Excerpt: If the presence of surviving waterhemp and horseweed/marestail is more widespread, a trip back in time using a cultivator is really the only option to reduce the problems with these escapes. In a message dated 7/24/2011 10:00:22 A.M. Central Daylight Time, [log in to unmask] writes: This is just out from Iowa State University weed scientists. Apparently the best option they can come up with for controlling glyphosate-resistant weeds is cultivation. Ah -- the same conclusion some of us came to a LONG time ago... Managing Glyphosate Failures By Bob Hartzler and Mike Owen, Department of Agronomy, Iowa State University In the past week we have received numerous calls from farmers, agchem dealers and industry representatives regarding waterhemp and horseweed/marestail surviving glyphosate applications made in late June and early July. Although there are numerous reasons why a herbicide application might fail at controlling weeds, we are certain that a significant percentage of these failures are due to the presence of glyphosate-resistant biotypes in the field. The common question is what can be done to rescue the situation in the field. Unfortunately, at this time of the year there are few options. If glyphosate failed earlier to control the weeds, it is unlikely that a repeat application will do any good in controlling the surviving weeds. The PPO inhibitors (Reflex, Cobra, Phoenix, UltraBlazer, etc.) are the other postemergence option available for waterhemp in soybean. However, the label restrictions regarding weed size are long past and thus these herbicides are unlikely to provide affective control. There also is a potential for serious crop injury with the high temperature forecast for the coming week. Furthermore, the harvest interval restrictions for each of these products should be reviewed. Although not popular with the majority of growers, mechanical control is really the only available option to manage escaped and/or herbicide-resistant waterhemp and horseweed/marestail at this time. If only scattered plants are present in the field, hand-weeding the field would be worth the effort since this will slow the establishment and spread of resistance within the field. If the presence of surviving waterhemp and horseweed/marestail is more widespread, a trip back in time using a cultivator is really the only option to reduce the problems with these escapes. Bob Hartzler and Micheal Owen are professors of agronomy and weed science extension specialists with responsibilities in weed management and herbicide use. ____________________________________ From: Biotech Forum [mailto:[log in to unmask]] On Behalf Of Laurel Hopwood Sent: Monday, July 18, 2011 9:40 AM To: [log in to unmask] Subject: Resistant weeds leave farmers desperate http://www.stltoday.com/business/local/article_f01139be-ace0-502b-944a-0c534 b70511c.html#ixzz1SNadASFT Resistant weeds leave farmers desperate St Louis Today, July 17 2011 by Georgina Gustin EDITED Weeds are becoming increasingly resistant to Monsanto's Roundup forcing farmers to use other herbicides or multiple modes of action. But farmers are finding that these other modes of action aren't working either - and there appears to be little relief on the horizon. Farmers are also frustrated because these additional herbicides are costing them profits. Critics of the industry point out that Monsanto and its competitors have known about glyphosate resistance. Brett Lorenzen, a legal analyst with the Environmental Working Group, stated "It's hard to read a 54-page booklet." Laurel writes: Monsanto apparently had an aggressive PR campaign to convince farmers that GM crops would make it easier and cheaper to farm. It's unfortunate that farmers are now seeing the truth and are apparently having a difficult time purchasing non GM crops. The quote about the 54 page booklet being "hard to read" is very telling. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - To unsubscribe from the CONS-SPST-BIOTECH-FORUM list, send any message to: [log in to unmask] Check out our Listserv Lists support site for more information: http://www.sierraclub.org/lists/faq.asp To view the Sierra Club List Terms & Conditions, see: http://www.sierraclub.org/lists/terms.asp - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - To unsubscribe from the CONS-SPST-BIOTECH-FORUM list, send any message to: [log in to unmask] Check out our Listserv Lists support site for more information: http://www.sierraclub.org/lists/faq.asp To view the Sierra Club List Terms & Conditions, see: http://www.sierraclub.org/lists/terms.asp ____________________________________ Iowa Native Plants mailing list [log in to unmask] _ (mailto:[log in to unmask]) _http://atmos.cgrer.uiowa.edu/herbarium/MailingList.htm _ (http://atmos.cgrer.uiowa.edu/herbarium/MailingList.htm) The Iowa Native Plants Mailing List provides a forum for those interested in Iowa's natural vegetation and in general conservation issues. 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