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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Publications at this Location » Publication #273516
Title: Fumigant use and transition from methyl bromide to alternatives in California

Author
item Gao, Suduan
item WILHOIT, LARRY - California Department Of Pesticide Regulation

Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 9/26/2011
Publication Date: 10/30/2011
Citation: Gao, S., Wilhoit, L. 2011. Fumigant use and transition from methyl bromide to alternatives in California. International Conference on Methyl Bromide Alternatives and Emissions Reductions. San Diego, California, October 31-November 2, 2011. p. 74.1-74.4.

Interpretive Summary: Fumigants have been used for control of soil-borne pests or replant diseases through soil fumigation or post-harvest commodity protection. Use of five major soil fumigants in California was analyzed during the period of 2000-2009. Methyl iodide was not used during this period as it was registered in December 2010 in CA. Because of contribution to the depletion of stratosphere ozone, methyl bromide (MeBr) began to be phased out in 2005 in the U.S.; but allowed for some uses under the Critical Use Exemptions and Quarantine and Pre-shipment criteria. Total fumigant use in CA was relatively stable from 2000 to 2009 and 30.8 million lbs were used in 2009 with 43%, 21%, 18%, and 18% as metam-sodium and metam potassium, 1,3-dchloropropene (1,3-D), chloropicrin (CP), and MeBr, respectively. Large users for MeBr in pre-plant soil fumigation are strawberry (production and nursery), orchard nursery seedlings, and ornamentals. Up to 8% of MeBr was used for post-harvest fumigation. Annual vegetable and fruit crops depend mainly on metam products because of low cost. Perennial fruit and nut trees and vineyard replanting heavily use 1,3-D (Telone products). Chloropicrin use (in mixture with MeBr and 1,3-D or alone) is on a slow but steady increase, largely on strawberry (70%) and equally distributed for the remainder among other sectors. 1,3-D and chloropicrin are the major chemicals in replacing MeBr. The data show continuous challenges in the transition of MeBr to alternatives in some sectors. The information helps plan further research and address issues for some important commodities without MeBr.

Technical Abstract: This paper reports fumigant use status and changes in response to the phase-out of methyl bromide (MeBr) and transition to alternative chemicals based on the 2010 Pesticide Use Reporting (PUR) database compiled by California Department of Pesticide Regulation. The data were analyzed from 2000 through 2009 covering the transition before and after the official phase-out of MeBr in January 2005. Five primary fumigants are used in CA: 1,3-dichloropropene (1,3-D) (Telone®), chloropicrin (CP), metam sodium (metam-Na), metam potassium (metam-K), and MeBr. MeBr use has been declining; but some uses continue under the Critical Use Exemptions and Quarantine and Pre-shipment allowances. Although total fumigated acres decreased 27% from 2000 to 2009, total fumigant use in lbs has not changed much, but with significant shifting in the products for different commodities. Total 30.8 million lbs were used in 2009 with 43%, 21%, 18%, and 18% as metam-Na and metam-K salts, 1,3-D, CP, and MeBr, respectively. In 2000, uses of metam salts, 1,3-D, CP and MeBr were 41%, 14%, 12% and 34%, respectively. Large users for MeBr in pre-plant soil fumigation are strawberry (production and nursery), orchard nursery seedlings and ornamentals and post-harvest fumigation uses up to 8%. Annual vegetable and fruit crops depend mainly on metam products because of low cost. Perennial fruit and nut trees and vineyard replanting heavily use 1,3-dichloropropine (Telone products). Chloropicrin use (in mixture with MeBr and 1,3-D or alone) is on a steady increase, largely on strawberry (70%) and equally distributed in other sectors. There was no use of methyl iodide during the reporting period because it was not registered until end of 2010 in CA. 1,3-D and chloropicrin are the major chemical in replacing MeBr. The information indicates continuous challenges in replacing MeBr and the needs of research for some commodities.