Maryland May 21, 2009 R. David Myers

Transcription

1 Fumigant Update Strawberry Twilight Wye REC, Queenstown Maryland May 21, 2009 R. David Myers Senior Agent, Agriculture University of Maryland Extension Methyl Bromide Status In 1992 Methyl Bromide was added to the Montreal Protocol: An International treaty that regulates Ozone Depleting Substances. In the U..S. Methyl Bromide phase out began in 1998 based upon 1991 baseline use rates. Production of Methyl Bromide, except for exempt uses, has been prohibited since Currently, approved exempted use rates of Methyl Bromide are at 26% of the 1991 baseline. Later in 2009 EPA will render a final decision on the Methyl Bromide 2006 Reregistration Eligibility Decision (RED). Methyl Bromide 2006 RED required phased in label changes include: 1) Fumigation Management Plans; 2) Applicator Education; 3) Buffer Zones; and 4) )Neighbor Notification Current Labeled Fumigant Buffer Zone Requirements Buffer Zone determination for MIDAS 50:50 (50% Iodomethane & 50% Chloropicrin) label excerpt:

2 Current Labeled Fumigant Raised Bed Application Rate Raised Bed Application Rate determinationn for MIDAS 50:50 (50% Iodomethane & 50% Chloropicrin) label excerpt:

3 Current Fumigant Price Examples Price estimate for a Raised Bed Application of Methyl Bromide 50:50 (14. 1 lbs/gal 50% Methyl Bromide & 50% Chloropicrin) at $5.98/lb: 350 lb/a Use Rate: Row Spacing 60 X Bed Width 30 =.50 Rate Modifier Actual Use: (350 lb/a) (.50) = 175 $5.98 = $1,047/A Price estimate for a Raised Bed Application of Telone C-35 (11. 2 lbs/gal 63% Dichloropropene & 35% Chloropicrin) at $2.75/lb: 400 lb/a Use Rate: Row Spacing 60 X Bed Width 30 =.50 Rate Modifier Actual Use: (4000 lb/a) (.50) = 200 $2.75 = $550/A Fumigant Options Product Methyl Bromide BRO-MEAN C-50 TELONE II (DP 97 TELONE C-17 (D TELONE C-35 (D TELONE EC (DP 9 IN-LINE (TELONE VAPAM HL (MS 4 K-PAM HL (MK 54 MIDAS 98:2 (IM MIDAS 50:50 (IM MIDAS 33:67 (IM MIDAS 25:75 (IM MIDAS EC Bronz MIDAS EC Gold e (MB 100%) 0 (MB 50% + CP 50%) 7.5%) DP 81% + CP 16.5%) DP 63.4% %) 93.6%) E DP 60.8% + CP 33.3 %) 2%) 4%) 97.9%+ CP 1..9%) M 49.9%+ CP 49.8%) M 32.9%+ CP 66.7%) M 25%+ CP 74.6%) ze (IM 49.9% + CP 44.8%) (IM 32.9%+ CP 61.7%) Disease Nematodes Weeds Soil Injected maybe Chemigation

4 Excerpted from The Strawberry Grower, May 2009, Vol. 15, No. 4 Methyl Bromide 2009 Critical Use Exemption The U.S. Environmental Protection Agency is in the process of releasing its final rule authorizing uses of methyl bromide that qualify for the 2009 critical use exemption and the amount of methyl bromide that may be produced, imported, or supplied from existing inventory for those uses in The reduction in MB use is regulated by EPA under the authority of the Clean Air Act as part of the Montreal Protocol on Substances that Deplete the Ozone Layer. Methyl bromide consumption (and production) was phased out on January 1, 2005, except for critical use exemptions, which must be requested and authorized annually, and quarantine and preshipment exemptions. Authorized critical uses for strawberry producers in our region are: Moderatee to severe yellow or purple nutsedge infestationn Moderatee to severe nematode infestation Moderatee to severe black root and crown rot A need for methyl bromide for research purposes Florida strawberry production has several additional critical uses, included Carolina geranium or cut-leaf evening primrose infestation while California production adds local township limits prohibiting 1,3- dichloropropene (Telone) and time to transition to an alternative. Each of these areas submitted separate CUE applications. EPA s calculations and rationale are complex, but the final rule allocates a total of 4,194,908 kg 16.4% of the original baselinee amount, with 1,919,193 kg from existing stocks. After accounting for the additional reductions for unsold critical use methyl bromide from previous years, EPA is allowing 2,275,715 kg of new production and import for critical uses in It is t permitting stockpiling of methyl bromide produced or imported after January 1, 2005 under the critical use exemption, so existing stocks will continue to decrease. EPA ted that in setting CUE allocations for 2009, it considered transitionn to alternatives (tably methyl iodide/midas) by some users and also the reduced availability of Telone this year. How will all this affect Strawberry growers? According to Victor Lilley, NCSA board member and president of Reddick Fumigants, the main thing that will affect both price and availability for strawberry growers is t the CUE itself but how many spring users of methyl bromide like tomatoo growers change over to alternatives. If a lot of them do, there will be more product available in the fall, and he is seeing signs that a number of large producers are changing over. This spring, the cost of methyl bromide went up to $5.40/ /lb, says Victor. This increases the cost per acre by $ For large omato grower with several hundred acres, that is significant. For a small strawberry grower like me I have two acres who may want the security that methyl bromide offers, that increase is t as important. This fall, we can expect to see more growers planting under VIF plastic, which reduces the amount of methyl bromide needed, and trying alternatives such as MIDAS and PicChlor 60, which is a combination of chloropicrin and Telone and is a lower-cost alternative to methyl bromide. It works fine if nutgrasss is t an issue, tes Victor. This is just a combination of products thatt have been around for 50 years. It s got good disease and nematode control, but t a lot of weed control.

