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Posted 15 May 2010. Crop Management. Weed Resistance Management Advice Offered by Grower, Retailer, Researchers Source: Syngenta Crop Protection Press Release. www.syngentacropprotection-us.com Greensboro, North Carolina (April 28, 2010)--Syngenta gathered a panel of weed resistance experts, including a grower, a retailer and university researchers, to provide practical, timely recommendations to manage weed resistance during the 2010 season. Their discussion was held during this year’s Commodity Classic in Anaheim, Calif.
The panelists focused on the need to diversify weed control practices, even with the lower cost of glyphosate. “Growers are always looking at their bottom line,” said Paul Barchenger, agronomy manager of Hutchinson Coop in Hutchinson, Minn., and a Syngenta Resistance Fighter of the Year winner. “But not controlling weeds early in the season can actually cost more in yield in the long run. I encourage my growers to include residual herbicides and multiple modes of action to control weeds – including resistant weeds – and protect crop yields. That’s better than just going with an inexpensive program.” Christy Sprague, associate professor and extension weed scientist, Michigan State University, agreed. “If you look at the long-term economics, you’re going to be better off using a pre-emergence herbicide or tank mixing,” she said. “It may cost a little bit more up front, but when you are harvesting, you’ll see better yields.” Grower Mike Flanary of Grossnickle Farms in Walkersville, Md., manages more than 2,000 acres of wheat, barley, corn and soybean. The Syngenta cereals Farming for the Future winner said sound management practices don’t require much extra effort. “I know how difficult it can be for farmers to make changes,” he said. “But with some of the things we’ve done on our farm, we’ve found it’s not much harder. In fact, sometimes it’s a little bit easier.” Panel recommendations to manage tough weeds • Apply herbicides at the right time: According to University of Arkansas associate professor Nilda Burgos, “The duration of a weed-free period, which is very important, varies across crops. For example, in cotton in the South, one major weed we are fighting is Palmer pigweed. Studies show that if you allow Palmer pigweed to compete with cotton within the first 21 days of the season, it can already hurt yield, even though you could try to clean it up later.” Sprague added, “And our recommendations in corn are to control weeds pre-emergence or when they are 2 to 4 inches tall to avoid yield losses.” • Use multiple herbicide modes of action: “Using one herbicide mode of action over and over allows the weeds that are naturally tolerant to that herbicide to increase,” said Burgos. Rotating modes of action and diversifying crop management practices prevents this. “Incorporating multiple modes of action is especially important in soybean, because that’s where resistance, including multiple resistance, often seems to develop,” Sprague said. “In fact, in Illinois there is waterhemp with resistance to four modes of action.” • Rotate to crops with effective weed control options: “For example, in the field where glyphosate-resistant giant ragweed first appeared in soybean in my area of Minnesota, the grower has gone to continuous corn because there are more options to control the weed in corn,” Barchenger said. • Change tillage practices: Flanary said, “We switch up our tillage a lot, which actually saves time and fuel, and it helps manage tough weeds.” • Manage weeds on the field perimeter: Barchenger noted that one key is controlling weeds around the fields. “I encourage my customers to go around the edges of their fields to clean up the weeds in their fencerows,” he said. “Field perimeter management can really help slow the development of resistance and minimize its spread.” • Use available resources: Flanary recommended taking advantage of online resources to find information. “As a farmer, I use www.FarmAssist.com quite a bit – a couple times a day when I’m spraying,” he said. “Although I could call someone, they may not answer right away. Online, I can get my answers right away.” Another online resource is www.resistancefighter.com, which includes a Solutions Builder that creates customized weed control recommendations based on weed spectrum and geography. To better verify the occurrence of weed resistance, Burgos described a current joint university-Syngenta research project to help develop a rapid seedling test for resistance. This “Petri dish” test provides results in 10 days, compared to the traditional seedling bioassay in the greenhouse, which generally takes a month and a half. “Growers will be able to use this tool to understand the level of resistance in their field before they make a post-emergence herbicide application,” she said. “They will be able to make in-season adjustments to their weed control plan to protect their crop.” Contact: |
