![\"Bill-Johnson-8\"](\"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-content\/uploads\/2021\/01\/Bill-Johnson-8.jpg\" "\\"Bill-Johnson-8\\"")
\n\tDr. Bill Johnson | Professor of Weed Science<\/p>\n\t\t\tContact me<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t Botany and Plant Pathology Department, Purdue University<\/p>\n Office: Lilly Hall<\/strong> (Room 1-361), 915 West State Street, West Lafayette, IN 47907-2054<\/p>\n Phone: (765) 494-4656<\/p>\n\n\n\t\t\t\t Dr. Tommy Butts | Clinical Assistant Professor of Weed Science<\/p>\n\t\t\tContact me<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t Botany and Plant Pathology Department, Purdue University<\/p>\n Office: Lilly Hall<\/strong> (Room 1-236), 915 Mitch Daniels Blvd , West Lafayette IN, 47907<\/p>\n Phone: (765) 494-0598<\/p>\n\n\n The estimated average monetary loss caused by weeds in field crops grown in the U.S. is over several billion dollars each year. Weed management expenses are one of the largest variable costs incurred by growers annually. Weeds growing on cropland are like crop plants themselves, drawing upon the soil and air for essential elements. Unfortunately, weeds obtain essential elements at the expense of adjacent crop plants. The result of inadequate weed control is a reduction of crop yield and quality. Traditionally, weed management practices have included preventative, cultural, mechanical, biological, and chemical tactics. However, with the rapid increase in the number of effective herbicides in the 1960-1990’s, weed management techniques have become more reliant on herbicides in the last 30 years. In any biological system, strong dependence on any single tactic results in selection pressure for species (weeds, insects, and\/or diseases) which can exploit the niche left by the single tactic. As a result of overdependence on herbicides, the number of herbicide-resistant weeds has grown from less than 10 in the 1960’s to over 300 today. Additionally, there are over 1000 non-indigenous plant species which can potentially infest crop production systems if given the opportunity. Therefore, production of food for humans and livestock and the economic well being of Indiana farmers depends heavily on effective, integrated management of weeds and other plant pests in all of our food crops.\u200b<\/p>\n The GWC series of publications explore weed resistance to glyphosate (Roundup and others) in the mid-west US.\u00a0 The weeds that have been reported to be resistant and their biology and control.\u00a0 The authors have been compiled from Universities across the US including the University of Delaware, University of Illinois, Iowa State University, Kansas State University, Michigan State University, University of Minnesota, University of Missouri, University of Nebraska, North Dakota State University, The OhioState University, The Pennsylvania State University, Purdue University, South Dakota State University, Southern Illinois University, University of Wisconsin.<\/p>\n\n\n\n\n\n\n\n\n\t\t\tBenchmark Studies<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t\n\n\n\n\n\t\t\tAquatic Weeds<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t\n\n\n\n\t\t\tHorticulture<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t\n\n\n","protected":false},"excerpt":{"rendered":" Extension Weed Science Personnel Dr. Bill Johnson | Professor of Weed Science Contact me Expand Botany and Plant Pathology Department, Purdue University Office: Lilly Hall (Room 1-361), 915 West State Street, West Lafayette, IN 47907-2054 Phone: (765) 494-4656 Dr. Tommy Butts | Clinical Assistant Professor of Weed Science Contact me Expand Botany and Plant Pathology…<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-43","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/pages\/43","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/comments?post=43"}],"version-history":[{"count":138,"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/pages\/43\/revisions"}],"predecessor-version":[{"id":9123,"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/pages\/43\/revisions\/9123"}],"wp:attachment":[{"href":"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-json\/wp\/v2\/media?parent=43"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"citations\"](\"https:\/\/ag.purdue.edu\/btny\/purdueweedscience\/wp-content\/uploads\/2025\/02\/citations.jpg\" "\\"citations\\"")
\n\t\n\t\tProgram Description\n\t<\/h2>\n\t
\n\t\tWeed Science Extension Program Objectives\n\t<\/h2>\n\t
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\n\t\tExtension Publications\n\t<\/h2>\n\t\t\tWeed Biology and Management<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\t\t\tRow Crops, Herbicides, and Application Technology<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\t\t\tThe Glyphosate, Weeds, And Crops Series<\/a>\n\t\t\t\t\t\t\tExpand<\/i><\/a>\n\t\t