James Schaeffer and his UCCE and CSU Fresno colleagues are conducting a survey to gather information on a relatively new weed problem in orchard crops of the San Joaquin Valley. The species, alkaliweed (Cressa truxillensis) is a native perennial that can be a really difficult weed to control because 1) it is a perennial so not very senstive to PRE herbidies, 2) it is not very sensitive to glyphosate, and 3) it is very tolerant of saline soils where many other plant species do not grow well.
James' request and link to the survey is below
Several researchers in the UCD weed science program have been working on various aspects of glyphosate-resistant junglerice (Echinochloa colona) for the past few years. One of our undergraduate student interns, presented a poster at the 2018 Plant and Soil Conference (the California Chapter of the American Society of Agronomy) earlier this month in Fresno.
Drew reported on the (still in process) results of an experiment in which we grew seven populations of junglerice in growth chambers at 20, 30, and 40 C (~68, 86, 104 F) and treated them with a range of glyphosate doses (0, 0.5, and 1 lb ae/A). Drew, Sarah, and other lab members collected data on growth (biomass...
- Author: David Doll
- posted by: Brad Hanson
by David Doll, UCCE Pomology Farm Advisor (see also http://thealmonddoctor.com/)
With the emergence of herbicide-resistant weed populations, several perennial nut crop spray programs incorporate the use of pre-emergent herbicides. The correct use of these types of products provide the ability to control weeds for an extended period – sometimes into the late spring or early summer – reducing in-season burndown applications. When applying these products, proper application is critical to maximize weed control and the following points should be considered.
Herbicide selection. Pre-emergent herbicide selection should be based on the weed spectrum...
I received the information below regarding Zeus Herbicide (sulfentrazone) that is relevant to the California tree and vine market. The product was registered (supplemental label) for T&V in 2014.
Info from FMC (10/24/17):
As you work with your clients and make herbicide recommendations, please be aware that the supplemental labels for Zeus herbicide in California for many key crops have expired. Currently, growers may not apply Zeus herbicide on the crops included in the expired supplemental labels including grapes, lemon, orange, pistachio, walnut, tomato transplants and...
A quick post today to share a link to the recently revised "UC IPM Pest Management Guidelines for Walnut" (UC ANR Publication #3471). You can download the whole document as a pdf here, or use it online at the above link
Lots of great sections on management of non-weed pests of walnut, but since this is the Weed Science blog, here's the direct link to Integrated Weed Management section authored this time by:
- J. A. Roncoroni, UC Cooperative Extension, Napa County
- B. D....