24C Metam Petition
March 7, 2013
Mr. Lee Davis
Pesticide Registration Manager
1090 Mail Service Center
Raleigh, NC 27699-1090
Dear Mr. Davis:
I am writing to you as the Research/Extension plant pathologist with responsibility for peanut disease control recommendations and education in North Carolina. I express my full support for a special local need label for North Carolina with revision of the soil fumigant buffer zone tables to reflect the low rates of metam sodium applied in peanuts for control of nematodes and Cylindrocladium black rot (CBR) in this state.
The labeled rate for metam sodium products (Sectagon 42, Vapam HL, Metam CLR 42%) used in peanut fields is 7.5 gal/A, applied with a single shank per row. Applications are made 8 to 10 inches under rows in land prepared by strip tillage (12-inch wide, raised beds) or conventional tillage (24-inch wide, raised beds). The broadcast equivalent (BCE) rates as calculated according to label instructions for shank injected – bedded applications are as follows:
1. Conventional tillage – raised beds, 24 inches wide, 36 inch row spacing
7.5 gal/A = 5 gal/A BCE
10 gal/A = 6.7 gal/A BCE
12.5 gal/A = 8.3 gal/A BCE
15 gal/A = 10 gal/A BCE
2. Strip tillage – raised beds, 12 inches wide, 36 inch row spacing
7.5 gal/A = 2.5 gal/A BCE
10 gal/A = 3.3 gal/A BCE
12.5 gal/A = 4.1 gal/A BCE
15 gal/A = 5 gal/A BCE
NOTE: Tillage involves fluted coulters on each side of bed and trailing press wheels for firming beds
In North Carolina, plantings in strip tillage are mostly in single rows with metam sodium applied under each row, whereas some (<10%) conventional plantings are in twin-rows, spaced 6 inches apart in the center of 24-inch wide beds. Soil temperatures at the 4-inch depth average 60 to 65 ⁰F at the time of application (April) and do not reach 70 ⁰F until after planting (mid- to late May). Peanut fields in North Carolina are located in the Coastal Plain, where typical individual fields are about 30 acres in size; only a few fields exceed 60 acres.
The lowest BCE rate shown in tables for finding the appropriate buffer zones for shank-injected bedded applications (for example, Table 3, ‘Shank Injected-Bedded’ in the Vapam HL label) is 18 gal/A, much higher than the BCE rates used for peanuts (above). For a typical 30-acre field, growers would be forced to use buffer zones of 75 feet simply because of limited lower range of BCE’s in the tables, whereas the buffer zone for BCE’s of 2.5-10 gal/A should be 25 feet for nearly all peanut fields in North Carolina.
Currently, metam sodium is the only product that is effective for control of both nematodes and CBR in peanuts. Alternatives include applying the fungicide Proline (prothioconazole) 480SC 5.7 fl oz/A in seed furrow ($22/A) at planting for suppression of CBR or fumigating with Telone II at 3 to 6 gal/A ($35 to $70/A) under rows in 36-inch row spacing for nematode control. Proline has replaced some use of metam sodium, but it is not a substitute for metam sodium in problem fields, nor does it control nematodes. The high cost and limited availability of Telone II have resulted in essentially no Telone II being applied in peanuts for nematode control in North Carolina.
Complying with new regulations and requirements for the use of metam sodium has been costly in time and resources for peanut growers. Peanuts are a much lower value crop compared to those in which the product is used at much higher rates, making it difficult for growers to absorb the additional costs of compliance. Our peanut growers do have concerns about worker safety, especially when much of the work is done by only a few workers who live and work on a family farm. Revision of the buffer zone tables to include the low rates applied to peanuts and/or reduction of requirements governing application of such low rates would appropriately address safety concerns while helping to sustain North Carolina’s peanut industry.
Please do not hesitate to contact me if additional information is needed in support of this request.
Barbara B. Shew, Ph.D.
Research Assistant Professor
Article first appeared as North Carolina Peanut Note (PNNC-2013-16) including copy of signed version on letterhead.