Tennessee weed control hampered by cool temperatures

July starts cool in Tennessee, putting Liberty application timing in question. Liberty weed control is spotty when night temps are in 60s and daytime barely much higher.

We have gotten a number of calls on how effective Liberty will control weeds during this unseasonably cold first week of July.  

It does seem hard to believe that this is July 4th week with night time low temperatures in the 60s and highs in the upper 70s. 

We have quite a bit of data on Liberty efficacy on weeds under these type of temperatures and control is often inconsistent. 

We have about a half million acres of soybeans that are late planted and a fair percentage of these are LibertyLink. In many cases the Palmer amaranth is just a couple inches tall if a pre-applied was not used. In these cases it would probably be best to hold off the Liberty application until temperatures are warmer. 

Of course the pigweed will be larger if you wait to spray, but I would rather take my chances with a very active Liberty on a warm day than spraying smaller Palmer when it is cold.

Fields where a pre- was applied at planting will likely hold for about 14 days and in many cases the Palmer is just emerging. The Palmer in these fields should be easier to control with a Liberty application later this week.   

Cotton is a different story as planting date and maturity is quite diverse. In most cases, the first application of Liberty has been applied over-the-top in many fields. In a few of the earliest planted fields, two applications of Liberty has been sprayed. 

Now would be a good time to get the hoods out and, hopefully, we can at least start laying by the earliest planted cotton. 

A popular layby application is diuron plus MSMA. MSMA like Liberty also works better under warmer environments. Therefore, during this cold snap I would go with diuron plus 1 percent COC instead of MSMA. As the temperatures warm up, then switch the COC for MSMA.

For more Tennessee crop information, go to http://news.utcrops.com.



TAGS: Cotton
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