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What is the current phase out schedule?
The U.S. Environmental Protection Agency is currently phasing out the
use of methyl bromide. Methyl bromide production and importation will
be reduced from 1991 levels as follows:
25% reduction in 1999
50% reduction in 2001
70% reduction in 2003
100% reduction in 2005
What research is underway at NCSU?
In response to this phase-out, researchers at North Carolina State University
have been investigating alternatives to methyl bromide as a soil fumigant
in strawberry production since 1997. Studies underway include the chemical
alternatives 61.1%1,3-dichloropropene:34.7% chloripicirn (TeloneŽ C-35),
dazomet (BasamidŽ), and metam sodium (VapamŽ). Non-chemical alternatives
include plant residues, solar heating, composting, and biological control
agents. The latter two alternatives will be discussed in another report
in these proceedings (Grabowski et al).
Trials were established in Clayton, Bunn, Plymouth and Fletcher, NC in
1997. In Plymouth, Vapam, Basamid, Telone-chloropicrin, methyl bromide,
solarization, solarization/cabbage residue and compost were applied to
the same plots two consecutive years. In Clayton, Vapam, Basamid, Telone-choloropicirn
and methyl bromide were applied to two separate fields 1997-8 and 1998-9
production seasons. At Fletcher, Telone-chloropicrin, methyl bromide were
applied to the same plots two consecutive years. The cultivar Chandler
was used in Plymouth, Bunn and Clayton. At Fletcher, Chandler, Jewell,
Latestar, Northeaster and Cavendish were yields were evaluated in response
to the various fumigants.
What are the results so far?
Plymouth. -Year 1 (1997-8), there were no differences in marketable
yield between the chemical and non chemical alternatives (Table 1).
-Year 2 (1998-9) yields were equivalent in all chemically fumigated plots
and markedly lower in all non fumigated plots (Table 1).
-Visible pest problems in non fumigated plots (solarization, compost and
control) were primarily weeds in both production seasons.
-All three of the fumigated plots had a high amount of cull fruit loss
primarily to diseases (gray mold).
-Although yields were lower in solarization plots fruit quality in solarization
plots was superior to all other treatments. Clayton.
-First years results at Clayton were reported in the 1998 Southeastern
Strawberry Expo Proceedings (p 55-6).
-In the 1998-9 production season, plots fumigated methyl bromide, T-C35,
Basamid and Vapam had equivalent total, marketable and cull yields (Table
2).
Fletcher. -There were no differences in yields between non fumigated
plots and those fumigated with either chemical (Table 3).
-Marketable yield was very low, due to severe disease pressure (Table
3).
-Chandler had the highest marketable yield (16225 lbs/acre), followed
by Latestar (10505 lbs/acre), Jewell (9152 lbs/acre) and Northeaster (9152
lbs/acre).
Bunn. See separate report (Grabowski et al).
Summary
Methyl bromide is used by the majority of plasticulture strawberry growers
in North Carolina as a preplant soil fumigant. Thus far all alternative
fumigants we have studied have the potential to control pests currently
controlled by methyl bromide. However, long term integration of any of
these alternatives into current production systems will depend on availability
of product, mode of application, economics, long term control of pests
and weeds and grower acceptance. In all these cases, adoption of any alternative
will likely involve the adaption of new cultural practices.
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