Over the past few years, herbicides with the active ingredient glufosinate (Rely, Rely 200, Rely 280) have become very important in California tree nut orchards and grape vineyards. Because it has a different mode of action than glyphosate, glufosinate is especially useful in those vineyards struggling with glyphosate-resistant weeds like horseweed (eg mare's tail), hairy fleabane, ryegrass, and junglerice.
Brad Hanson of UC Weed Science anticipates glufosinate is going to be in very short supply in California during 2013 and possibly into 2014 so growers and pest control advisors should plan ahead. He says the scarcity of glufosinate in California seems to driven by glyphosate-resistant weeds in other cropping systems in other parts of the country.
Read more, UC Weed Science Blog