Comments About Mid to Late Season Weed Control

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The Butyrac 200 label indicates that two applications can be made at 0.8 to 1 pint followed by a second application at these rates. There is also verbiage on the same label for other states indicating that 1 to 1.6 pints/acre can be applied and that a repeat application can be made (total of 3.2 pints/acre.) A number of years ago we looked at a wide range of applications of 2,4-DB at rates exceeding the NC rate on the label applied at different times (see below, 0.45 kg ae/ha is 0.4 lb/acre or 1.6 pints/acre.) We also looked at applications of 2,4-DB at 1 pint/acre 7, 5, and 3 weeks before harvest. We did not see problems in terms of peanut injury or a negative influence on yield in any of
these trials.

I know some of you are having weeds creep in at this point in the season, and I have had a number of questions on how to handle sicklepod this late. I would not spray Classic and it is too late to apply Cadre. 2,4-DB is the only reasonable option at this point for suppression. A final repeat application of 2,4-DB is in order in many fields as long as it is applied no closer to harvest than 45 days.

2011-035-chart

Tolerance of Virginia-Type Peanut to Different Application Timings of 2,4-DB

T. A. Baughman, W. J. Grichar, and D. L. Jordan

Peanut Science 29:126-128

Field studies were conducted to determine the effects of 2,4-DB application timings on yield and market quality of virginia-type peanut. Trials were conducted at three locations in Texas and one location in North Carolina in 1997, 1998, and 1999. 2,4-DB at 0.45 kg ae/ha was applied 30, 45, 60, 90, and 120 d after planting (DAP). Additional timings included combinations of 30 DAP followed by (fb) 60, 90, or 120 DAP; 60 DAP fb 90 or 120 DAP; and 90 DAP fb 120 DAP. Peanut yield, market grade factors, and pod and seed weight were not influenced by various application timings of 2,4-DB.

Tolerance of Peanut (Arachis hypogaea L.) to Herbicides Applied Postemergence

David L. Jordan, Janet F. Spears, and John W. Wilcut

Peanut Science 30:8-13

…when pooled over nine sites, 2,4-DB did not adversely affect pod yield, gross economic value, or percent seed germination when applied 7, 5, or 3 wk before vine inversion.

Article first appeared as North Carolina Peanut Note (PNNC-2011-035)