RESPONSE OF PEANUT TO LOW RATES OF MSMA.

Authors: Johnson, Wiley - Carroll; Wauchope, Robert - Don; MULLINIX JR, B - UNIVERSITY OF GEORGIA

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: With the increased awareness of pesticide use on food crops, nonregistered pesticide residues in staple foods could adversely affect consumer demand for the commodity. MSMA is an organic arsenical herbicide registered and commonly used on cotton. Cotton and peanut are often planted in adjacent fields in the coastal plain, making peanut exposure to MSMA possible. There are occasional reports of MSMA illegally applied to peanu for inexpensive Florida beggarweed control. Studies were conducted in 1992 and 1994 near Tifton, GA to measure the response of peanut to low rates of MSMA. MSMA was applied 40, 70, 100, or 130 days after emergence (DAE). At each application timing, MSMA was applied at 0, 90, 168, and 336 g ai/ha. MSMA application timing did not affect peanut yields. Increasing rates of MSMA caused minor reduction in peanut yields. Analysis showed elemental arsenic accumulation of <0.7 ppm in peanut kernels from MSMA applied 70 and d100 DAE. This approximates the time interval of peanut pod and kernel formation. MSMA applied 40 and 130 DAE resulted in little detectable arsenic in kernels. These results indicate that low rates of MSMA, originating as drift from aerial applications to cotton or nonregistered direct applications to peanut from Florida beggarweed control, is not likely to reduce peanut yields. The greatest hazard from peanut exposure to MSMA is accumulation of arsenic in kernels, which could adversely affect peanut marketability and consumer demand.

Technical Abstract: Studies were conducted in 1992 and 1994 near Tifton, GA on the response of peanut to low rates of MSMA under weed-free conditions. MSMA was applied at 40, 70, 100, or 130 days after emergence (DAE). At each application timing, MSMA was applied at 0, 90, 168, and 336 g ai/ha. MSMA application timing did not affect peanut yields. Increasing rates of MSMA caused minor rreduction in peanut yields. Analysis using atomic adsorption spectroscopy showed elemental arsenic accumulation of <0.7 ppm in peanut kernels, from MSMA applied 70 and 100 DAE. This approximates the time interval of peanut pod and kernel formation. MSMA applied 40 and 130 DAE resulted in little detectable arsenic in kernels. The results indicate that low rates of MSMA, originating as drift from aerial applications to cotton or nonregistered intentional applications to peanut for Florida beggarweed control, is not likely to reduce peanut yields. The greatest hazard from peanut exposure to MSMA is accumulation of arsenic in kernels, which could adversely affect peanut marketability and consumer demand.