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6 Alternative Chemistries in Annual Production Systems Of sixty-five unregistered compounds evaluated for herbicidal and fungicidal activity in laboratory and greenhouse assays, six were identified with broad-spectrum, biocidal effects and two were field tested on multiple crops to confirm their activity. The combination of 2-bromoethal and chloropicrin applied through drip irrigation lines was found to be as effective as MB for control of broad-leaf weeds, root- kt nematode and Pythium root rot in the cut flower Celosia argentea. Two patent applications have been filed on six of the vel compounds and a Cooperative Research and Development Agreement (13) was negotiated and entered into by ARS and Ajay North America, LLC. At this point these chemicals are t registered and are therefore, t available for use as alternatives. Propargyl bromide has been determined to be efficacious against most pests including nematodes, diseases, and weeds at rates above 100 pounds per acre, which is about 1/3 the current MB rate, and generally resulted in good plant growth and yield, although some phytotoxicity was ted in two trials. This information was generated by a multiagency (ARS and university) and multi-state (California and Florida) effort that was carried out by studies on tomato, strawberry, carrot, fruit trees, grape vines, and ornamentals by 14 scientists from 6 locations with USDA funding. These coordinated studies indicate thatt propargyl bromide can be an efficacious replacement for MB. Although a private company expressed strong interest in registering propargyl bromide at the time these tests were being conducted, there is currently private sector interest in pursuing registration of this material. ARS scientists identifiedd deficiencies in uniformity of distribution of water through drip irrigation systems, which would impact fumigant dispersion when such an application techlogy is employed. In California strawberry production systems, distribution uniformity varied from 45% to 93% and averaged 81%, resulting in the need for additional water (or drip applied fumigant) to achieve the target amount on the drier areas of the field (36). This work identified problems related to improper plot design, equipment, and management attributes contributing to the problem of limited fumigant distribution. Similarly, in Florida, chemical distributions of MITC released by drip-tube application of metam-sodium, and1,3-d chloropicrin (Telone-Inline ) in the soil in driptube applied beds were variable (4-8). Differential cross-bed soil compaction of the sandy Florida soil during the bed-forming process might have contributed to this problem, but the cause has t been determined. In strawberry, alternative fumigant research was conducted by ARS in conjunctionn with University of California-Davis scientists to assess the relative efficacy of MB (MB) +chloropicrin, iodomethane (IM) +chloropicrin, propargyl bromide, 1,3- dichloropropene (1,3-D) + chloropicrin, and chloropicrin for control of Phytophthora cactorum (10). Propargyl bromide was more effective than all other alternative fumigants and usually eradicated test iculum of the pathogen. Furthermore, it was determined that >300 lbs/a rates of the 1,3-D-chloropicrin products or chloropicrin alone are required to get close to the efficacy of MB+chloropicrin. The California strawberry industry currently uses MB alternatives on more than 30% of its acreage, and assessments of IM+chloropicrin have contributed to registration efforts for the fumigant.

7 Virtually impermeable film can effectively reduce fumigant emissions in field applications. There have been uncertainties on whether low permeable tarps such as virtually impermeable film (VIF) can reduce fumigant emissions in large field applications. ARS scientists in Parlier, California, demonstrated that VIF can significantly reduce fumigant emissions when fumigant was drip applied to raised-beds in large strawberry fields. In studies in Gainesville, Florida, ARS scientistss showed that VIF consistently decreased emissions to the atmosphere of all of the fumigants that were tested [methyl bromide, 1,3-dichloropropene, chloropicrin, methyl isothiosyanate (from metam sodium)] in raised bed plasticulture conditions. One study showed that use of VIF film could reduce the amount of fumigant required to achievee equal effectiveness compared with use of standard polyethylene films. VIF provides a techlogy for reducing emissions and offers a feasible method on emission control from fumigation for high- for the valued crops. Iodomethane as a short-term methyl bromide alternativee Florida floriculture industry. ARS scientists in Fort Pierce, Florida, in collaboration with the University of Florida researchers, evaluated the use of soil solarization and fumigants including iodomethane (Midas iodomethane:chloropicrin, 50:50, 200 lb/ /acre) under metalized films as an alternative to methyl bromide for soil fumigation. Four field trials were performed under both commercial and experimental field conditions at three locations in Florida. Pest pressure varied according to location and ranged from high nematode and weed pressure, to low nematode, but high weed pressure. Cut-floweshow that Midas applied under metalized film provided weed control comparable to high rates of methyl crops evaluated were Celosia (Celosia argentea) and snapdragon (Antirrhinum majus). Results bromide (98:2 400 lb/acre) under highh density polyethylene film, and lower rates of methyl bromide (98:2 200 lb/acre) under metalized film. Low rates of methyl bromide (67:33 mbr:chloropicrin 200 lb/ /acre) under metalized film did t provide good weed control. Soil solarization provided better control of white clover (Trifolium repens) than any fumigant tested.