Marcelo Zimmer

42 articles by this author

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In last week’s article we discussed the herbicide shortage for the 2022 growing season and outlined a couple of scenarios where we can switch to alternative herbicides to accomplish the same weed control objectives.  



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Each fall we revise and update our Weed Control Guide for Ohio, Indiana, and Illinois (WS-16) publication. This year, in addition to incorporating a few new herbicide names and subtle label change information, we are adding information to the problem weed section on control of Cressleaf Groundsel, Poison Hemlock, and Annual Bluegrass.  Since some of the best control strategies for all three of these weeds involve using herbicides applied in the fall, I decided to use this information in newsletter article.     Cressleaf groundsel is a winter annual weed that has become more prevalent in pastures and agronomic crop ground over the past decade.  The small seeds produced by this weed allow it to thrive in reduced and no-till systems as well as poorly established pastures.  Cressleaf groundsel emerges as a rosette in the fall then bolts, flowers, and produces seed in the spring.  Basal rosette leaves are deep[Read More…]


Indiana growers have shown increased interest in utilizing cover crops in our corn and soybean production systems over the last decade.  Concurrently, there has also been increased utilization of soil residual herbicides to help manage herbicide-resistant weeds such as marestail (horseweed), waterhemp, and giant ragweed in our corn and soybean production systems.  Soil residual herbicides can remain active in the soil for a period of weeks to months after application.  The length of time a residual herbicide remains biologically active in the soil is influenced by soil texture, soil pH, organic matter, rainfall, and temperature.  Since these factors will vary from field to field, definitive time intervals of residual herbicide activity can be difficult to predict. The use of residual herbicides in our corn and soybean production systems may interfere with establishment of fall seeded cover crops under certain conditions.  Unfortunately, many of the species being used for cover crops[Read More…]