Fruit and nut growers, especially in the West, are facing shortages of the popular herbicide Rely (glufosinate, Bayer CropScience). According to Bayer, demand for the active ingredient in Rely 280 (glufosinate) increased significantly in 2012 and is expected to increase again in 2013. This increase is due to the rapid spread of herbicide-resistant weeds across crops and geographies.
Rely has become a mainstay for fruit and nut growers needing a broad-spectrum burndown herbicide to control tough weeds like filaree, willow weed, or glyphosate-resistant fleabane and marestail, according to Brad Hanson, University of California Cooperative Extension weed specialist. During the 2012 season, California was in short supply of Rely due to the high demand in the Midwest for planting glufosinate corn varieties, he says, and in recent years, the development and spread of Roundup-resistant weeds is forcing a change from Roundup Ready corn and soybeans varieties to planting LibertyLink varieties which require the use of glufosinate herbicide (Rely, Liberty).
In a written statement, Bayer says it is investing to increase the global production of the active ingredient in Rely to help ensure an adequate supply in coming years. “In the short term, demand for the active ingredient in Rely 280 will continue to increase more rapidly than manufacturing capabilities can be expanded, and we anticipate a shortage of the active ingredient in 2013. Bayer CropScience remains committed to providing producers in the horticulture market with viable pest control solutions and will continue to keep the market informed of updates.”
Only Look Alike
Glufosinate is classified as a “Group 10, or Group B” herbicide and inhibits an enzyme important in the production of the amino acid glutamine in plants, says Hanson. Although it sounds similar to another amino acid inhibitor, glyphosate (the active ingredient in Roundup and others), glufosinate works quite differently than the Group 9 herbicide glyphosate.
Because it has a different mode of action than glyphosate, glufosinate has become very important in California orchards and vineyards — especially those struggling with glyphosate-resistant weeds like horseweed (e.g. mare’s tail), hairy fleabane, rye grass, and jungle rice. The scarcity of glufosinate in California seems to driven by glyphosate-resistant weeds in other cropping systems in other parts of the country, he says. The active ingredient glufosinate in Rely 280 is the same one used in Ignite, Liberty, Basta, and Finale herbicides, and several of these are used in LibertyLink crops such as cotton, corn, canola, and soybeans, as well as a few other crops.
As well as being much larger markets (several hundred million acres) than such “minor” crops as trees and vines, Hanson says some of these cropping systems have much more serious glyphosate-resistant weed problems than fruit growers do. Hanson says if you want to see how bad the Midwesterners have it, do an Internet search for glyphosate-resistant Palmer amaranth or water hemp. “Until production of the active ingredient can be ramped up to meet the national demand, most of the glufosinate will be sucked out of our markets in California in 2013,” he says, “and the forecast for 2014 is not very optimistic either.”
Make Plans Now
With the heavy use expected in corn states, fruit growers should plan on alternative weed control strategies that will replace the use of Rely, says Hanson. “We are confident with the post- and pre-emergent herbicide combinations we have available and used in a timely manner, we can still expect excellent weed control results,” he says.
What should fruit growers do? Actually, a sound strategy should start with the same things you should be doing every year: planning ahead, scouting fields, and rotating herbicide modes of action. For growers in California, because as 2013 was dawning it was looking like a soaker of a rain year, it would be a good time to investigate some of the pre-emergence herbicides available. The herbicide susceptibility chart at the University of California’s Weed Research & Information Center, which can be found online at http://wric.ucdavis.edu, is still a good resource for growers and crop advisors planning weed management strategies for the coming season, says Hanson.
In its statement, Bayer notes Alion herbicide offers outstanding pre-emergence weed control in many of the same fruit, nut, and vine crops that are managed by Rely 280. “Bayer CropScience remains committed to providing producers in the horticulture market with viable pest control solutions and will resume production of Rely 280 when supplies reach a sufficient level.”