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(Not A) Disease Update (3/11/2011)

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Sure Sign That Spring is Coming


Spring is definitely in the air.  Our clocks spring forward this Sunday morning, and the spring equinox and official start of spring occurs next Sunday, March 20th.   I’m excited about warming up and starting the season, particularly with the record snowfall amounts of this past winter.  However, where turf care is concerned, it isn’t quite time to start thinking about spreading pre-emergent herbicides quite yet...

Stop Crabgrass Now Sign

Crabgrass Pre-emergent Timing

I’m not a weed scientist by any means, but Dr. Fresenburg has been getting some calls asking if it is time to apply crabgrass pre-emergents.  Despite what the above photo suggests, (which was taken Wednesday of this week) the answer is a resounding NO!.

Pre-emergent applications should be timed when average daily soil temperatures reach 50 – 55°F consistently, which normally occurs the first few weeks of April for most of MO.  This timing is well before the 80% crabgrass germination rate that occurs when soil temperatures reach 60 – 70°F.  

The maximum soil temperature yesterday was 43°F in Columbia and in Portagesville (our southernmost station) it is 50°F; not to mention there was quite a heavy frost on the pumpkin this morning. Forecasts call for a slight warm-up next week into the mid 60’s, but this shouldn’t take us into the application window.  

So bottom-line - it is way too early.  Go ahead and buy it, but wait to apply it.    

Save the Date:  July 26, 2011

Make plans to join us at the University Missouri Turf & Ornamental Research Farm on July 26th for our annual field day!  We will be presenting the latest research on cultivar evaluations, pest controls, and management considerations for turf, trees, and woody ornamentals.  It’s a fine day and a fine way to interact with colleagues and your local Mizzou research team.

Lee Miller
Extension Turfgrass Pathologist
University of Missouri

Brad Fresenburg
Extension Turfgrass Specialist
University of Missouri