). The 25 day preharvest interval is significant because it allows the use of Kerb on baby lettuce which is typically harvested in 25-30 days after the first wet date during the summer months (Figure 1). The 25 day preharvest interval gives growers an option for controlling weeds in high density plantings; this change is very helpful because high density plantings cannot be cultivated and weeds that occur must be removed by hand prior to mechanical...
- Author: Sarah Morran
- Posted by: Gale Perez
Each of us have the entire blueprint for our bodies contained in every cell, and the same is true of plants. This information is stored in the form of an extremely long molecule known as DNA (in human cells its length is ~6 feet). Studying and understanding DNA in plants has led to many advances in weed science including; the development of herbicide- tolerant crop varieties, understanding the causes of herbicide resistance and understanding the origins and spread of weeds in our environment.
Here in California, the weed science group at UC Davis is utilizing this technology to investigate glyphosate resistance that has been detected in California populations of junglerice. Junglerice is a summer grass weed present in many...
- Author: Richard Smith
- Posted by: Gale Perez
The following information is from the Salinas Valley Agriculture blog.
On January 12, 2016 the Federal EPA label for Kerb SC was reinstated for leaf lettuce. The registration on leaf lettuce was pulled in 2009 and Dow AgroSciences has been working to reregister Kerb since that time. As part of this reregistration effort, Kerb was reclassified as “not likely to be carcinogenic to humans” which freed up space in the risk cup. Of particular interest are the preharvest intervals allowed in the label:
- Author: Guy B Kyser
- Author: John Madsen
In summer 2015, USDA-ARS and UC Davis Dept of Plant Sciences set up a water hyacinth control study with California Department of Boating & Waterways. The goal of the study was to determine the best of several different surfactants to pair with an aquatic-use formulation of glyphosate.
Aquatic weed trials are tricky compared to terrestrial trials, because the test sites are three-dimensional and they move around. In addition, water hyacinth is free-floating. In order to establish secure test plots, we built floating 1-m2 quadrats out of PVC pipe, swim noodles, and construction fencing.
On 31 July, we anchored the quadrats in open water within a sunken island in the Sacramento delta. Quadrats were...