{"id":1039,"date":"2023-03-15T11:30:33","date_gmt":"2023-03-15T15:30:33","guid":{"rendered":"https:\/\/site.extension.uga.edu\/benhillcoag\/?p=1039"},"modified":"2023-03-15T11:30:34","modified_gmt":"2023-03-15T15:30:34","slug":"cold-weather-and-burndowns-by-dr-prostko-uga","status":"publish","type":"post","link":"https:\/\/site.extension.uga.edu\/benhillcoag\/2023\/03\/cold-weather-and-burndowns-by-dr-prostko-uga\/","title":{"rendered":"Cold Weather and Burndowns (By Dr. Prostko UGA)"},"content":{"rendered":"\n<p><\/p>\n\n\n\n<p>Many growers are now in the process of spraying pre-plant burndown herbicides.&nbsp; Low temperatures over most of Georgia are expected to drop below 40 F over the next three days.&nbsp; These temperatures are not very favorable for optimum weed control with herbicides such as Roundup (glyphosate) or Gramoxone (paraquat).&nbsp; Thus, you might want to advise your growers to hold off for a few days until temperatures warm up again (above 40 F but I would prefer warmer).&nbsp; Here is some data to chew on:<\/p>\n\n\n\n<p>1) From some older air temperature research (47 F, 56 F, 65 F, 75 F, and 87 F) conducted by my colleague at Michigan State University, Dr. Christy Sprague:<\/p>\n\n\n\n<p><em>a) Air temperatures had very little effect on the control of common chickweed with Roundup.&nbsp; However, common chickweed control at lower temperatures was compromised with Gramoxone (<strong>only 70% control at 47 F<\/strong>).<\/em><\/p>\n\n\n\n<p><em>b) Air temperature had a significant effect on the control of henbit with both Roundup and Gramoxone.&nbsp; When applied at 47 F, henbit control was &lt; 30% with both herbicides.<\/em><\/p>\n\n\n\n<p>2) From Harre et al. (2021) in Weed Technology 35:279-288:<\/p>\n\n\n\n<p><em>a) Shoot biomass reduction of horseweed and purple deadnettle was 34% and 28% greater, respectively, when paraquat was applied at day\/night temperatures of 81\/61 F than when applied at 64\/55 F.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Many growers are now in the process of spraying pre-plant burndown herbicides.&nbsp; Low temperatures over most of Georgia are expected to drop below 40 F over the next three days.&nbsp; These temperatures are not very favorable for optimum weed control with herbicides such as Roundup (glyphosate) or Gramoxone (paraquat).&nbsp; Thus, you might want to advise [&hellip;]<\/p>\n","protected":false},"author":234,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-1039","post","type-post","status-publish","format-standard","hentry","category-herbicides"],"_links":{"self":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/1039","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/users\/234"}],"replies":[{"embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/comments?post=1039"}],"version-history":[{"count":1,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/1039\/revisions"}],"predecessor-version":[{"id":1040,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/posts\/1039\/revisions\/1040"}],"wp:attachment":[{"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/media?parent=1039"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/categories?post=1039"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/site.extension.uga.edu\/benhillcoag\/wp-json\/wp\/v2\/tags?post=1039"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}